v4.19.13 snapshot.
diff --git a/drivers/xen/xenbus/Makefile b/drivers/xen/xenbus/Makefile
new file mode 100644
index 0000000..0c75321
--- /dev/null
+++ b/drivers/xen/xenbus/Makefile
@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-y += xenbus.o
+obj-y += xenbus_dev_frontend.o
+
+xenbus-objs =
+xenbus-objs += xenbus_client.o
+xenbus-objs += xenbus_comms.o
+xenbus-objs += xenbus_xs.o
+xenbus-objs += xenbus_probe.o
+
+xenbus-be-objs-$(CONFIG_XEN_BACKEND) += xenbus_probe_backend.o
+xenbus-objs += $(xenbus-be-objs-y)
+
+obj-$(CONFIG_XEN_BACKEND) += xenbus_dev_backend.o
+obj-$(CONFIG_XEN_XENBUS_FRONTEND) += xenbus_probe_frontend.o
diff --git a/drivers/xen/xenbus/xenbus.h b/drivers/xen/xenbus/xenbus.h
new file mode 100644
index 0000000..0929811
--- /dev/null
+++ b/drivers/xen/xenbus/xenbus.h
@@ -0,0 +1,136 @@
+/*
+ * Private include for xenbus communications.
+ *
+ * Copyright (C) 2005 Rusty Russell, IBM Corporation
+ * Copyright (C) 2005 XenSource Ltd.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef _XENBUS_XENBUS_H
+#define _XENBUS_XENBUS_H
+
+#include <linux/mutex.h>
+#include <linux/uio.h>
+#include <xen/xenbus.h>
+
+#define XEN_BUS_ID_SIZE 20
+
+struct xen_bus_type {
+ char *root;
+ unsigned int levels;
+ int (*get_bus_id)(char bus_id[XEN_BUS_ID_SIZE], const char *nodename);
+ int (*probe)(struct xen_bus_type *bus, const char *type,
+ const char *dir);
+ void (*otherend_changed)(struct xenbus_watch *watch, const char *path,
+ const char *token);
+ struct bus_type bus;
+};
+
+enum xenstore_init {
+ XS_UNKNOWN,
+ XS_PV,
+ XS_HVM,
+ XS_LOCAL,
+};
+
+struct xs_watch_event {
+ struct list_head list;
+ unsigned int len;
+ struct xenbus_watch *handle;
+ const char *path;
+ const char *token;
+ char body[];
+};
+
+enum xb_req_state {
+ xb_req_state_queued,
+ xb_req_state_wait_reply,
+ xb_req_state_got_reply,
+ xb_req_state_aborted
+};
+
+struct xb_req_data {
+ struct list_head list;
+ wait_queue_head_t wq;
+ struct xsd_sockmsg msg;
+ uint32_t caller_req_id;
+ enum xsd_sockmsg_type type;
+ char *body;
+ const struct kvec *vec;
+ int num_vecs;
+ int err;
+ enum xb_req_state state;
+ void (*cb)(struct xb_req_data *);
+ void *par;
+};
+
+extern enum xenstore_init xen_store_domain_type;
+extern const struct attribute_group *xenbus_dev_groups[];
+extern struct mutex xs_response_mutex;
+extern struct list_head xs_reply_list;
+extern struct list_head xb_write_list;
+extern wait_queue_head_t xb_waitq;
+extern struct mutex xb_write_mutex;
+
+int xs_init(void);
+int xb_init_comms(void);
+void xb_deinit_comms(void);
+int xs_watch_msg(struct xs_watch_event *event);
+void xs_request_exit(struct xb_req_data *req);
+
+int xenbus_match(struct device *_dev, struct device_driver *_drv);
+int xenbus_dev_probe(struct device *_dev);
+int xenbus_dev_remove(struct device *_dev);
+int xenbus_register_driver_common(struct xenbus_driver *drv,
+ struct xen_bus_type *bus,
+ struct module *owner,
+ const char *mod_name);
+int xenbus_probe_node(struct xen_bus_type *bus,
+ const char *type,
+ const char *nodename);
+int xenbus_probe_devices(struct xen_bus_type *bus);
+
+void xenbus_dev_changed(const char *node, struct xen_bus_type *bus);
+
+void xenbus_dev_shutdown(struct device *_dev);
+
+int xenbus_dev_suspend(struct device *dev);
+int xenbus_dev_resume(struct device *dev);
+int xenbus_dev_cancel(struct device *dev);
+
+void xenbus_otherend_changed(struct xenbus_watch *watch,
+ const char *path, const char *token,
+ int ignore_on_shutdown);
+
+int xenbus_read_otherend_details(struct xenbus_device *xendev,
+ char *id_node, char *path_node);
+
+void xenbus_ring_ops_init(void);
+
+int xenbus_dev_request_and_reply(struct xsd_sockmsg *msg, void *par);
+void xenbus_dev_queue_reply(struct xb_req_data *req);
+
+#endif
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
new file mode 100644
index 0000000..a1c1700
--- /dev/null
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -0,0 +1,939 @@
+/******************************************************************************
+ * Client-facing interface for the Xenbus driver. In other words, the
+ * interface between the Xenbus and the device-specific code, be it the
+ * frontend or the backend of that driver.
+ *
+ * Copyright (C) 2005 XenSource Ltd
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/spinlock.h>
+#include <linux/vmalloc.h>
+#include <linux/export.h>
+#include <asm/xen/hypervisor.h>
+#include <xen/page.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/event_channel.h>
+#include <xen/balloon.h>
+#include <xen/events.h>
+#include <xen/grant_table.h>
+#include <xen/xenbus.h>
+#include <xen/xen.h>
+#include <xen/features.h>
+
+#include "xenbus.h"
+
+#define XENBUS_PAGES(_grants) (DIV_ROUND_UP(_grants, XEN_PFN_PER_PAGE))
+
+#define XENBUS_MAX_RING_PAGES (XENBUS_PAGES(XENBUS_MAX_RING_GRANTS))
+
+struct xenbus_map_node {
+ struct list_head next;
+ union {
+ struct {
+ struct vm_struct *area;
+ } pv;
+ struct {
+ struct page *pages[XENBUS_MAX_RING_PAGES];
+ unsigned long addrs[XENBUS_MAX_RING_GRANTS];
+ void *addr;
+ } hvm;
+ };
+ grant_handle_t handles[XENBUS_MAX_RING_GRANTS];
+ unsigned int nr_handles;
+};
+
+static DEFINE_SPINLOCK(xenbus_valloc_lock);
+static LIST_HEAD(xenbus_valloc_pages);
+
+struct xenbus_ring_ops {
+ int (*map)(struct xenbus_device *dev,
+ grant_ref_t *gnt_refs, unsigned int nr_grefs,
+ void **vaddr);
+ int (*unmap)(struct xenbus_device *dev, void *vaddr);
+};
+
+static const struct xenbus_ring_ops *ring_ops __read_mostly;
+
+const char *xenbus_strstate(enum xenbus_state state)
+{
+ static const char *const name[] = {
+ [ XenbusStateUnknown ] = "Unknown",
+ [ XenbusStateInitialising ] = "Initialising",
+ [ XenbusStateInitWait ] = "InitWait",
+ [ XenbusStateInitialised ] = "Initialised",
+ [ XenbusStateConnected ] = "Connected",
+ [ XenbusStateClosing ] = "Closing",
+ [ XenbusStateClosed ] = "Closed",
+ [XenbusStateReconfiguring] = "Reconfiguring",
+ [XenbusStateReconfigured] = "Reconfigured",
+ };
+ return (state < ARRAY_SIZE(name)) ? name[state] : "INVALID";
+}
+EXPORT_SYMBOL_GPL(xenbus_strstate);
+
+/**
+ * xenbus_watch_path - register a watch
+ * @dev: xenbus device
+ * @path: path to watch
+ * @watch: watch to register
+ * @callback: callback to register
+ *
+ * Register a @watch on the given path, using the given xenbus_watch structure
+ * for storage, and the given @callback function as the callback. Return 0 on
+ * success, or -errno on error. On success, the given @path will be saved as
+ * @watch->node, and remains the caller's to free. On error, @watch->node will
+ * be NULL, the device will switch to %XenbusStateClosing, and the error will
+ * be saved in the store.
+ */
+int xenbus_watch_path(struct xenbus_device *dev, const char *path,
+ struct xenbus_watch *watch,
+ void (*callback)(struct xenbus_watch *,
+ const char *, const char *))
+{
+ int err;
+
+ watch->node = path;
+ watch->callback = callback;
+
+ err = register_xenbus_watch(watch);
+
+ if (err) {
+ watch->node = NULL;
+ watch->callback = NULL;
+ xenbus_dev_fatal(dev, err, "adding watch on %s", path);
+ }
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_watch_path);
+
+
+/**
+ * xenbus_watch_pathfmt - register a watch on a sprintf-formatted path
+ * @dev: xenbus device
+ * @watch: watch to register
+ * @callback: callback to register
+ * @pathfmt: format of path to watch
+ *
+ * Register a watch on the given @path, using the given xenbus_watch
+ * structure for storage, and the given @callback function as the callback.
+ * Return 0 on success, or -errno on error. On success, the watched path
+ * (@path/@path2) will be saved as @watch->node, and becomes the caller's to
+ * kfree(). On error, watch->node will be NULL, so the caller has nothing to
+ * free, the device will switch to %XenbusStateClosing, and the error will be
+ * saved in the store.
+ */
+int xenbus_watch_pathfmt(struct xenbus_device *dev,
+ struct xenbus_watch *watch,
+ void (*callback)(struct xenbus_watch *,
+ const char *, const char *),
+ const char *pathfmt, ...)
+{
+ int err;
+ va_list ap;
+ char *path;
+
+ va_start(ap, pathfmt);
+ path = kvasprintf(GFP_NOIO | __GFP_HIGH, pathfmt, ap);
+ va_end(ap);
+
+ if (!path) {
+ xenbus_dev_fatal(dev, -ENOMEM, "allocating path for watch");
+ return -ENOMEM;
+ }
+ err = xenbus_watch_path(dev, path, watch, callback);
+
+ if (err)
+ kfree(path);
+ return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_watch_pathfmt);
+
+static void xenbus_switch_fatal(struct xenbus_device *, int, int,
+ const char *, ...);
+
+static int
+__xenbus_switch_state(struct xenbus_device *dev,
+ enum xenbus_state state, int depth)
+{
+ /* We check whether the state is currently set to the given value, and
+ if not, then the state is set. We don't want to unconditionally
+ write the given state, because we don't want to fire watches
+ unnecessarily. Furthermore, if the node has gone, we don't write
+ to it, as the device will be tearing down, and we don't want to
+ resurrect that directory.
+
+ Note that, because of this cached value of our state, this
+ function will not take a caller's Xenstore transaction
+ (something it was trying to in the past) because dev->state
+ would not get reset if the transaction was aborted.
+ */
+
+ struct xenbus_transaction xbt;
+ int current_state;
+ int err, abort;
+
+ if (state == dev->state)
+ return 0;
+
+again:
+ abort = 1;
+
+ err = xenbus_transaction_start(&xbt);
+ if (err) {
+ xenbus_switch_fatal(dev, depth, err, "starting transaction");
+ return 0;
+ }
+
+ err = xenbus_scanf(xbt, dev->nodename, "state", "%d", ¤t_state);
+ if (err != 1)
+ goto abort;
+
+ err = xenbus_printf(xbt, dev->nodename, "state", "%d", state);
+ if (err) {
+ xenbus_switch_fatal(dev, depth, err, "writing new state");
+ goto abort;
+ }
+
+ abort = 0;
+abort:
+ err = xenbus_transaction_end(xbt, abort);
+ if (err) {
+ if (err == -EAGAIN && !abort)
+ goto again;
+ xenbus_switch_fatal(dev, depth, err, "ending transaction");
+ } else
+ dev->state = state;
+
+ return 0;
+}
+
+/**
+ * xenbus_switch_state
+ * @dev: xenbus device
+ * @state: new state
+ *
+ * Advertise in the store a change of the given driver to the given new_state.
+ * Return 0 on success, or -errno on error. On error, the device will switch
+ * to XenbusStateClosing, and the error will be saved in the store.
+ */
+int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state state)
+{
+ return __xenbus_switch_state(dev, state, 0);
+}
+
+EXPORT_SYMBOL_GPL(xenbus_switch_state);
+
+int xenbus_frontend_closed(struct xenbus_device *dev)
+{
+ xenbus_switch_state(dev, XenbusStateClosed);
+ complete(&dev->down);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(xenbus_frontend_closed);
+
+static void xenbus_va_dev_error(struct xenbus_device *dev, int err,
+ const char *fmt, va_list ap)
+{
+ unsigned int len;
+ char *printf_buffer;
+ char *path_buffer;
+
+#define PRINTF_BUFFER_SIZE 4096
+
+ printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_KERNEL);
+ if (!printf_buffer)
+ return;
+
+ len = sprintf(printf_buffer, "%i ", -err);
+ vsnprintf(printf_buffer + len, PRINTF_BUFFER_SIZE - len, fmt, ap);
+
+ dev_err(&dev->dev, "%s\n", printf_buffer);
+
+ path_buffer = kasprintf(GFP_KERNEL, "error/%s", dev->nodename);
+ if (!path_buffer ||
+ xenbus_write(XBT_NIL, path_buffer, "error", printf_buffer))
+ dev_err(&dev->dev, "failed to write error node for %s (%s)\n",
+ dev->nodename, printf_buffer);
+
+ kfree(printf_buffer);
+ kfree(path_buffer);
+}
+
+/**
+ * xenbus_dev_error
+ * @dev: xenbus device
+ * @err: error to report
+ * @fmt: error message format
+ *
+ * Report the given negative errno into the store, along with the given
+ * formatted message.
+ */
+void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...)
+{
+ va_list ap;
+
+ va_start(ap, fmt);
+ xenbus_va_dev_error(dev, err, fmt, ap);
+ va_end(ap);
+}
+EXPORT_SYMBOL_GPL(xenbus_dev_error);
+
+/**
+ * xenbus_dev_fatal
+ * @dev: xenbus device
+ * @err: error to report
+ * @fmt: error message format
+ *
+ * Equivalent to xenbus_dev_error(dev, err, fmt, args), followed by
+ * xenbus_switch_state(dev, XenbusStateClosing) to schedule an orderly
+ * closedown of this driver and its peer.
+ */
+
+void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...)
+{
+ va_list ap;
+
+ va_start(ap, fmt);
+ xenbus_va_dev_error(dev, err, fmt, ap);
+ va_end(ap);
+
+ xenbus_switch_state(dev, XenbusStateClosing);
+}
+EXPORT_SYMBOL_GPL(xenbus_dev_fatal);
+
+/**
+ * Equivalent to xenbus_dev_fatal(dev, err, fmt, args), but helps
+ * avoiding recursion within xenbus_switch_state.
+ */
+static void xenbus_switch_fatal(struct xenbus_device *dev, int depth, int err,
+ const char *fmt, ...)
+{
+ va_list ap;
+
+ va_start(ap, fmt);
+ xenbus_va_dev_error(dev, err, fmt, ap);
+ va_end(ap);
+
+ if (!depth)
+ __xenbus_switch_state(dev, XenbusStateClosing, 1);
+}
+
+/**
+ * xenbus_grant_ring
+ * @dev: xenbus device
+ * @vaddr: starting virtual address of the ring
+ * @nr_pages: number of pages to be granted
+ * @grefs: grant reference array to be filled in
+ *
+ * Grant access to the given @vaddr to the peer of the given device.
+ * Then fill in @grefs with grant references. Return 0 on success, or
+ * -errno on error. On error, the device will switch to
+ * XenbusStateClosing, and the error will be saved in the store.
+ */
+int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
+ unsigned int nr_pages, grant_ref_t *grefs)
+{
+ int err;
+ int i, j;
+
+ for (i = 0; i < nr_pages; i++) {
+ err = gnttab_grant_foreign_access(dev->otherend_id,
+ virt_to_gfn(vaddr), 0);
+ if (err < 0) {
+ xenbus_dev_fatal(dev, err,
+ "granting access to ring page");
+ goto fail;
+ }
+ grefs[i] = err;
+
+ vaddr = vaddr + XEN_PAGE_SIZE;
+ }
+
+ return 0;
+
+fail:
+ for (j = 0; j < i; j++)
+ gnttab_end_foreign_access_ref(grefs[j], 0);
+ return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_grant_ring);
+
+
+/**
+ * Allocate an event channel for the given xenbus_device, assigning the newly
+ * created local port to *port. Return 0 on success, or -errno on error. On
+ * error, the device will switch to XenbusStateClosing, and the error will be
+ * saved in the store.
+ */
+int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port)
+{
+ struct evtchn_alloc_unbound alloc_unbound;
+ int err;
+
+ alloc_unbound.dom = DOMID_SELF;
+ alloc_unbound.remote_dom = dev->otherend_id;
+
+ err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
+ &alloc_unbound);
+ if (err)
+ xenbus_dev_fatal(dev, err, "allocating event channel");
+ else
+ *port = alloc_unbound.port;
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_alloc_evtchn);
+
+
+/**
+ * Free an existing event channel. Returns 0 on success or -errno on error.
+ */
+int xenbus_free_evtchn(struct xenbus_device *dev, int port)
+{
+ struct evtchn_close close;
+ int err;
+
+ close.port = port;
+
+ err = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close);
+ if (err)
+ xenbus_dev_error(dev, err, "freeing event channel %d", port);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_free_evtchn);
+
+
+/**
+ * xenbus_map_ring_valloc
+ * @dev: xenbus device
+ * @gnt_refs: grant reference array
+ * @nr_grefs: number of grant references
+ * @vaddr: pointer to address to be filled out by mapping
+ *
+ * Map @nr_grefs pages of memory into this domain from another
+ * domain's grant table. xenbus_map_ring_valloc allocates @nr_grefs
+ * pages of virtual address space, maps the pages to that address, and
+ * sets *vaddr to that address. Returns 0 on success, and GNTST_*
+ * (see xen/include/interface/grant_table.h) or -ENOMEM / -EINVAL on
+ * error. If an error is returned, device will switch to
+ * XenbusStateClosing and the error message will be saved in XenStore.
+ */
+int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs,
+ unsigned int nr_grefs, void **vaddr)
+{
+ return ring_ops->map(dev, gnt_refs, nr_grefs, vaddr);
+}
+EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc);
+
+/* N.B. sizeof(phys_addr_t) doesn't always equal to sizeof(unsigned
+ * long), e.g. 32-on-64. Caller is responsible for preparing the
+ * right array to feed into this function */
+static int __xenbus_map_ring(struct xenbus_device *dev,
+ grant_ref_t *gnt_refs,
+ unsigned int nr_grefs,
+ grant_handle_t *handles,
+ phys_addr_t *addrs,
+ unsigned int flags,
+ bool *leaked)
+{
+ struct gnttab_map_grant_ref map[XENBUS_MAX_RING_GRANTS];
+ struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS];
+ int i, j;
+ int err = GNTST_okay;
+
+ if (nr_grefs > XENBUS_MAX_RING_GRANTS)
+ return -EINVAL;
+
+ for (i = 0; i < nr_grefs; i++) {
+ memset(&map[i], 0, sizeof(map[i]));
+ gnttab_set_map_op(&map[i], addrs[i], flags, gnt_refs[i],
+ dev->otherend_id);
+ handles[i] = INVALID_GRANT_HANDLE;
+ }
+
+ gnttab_batch_map(map, i);
+
+ for (i = 0; i < nr_grefs; i++) {
+ if (map[i].status != GNTST_okay) {
+ err = map[i].status;
+ xenbus_dev_fatal(dev, map[i].status,
+ "mapping in shared page %d from domain %d",
+ gnt_refs[i], dev->otherend_id);
+ goto fail;
+ } else
+ handles[i] = map[i].handle;
+ }
+
+ return GNTST_okay;
+
+ fail:
+ for (i = j = 0; i < nr_grefs; i++) {
+ if (handles[i] != INVALID_GRANT_HANDLE) {
+ memset(&unmap[j], 0, sizeof(unmap[j]));
+ gnttab_set_unmap_op(&unmap[j], (phys_addr_t)addrs[i],
+ GNTMAP_host_map, handles[i]);
+ j++;
+ }
+ }
+
+ if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, j))
+ BUG();
+
+ *leaked = false;
+ for (i = 0; i < j; i++) {
+ if (unmap[i].status != GNTST_okay) {
+ *leaked = true;
+ break;
+ }
+ }
+
+ return err;
+}
+
+struct map_ring_valloc_hvm
+{
+ unsigned int idx;
+
+ /* Why do we need two arrays? See comment of __xenbus_map_ring */
+ phys_addr_t phys_addrs[XENBUS_MAX_RING_GRANTS];
+ unsigned long addrs[XENBUS_MAX_RING_GRANTS];
+};
+
+static void xenbus_map_ring_setup_grant_hvm(unsigned long gfn,
+ unsigned int goffset,
+ unsigned int len,
+ void *data)
+{
+ struct map_ring_valloc_hvm *info = data;
+ unsigned long vaddr = (unsigned long)gfn_to_virt(gfn);
+
+ info->phys_addrs[info->idx] = vaddr;
+ info->addrs[info->idx] = vaddr;
+
+ info->idx++;
+}
+
+static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
+ grant_ref_t *gnt_ref,
+ unsigned int nr_grefs,
+ void **vaddr)
+{
+ struct xenbus_map_node *node;
+ int err;
+ void *addr;
+ bool leaked = false;
+ struct map_ring_valloc_hvm info = {
+ .idx = 0,
+ };
+ unsigned int nr_pages = XENBUS_PAGES(nr_grefs);
+
+ if (nr_grefs > XENBUS_MAX_RING_GRANTS)
+ return -EINVAL;
+
+ *vaddr = NULL;
+
+ node = kzalloc(sizeof(*node), GFP_KERNEL);
+ if (!node)
+ return -ENOMEM;
+
+ err = alloc_xenballooned_pages(nr_pages, node->hvm.pages);
+ if (err)
+ goto out_err;
+
+ gnttab_foreach_grant(node->hvm.pages, nr_grefs,
+ xenbus_map_ring_setup_grant_hvm,
+ &info);
+
+ err = __xenbus_map_ring(dev, gnt_ref, nr_grefs, node->handles,
+ info.phys_addrs, GNTMAP_host_map, &leaked);
+ node->nr_handles = nr_grefs;
+
+ if (err)
+ goto out_free_ballooned_pages;
+
+ addr = vmap(node->hvm.pages, nr_pages, VM_MAP | VM_IOREMAP,
+ PAGE_KERNEL);
+ if (!addr) {
+ err = -ENOMEM;
+ goto out_xenbus_unmap_ring;
+ }
+
+ node->hvm.addr = addr;
+
+ spin_lock(&xenbus_valloc_lock);
+ list_add(&node->next, &xenbus_valloc_pages);
+ spin_unlock(&xenbus_valloc_lock);
+
+ *vaddr = addr;
+ return 0;
+
+ out_xenbus_unmap_ring:
+ if (!leaked)
+ xenbus_unmap_ring(dev, node->handles, nr_grefs, info.addrs);
+ else
+ pr_alert("leaking %p size %u page(s)",
+ addr, nr_pages);
+ out_free_ballooned_pages:
+ if (!leaked)
+ free_xenballooned_pages(nr_pages, node->hvm.pages);
+ out_err:
+ kfree(node);
+ return err;
+}
+
+
+/**
+ * xenbus_map_ring
+ * @dev: xenbus device
+ * @gnt_refs: grant reference array
+ * @nr_grefs: number of grant reference
+ * @handles: pointer to grant handle to be filled
+ * @vaddrs: addresses to be mapped to
+ * @leaked: fail to clean up a failed map, caller should not free vaddr
+ *
+ * Map pages of memory into this domain from another domain's grant table.
+ * xenbus_map_ring does not allocate the virtual address space (you must do
+ * this yourself!). It only maps in the pages to the specified address.
+ * Returns 0 on success, and GNTST_* (see xen/include/interface/grant_table.h)
+ * or -ENOMEM / -EINVAL on error. If an error is returned, device will switch to
+ * XenbusStateClosing and the first error message will be saved in XenStore.
+ * Further more if we fail to map the ring, caller should check @leaked.
+ * If @leaked is not zero it means xenbus_map_ring fails to clean up, caller
+ * should not free the address space of @vaddr.
+ */
+int xenbus_map_ring(struct xenbus_device *dev, grant_ref_t *gnt_refs,
+ unsigned int nr_grefs, grant_handle_t *handles,
+ unsigned long *vaddrs, bool *leaked)
+{
+ phys_addr_t phys_addrs[XENBUS_MAX_RING_GRANTS];
+ int i;
+
+ if (nr_grefs > XENBUS_MAX_RING_GRANTS)
+ return -EINVAL;
+
+ for (i = 0; i < nr_grefs; i++)
+ phys_addrs[i] = (unsigned long)vaddrs[i];
+
+ return __xenbus_map_ring(dev, gnt_refs, nr_grefs, handles,
+ phys_addrs, GNTMAP_host_map, leaked);
+}
+EXPORT_SYMBOL_GPL(xenbus_map_ring);
+
+
+/**
+ * xenbus_unmap_ring_vfree
+ * @dev: xenbus device
+ * @vaddr: addr to unmap
+ *
+ * Based on Rusty Russell's skeleton driver's unmap_page.
+ * Unmap a page of memory in this domain that was imported from another domain.
+ * Use xenbus_unmap_ring_vfree if you mapped in your memory with
+ * xenbus_map_ring_valloc (it will free the virtual address space).
+ * Returns 0 on success and returns GNTST_* on error
+ * (see xen/include/interface/grant_table.h).
+ */
+int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr)
+{
+ return ring_ops->unmap(dev, vaddr);
+}
+EXPORT_SYMBOL_GPL(xenbus_unmap_ring_vfree);
+
+#ifdef CONFIG_XEN_PV
+static int xenbus_map_ring_valloc_pv(struct xenbus_device *dev,
+ grant_ref_t *gnt_refs,
+ unsigned int nr_grefs,
+ void **vaddr)
+{
+ struct xenbus_map_node *node;
+ struct vm_struct *area;
+ pte_t *ptes[XENBUS_MAX_RING_GRANTS];
+ phys_addr_t phys_addrs[XENBUS_MAX_RING_GRANTS];
+ int err = GNTST_okay;
+ int i;
+ bool leaked;
+
+ *vaddr = NULL;
+
+ if (nr_grefs > XENBUS_MAX_RING_GRANTS)
+ return -EINVAL;
+
+ node = kzalloc(sizeof(*node), GFP_KERNEL);
+ if (!node)
+ return -ENOMEM;
+
+ area = alloc_vm_area(XEN_PAGE_SIZE * nr_grefs, ptes);
+ if (!area) {
+ kfree(node);
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < nr_grefs; i++)
+ phys_addrs[i] = arbitrary_virt_to_machine(ptes[i]).maddr;
+
+ err = __xenbus_map_ring(dev, gnt_refs, nr_grefs, node->handles,
+ phys_addrs,
+ GNTMAP_host_map | GNTMAP_contains_pte,
+ &leaked);
+ if (err)
+ goto failed;
+
+ node->nr_handles = nr_grefs;
+ node->pv.area = area;
+
+ spin_lock(&xenbus_valloc_lock);
+ list_add(&node->next, &xenbus_valloc_pages);
+ spin_unlock(&xenbus_valloc_lock);
+
+ *vaddr = area->addr;
+ return 0;
+
+failed:
+ if (!leaked)
+ free_vm_area(area);
+ else
+ pr_alert("leaking VM area %p size %u page(s)", area, nr_grefs);
+
+ kfree(node);
+ return err;
+}
+
+static int xenbus_unmap_ring_vfree_pv(struct xenbus_device *dev, void *vaddr)
+{
+ struct xenbus_map_node *node;
+ struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS];
+ unsigned int level;
+ int i;
+ bool leaked = false;
+ int err;
+
+ spin_lock(&xenbus_valloc_lock);
+ list_for_each_entry(node, &xenbus_valloc_pages, next) {
+ if (node->pv.area->addr == vaddr) {
+ list_del(&node->next);
+ goto found;
+ }
+ }
+ node = NULL;
+ found:
+ spin_unlock(&xenbus_valloc_lock);
+
+ if (!node) {
+ xenbus_dev_error(dev, -ENOENT,
+ "can't find mapped virtual address %p", vaddr);
+ return GNTST_bad_virt_addr;
+ }
+
+ for (i = 0; i < node->nr_handles; i++) {
+ unsigned long addr;
+
+ memset(&unmap[i], 0, sizeof(unmap[i]));
+ addr = (unsigned long)vaddr + (XEN_PAGE_SIZE * i);
+ unmap[i].host_addr = arbitrary_virt_to_machine(
+ lookup_address(addr, &level)).maddr;
+ unmap[i].dev_bus_addr = 0;
+ unmap[i].handle = node->handles[i];
+ }
+
+ if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i))
+ BUG();
+
+ err = GNTST_okay;
+ leaked = false;
+ for (i = 0; i < node->nr_handles; i++) {
+ if (unmap[i].status != GNTST_okay) {
+ leaked = true;
+ xenbus_dev_error(dev, unmap[i].status,
+ "unmapping page at handle %d error %d",
+ node->handles[i], unmap[i].status);
+ err = unmap[i].status;
+ break;
+ }
+ }
+
+ if (!leaked)
+ free_vm_area(node->pv.area);
+ else
+ pr_alert("leaking VM area %p size %u page(s)",
+ node->pv.area, node->nr_handles);
+
+ kfree(node);
+ return err;
+}
+
+static const struct xenbus_ring_ops ring_ops_pv = {
+ .map = xenbus_map_ring_valloc_pv,
+ .unmap = xenbus_unmap_ring_vfree_pv,
+};
+#endif
+
+struct unmap_ring_vfree_hvm
+{
+ unsigned int idx;
+ unsigned long addrs[XENBUS_MAX_RING_GRANTS];
+};
+
+static void xenbus_unmap_ring_setup_grant_hvm(unsigned long gfn,
+ unsigned int goffset,
+ unsigned int len,
+ void *data)
+{
+ struct unmap_ring_vfree_hvm *info = data;
+
+ info->addrs[info->idx] = (unsigned long)gfn_to_virt(gfn);
+
+ info->idx++;
+}
+
+static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)
+{
+ int rv;
+ struct xenbus_map_node *node;
+ void *addr;
+ struct unmap_ring_vfree_hvm info = {
+ .idx = 0,
+ };
+ unsigned int nr_pages;
+
+ spin_lock(&xenbus_valloc_lock);
+ list_for_each_entry(node, &xenbus_valloc_pages, next) {
+ addr = node->hvm.addr;
+ if (addr == vaddr) {
+ list_del(&node->next);
+ goto found;
+ }
+ }
+ node = addr = NULL;
+ found:
+ spin_unlock(&xenbus_valloc_lock);
+
+ if (!node) {
+ xenbus_dev_error(dev, -ENOENT,
+ "can't find mapped virtual address %p", vaddr);
+ return GNTST_bad_virt_addr;
+ }
+
+ nr_pages = XENBUS_PAGES(node->nr_handles);
+
+ gnttab_foreach_grant(node->hvm.pages, node->nr_handles,
+ xenbus_unmap_ring_setup_grant_hvm,
+ &info);
+
+ rv = xenbus_unmap_ring(dev, node->handles, node->nr_handles,
+ info.addrs);
+ if (!rv) {
+ vunmap(vaddr);
+ free_xenballooned_pages(nr_pages, node->hvm.pages);
+ }
+ else
+ WARN(1, "Leaking %p, size %u page(s)\n", vaddr, nr_pages);
+
+ kfree(node);
+ return rv;
+}
+
+/**
+ * xenbus_unmap_ring
+ * @dev: xenbus device
+ * @handles: grant handle array
+ * @nr_handles: number of handles in the array
+ * @vaddrs: addresses to unmap
+ *
+ * Unmap memory in this domain that was imported from another domain.
+ * Returns 0 on success and returns GNTST_* on error
+ * (see xen/include/interface/grant_table.h).
+ */
+int xenbus_unmap_ring(struct xenbus_device *dev,
+ grant_handle_t *handles, unsigned int nr_handles,
+ unsigned long *vaddrs)
+{
+ struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS];
+ int i;
+ int err;
+
+ if (nr_handles > XENBUS_MAX_RING_GRANTS)
+ return -EINVAL;
+
+ for (i = 0; i < nr_handles; i++)
+ gnttab_set_unmap_op(&unmap[i], vaddrs[i],
+ GNTMAP_host_map, handles[i]);
+
+ if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i))
+ BUG();
+
+ err = GNTST_okay;
+ for (i = 0; i < nr_handles; i++) {
+ if (unmap[i].status != GNTST_okay) {
+ xenbus_dev_error(dev, unmap[i].status,
+ "unmapping page at handle %d error %d",
+ handles[i], unmap[i].status);
+ err = unmap[i].status;
+ break;
+ }
+ }
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_unmap_ring);
+
+
+/**
+ * xenbus_read_driver_state
+ * @path: path for driver
+ *
+ * Return the state of the driver rooted at the given store path, or
+ * XenbusStateUnknown if no state can be read.
+ */
+enum xenbus_state xenbus_read_driver_state(const char *path)
+{
+ enum xenbus_state result;
+ int err = xenbus_gather(XBT_NIL, path, "state", "%d", &result, NULL);
+ if (err)
+ result = XenbusStateUnknown;
+
+ return result;
+}
+EXPORT_SYMBOL_GPL(xenbus_read_driver_state);
+
+static const struct xenbus_ring_ops ring_ops_hvm = {
+ .map = xenbus_map_ring_valloc_hvm,
+ .unmap = xenbus_unmap_ring_vfree_hvm,
+};
+
+void __init xenbus_ring_ops_init(void)
+{
+#ifdef CONFIG_XEN_PV
+ if (!xen_feature(XENFEAT_auto_translated_physmap))
+ ring_ops = &ring_ops_pv;
+ else
+#endif
+ ring_ops = &ring_ops_hvm;
+}
diff --git a/drivers/xen/xenbus/xenbus_comms.c b/drivers/xen/xenbus/xenbus_comms.c
new file mode 100644
index 0000000..d239fc3
--- /dev/null
+++ b/drivers/xen/xenbus/xenbus_comms.c
@@ -0,0 +1,488 @@
+/******************************************************************************
+ * xenbus_comms.c
+ *
+ * Low level code to talks to Xen Store: ringbuffer and event channel.
+ *
+ * Copyright (C) 2005 Rusty Russell, IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/wait.h>
+#include <linux/interrupt.h>
+#include <linux/kthread.h>
+#include <linux/sched.h>
+#include <linux/err.h>
+#include <xen/xenbus.h>
+#include <asm/xen/hypervisor.h>
+#include <xen/events.h>
+#include <xen/page.h>
+#include "xenbus.h"
+
+/* A list of replies. Currently only one will ever be outstanding. */
+LIST_HEAD(xs_reply_list);
+
+/* A list of write requests. */
+LIST_HEAD(xb_write_list);
+DECLARE_WAIT_QUEUE_HEAD(xb_waitq);
+DEFINE_MUTEX(xb_write_mutex);
+
+/* Protect xenbus reader thread against save/restore. */
+DEFINE_MUTEX(xs_response_mutex);
+
+static int xenbus_irq;
+static struct task_struct *xenbus_task;
+
+static DECLARE_WORK(probe_work, xenbus_probe);
+
+
+static irqreturn_t wake_waiting(int irq, void *unused)
+{
+ if (unlikely(xenstored_ready == 0)) {
+ xenstored_ready = 1;
+ schedule_work(&probe_work);
+ }
+
+ wake_up(&xb_waitq);
+ return IRQ_HANDLED;
+}
+
+static int check_indexes(XENSTORE_RING_IDX cons, XENSTORE_RING_IDX prod)
+{
+ return ((prod - cons) <= XENSTORE_RING_SIZE);
+}
+
+static void *get_output_chunk(XENSTORE_RING_IDX cons,
+ XENSTORE_RING_IDX prod,
+ char *buf, uint32_t *len)
+{
+ *len = XENSTORE_RING_SIZE - MASK_XENSTORE_IDX(prod);
+ if ((XENSTORE_RING_SIZE - (prod - cons)) < *len)
+ *len = XENSTORE_RING_SIZE - (prod - cons);
+ return buf + MASK_XENSTORE_IDX(prod);
+}
+
+static const void *get_input_chunk(XENSTORE_RING_IDX cons,
+ XENSTORE_RING_IDX prod,
+ const char *buf, uint32_t *len)
+{
+ *len = XENSTORE_RING_SIZE - MASK_XENSTORE_IDX(cons);
+ if ((prod - cons) < *len)
+ *len = prod - cons;
+ return buf + MASK_XENSTORE_IDX(cons);
+}
+
+static int xb_data_to_write(void)
+{
+ struct xenstore_domain_interface *intf = xen_store_interface;
+
+ return (intf->req_prod - intf->req_cons) != XENSTORE_RING_SIZE &&
+ !list_empty(&xb_write_list);
+}
+
+/**
+ * xb_write - low level write
+ * @data: buffer to send
+ * @len: length of buffer
+ *
+ * Returns number of bytes written or -err.
+ */
+static int xb_write(const void *data, unsigned int len)
+{
+ struct xenstore_domain_interface *intf = xen_store_interface;
+ XENSTORE_RING_IDX cons, prod;
+ unsigned int bytes = 0;
+
+ while (len != 0) {
+ void *dst;
+ unsigned int avail;
+
+ /* Read indexes, then verify. */
+ cons = intf->req_cons;
+ prod = intf->req_prod;
+ if (!check_indexes(cons, prod)) {
+ intf->req_cons = intf->req_prod = 0;
+ return -EIO;
+ }
+ if (!xb_data_to_write())
+ return bytes;
+
+ /* Must write data /after/ reading the consumer index. */
+ virt_mb();
+
+ dst = get_output_chunk(cons, prod, intf->req, &avail);
+ if (avail == 0)
+ continue;
+ if (avail > len)
+ avail = len;
+
+ memcpy(dst, data, avail);
+ data += avail;
+ len -= avail;
+ bytes += avail;
+
+ /* Other side must not see new producer until data is there. */
+ virt_wmb();
+ intf->req_prod += avail;
+
+ /* Implies mb(): other side will see the updated producer. */
+ if (prod <= intf->req_cons)
+ notify_remote_via_evtchn(xen_store_evtchn);
+ }
+
+ return bytes;
+}
+
+static int xb_data_to_read(void)
+{
+ struct xenstore_domain_interface *intf = xen_store_interface;
+ return (intf->rsp_cons != intf->rsp_prod);
+}
+
+static int xb_read(void *data, unsigned int len)
+{
+ struct xenstore_domain_interface *intf = xen_store_interface;
+ XENSTORE_RING_IDX cons, prod;
+ unsigned int bytes = 0;
+
+ while (len != 0) {
+ unsigned int avail;
+ const char *src;
+
+ /* Read indexes, then verify. */
+ cons = intf->rsp_cons;
+ prod = intf->rsp_prod;
+ if (cons == prod)
+ return bytes;
+
+ if (!check_indexes(cons, prod)) {
+ intf->rsp_cons = intf->rsp_prod = 0;
+ return -EIO;
+ }
+
+ src = get_input_chunk(cons, prod, intf->rsp, &avail);
+ if (avail == 0)
+ continue;
+ if (avail > len)
+ avail = len;
+
+ /* Must read data /after/ reading the producer index. */
+ virt_rmb();
+
+ memcpy(data, src, avail);
+ data += avail;
+ len -= avail;
+ bytes += avail;
+
+ /* Other side must not see free space until we've copied out */
+ virt_mb();
+ intf->rsp_cons += avail;
+
+ /* Implies mb(): other side will see the updated consumer. */
+ if (intf->rsp_prod - cons >= XENSTORE_RING_SIZE)
+ notify_remote_via_evtchn(xen_store_evtchn);
+ }
+
+ return bytes;
+}
+
+static int process_msg(void)
+{
+ static struct {
+ struct xsd_sockmsg msg;
+ char *body;
+ union {
+ void *alloc;
+ struct xs_watch_event *watch;
+ };
+ bool in_msg;
+ bool in_hdr;
+ unsigned int read;
+ } state;
+ struct xb_req_data *req;
+ int err;
+ unsigned int len;
+
+ if (!state.in_msg) {
+ state.in_msg = true;
+ state.in_hdr = true;
+ state.read = 0;
+
+ /*
+ * We must disallow save/restore while reading a message.
+ * A partial read across s/r leaves us out of sync with
+ * xenstored.
+ * xs_response_mutex is locked as long as we are processing one
+ * message. state.in_msg will be true as long as we are holding
+ * the lock here.
+ */
+ mutex_lock(&xs_response_mutex);
+
+ if (!xb_data_to_read()) {
+ /* We raced with save/restore: pending data 'gone'. */
+ mutex_unlock(&xs_response_mutex);
+ state.in_msg = false;
+ return 0;
+ }
+ }
+
+ if (state.in_hdr) {
+ if (state.read != sizeof(state.msg)) {
+ err = xb_read((void *)&state.msg + state.read,
+ sizeof(state.msg) - state.read);
+ if (err < 0)
+ goto out;
+ state.read += err;
+ if (state.read != sizeof(state.msg))
+ return 0;
+ if (state.msg.len > XENSTORE_PAYLOAD_MAX) {
+ err = -EINVAL;
+ goto out;
+ }
+ }
+
+ len = state.msg.len + 1;
+ if (state.msg.type == XS_WATCH_EVENT)
+ len += sizeof(*state.watch);
+
+ state.alloc = kmalloc(len, GFP_NOIO | __GFP_HIGH);
+ if (!state.alloc)
+ return -ENOMEM;
+
+ if (state.msg.type == XS_WATCH_EVENT)
+ state.body = state.watch->body;
+ else
+ state.body = state.alloc;
+ state.in_hdr = false;
+ state.read = 0;
+ }
+
+ err = xb_read(state.body + state.read, state.msg.len - state.read);
+ if (err < 0)
+ goto out;
+
+ state.read += err;
+ if (state.read != state.msg.len)
+ return 0;
+
+ state.body[state.msg.len] = '\0';
+
+ if (state.msg.type == XS_WATCH_EVENT) {
+ state.watch->len = state.msg.len;
+ err = xs_watch_msg(state.watch);
+ } else {
+ err = -ENOENT;
+ mutex_lock(&xb_write_mutex);
+ list_for_each_entry(req, &xs_reply_list, list) {
+ if (req->msg.req_id == state.msg.req_id) {
+ list_del(&req->list);
+ err = 0;
+ break;
+ }
+ }
+ mutex_unlock(&xb_write_mutex);
+ if (err)
+ goto out;
+
+ if (req->state == xb_req_state_wait_reply) {
+ req->msg.req_id = req->caller_req_id;
+ req->msg.type = state.msg.type;
+ req->msg.len = state.msg.len;
+ req->body = state.body;
+ req->state = xb_req_state_got_reply;
+ req->cb(req);
+ } else
+ kfree(req);
+ }
+
+ mutex_unlock(&xs_response_mutex);
+
+ state.in_msg = false;
+ state.alloc = NULL;
+ return err;
+
+ out:
+ mutex_unlock(&xs_response_mutex);
+ state.in_msg = false;
+ kfree(state.alloc);
+ state.alloc = NULL;
+ return err;
+}
+
+static int process_writes(void)
+{
+ static struct {
+ struct xb_req_data *req;
+ int idx;
+ unsigned int written;
+ } state;
+ void *base;
+ unsigned int len;
+ int err = 0;
+
+ if (!xb_data_to_write())
+ return 0;
+
+ mutex_lock(&xb_write_mutex);
+
+ if (!state.req) {
+ state.req = list_first_entry(&xb_write_list,
+ struct xb_req_data, list);
+ state.idx = -1;
+ state.written = 0;
+ }
+
+ if (state.req->state == xb_req_state_aborted)
+ goto out_err;
+
+ while (state.idx < state.req->num_vecs) {
+ if (state.idx < 0) {
+ base = &state.req->msg;
+ len = sizeof(state.req->msg);
+ } else {
+ base = state.req->vec[state.idx].iov_base;
+ len = state.req->vec[state.idx].iov_len;
+ }
+ err = xb_write(base + state.written, len - state.written);
+ if (err < 0)
+ goto out_err;
+ state.written += err;
+ if (state.written != len)
+ goto out;
+
+ state.idx++;
+ state.written = 0;
+ }
+
+ list_del(&state.req->list);
+ state.req->state = xb_req_state_wait_reply;
+ list_add_tail(&state.req->list, &xs_reply_list);
+ state.req = NULL;
+
+ out:
+ mutex_unlock(&xb_write_mutex);
+
+ return 0;
+
+ out_err:
+ state.req->msg.type = XS_ERROR;
+ state.req->err = err;
+ list_del(&state.req->list);
+ if (state.req->state == xb_req_state_aborted)
+ kfree(state.req);
+ else {
+ state.req->state = xb_req_state_got_reply;
+ wake_up(&state.req->wq);
+ }
+
+ mutex_unlock(&xb_write_mutex);
+
+ state.req = NULL;
+
+ return err;
+}
+
+static int xb_thread_work(void)
+{
+ return xb_data_to_read() || xb_data_to_write();
+}
+
+static int xenbus_thread(void *unused)
+{
+ int err;
+
+ while (!kthread_should_stop()) {
+ if (wait_event_interruptible(xb_waitq, xb_thread_work()))
+ continue;
+
+ err = process_msg();
+ if (err == -ENOMEM)
+ schedule();
+ else if (err)
+ pr_warn_ratelimited("error %d while reading message\n",
+ err);
+
+ err = process_writes();
+ if (err)
+ pr_warn_ratelimited("error %d while writing message\n",
+ err);
+ }
+
+ xenbus_task = NULL;
+ return 0;
+}
+
+/**
+ * xb_init_comms - Set up interrupt handler off store event channel.
+ */
+int xb_init_comms(void)
+{
+ struct xenstore_domain_interface *intf = xen_store_interface;
+
+ if (intf->req_prod != intf->req_cons)
+ pr_err("request ring is not quiescent (%08x:%08x)!\n",
+ intf->req_cons, intf->req_prod);
+
+ if (intf->rsp_prod != intf->rsp_cons) {
+ pr_warn("response ring is not quiescent (%08x:%08x): fixing up\n",
+ intf->rsp_cons, intf->rsp_prod);
+ /* breaks kdump */
+ if (!reset_devices)
+ intf->rsp_cons = intf->rsp_prod;
+ }
+
+ if (xenbus_irq) {
+ /* Already have an irq; assume we're resuming */
+ rebind_evtchn_irq(xen_store_evtchn, xenbus_irq);
+ } else {
+ int err;
+
+ err = bind_evtchn_to_irqhandler(xen_store_evtchn, wake_waiting,
+ 0, "xenbus", &xb_waitq);
+ if (err < 0) {
+ pr_err("request irq failed %i\n", err);
+ return err;
+ }
+
+ xenbus_irq = err;
+
+ if (!xenbus_task) {
+ xenbus_task = kthread_run(xenbus_thread, NULL,
+ "xenbus");
+ if (IS_ERR(xenbus_task))
+ return PTR_ERR(xenbus_task);
+ }
+ }
+
+ return 0;
+}
+
+void xb_deinit_comms(void)
+{
+ unbind_from_irqhandler(xenbus_irq, &xb_waitq);
+ xenbus_irq = 0;
+}
diff --git a/drivers/xen/xenbus/xenbus_dev_backend.c b/drivers/xen/xenbus/xenbus_dev_backend.c
new file mode 100644
index 0000000..edba5fe
--- /dev/null
+++ b/drivers/xen/xenbus/xenbus_dev_backend.c
@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-2.0
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/init.h>
+#include <linux/capability.h>
+
+#include <xen/xen.h>
+#include <xen/page.h>
+#include <xen/xenbus.h>
+#include <xen/xenbus_dev.h>
+#include <xen/grant_table.h>
+#include <xen/events.h>
+#include <asm/xen/hypervisor.h>
+
+#include "xenbus.h"
+
+static int xenbus_backend_open(struct inode *inode, struct file *filp)
+{
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ return nonseekable_open(inode, filp);
+}
+
+static long xenbus_alloc(domid_t domid)
+{
+ struct evtchn_alloc_unbound arg;
+ int err = -EEXIST;
+
+ xs_suspend();
+
+ /* If xenstored_ready is nonzero, that means we have already talked to
+ * xenstore and set up watches. These watches will be restored by
+ * xs_resume, but that requires communication over the port established
+ * below that is not visible to anyone until the ioctl returns.
+ *
+ * This can be resolved by splitting the ioctl into two parts
+ * (postponing the resume until xenstored is active) but this is
+ * unnecessarily complex for the intended use where xenstored is only
+ * started once - so return -EEXIST if it's already running.
+ */
+ if (xenstored_ready)
+ goto out_err;
+
+ gnttab_grant_foreign_access_ref(GNTTAB_RESERVED_XENSTORE, domid,
+ virt_to_gfn(xen_store_interface), 0 /* writable */);
+
+ arg.dom = DOMID_SELF;
+ arg.remote_dom = domid;
+
+ err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, &arg);
+ if (err)
+ goto out_err;
+
+ if (xen_store_evtchn > 0)
+ xb_deinit_comms();
+
+ xen_store_evtchn = arg.port;
+
+ xs_resume();
+
+ return arg.port;
+
+ out_err:
+ xs_suspend_cancel();
+ return err;
+}
+
+static long xenbus_backend_ioctl(struct file *file, unsigned int cmd,
+ unsigned long data)
+{
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ switch (cmd) {
+ case IOCTL_XENBUS_BACKEND_EVTCHN:
+ if (xen_store_evtchn > 0)
+ return xen_store_evtchn;
+ return -ENODEV;
+ case IOCTL_XENBUS_BACKEND_SETUP:
+ return xenbus_alloc(data);
+ default:
+ return -ENOTTY;
+ }
+}
+
+static int xenbus_backend_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ size_t size = vma->vm_end - vma->vm_start;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if ((size > PAGE_SIZE) || (vma->vm_pgoff != 0))
+ return -EINVAL;
+
+ if (remap_pfn_range(vma, vma->vm_start,
+ virt_to_pfn(xen_store_interface),
+ size, vma->vm_page_prot))
+ return -EAGAIN;
+
+ return 0;
+}
+
+static const struct file_operations xenbus_backend_fops = {
+ .open = xenbus_backend_open,
+ .mmap = xenbus_backend_mmap,
+ .unlocked_ioctl = xenbus_backend_ioctl,
+};
+
+static struct miscdevice xenbus_backend_dev = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "xen/xenbus_backend",
+ .fops = &xenbus_backend_fops,
+};
+
+static int __init xenbus_backend_init(void)
+{
+ int err;
+
+ if (!xen_initial_domain())
+ return -ENODEV;
+
+ err = misc_register(&xenbus_backend_dev);
+ if (err)
+ pr_err("Could not register xenbus backend device\n");
+ return err;
+}
+device_initcall(xenbus_backend_init);
diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c
new file mode 100644
index 0000000..c3e2010
--- /dev/null
+++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
@@ -0,0 +1,695 @@
+/*
+ * Driver giving user-space access to the kernel's xenbus connection
+ * to xenstore.
+ *
+ * Copyright (c) 2005, Christian Limpach
+ * Copyright (c) 2005, Rusty Russell, IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Changes:
+ * 2008-10-07 Alex Zeffertt Replaced /proc/xen/xenbus with xenfs filesystem
+ * and /proc/xen compatibility mount point.
+ * Turned xenfs into a loadable module.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/uio.h>
+#include <linux/notifier.h>
+#include <linux/wait.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/mount.h>
+#include <linux/pagemap.h>
+#include <linux/uaccess.h>
+#include <linux/init.h>
+#include <linux/namei.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/miscdevice.h>
+
+#include <xen/xenbus.h>
+#include <xen/xen.h>
+#include <asm/xen/hypervisor.h>
+
+#include "xenbus.h"
+
+/*
+ * An element of a list of outstanding transactions, for which we're
+ * still waiting a reply.
+ */
+struct xenbus_transaction_holder {
+ struct list_head list;
+ struct xenbus_transaction handle;
+};
+
+/*
+ * A buffer of data on the queue.
+ */
+struct read_buffer {
+ struct list_head list;
+ unsigned int cons;
+ unsigned int len;
+ char msg[];
+};
+
+struct xenbus_file_priv {
+ /*
+ * msgbuffer_mutex is held while partial requests are built up
+ * and complete requests are acted on. It therefore protects
+ * the "transactions" and "watches" lists, and the partial
+ * request length and buffer.
+ *
+ * reply_mutex protects the reply being built up to return to
+ * usermode. It nests inside msgbuffer_mutex but may be held
+ * alone during a watch callback.
+ */
+ struct mutex msgbuffer_mutex;
+
+ /* In-progress transactions */
+ struct list_head transactions;
+
+ /* Active watches. */
+ struct list_head watches;
+
+ /* Partial request. */
+ unsigned int len;
+ union {
+ struct xsd_sockmsg msg;
+ char buffer[XENSTORE_PAYLOAD_MAX];
+ } u;
+
+ /* Response queue. */
+ struct mutex reply_mutex;
+ struct list_head read_buffers;
+ wait_queue_head_t read_waitq;
+
+ struct kref kref;
+};
+
+/* Read out any raw xenbus messages queued up. */
+static ssize_t xenbus_file_read(struct file *filp,
+ char __user *ubuf,
+ size_t len, loff_t *ppos)
+{
+ struct xenbus_file_priv *u = filp->private_data;
+ struct read_buffer *rb;
+ unsigned i;
+ int ret;
+
+ mutex_lock(&u->reply_mutex);
+again:
+ while (list_empty(&u->read_buffers)) {
+ mutex_unlock(&u->reply_mutex);
+ if (filp->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+
+ ret = wait_event_interruptible(u->read_waitq,
+ !list_empty(&u->read_buffers));
+ if (ret)
+ return ret;
+ mutex_lock(&u->reply_mutex);
+ }
+
+ rb = list_entry(u->read_buffers.next, struct read_buffer, list);
+ i = 0;
+ while (i < len) {
+ unsigned sz = min((unsigned)len - i, rb->len - rb->cons);
+
+ ret = copy_to_user(ubuf + i, &rb->msg[rb->cons], sz);
+
+ i += sz - ret;
+ rb->cons += sz - ret;
+
+ if (ret != 0) {
+ if (i == 0)
+ i = -EFAULT;
+ goto out;
+ }
+
+ /* Clear out buffer if it has been consumed */
+ if (rb->cons == rb->len) {
+ list_del(&rb->list);
+ kfree(rb);
+ if (list_empty(&u->read_buffers))
+ break;
+ rb = list_entry(u->read_buffers.next,
+ struct read_buffer, list);
+ }
+ }
+ if (i == 0)
+ goto again;
+
+out:
+ mutex_unlock(&u->reply_mutex);
+ return i;
+}
+
+/*
+ * Add a buffer to the queue. Caller must hold the appropriate lock
+ * if the queue is not local. (Commonly the caller will build up
+ * multiple queued buffers on a temporary local list, and then add it
+ * to the appropriate list under lock once all the buffers have een
+ * successfully allocated.)
+ */
+static int queue_reply(struct list_head *queue, const void *data, size_t len)
+{
+ struct read_buffer *rb;
+
+ if (len == 0)
+ return 0;
+ if (len > XENSTORE_PAYLOAD_MAX)
+ return -EINVAL;
+
+ rb = kmalloc(sizeof(*rb) + len, GFP_KERNEL);
+ if (rb == NULL)
+ return -ENOMEM;
+
+ rb->cons = 0;
+ rb->len = len;
+
+ memcpy(rb->msg, data, len);
+
+ list_add_tail(&rb->list, queue);
+ return 0;
+}
+
+/*
+ * Free all the read_buffer s on a list.
+ * Caller must have sole reference to list.
+ */
+static void queue_cleanup(struct list_head *list)
+{
+ struct read_buffer *rb;
+
+ while (!list_empty(list)) {
+ rb = list_entry(list->next, struct read_buffer, list);
+ list_del(list->next);
+ kfree(rb);
+ }
+}
+
+struct watch_adapter {
+ struct list_head list;
+ struct xenbus_watch watch;
+ struct xenbus_file_priv *dev_data;
+ char *token;
+};
+
+static void free_watch_adapter(struct watch_adapter *watch)
+{
+ kfree(watch->watch.node);
+ kfree(watch->token);
+ kfree(watch);
+}
+
+static struct watch_adapter *alloc_watch_adapter(const char *path,
+ const char *token)
+{
+ struct watch_adapter *watch;
+
+ watch = kzalloc(sizeof(*watch), GFP_KERNEL);
+ if (watch == NULL)
+ goto out_fail;
+
+ watch->watch.node = kstrdup(path, GFP_KERNEL);
+ if (watch->watch.node == NULL)
+ goto out_free;
+
+ watch->token = kstrdup(token, GFP_KERNEL);
+ if (watch->token == NULL)
+ goto out_free;
+
+ return watch;
+
+out_free:
+ free_watch_adapter(watch);
+
+out_fail:
+ return NULL;
+}
+
+static void watch_fired(struct xenbus_watch *watch,
+ const char *path,
+ const char *token)
+{
+ struct watch_adapter *adap;
+ struct xsd_sockmsg hdr;
+ const char *token_caller;
+ int path_len, tok_len, body_len;
+ int ret;
+ LIST_HEAD(staging_q);
+
+ adap = container_of(watch, struct watch_adapter, watch);
+
+ token_caller = adap->token;
+
+ path_len = strlen(path) + 1;
+ tok_len = strlen(token_caller) + 1;
+ body_len = path_len + tok_len;
+
+ hdr.type = XS_WATCH_EVENT;
+ hdr.len = body_len;
+
+ mutex_lock(&adap->dev_data->reply_mutex);
+
+ ret = queue_reply(&staging_q, &hdr, sizeof(hdr));
+ if (!ret)
+ ret = queue_reply(&staging_q, path, path_len);
+ if (!ret)
+ ret = queue_reply(&staging_q, token_caller, tok_len);
+
+ if (!ret) {
+ /* success: pass reply list onto watcher */
+ list_splice_tail(&staging_q, &adap->dev_data->read_buffers);
+ wake_up(&adap->dev_data->read_waitq);
+ } else
+ queue_cleanup(&staging_q);
+
+ mutex_unlock(&adap->dev_data->reply_mutex);
+}
+
+static void xenbus_file_free(struct kref *kref)
+{
+ struct xenbus_file_priv *u;
+ struct xenbus_transaction_holder *trans, *tmp;
+ struct watch_adapter *watch, *tmp_watch;
+ struct read_buffer *rb, *tmp_rb;
+
+ u = container_of(kref, struct xenbus_file_priv, kref);
+
+ /*
+ * No need for locking here because there are no other users,
+ * by definition.
+ */
+
+ list_for_each_entry_safe(trans, tmp, &u->transactions, list) {
+ xenbus_transaction_end(trans->handle, 1);
+ list_del(&trans->list);
+ kfree(trans);
+ }
+
+ list_for_each_entry_safe(watch, tmp_watch, &u->watches, list) {
+ unregister_xenbus_watch(&watch->watch);
+ list_del(&watch->list);
+ free_watch_adapter(watch);
+ }
+
+ list_for_each_entry_safe(rb, tmp_rb, &u->read_buffers, list) {
+ list_del(&rb->list);
+ kfree(rb);
+ }
+ kfree(u);
+}
+
+static struct xenbus_transaction_holder *xenbus_get_transaction(
+ struct xenbus_file_priv *u, uint32_t tx_id)
+{
+ struct xenbus_transaction_holder *trans;
+
+ list_for_each_entry(trans, &u->transactions, list)
+ if (trans->handle.id == tx_id)
+ return trans;
+
+ return NULL;
+}
+
+void xenbus_dev_queue_reply(struct xb_req_data *req)
+{
+ struct xenbus_file_priv *u = req->par;
+ struct xenbus_transaction_holder *trans = NULL;
+ int rc;
+ LIST_HEAD(staging_q);
+
+ xs_request_exit(req);
+
+ mutex_lock(&u->msgbuffer_mutex);
+
+ if (req->type == XS_TRANSACTION_START) {
+ trans = xenbus_get_transaction(u, 0);
+ if (WARN_ON(!trans))
+ goto out;
+ if (req->msg.type == XS_ERROR) {
+ list_del(&trans->list);
+ kfree(trans);
+ } else {
+ rc = kstrtou32(req->body, 10, &trans->handle.id);
+ if (WARN_ON(rc))
+ goto out;
+ }
+ } else if (req->type == XS_TRANSACTION_END) {
+ trans = xenbus_get_transaction(u, req->msg.tx_id);
+ if (WARN_ON(!trans))
+ goto out;
+ list_del(&trans->list);
+ kfree(trans);
+ }
+
+ mutex_unlock(&u->msgbuffer_mutex);
+
+ mutex_lock(&u->reply_mutex);
+ rc = queue_reply(&staging_q, &req->msg, sizeof(req->msg));
+ if (!rc)
+ rc = queue_reply(&staging_q, req->body, req->msg.len);
+ if (!rc) {
+ list_splice_tail(&staging_q, &u->read_buffers);
+ wake_up(&u->read_waitq);
+ } else {
+ queue_cleanup(&staging_q);
+ }
+ mutex_unlock(&u->reply_mutex);
+
+ kfree(req->body);
+ kfree(req);
+
+ kref_put(&u->kref, xenbus_file_free);
+
+ return;
+
+ out:
+ mutex_unlock(&u->msgbuffer_mutex);
+}
+
+static int xenbus_command_reply(struct xenbus_file_priv *u,
+ unsigned int msg_type, const char *reply)
+{
+ struct {
+ struct xsd_sockmsg hdr;
+ char body[16];
+ } msg;
+ int rc;
+
+ msg.hdr = u->u.msg;
+ msg.hdr.type = msg_type;
+ msg.hdr.len = strlen(reply) + 1;
+ if (msg.hdr.len > sizeof(msg.body))
+ return -E2BIG;
+ memcpy(&msg.body, reply, msg.hdr.len);
+
+ mutex_lock(&u->reply_mutex);
+ rc = queue_reply(&u->read_buffers, &msg, sizeof(msg.hdr) + msg.hdr.len);
+ wake_up(&u->read_waitq);
+ mutex_unlock(&u->reply_mutex);
+
+ if (!rc)
+ kref_put(&u->kref, xenbus_file_free);
+
+ return rc;
+}
+
+static int xenbus_write_transaction(unsigned msg_type,
+ struct xenbus_file_priv *u)
+{
+ int rc;
+ struct xenbus_transaction_holder *trans = NULL;
+ struct {
+ struct xsd_sockmsg hdr;
+ char body[];
+ } *msg = (void *)u->u.buffer;
+
+ if (msg_type == XS_TRANSACTION_START) {
+ trans = kzalloc(sizeof(*trans), GFP_KERNEL);
+ if (!trans) {
+ rc = -ENOMEM;
+ goto out;
+ }
+ list_add(&trans->list, &u->transactions);
+ } else if (msg->hdr.tx_id != 0 &&
+ !xenbus_get_transaction(u, msg->hdr.tx_id))
+ return xenbus_command_reply(u, XS_ERROR, "ENOENT");
+ else if (msg_type == XS_TRANSACTION_END &&
+ !(msg->hdr.len == 2 &&
+ (!strcmp(msg->body, "T") || !strcmp(msg->body, "F"))))
+ return xenbus_command_reply(u, XS_ERROR, "EINVAL");
+
+ rc = xenbus_dev_request_and_reply(&msg->hdr, u);
+ if (rc && trans) {
+ list_del(&trans->list);
+ kfree(trans);
+ }
+
+out:
+ return rc;
+}
+
+static int xenbus_write_watch(unsigned msg_type, struct xenbus_file_priv *u)
+{
+ struct watch_adapter *watch;
+ char *path, *token;
+ int err, rc;
+ LIST_HEAD(staging_q);
+
+ path = u->u.buffer + sizeof(u->u.msg);
+ token = memchr(path, 0, u->u.msg.len);
+ if (token == NULL) {
+ rc = xenbus_command_reply(u, XS_ERROR, "EINVAL");
+ goto out;
+ }
+ token++;
+ if (memchr(token, 0, u->u.msg.len - (token - path)) == NULL) {
+ rc = xenbus_command_reply(u, XS_ERROR, "EINVAL");
+ goto out;
+ }
+
+ if (msg_type == XS_WATCH) {
+ watch = alloc_watch_adapter(path, token);
+ if (watch == NULL) {
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ watch->watch.callback = watch_fired;
+ watch->dev_data = u;
+
+ err = register_xenbus_watch(&watch->watch);
+ if (err) {
+ free_watch_adapter(watch);
+ rc = err;
+ goto out;
+ }
+ list_add(&watch->list, &u->watches);
+ } else {
+ list_for_each_entry(watch, &u->watches, list) {
+ if (!strcmp(watch->token, token) &&
+ !strcmp(watch->watch.node, path)) {
+ unregister_xenbus_watch(&watch->watch);
+ list_del(&watch->list);
+ free_watch_adapter(watch);
+ break;
+ }
+ }
+ }
+
+ /* Success. Synthesize a reply to say all is OK. */
+ rc = xenbus_command_reply(u, msg_type, "OK");
+
+out:
+ return rc;
+}
+
+static ssize_t xenbus_file_write(struct file *filp,
+ const char __user *ubuf,
+ size_t len, loff_t *ppos)
+{
+ struct xenbus_file_priv *u = filp->private_data;
+ uint32_t msg_type;
+ int rc = len;
+ int ret;
+ LIST_HEAD(staging_q);
+
+ /*
+ * We're expecting usermode to be writing properly formed
+ * xenbus messages. If they write an incomplete message we
+ * buffer it up. Once it is complete, we act on it.
+ */
+
+ /*
+ * Make sure concurrent writers can't stomp all over each
+ * other's messages and make a mess of our partial message
+ * buffer. We don't make any attemppt to stop multiple
+ * writers from making a mess of each other's incomplete
+ * messages; we're just trying to guarantee our own internal
+ * consistency and make sure that single writes are handled
+ * atomically.
+ */
+ mutex_lock(&u->msgbuffer_mutex);
+
+ /* Get this out of the way early to avoid confusion */
+ if (len == 0)
+ goto out;
+
+ /* Can't write a xenbus message larger we can buffer */
+ if (len > sizeof(u->u.buffer) - u->len) {
+ /* On error, dump existing buffer */
+ u->len = 0;
+ rc = -EINVAL;
+ goto out;
+ }
+
+ ret = copy_from_user(u->u.buffer + u->len, ubuf, len);
+
+ if (ret != 0) {
+ rc = -EFAULT;
+ goto out;
+ }
+
+ /* Deal with a partial copy. */
+ len -= ret;
+ rc = len;
+
+ u->len += len;
+
+ /* Return if we haven't got a full message yet */
+ if (u->len < sizeof(u->u.msg))
+ goto out; /* not even the header yet */
+
+ /* If we're expecting a message that's larger than we can
+ possibly send, dump what we have and return an error. */
+ if ((sizeof(u->u.msg) + u->u.msg.len) > sizeof(u->u.buffer)) {
+ rc = -E2BIG;
+ u->len = 0;
+ goto out;
+ }
+
+ if (u->len < (sizeof(u->u.msg) + u->u.msg.len))
+ goto out; /* incomplete data portion */
+
+ /*
+ * OK, now we have a complete message. Do something with it.
+ */
+
+ kref_get(&u->kref);
+
+ msg_type = u->u.msg.type;
+
+ switch (msg_type) {
+ case XS_WATCH:
+ case XS_UNWATCH:
+ /* (Un)Ask for some path to be watched for changes */
+ ret = xenbus_write_watch(msg_type, u);
+ break;
+
+ default:
+ /* Send out a transaction */
+ ret = xenbus_write_transaction(msg_type, u);
+ break;
+ }
+ if (ret != 0) {
+ rc = ret;
+ kref_put(&u->kref, xenbus_file_free);
+ }
+
+ /* Buffered message consumed */
+ u->len = 0;
+
+ out:
+ mutex_unlock(&u->msgbuffer_mutex);
+ return rc;
+}
+
+static int xenbus_file_open(struct inode *inode, struct file *filp)
+{
+ struct xenbus_file_priv *u;
+
+ if (xen_store_evtchn == 0)
+ return -ENOENT;
+
+ nonseekable_open(inode, filp);
+
+ filp->f_mode &= ~FMODE_ATOMIC_POS; /* cdev-style semantics */
+
+ u = kzalloc(sizeof(*u), GFP_KERNEL);
+ if (u == NULL)
+ return -ENOMEM;
+
+ kref_init(&u->kref);
+
+ INIT_LIST_HEAD(&u->transactions);
+ INIT_LIST_HEAD(&u->watches);
+ INIT_LIST_HEAD(&u->read_buffers);
+ init_waitqueue_head(&u->read_waitq);
+
+ mutex_init(&u->reply_mutex);
+ mutex_init(&u->msgbuffer_mutex);
+
+ filp->private_data = u;
+
+ return 0;
+}
+
+static int xenbus_file_release(struct inode *inode, struct file *filp)
+{
+ struct xenbus_file_priv *u = filp->private_data;
+
+ kref_put(&u->kref, xenbus_file_free);
+
+ return 0;
+}
+
+static __poll_t xenbus_file_poll(struct file *file, poll_table *wait)
+{
+ struct xenbus_file_priv *u = file->private_data;
+
+ poll_wait(file, &u->read_waitq, wait);
+ if (!list_empty(&u->read_buffers))
+ return EPOLLIN | EPOLLRDNORM;
+ return 0;
+}
+
+const struct file_operations xen_xenbus_fops = {
+ .read = xenbus_file_read,
+ .write = xenbus_file_write,
+ .open = xenbus_file_open,
+ .release = xenbus_file_release,
+ .poll = xenbus_file_poll,
+ .llseek = no_llseek,
+};
+EXPORT_SYMBOL_GPL(xen_xenbus_fops);
+
+static struct miscdevice xenbus_dev = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "xen/xenbus",
+ .fops = &xen_xenbus_fops,
+};
+
+static int __init xenbus_init(void)
+{
+ int err;
+
+ if (!xen_domain())
+ return -ENODEV;
+
+ err = misc_register(&xenbus_dev);
+ if (err)
+ pr_err("Could not register xenbus frontend device\n");
+ return err;
+}
+device_initcall(xenbus_init);
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
new file mode 100644
index 0000000..5b47188
--- /dev/null
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -0,0 +1,845 @@
+/******************************************************************************
+ * Talks to Xen Store to figure out what devices we have.
+ *
+ * Copyright (C) 2005 Rusty Russell, IBM Corporation
+ * Copyright (C) 2005 Mike Wray, Hewlett-Packard
+ * Copyright (C) 2005, 2006 XenSource Ltd
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#define DPRINTK(fmt, args...) \
+ pr_debug("xenbus_probe (%s:%d) " fmt ".\n", \
+ __func__, __LINE__, ##args)
+
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/proc_fs.h>
+#include <linux/notifier.h>
+#include <linux/kthread.h>
+#include <linux/mutex.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/xen/hypervisor.h>
+
+#include <xen/xen.h>
+#include <xen/xenbus.h>
+#include <xen/events.h>
+#include <xen/xen-ops.h>
+#include <xen/page.h>
+
+#include <xen/hvm.h>
+
+#include "xenbus.h"
+
+
+int xen_store_evtchn;
+EXPORT_SYMBOL_GPL(xen_store_evtchn);
+
+struct xenstore_domain_interface *xen_store_interface;
+EXPORT_SYMBOL_GPL(xen_store_interface);
+
+enum xenstore_init xen_store_domain_type;
+EXPORT_SYMBOL_GPL(xen_store_domain_type);
+
+static unsigned long xen_store_gfn;
+
+static BLOCKING_NOTIFIER_HEAD(xenstore_chain);
+
+/* If something in array of ids matches this device, return it. */
+static const struct xenbus_device_id *
+match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
+{
+ for (; *arr->devicetype != '\0'; arr++) {
+ if (!strcmp(arr->devicetype, dev->devicetype))
+ return arr;
+ }
+ return NULL;
+}
+
+int xenbus_match(struct device *_dev, struct device_driver *_drv)
+{
+ struct xenbus_driver *drv = to_xenbus_driver(_drv);
+
+ if (!drv->ids)
+ return 0;
+
+ return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
+}
+EXPORT_SYMBOL_GPL(xenbus_match);
+
+
+static void free_otherend_details(struct xenbus_device *dev)
+{
+ kfree(dev->otherend);
+ dev->otherend = NULL;
+}
+
+
+static void free_otherend_watch(struct xenbus_device *dev)
+{
+ if (dev->otherend_watch.node) {
+ unregister_xenbus_watch(&dev->otherend_watch);
+ kfree(dev->otherend_watch.node);
+ dev->otherend_watch.node = NULL;
+ }
+}
+
+
+static int talk_to_otherend(struct xenbus_device *dev)
+{
+ struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
+
+ free_otherend_watch(dev);
+ free_otherend_details(dev);
+
+ return drv->read_otherend_details(dev);
+}
+
+
+
+static int watch_otherend(struct xenbus_device *dev)
+{
+ struct xen_bus_type *bus =
+ container_of(dev->dev.bus, struct xen_bus_type, bus);
+
+ return xenbus_watch_pathfmt(dev, &dev->otherend_watch,
+ bus->otherend_changed,
+ "%s/%s", dev->otherend, "state");
+}
+
+
+int xenbus_read_otherend_details(struct xenbus_device *xendev,
+ char *id_node, char *path_node)
+{
+ int err = xenbus_gather(XBT_NIL, xendev->nodename,
+ id_node, "%i", &xendev->otherend_id,
+ path_node, NULL, &xendev->otherend,
+ NULL);
+ if (err) {
+ xenbus_dev_fatal(xendev, err,
+ "reading other end details from %s",
+ xendev->nodename);
+ return err;
+ }
+ if (strlen(xendev->otherend) == 0 ||
+ !xenbus_exists(XBT_NIL, xendev->otherend, "")) {
+ xenbus_dev_fatal(xendev, -ENOENT,
+ "unable to read other end from %s. "
+ "missing or inaccessible.",
+ xendev->nodename);
+ free_otherend_details(xendev);
+ return -ENOENT;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(xenbus_read_otherend_details);
+
+void xenbus_otherend_changed(struct xenbus_watch *watch,
+ const char *path, const char *token,
+ int ignore_on_shutdown)
+{
+ struct xenbus_device *dev =
+ container_of(watch, struct xenbus_device, otherend_watch);
+ struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
+ enum xenbus_state state;
+
+ /* Protect us against watches firing on old details when the otherend
+ details change, say immediately after a resume. */
+ if (!dev->otherend ||
+ strncmp(dev->otherend, path, strlen(dev->otherend))) {
+ dev_dbg(&dev->dev, "Ignoring watch at %s\n", path);
+ return;
+ }
+
+ state = xenbus_read_driver_state(dev->otherend);
+
+ dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
+ state, xenbus_strstate(state), dev->otherend_watch.node, path);
+
+ /*
+ * Ignore xenbus transitions during shutdown. This prevents us doing
+ * work that can fail e.g., when the rootfs is gone.
+ */
+ if (system_state > SYSTEM_RUNNING) {
+ if (ignore_on_shutdown && (state == XenbusStateClosing))
+ xenbus_frontend_closed(dev);
+ return;
+ }
+
+ if (drv->otherend_changed)
+ drv->otherend_changed(dev, state);
+}
+EXPORT_SYMBOL_GPL(xenbus_otherend_changed);
+
+int xenbus_dev_probe(struct device *_dev)
+{
+ struct xenbus_device *dev = to_xenbus_device(_dev);
+ struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
+ const struct xenbus_device_id *id;
+ int err;
+
+ DPRINTK("%s", dev->nodename);
+
+ if (!drv->probe) {
+ err = -ENODEV;
+ goto fail;
+ }
+
+ id = match_device(drv->ids, dev);
+ if (!id) {
+ err = -ENODEV;
+ goto fail;
+ }
+
+ err = talk_to_otherend(dev);
+ if (err) {
+ dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
+ dev->nodename);
+ return err;
+ }
+
+ err = drv->probe(dev, id);
+ if (err)
+ goto fail;
+
+ err = watch_otherend(dev);
+ if (err) {
+ dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
+ dev->nodename);
+ return err;
+ }
+
+ return 0;
+fail:
+ xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
+ xenbus_switch_state(dev, XenbusStateClosed);
+ return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_dev_probe);
+
+int xenbus_dev_remove(struct device *_dev)
+{
+ struct xenbus_device *dev = to_xenbus_device(_dev);
+ struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
+
+ DPRINTK("%s", dev->nodename);
+
+ free_otherend_watch(dev);
+
+ if (drv->remove)
+ drv->remove(dev);
+
+ free_otherend_details(dev);
+
+ xenbus_switch_state(dev, XenbusStateClosed);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(xenbus_dev_remove);
+
+void xenbus_dev_shutdown(struct device *_dev)
+{
+ struct xenbus_device *dev = to_xenbus_device(_dev);
+ unsigned long timeout = 5*HZ;
+
+ DPRINTK("%s", dev->nodename);
+
+ get_device(&dev->dev);
+ if (dev->state != XenbusStateConnected) {
+ pr_info("%s: %s: %s != Connected, skipping\n",
+ __func__, dev->nodename, xenbus_strstate(dev->state));
+ goto out;
+ }
+ xenbus_switch_state(dev, XenbusStateClosing);
+ timeout = wait_for_completion_timeout(&dev->down, timeout);
+ if (!timeout)
+ pr_info("%s: %s timeout closing device\n",
+ __func__, dev->nodename);
+ out:
+ put_device(&dev->dev);
+}
+EXPORT_SYMBOL_GPL(xenbus_dev_shutdown);
+
+int xenbus_register_driver_common(struct xenbus_driver *drv,
+ struct xen_bus_type *bus,
+ struct module *owner, const char *mod_name)
+{
+ drv->driver.name = drv->name ? drv->name : drv->ids[0].devicetype;
+ drv->driver.bus = &bus->bus;
+ drv->driver.owner = owner;
+ drv->driver.mod_name = mod_name;
+
+ return driver_register(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(xenbus_register_driver_common);
+
+void xenbus_unregister_driver(struct xenbus_driver *drv)
+{
+ driver_unregister(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
+
+struct xb_find_info {
+ struct xenbus_device *dev;
+ const char *nodename;
+};
+
+static int cmp_dev(struct device *dev, void *data)
+{
+ struct xenbus_device *xendev = to_xenbus_device(dev);
+ struct xb_find_info *info = data;
+
+ if (!strcmp(xendev->nodename, info->nodename)) {
+ info->dev = xendev;
+ get_device(dev);
+ return 1;
+ }
+ return 0;
+}
+
+static struct xenbus_device *xenbus_device_find(const char *nodename,
+ struct bus_type *bus)
+{
+ struct xb_find_info info = { .dev = NULL, .nodename = nodename };
+
+ bus_for_each_dev(bus, NULL, &info, cmp_dev);
+ return info.dev;
+}
+
+static int cleanup_dev(struct device *dev, void *data)
+{
+ struct xenbus_device *xendev = to_xenbus_device(dev);
+ struct xb_find_info *info = data;
+ int len = strlen(info->nodename);
+
+ DPRINTK("%s", info->nodename);
+
+ /* Match the info->nodename path, or any subdirectory of that path. */
+ if (strncmp(xendev->nodename, info->nodename, len))
+ return 0;
+
+ /* If the node name is longer, ensure it really is a subdirectory. */
+ if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
+ return 0;
+
+ info->dev = xendev;
+ get_device(dev);
+ return 1;
+}
+
+static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
+{
+ struct xb_find_info info = { .nodename = path };
+
+ do {
+ info.dev = NULL;
+ bus_for_each_dev(bus, NULL, &info, cleanup_dev);
+ if (info.dev) {
+ device_unregister(&info.dev->dev);
+ put_device(&info.dev->dev);
+ }
+ } while (info.dev);
+}
+
+static void xenbus_dev_release(struct device *dev)
+{
+ if (dev)
+ kfree(to_xenbus_device(dev));
+}
+
+static ssize_t nodename_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
+}
+static DEVICE_ATTR_RO(nodename);
+
+static ssize_t devtype_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
+}
+static DEVICE_ATTR_RO(devtype);
+
+static ssize_t modalias_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%s:%s\n", dev->bus->name,
+ to_xenbus_device(dev)->devicetype);
+}
+static DEVICE_ATTR_RO(modalias);
+
+static ssize_t state_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%s\n",
+ xenbus_strstate(to_xenbus_device(dev)->state));
+}
+static DEVICE_ATTR_RO(state);
+
+static struct attribute *xenbus_dev_attrs[] = {
+ &dev_attr_nodename.attr,
+ &dev_attr_devtype.attr,
+ &dev_attr_modalias.attr,
+ &dev_attr_state.attr,
+ NULL,
+};
+
+static const struct attribute_group xenbus_dev_group = {
+ .attrs = xenbus_dev_attrs,
+};
+
+const struct attribute_group *xenbus_dev_groups[] = {
+ &xenbus_dev_group,
+ NULL,
+};
+EXPORT_SYMBOL_GPL(xenbus_dev_groups);
+
+int xenbus_probe_node(struct xen_bus_type *bus,
+ const char *type,
+ const char *nodename)
+{
+ char devname[XEN_BUS_ID_SIZE];
+ int err;
+ struct xenbus_device *xendev;
+ size_t stringlen;
+ char *tmpstring;
+
+ enum xenbus_state state = xenbus_read_driver_state(nodename);
+
+ if (state != XenbusStateInitialising) {
+ /* Device is not new, so ignore it. This can happen if a
+ device is going away after switching to Closed. */
+ return 0;
+ }
+
+ stringlen = strlen(nodename) + 1 + strlen(type) + 1;
+ xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
+ if (!xendev)
+ return -ENOMEM;
+
+ xendev->state = XenbusStateInitialising;
+
+ /* Copy the strings into the extra space. */
+
+ tmpstring = (char *)(xendev + 1);
+ strcpy(tmpstring, nodename);
+ xendev->nodename = tmpstring;
+
+ tmpstring += strlen(tmpstring) + 1;
+ strcpy(tmpstring, type);
+ xendev->devicetype = tmpstring;
+ init_completion(&xendev->down);
+
+ xendev->dev.bus = &bus->bus;
+ xendev->dev.release = xenbus_dev_release;
+
+ err = bus->get_bus_id(devname, xendev->nodename);
+ if (err)
+ goto fail;
+
+ dev_set_name(&xendev->dev, "%s", devname);
+
+ /* Register with generic device framework. */
+ err = device_register(&xendev->dev);
+ if (err) {
+ put_device(&xendev->dev);
+ xendev = NULL;
+ goto fail;
+ }
+
+ return 0;
+fail:
+ kfree(xendev);
+ return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_probe_node);
+
+static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
+{
+ int err = 0;
+ char **dir;
+ unsigned int dir_n = 0;
+ int i;
+
+ dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
+ if (IS_ERR(dir))
+ return PTR_ERR(dir);
+
+ for (i = 0; i < dir_n; i++) {
+ err = bus->probe(bus, type, dir[i]);
+ if (err)
+ break;
+ }
+
+ kfree(dir);
+ return err;
+}
+
+int xenbus_probe_devices(struct xen_bus_type *bus)
+{
+ int err = 0;
+ char **dir;
+ unsigned int i, dir_n;
+
+ dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
+ if (IS_ERR(dir))
+ return PTR_ERR(dir);
+
+ for (i = 0; i < dir_n; i++) {
+ err = xenbus_probe_device_type(bus, dir[i]);
+ if (err)
+ break;
+ }
+
+ kfree(dir);
+ return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_probe_devices);
+
+static unsigned int char_count(const char *str, char c)
+{
+ unsigned int i, ret = 0;
+
+ for (i = 0; str[i]; i++)
+ if (str[i] == c)
+ ret++;
+ return ret;
+}
+
+static int strsep_len(const char *str, char c, unsigned int len)
+{
+ unsigned int i;
+
+ for (i = 0; str[i]; i++)
+ if (str[i] == c) {
+ if (len == 0)
+ return i;
+ len--;
+ }
+ return (len == 0) ? i : -ERANGE;
+}
+
+void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
+{
+ int exists, rootlen;
+ struct xenbus_device *dev;
+ char type[XEN_BUS_ID_SIZE];
+ const char *p, *root;
+
+ if (char_count(node, '/') < 2)
+ return;
+
+ exists = xenbus_exists(XBT_NIL, node, "");
+ if (!exists) {
+ xenbus_cleanup_devices(node, &bus->bus);
+ return;
+ }
+
+ /* backend/<type>/... or device/<type>/... */
+ p = strchr(node, '/') + 1;
+ snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
+ type[XEN_BUS_ID_SIZE-1] = '\0';
+
+ rootlen = strsep_len(node, '/', bus->levels);
+ if (rootlen < 0)
+ return;
+ root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
+ if (!root)
+ return;
+
+ dev = xenbus_device_find(root, &bus->bus);
+ if (!dev)
+ xenbus_probe_node(bus, type, root);
+ else
+ put_device(&dev->dev);
+
+ kfree(root);
+}
+EXPORT_SYMBOL_GPL(xenbus_dev_changed);
+
+int xenbus_dev_suspend(struct device *dev)
+{
+ int err = 0;
+ struct xenbus_driver *drv;
+ struct xenbus_device *xdev
+ = container_of(dev, struct xenbus_device, dev);
+
+ DPRINTK("%s", xdev->nodename);
+
+ if (dev->driver == NULL)
+ return 0;
+ drv = to_xenbus_driver(dev->driver);
+ if (drv->suspend)
+ err = drv->suspend(xdev);
+ if (err)
+ pr_warn("suspend %s failed: %i\n", dev_name(dev), err);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(xenbus_dev_suspend);
+
+int xenbus_dev_resume(struct device *dev)
+{
+ int err;
+ struct xenbus_driver *drv;
+ struct xenbus_device *xdev
+ = container_of(dev, struct xenbus_device, dev);
+
+ DPRINTK("%s", xdev->nodename);
+
+ if (dev->driver == NULL)
+ return 0;
+ drv = to_xenbus_driver(dev->driver);
+ err = talk_to_otherend(xdev);
+ if (err) {
+ pr_warn("resume (talk_to_otherend) %s failed: %i\n",
+ dev_name(dev), err);
+ return err;
+ }
+
+ xdev->state = XenbusStateInitialising;
+
+ if (drv->resume) {
+ err = drv->resume(xdev);
+ if (err) {
+ pr_warn("resume %s failed: %i\n", dev_name(dev), err);
+ return err;
+ }
+ }
+
+ err = watch_otherend(xdev);
+ if (err) {
+ pr_warn("resume (watch_otherend) %s failed: %d.\n",
+ dev_name(dev), err);
+ return err;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(xenbus_dev_resume);
+
+int xenbus_dev_cancel(struct device *dev)
+{
+ /* Do nothing */
+ DPRINTK("cancel");
+ return 0;
+}
+EXPORT_SYMBOL_GPL(xenbus_dev_cancel);
+
+/* A flag to determine if xenstored is 'ready' (i.e. has started) */
+int xenstored_ready;
+
+
+int register_xenstore_notifier(struct notifier_block *nb)
+{
+ int ret = 0;
+
+ if (xenstored_ready > 0)
+ ret = nb->notifier_call(nb, 0, NULL);
+ else
+ blocking_notifier_chain_register(&xenstore_chain, nb);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(register_xenstore_notifier);
+
+void unregister_xenstore_notifier(struct notifier_block *nb)
+{
+ blocking_notifier_chain_unregister(&xenstore_chain, nb);
+}
+EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
+
+void xenbus_probe(struct work_struct *unused)
+{
+ xenstored_ready = 1;
+
+ /* Notify others that xenstore is up */
+ blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
+}
+EXPORT_SYMBOL_GPL(xenbus_probe);
+
+static int __init xenbus_probe_initcall(void)
+{
+ if (!xen_domain())
+ return -ENODEV;
+
+ if (xen_initial_domain() || xen_hvm_domain())
+ return 0;
+
+ xenbus_probe(NULL);
+ return 0;
+}
+
+device_initcall(xenbus_probe_initcall);
+
+/* Set up event channel for xenstored which is run as a local process
+ * (this is normally used only in dom0)
+ */
+static int __init xenstored_local_init(void)
+{
+ int err = -ENOMEM;
+ unsigned long page = 0;
+ struct evtchn_alloc_unbound alloc_unbound;
+
+ /* Allocate Xenstore page */
+ page = get_zeroed_page(GFP_KERNEL);
+ if (!page)
+ goto out_err;
+
+ xen_store_gfn = virt_to_gfn((void *)page);
+
+ /* Next allocate a local port which xenstored can bind to */
+ alloc_unbound.dom = DOMID_SELF;
+ alloc_unbound.remote_dom = DOMID_SELF;
+
+ err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
+ &alloc_unbound);
+ if (err == -ENOSYS)
+ goto out_err;
+
+ BUG_ON(err);
+ xen_store_evtchn = alloc_unbound.port;
+
+ return 0;
+
+ out_err:
+ if (page != 0)
+ free_page(page);
+ return err;
+}
+
+static int xenbus_resume_cb(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ int err = 0;
+
+ if (xen_hvm_domain()) {
+ uint64_t v = 0;
+
+ err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
+ if (!err && v)
+ xen_store_evtchn = v;
+ else
+ pr_warn("Cannot update xenstore event channel: %d\n",
+ err);
+ } else
+ xen_store_evtchn = xen_start_info->store_evtchn;
+
+ return err;
+}
+
+static struct notifier_block xenbus_resume_nb = {
+ .notifier_call = xenbus_resume_cb,
+};
+
+static int __init xenbus_init(void)
+{
+ int err = 0;
+ uint64_t v = 0;
+ xen_store_domain_type = XS_UNKNOWN;
+
+ if (!xen_domain())
+ return -ENODEV;
+
+ xenbus_ring_ops_init();
+
+ if (xen_pv_domain())
+ xen_store_domain_type = XS_PV;
+ if (xen_hvm_domain())
+ xen_store_domain_type = XS_HVM;
+ if (xen_hvm_domain() && xen_initial_domain())
+ xen_store_domain_type = XS_LOCAL;
+ if (xen_pv_domain() && !xen_start_info->store_evtchn)
+ xen_store_domain_type = XS_LOCAL;
+ if (xen_pv_domain() && xen_start_info->store_evtchn)
+ xenstored_ready = 1;
+
+ switch (xen_store_domain_type) {
+ case XS_LOCAL:
+ err = xenstored_local_init();
+ if (err)
+ goto out_error;
+ xen_store_interface = gfn_to_virt(xen_store_gfn);
+ break;
+ case XS_PV:
+ xen_store_evtchn = xen_start_info->store_evtchn;
+ xen_store_gfn = xen_start_info->store_mfn;
+ xen_store_interface = gfn_to_virt(xen_store_gfn);
+ break;
+ case XS_HVM:
+ err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
+ if (err)
+ goto out_error;
+ xen_store_evtchn = (int)v;
+ err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
+ if (err)
+ goto out_error;
+ xen_store_gfn = (unsigned long)v;
+ xen_store_interface =
+ xen_remap(xen_store_gfn << XEN_PAGE_SHIFT,
+ XEN_PAGE_SIZE);
+ break;
+ default:
+ pr_warn("Xenstore state unknown\n");
+ break;
+ }
+
+ /* Initialize the interface to xenstore. */
+ err = xs_init();
+ if (err) {
+ pr_warn("Error initializing xenstore comms: %i\n", err);
+ goto out_error;
+ }
+
+ if ((xen_store_domain_type != XS_LOCAL) &&
+ (xen_store_domain_type != XS_UNKNOWN))
+ xen_resume_notifier_register(&xenbus_resume_nb);
+
+#ifdef CONFIG_XEN_COMPAT_XENFS
+ /*
+ * Create xenfs mountpoint in /proc for compatibility with
+ * utilities that expect to find "xenbus" under "/proc/xen".
+ */
+ proc_create_mount_point("xen");
+#endif
+
+out_error:
+ return err;
+}
+
+postcore_initcall(xenbus_init);
+
+MODULE_LICENSE("GPL");
diff --git a/drivers/xen/xenbus/xenbus_probe_backend.c b/drivers/xen/xenbus/xenbus_probe_backend.c
new file mode 100644
index 0000000..b0bed4f
--- /dev/null
+++ b/drivers/xen/xenbus/xenbus_probe_backend.c
@@ -0,0 +1,269 @@
+/******************************************************************************
+ * Talks to Xen Store to figure out what devices we have (backend half).
+ *
+ * Copyright (C) 2005 Rusty Russell, IBM Corporation
+ * Copyright (C) 2005 Mike Wray, Hewlett-Packard
+ * Copyright (C) 2005, 2006 XenSource Ltd
+ * Copyright (C) 2007 Solarflare Communications, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#define DPRINTK(fmt, ...) \
+ pr_debug("(%s:%d) " fmt "\n", \
+ __func__, __LINE__, ##__VA_ARGS__)
+
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/notifier.h>
+#include <linux/export.h>
+
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/xen/hypervisor.h>
+#include <asm/hypervisor.h>
+#include <xen/xenbus.h>
+#include <xen/features.h>
+
+#include "xenbus.h"
+
+/* backend/<type>/<fe-uuid>/<id> => <type>-<fe-domid>-<id> */
+static int backend_bus_id(char bus_id[XEN_BUS_ID_SIZE], const char *nodename)
+{
+ int domid, err;
+ const char *devid, *type, *frontend;
+ unsigned int typelen;
+
+ type = strchr(nodename, '/');
+ if (!type)
+ return -EINVAL;
+ type++;
+ typelen = strcspn(type, "/");
+ if (!typelen || type[typelen] != '/')
+ return -EINVAL;
+
+ devid = strrchr(nodename, '/') + 1;
+
+ err = xenbus_gather(XBT_NIL, nodename, "frontend-id", "%i", &domid,
+ "frontend", NULL, &frontend,
+ NULL);
+ if (err)
+ return err;
+ if (strlen(frontend) == 0)
+ err = -ERANGE;
+ if (!err && !xenbus_exists(XBT_NIL, frontend, ""))
+ err = -ENOENT;
+ kfree(frontend);
+
+ if (err)
+ return err;
+
+ if (snprintf(bus_id, XEN_BUS_ID_SIZE, "%.*s-%i-%s",
+ typelen, type, domid, devid) >= XEN_BUS_ID_SIZE)
+ return -ENOSPC;
+ return 0;
+}
+
+static int xenbus_uevent_backend(struct device *dev,
+ struct kobj_uevent_env *env)
+{
+ struct xenbus_device *xdev;
+ struct xenbus_driver *drv;
+ struct xen_bus_type *bus;
+
+ DPRINTK("");
+
+ if (dev == NULL)
+ return -ENODEV;
+
+ xdev = to_xenbus_device(dev);
+ bus = container_of(xdev->dev.bus, struct xen_bus_type, bus);
+
+ if (add_uevent_var(env, "MODALIAS=xen-backend:%s", xdev->devicetype))
+ return -ENOMEM;
+
+ /* stuff we want to pass to /sbin/hotplug */
+ if (add_uevent_var(env, "XENBUS_TYPE=%s", xdev->devicetype))
+ return -ENOMEM;
+
+ if (add_uevent_var(env, "XENBUS_PATH=%s", xdev->nodename))
+ return -ENOMEM;
+
+ if (add_uevent_var(env, "XENBUS_BASE_PATH=%s", bus->root))
+ return -ENOMEM;
+
+ if (dev->driver) {
+ drv = to_xenbus_driver(dev->driver);
+ if (drv && drv->uevent)
+ return drv->uevent(xdev, env);
+ }
+
+ return 0;
+}
+
+/* backend/<typename>/<frontend-uuid>/<name> */
+static int xenbus_probe_backend_unit(struct xen_bus_type *bus,
+ const char *dir,
+ const char *type,
+ const char *name)
+{
+ char *nodename;
+ int err;
+
+ nodename = kasprintf(GFP_KERNEL, "%s/%s", dir, name);
+ if (!nodename)
+ return -ENOMEM;
+
+ DPRINTK("%s\n", nodename);
+
+ err = xenbus_probe_node(bus, type, nodename);
+ kfree(nodename);
+ return err;
+}
+
+/* backend/<typename>/<frontend-domid> */
+static int xenbus_probe_backend(struct xen_bus_type *bus, const char *type,
+ const char *domid)
+{
+ char *nodename;
+ int err = 0;
+ char **dir;
+ unsigned int i, dir_n = 0;
+
+ DPRINTK("");
+
+ nodename = kasprintf(GFP_KERNEL, "%s/%s/%s", bus->root, type, domid);
+ if (!nodename)
+ return -ENOMEM;
+
+ dir = xenbus_directory(XBT_NIL, nodename, "", &dir_n);
+ if (IS_ERR(dir)) {
+ kfree(nodename);
+ return PTR_ERR(dir);
+ }
+
+ for (i = 0; i < dir_n; i++) {
+ err = xenbus_probe_backend_unit(bus, nodename, type, dir[i]);
+ if (err)
+ break;
+ }
+ kfree(dir);
+ kfree(nodename);
+ return err;
+}
+
+static void frontend_changed(struct xenbus_watch *watch,
+ const char *path, const char *token)
+{
+ xenbus_otherend_changed(watch, path, token, 0);
+}
+
+static struct xen_bus_type xenbus_backend = {
+ .root = "backend",
+ .levels = 3, /* backend/type/<frontend>/<id> */
+ .get_bus_id = backend_bus_id,
+ .probe = xenbus_probe_backend,
+ .otherend_changed = frontend_changed,
+ .bus = {
+ .name = "xen-backend",
+ .match = xenbus_match,
+ .uevent = xenbus_uevent_backend,
+ .probe = xenbus_dev_probe,
+ .remove = xenbus_dev_remove,
+ .shutdown = xenbus_dev_shutdown,
+ .dev_groups = xenbus_dev_groups,
+ },
+};
+
+static void backend_changed(struct xenbus_watch *watch,
+ const char *path, const char *token)
+{
+ DPRINTK("");
+
+ xenbus_dev_changed(path, &xenbus_backend);
+}
+
+static struct xenbus_watch be_watch = {
+ .node = "backend",
+ .callback = backend_changed,
+};
+
+static int read_frontend_details(struct xenbus_device *xendev)
+{
+ return xenbus_read_otherend_details(xendev, "frontend-id", "frontend");
+}
+
+int xenbus_dev_is_online(struct xenbus_device *dev)
+{
+ return !!xenbus_read_unsigned(dev->nodename, "online", 0);
+}
+EXPORT_SYMBOL_GPL(xenbus_dev_is_online);
+
+int __xenbus_register_backend(struct xenbus_driver *drv, struct module *owner,
+ const char *mod_name)
+{
+ drv->read_otherend_details = read_frontend_details;
+
+ return xenbus_register_driver_common(drv, &xenbus_backend,
+ owner, mod_name);
+}
+EXPORT_SYMBOL_GPL(__xenbus_register_backend);
+
+static int backend_probe_and_watch(struct notifier_block *notifier,
+ unsigned long event,
+ void *data)
+{
+ /* Enumerate devices in xenstore and watch for changes. */
+ xenbus_probe_devices(&xenbus_backend);
+ register_xenbus_watch(&be_watch);
+
+ return NOTIFY_DONE;
+}
+
+static int __init xenbus_probe_backend_init(void)
+{
+ static struct notifier_block xenstore_notifier = {
+ .notifier_call = backend_probe_and_watch
+ };
+ int err;
+
+ DPRINTK("");
+
+ /* Register ourselves with the kernel bus subsystem */
+ err = bus_register(&xenbus_backend.bus);
+ if (err)
+ return err;
+
+ register_xenstore_notifier(&xenstore_notifier);
+
+ return 0;
+}
+subsys_initcall(xenbus_probe_backend_init);
diff --git a/drivers/xen/xenbus/xenbus_probe_frontend.c b/drivers/xen/xenbus/xenbus_probe_frontend.c
new file mode 100644
index 0000000..07896f4
--- /dev/null
+++ b/drivers/xen/xenbus/xenbus_probe_frontend.c
@@ -0,0 +1,502 @@
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#define DPRINTK(fmt, ...) \
+ pr_debug("(%s:%d) " fmt "\n", \
+ __func__, __LINE__, ##__VA_ARGS__)
+
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/proc_fs.h>
+#include <linux/notifier.h>
+#include <linux/kthread.h>
+#include <linux/mutex.h>
+#include <linux/io.h>
+#include <linux/module.h>
+
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/xen/hypervisor.h>
+#include <xen/xenbus.h>
+#include <xen/events.h>
+#include <xen/page.h>
+#include <xen/xen.h>
+
+#include <xen/platform_pci.h>
+
+#include "xenbus.h"
+
+
+
+/* device/<type>/<id> => <type>-<id> */
+static int frontend_bus_id(char bus_id[XEN_BUS_ID_SIZE], const char *nodename)
+{
+ nodename = strchr(nodename, '/');
+ if (!nodename || strlen(nodename + 1) >= XEN_BUS_ID_SIZE) {
+ pr_warn("bad frontend %s\n", nodename);
+ return -EINVAL;
+ }
+
+ strlcpy(bus_id, nodename + 1, XEN_BUS_ID_SIZE);
+ if (!strchr(bus_id, '/')) {
+ pr_warn("bus_id %s no slash\n", bus_id);
+ return -EINVAL;
+ }
+ *strchr(bus_id, '/') = '-';
+ return 0;
+}
+
+/* device/<typename>/<name> */
+static int xenbus_probe_frontend(struct xen_bus_type *bus, const char *type,
+ const char *name)
+{
+ char *nodename;
+ int err;
+
+ /* ignore console/0 */
+ if (!strncmp(type, "console", 7) && !strncmp(name, "0", 1)) {
+ DPRINTK("Ignoring buggy device entry console/0");
+ return 0;
+ }
+
+ nodename = kasprintf(GFP_KERNEL, "%s/%s/%s", bus->root, type, name);
+ if (!nodename)
+ return -ENOMEM;
+
+ DPRINTK("%s", nodename);
+
+ err = xenbus_probe_node(bus, type, nodename);
+ kfree(nodename);
+ return err;
+}
+
+static int xenbus_uevent_frontend(struct device *_dev,
+ struct kobj_uevent_env *env)
+{
+ struct xenbus_device *dev = to_xenbus_device(_dev);
+
+ if (add_uevent_var(env, "MODALIAS=xen:%s", dev->devicetype))
+ return -ENOMEM;
+
+ return 0;
+}
+
+
+static void backend_changed(struct xenbus_watch *watch,
+ const char *path, const char *token)
+{
+ xenbus_otherend_changed(watch, path, token, 1);
+}
+
+static void xenbus_frontend_delayed_resume(struct work_struct *w)
+{
+ struct xenbus_device *xdev = container_of(w, struct xenbus_device, work);
+
+ xenbus_dev_resume(&xdev->dev);
+}
+
+static int xenbus_frontend_dev_resume(struct device *dev)
+{
+ /*
+ * If xenstored is running in this domain, we cannot access the backend
+ * state at the moment, so we need to defer xenbus_dev_resume
+ */
+ if (xen_store_domain_type == XS_LOCAL) {
+ struct xenbus_device *xdev = to_xenbus_device(dev);
+
+ schedule_work(&xdev->work);
+
+ return 0;
+ }
+
+ return xenbus_dev_resume(dev);
+}
+
+static int xenbus_frontend_dev_probe(struct device *dev)
+{
+ if (xen_store_domain_type == XS_LOCAL) {
+ struct xenbus_device *xdev = to_xenbus_device(dev);
+ INIT_WORK(&xdev->work, xenbus_frontend_delayed_resume);
+ }
+
+ return xenbus_dev_probe(dev);
+}
+
+static const struct dev_pm_ops xenbus_pm_ops = {
+ .suspend = xenbus_dev_suspend,
+ .resume = xenbus_frontend_dev_resume,
+ .freeze = xenbus_dev_suspend,
+ .thaw = xenbus_dev_cancel,
+ .restore = xenbus_dev_resume,
+};
+
+static struct xen_bus_type xenbus_frontend = {
+ .root = "device",
+ .levels = 2, /* device/type/<id> */
+ .get_bus_id = frontend_bus_id,
+ .probe = xenbus_probe_frontend,
+ .otherend_changed = backend_changed,
+ .bus = {
+ .name = "xen",
+ .match = xenbus_match,
+ .uevent = xenbus_uevent_frontend,
+ .probe = xenbus_frontend_dev_probe,
+ .remove = xenbus_dev_remove,
+ .shutdown = xenbus_dev_shutdown,
+ .dev_groups = xenbus_dev_groups,
+
+ .pm = &xenbus_pm_ops,
+ },
+};
+
+static void frontend_changed(struct xenbus_watch *watch,
+ const char *path, const char *token)
+{
+ DPRINTK("");
+
+ xenbus_dev_changed(path, &xenbus_frontend);
+}
+
+
+/* We watch for devices appearing and vanishing. */
+static struct xenbus_watch fe_watch = {
+ .node = "device",
+ .callback = frontend_changed,
+};
+
+static int read_backend_details(struct xenbus_device *xendev)
+{
+ return xenbus_read_otherend_details(xendev, "backend-id", "backend");
+}
+
+static int is_device_connecting(struct device *dev, void *data, bool ignore_nonessential)
+{
+ struct xenbus_device *xendev = to_xenbus_device(dev);
+ struct device_driver *drv = data;
+ struct xenbus_driver *xendrv;
+
+ /*
+ * A device with no driver will never connect. We care only about
+ * devices which should currently be in the process of connecting.
+ */
+ if (!dev->driver)
+ return 0;
+
+ /* Is this search limited to a particular driver? */
+ if (drv && (dev->driver != drv))
+ return 0;
+
+ if (ignore_nonessential) {
+ /* With older QEMU, for PVonHVM guests the guest config files
+ * could contain: vfb = [ 'vnc=1, vnclisten=0.0.0.0']
+ * which is nonsensical as there is no PV FB (there can be
+ * a PVKB) running as HVM guest. */
+
+ if ((strncmp(xendev->nodename, "device/vkbd", 11) == 0))
+ return 0;
+
+ if ((strncmp(xendev->nodename, "device/vfb", 10) == 0))
+ return 0;
+ }
+ xendrv = to_xenbus_driver(dev->driver);
+ return (xendev->state < XenbusStateConnected ||
+ (xendev->state == XenbusStateConnected &&
+ xendrv->is_ready && !xendrv->is_ready(xendev)));
+}
+static int essential_device_connecting(struct device *dev, void *data)
+{
+ return is_device_connecting(dev, data, true /* ignore PV[KBB+FB] */);
+}
+static int non_essential_device_connecting(struct device *dev, void *data)
+{
+ return is_device_connecting(dev, data, false);
+}
+
+static int exists_essential_connecting_device(struct device_driver *drv)
+{
+ return bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
+ essential_device_connecting);
+}
+static int exists_non_essential_connecting_device(struct device_driver *drv)
+{
+ return bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
+ non_essential_device_connecting);
+}
+
+static int print_device_status(struct device *dev, void *data)
+{
+ struct xenbus_device *xendev = to_xenbus_device(dev);
+ struct device_driver *drv = data;
+
+ /* Is this operation limited to a particular driver? */
+ if (drv && (dev->driver != drv))
+ return 0;
+
+ if (!dev->driver) {
+ /* Information only: is this too noisy? */
+ pr_info("Device with no driver: %s\n", xendev->nodename);
+ } else if (xendev->state < XenbusStateConnected) {
+ enum xenbus_state rstate = XenbusStateUnknown;
+ if (xendev->otherend)
+ rstate = xenbus_read_driver_state(xendev->otherend);
+ pr_warn("Timeout connecting to device: %s (local state %d, remote state %d)\n",
+ xendev->nodename, xendev->state, rstate);
+ }
+
+ return 0;
+}
+
+/* We only wait for device setup after most initcalls have run. */
+static int ready_to_wait_for_devices;
+
+static bool wait_loop(unsigned long start, unsigned int max_delay,
+ unsigned int *seconds_waited)
+{
+ if (time_after(jiffies, start + (*seconds_waited+5)*HZ)) {
+ if (!*seconds_waited)
+ pr_warn("Waiting for devices to initialise: ");
+ *seconds_waited += 5;
+ pr_cont("%us...", max_delay - *seconds_waited);
+ if (*seconds_waited == max_delay) {
+ pr_cont("\n");
+ return true;
+ }
+ }
+
+ schedule_timeout_interruptible(HZ/10);
+
+ return false;
+}
+/*
+ * On a 5-minute timeout, wait for all devices currently configured. We need
+ * to do this to guarantee that the filesystems and / or network devices
+ * needed for boot are available, before we can allow the boot to proceed.
+ *
+ * This needs to be on a late_initcall, to happen after the frontend device
+ * drivers have been initialised, but before the root fs is mounted.
+ *
+ * A possible improvement here would be to have the tools add a per-device
+ * flag to the store entry, indicating whether it is needed at boot time.
+ * This would allow people who knew what they were doing to accelerate their
+ * boot slightly, but of course needs tools or manual intervention to set up
+ * those flags correctly.
+ */
+static void wait_for_devices(struct xenbus_driver *xendrv)
+{
+ unsigned long start = jiffies;
+ struct device_driver *drv = xendrv ? &xendrv->driver : NULL;
+ unsigned int seconds_waited = 0;
+
+ if (!ready_to_wait_for_devices || !xen_domain())
+ return;
+
+ while (exists_non_essential_connecting_device(drv))
+ if (wait_loop(start, 30, &seconds_waited))
+ break;
+
+ /* Skips PVKB and PVFB check.*/
+ while (exists_essential_connecting_device(drv))
+ if (wait_loop(start, 270, &seconds_waited))
+ break;
+
+ if (seconds_waited)
+ printk("\n");
+
+ bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
+ print_device_status);
+}
+
+int __xenbus_register_frontend(struct xenbus_driver *drv, struct module *owner,
+ const char *mod_name)
+{
+ int ret;
+
+ drv->read_otherend_details = read_backend_details;
+
+ ret = xenbus_register_driver_common(drv, &xenbus_frontend,
+ owner, mod_name);
+ if (ret)
+ return ret;
+
+ /* If this driver is loaded as a module wait for devices to attach. */
+ wait_for_devices(drv);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(__xenbus_register_frontend);
+
+static DECLARE_WAIT_QUEUE_HEAD(backend_state_wq);
+static int backend_state;
+
+static void xenbus_reset_backend_state_changed(struct xenbus_watch *w,
+ const char *path, const char *token)
+{
+ if (xenbus_scanf(XBT_NIL, path, "", "%i",
+ &backend_state) != 1)
+ backend_state = XenbusStateUnknown;
+ printk(KERN_DEBUG "XENBUS: backend %s %s\n",
+ path, xenbus_strstate(backend_state));
+ wake_up(&backend_state_wq);
+}
+
+static void xenbus_reset_wait_for_backend(char *be, int expected)
+{
+ long timeout;
+ timeout = wait_event_interruptible_timeout(backend_state_wq,
+ backend_state == expected, 5 * HZ);
+ if (timeout <= 0)
+ pr_info("backend %s timed out\n", be);
+}
+
+/*
+ * Reset frontend if it is in Connected or Closed state.
+ * Wait for backend to catch up.
+ * State Connected happens during kdump, Closed after kexec.
+ */
+static void xenbus_reset_frontend(char *fe, char *be, int be_state)
+{
+ struct xenbus_watch be_watch;
+
+ printk(KERN_DEBUG "XENBUS: backend %s %s\n",
+ be, xenbus_strstate(be_state));
+
+ memset(&be_watch, 0, sizeof(be_watch));
+ be_watch.node = kasprintf(GFP_NOIO | __GFP_HIGH, "%s/state", be);
+ if (!be_watch.node)
+ return;
+
+ be_watch.callback = xenbus_reset_backend_state_changed;
+ backend_state = XenbusStateUnknown;
+
+ pr_info("triggering reconnect on %s\n", be);
+ register_xenbus_watch(&be_watch);
+
+ /* fall through to forward backend to state XenbusStateInitialising */
+ switch (be_state) {
+ case XenbusStateConnected:
+ xenbus_printf(XBT_NIL, fe, "state", "%d", XenbusStateClosing);
+ xenbus_reset_wait_for_backend(be, XenbusStateClosing);
+ /* fall through */
+
+ case XenbusStateClosing:
+ xenbus_printf(XBT_NIL, fe, "state", "%d", XenbusStateClosed);
+ xenbus_reset_wait_for_backend(be, XenbusStateClosed);
+ /* fall through */
+
+ case XenbusStateClosed:
+ xenbus_printf(XBT_NIL, fe, "state", "%d", XenbusStateInitialising);
+ xenbus_reset_wait_for_backend(be, XenbusStateInitWait);
+ }
+
+ unregister_xenbus_watch(&be_watch);
+ pr_info("reconnect done on %s\n", be);
+ kfree(be_watch.node);
+}
+
+static void xenbus_check_frontend(char *class, char *dev)
+{
+ int be_state, fe_state, err;
+ char *backend, *frontend;
+
+ frontend = kasprintf(GFP_NOIO | __GFP_HIGH, "device/%s/%s", class, dev);
+ if (!frontend)
+ return;
+
+ err = xenbus_scanf(XBT_NIL, frontend, "state", "%i", &fe_state);
+ if (err != 1)
+ goto out;
+
+ switch (fe_state) {
+ case XenbusStateConnected:
+ case XenbusStateClosed:
+ printk(KERN_DEBUG "XENBUS: frontend %s %s\n",
+ frontend, xenbus_strstate(fe_state));
+ backend = xenbus_read(XBT_NIL, frontend, "backend", NULL);
+ if (!backend || IS_ERR(backend))
+ goto out;
+ err = xenbus_scanf(XBT_NIL, backend, "state", "%i", &be_state);
+ if (err == 1)
+ xenbus_reset_frontend(frontend, backend, be_state);
+ kfree(backend);
+ break;
+ default:
+ break;
+ }
+out:
+ kfree(frontend);
+}
+
+static void xenbus_reset_state(void)
+{
+ char **devclass, **dev;
+ int devclass_n, dev_n;
+ int i, j;
+
+ devclass = xenbus_directory(XBT_NIL, "device", "", &devclass_n);
+ if (IS_ERR(devclass))
+ return;
+
+ for (i = 0; i < devclass_n; i++) {
+ dev = xenbus_directory(XBT_NIL, "device", devclass[i], &dev_n);
+ if (IS_ERR(dev))
+ continue;
+ for (j = 0; j < dev_n; j++)
+ xenbus_check_frontend(devclass[i], dev[j]);
+ kfree(dev);
+ }
+ kfree(devclass);
+}
+
+static int frontend_probe_and_watch(struct notifier_block *notifier,
+ unsigned long event,
+ void *data)
+{
+ /* reset devices in Connected or Closed state */
+ if (xen_hvm_domain())
+ xenbus_reset_state();
+ /* Enumerate devices in xenstore and watch for changes. */
+ xenbus_probe_devices(&xenbus_frontend);
+ register_xenbus_watch(&fe_watch);
+
+ return NOTIFY_DONE;
+}
+
+
+static int __init xenbus_probe_frontend_init(void)
+{
+ static struct notifier_block xenstore_notifier = {
+ .notifier_call = frontend_probe_and_watch
+ };
+ int err;
+
+ DPRINTK("");
+
+ /* Register ourselves with the kernel bus subsystem */
+ err = bus_register(&xenbus_frontend.bus);
+ if (err)
+ return err;
+
+ register_xenstore_notifier(&xenstore_notifier);
+
+ return 0;
+}
+subsys_initcall(xenbus_probe_frontend_init);
+
+#ifndef MODULE
+static int __init boot_wait_for_devices(void)
+{
+ if (!xen_has_pv_devices())
+ return -ENODEV;
+
+ ready_to_wait_for_devices = 1;
+ wait_for_devices(NULL);
+ return 0;
+}
+
+late_initcall(boot_wait_for_devices);
+#endif
+
+MODULE_LICENSE("GPL");
diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
new file mode 100644
index 0000000..49a3874
--- /dev/null
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -0,0 +1,940 @@
+/******************************************************************************
+ * xenbus_xs.c
+ *
+ * This is the kernel equivalent of the "xs" library. We don't need everything
+ * and we use xenbus_comms for communication.
+ *
+ * Copyright (C) 2005 Rusty Russell, IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/unistd.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/uio.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/fcntl.h>
+#include <linux/kthread.h>
+#include <linux/reboot.h>
+#include <linux/rwsem.h>
+#include <linux/mutex.h>
+#include <asm/xen/hypervisor.h>
+#include <xen/xenbus.h>
+#include <xen/xen.h>
+#include "xenbus.h"
+
+/*
+ * Framework to protect suspend/resume handling against normal Xenstore
+ * message handling:
+ * During suspend/resume there must be no open transaction and no pending
+ * Xenstore request.
+ * New watch events happening in this time can be ignored by firing all watches
+ * after resume.
+ */
+
+/* Lock protecting enter/exit critical region. */
+static DEFINE_SPINLOCK(xs_state_lock);
+/* Number of users in critical region (protected by xs_state_lock). */
+static unsigned int xs_state_users;
+/* Suspend handler waiting or already active (protected by xs_state_lock)? */
+static int xs_suspend_active;
+/* Unique Xenstore request id (protected by xs_state_lock). */
+static uint32_t xs_request_id;
+
+/* Wait queue for all callers waiting for critical region to become usable. */
+static DECLARE_WAIT_QUEUE_HEAD(xs_state_enter_wq);
+/* Wait queue for suspend handling waiting for critical region being empty. */
+static DECLARE_WAIT_QUEUE_HEAD(xs_state_exit_wq);
+
+/* List of registered watches, and a lock to protect it. */
+static LIST_HEAD(watches);
+static DEFINE_SPINLOCK(watches_lock);
+
+/* List of pending watch callback events, and a lock to protect it. */
+static LIST_HEAD(watch_events);
+static DEFINE_SPINLOCK(watch_events_lock);
+
+/* Protect watch (de)register against save/restore. */
+static DECLARE_RWSEM(xs_watch_rwsem);
+
+/*
+ * Details of the xenwatch callback kernel thread. The thread waits on the
+ * watch_events_waitq for work to do (queued on watch_events list). When it
+ * wakes up it acquires the xenwatch_mutex before reading the list and
+ * carrying out work.
+ */
+static pid_t xenwatch_pid;
+static DEFINE_MUTEX(xenwatch_mutex);
+static DECLARE_WAIT_QUEUE_HEAD(watch_events_waitq);
+
+static void xs_suspend_enter(void)
+{
+ spin_lock(&xs_state_lock);
+ xs_suspend_active++;
+ spin_unlock(&xs_state_lock);
+ wait_event(xs_state_exit_wq, xs_state_users == 0);
+}
+
+static void xs_suspend_exit(void)
+{
+ spin_lock(&xs_state_lock);
+ xs_suspend_active--;
+ spin_unlock(&xs_state_lock);
+ wake_up_all(&xs_state_enter_wq);
+}
+
+static uint32_t xs_request_enter(struct xb_req_data *req)
+{
+ uint32_t rq_id;
+
+ req->type = req->msg.type;
+
+ spin_lock(&xs_state_lock);
+
+ while (!xs_state_users && xs_suspend_active) {
+ spin_unlock(&xs_state_lock);
+ wait_event(xs_state_enter_wq, xs_suspend_active == 0);
+ spin_lock(&xs_state_lock);
+ }
+
+ if (req->type == XS_TRANSACTION_START)
+ xs_state_users++;
+ xs_state_users++;
+ rq_id = xs_request_id++;
+
+ spin_unlock(&xs_state_lock);
+
+ return rq_id;
+}
+
+void xs_request_exit(struct xb_req_data *req)
+{
+ spin_lock(&xs_state_lock);
+ xs_state_users--;
+ if ((req->type == XS_TRANSACTION_START && req->msg.type == XS_ERROR) ||
+ (req->type == XS_TRANSACTION_END &&
+ !WARN_ON_ONCE(req->msg.type == XS_ERROR &&
+ !strcmp(req->body, "ENOENT"))))
+ xs_state_users--;
+ spin_unlock(&xs_state_lock);
+
+ if (xs_suspend_active && !xs_state_users)
+ wake_up(&xs_state_exit_wq);
+}
+
+static int get_error(const char *errorstring)
+{
+ unsigned int i;
+
+ for (i = 0; strcmp(errorstring, xsd_errors[i].errstring) != 0; i++) {
+ if (i == ARRAY_SIZE(xsd_errors) - 1) {
+ pr_warn("xen store gave: unknown error %s\n",
+ errorstring);
+ return EINVAL;
+ }
+ }
+ return xsd_errors[i].errnum;
+}
+
+static bool xenbus_ok(void)
+{
+ switch (xen_store_domain_type) {
+ case XS_LOCAL:
+ switch (system_state) {
+ case SYSTEM_POWER_OFF:
+ case SYSTEM_RESTART:
+ case SYSTEM_HALT:
+ return false;
+ default:
+ break;
+ }
+ return true;
+ case XS_PV:
+ case XS_HVM:
+ /* FIXME: Could check that the remote domain is alive,
+ * but it is normally initial domain. */
+ return true;
+ default:
+ break;
+ }
+ return false;
+}
+
+static bool test_reply(struct xb_req_data *req)
+{
+ if (req->state == xb_req_state_got_reply || !xenbus_ok())
+ return true;
+
+ /* Make sure to reread req->state each time. */
+ barrier();
+
+ return false;
+}
+
+static void *read_reply(struct xb_req_data *req)
+{
+ while (req->state != xb_req_state_got_reply) {
+ wait_event(req->wq, test_reply(req));
+
+ if (!xenbus_ok())
+ /*
+ * If we are in the process of being shut-down there is
+ * no point of trying to contact XenBus - it is either
+ * killed (xenstored application) or the other domain
+ * has been killed or is unreachable.
+ */
+ return ERR_PTR(-EIO);
+ if (req->err)
+ return ERR_PTR(req->err);
+
+ }
+
+ return req->body;
+}
+
+static void xs_send(struct xb_req_data *req, struct xsd_sockmsg *msg)
+{
+ bool notify;
+
+ req->msg = *msg;
+ req->err = 0;
+ req->state = xb_req_state_queued;
+ init_waitqueue_head(&req->wq);
+
+ /* Save the caller req_id and restore it later in the reply */
+ req->caller_req_id = req->msg.req_id;
+ req->msg.req_id = xs_request_enter(req);
+
+ mutex_lock(&xb_write_mutex);
+ list_add_tail(&req->list, &xb_write_list);
+ notify = list_is_singular(&xb_write_list);
+ mutex_unlock(&xb_write_mutex);
+
+ if (notify)
+ wake_up(&xb_waitq);
+}
+
+static void *xs_wait_for_reply(struct xb_req_data *req, struct xsd_sockmsg *msg)
+{
+ void *ret;
+
+ ret = read_reply(req);
+
+ xs_request_exit(req);
+
+ msg->type = req->msg.type;
+ msg->len = req->msg.len;
+
+ mutex_lock(&xb_write_mutex);
+ if (req->state == xb_req_state_queued ||
+ req->state == xb_req_state_wait_reply)
+ req->state = xb_req_state_aborted;
+ else
+ kfree(req);
+ mutex_unlock(&xb_write_mutex);
+
+ return ret;
+}
+
+static void xs_wake_up(struct xb_req_data *req)
+{
+ wake_up(&req->wq);
+}
+
+int xenbus_dev_request_and_reply(struct xsd_sockmsg *msg, void *par)
+{
+ struct xb_req_data *req;
+ struct kvec *vec;
+
+ req = kmalloc(sizeof(*req) + sizeof(*vec), GFP_KERNEL);
+ if (!req)
+ return -ENOMEM;
+
+ vec = (struct kvec *)(req + 1);
+ vec->iov_len = msg->len;
+ vec->iov_base = msg + 1;
+
+ req->vec = vec;
+ req->num_vecs = 1;
+ req->cb = xenbus_dev_queue_reply;
+ req->par = par;
+
+ xs_send(req, msg);
+
+ return 0;
+}
+EXPORT_SYMBOL(xenbus_dev_request_and_reply);
+
+/* Send message to xs, get kmalloc'ed reply. ERR_PTR() on error. */
+static void *xs_talkv(struct xenbus_transaction t,
+ enum xsd_sockmsg_type type,
+ const struct kvec *iovec,
+ unsigned int num_vecs,
+ unsigned int *len)
+{
+ struct xb_req_data *req;
+ struct xsd_sockmsg msg;
+ void *ret = NULL;
+ unsigned int i;
+ int err;
+
+ req = kmalloc(sizeof(*req), GFP_NOIO | __GFP_HIGH);
+ if (!req)
+ return ERR_PTR(-ENOMEM);
+
+ req->vec = iovec;
+ req->num_vecs = num_vecs;
+ req->cb = xs_wake_up;
+
+ msg.req_id = 0;
+ msg.tx_id = t.id;
+ msg.type = type;
+ msg.len = 0;
+ for (i = 0; i < num_vecs; i++)
+ msg.len += iovec[i].iov_len;
+
+ xs_send(req, &msg);
+
+ ret = xs_wait_for_reply(req, &msg);
+ if (len)
+ *len = msg.len;
+
+ if (IS_ERR(ret))
+ return ret;
+
+ if (msg.type == XS_ERROR) {
+ err = get_error(ret);
+ kfree(ret);
+ return ERR_PTR(-err);
+ }
+
+ if (msg.type != type) {
+ pr_warn_ratelimited("unexpected type [%d], expected [%d]\n",
+ msg.type, type);
+ kfree(ret);
+ return ERR_PTR(-EINVAL);
+ }
+ return ret;
+}
+
+/* Simplified version of xs_talkv: single message. */
+static void *xs_single(struct xenbus_transaction t,
+ enum xsd_sockmsg_type type,
+ const char *string,
+ unsigned int *len)
+{
+ struct kvec iovec;
+
+ iovec.iov_base = (void *)string;
+ iovec.iov_len = strlen(string) + 1;
+ return xs_talkv(t, type, &iovec, 1, len);
+}
+
+/* Many commands only need an ack, don't care what it says. */
+static int xs_error(char *reply)
+{
+ if (IS_ERR(reply))
+ return PTR_ERR(reply);
+ kfree(reply);
+ return 0;
+}
+
+static unsigned int count_strings(const char *strings, unsigned int len)
+{
+ unsigned int num;
+ const char *p;
+
+ for (p = strings, num = 0; p < strings + len; p += strlen(p) + 1)
+ num++;
+
+ return num;
+}
+
+/* Return the path to dir with /name appended. Buffer must be kfree()'ed. */
+static char *join(const char *dir, const char *name)
+{
+ char *buffer;
+
+ if (strlen(name) == 0)
+ buffer = kasprintf(GFP_NOIO | __GFP_HIGH, "%s", dir);
+ else
+ buffer = kasprintf(GFP_NOIO | __GFP_HIGH, "%s/%s", dir, name);
+ return (!buffer) ? ERR_PTR(-ENOMEM) : buffer;
+}
+
+static char **split(char *strings, unsigned int len, unsigned int *num)
+{
+ char *p, **ret;
+
+ /* Count the strings. */
+ *num = count_strings(strings, len);
+
+ /* Transfer to one big alloc for easy freeing. */
+ ret = kmalloc(*num * sizeof(char *) + len, GFP_NOIO | __GFP_HIGH);
+ if (!ret) {
+ kfree(strings);
+ return ERR_PTR(-ENOMEM);
+ }
+ memcpy(&ret[*num], strings, len);
+ kfree(strings);
+
+ strings = (char *)&ret[*num];
+ for (p = strings, *num = 0; p < strings + len; p += strlen(p) + 1)
+ ret[(*num)++] = p;
+
+ return ret;
+}
+
+char **xenbus_directory(struct xenbus_transaction t,
+ const char *dir, const char *node, unsigned int *num)
+{
+ char *strings, *path;
+ unsigned int len;
+
+ path = join(dir, node);
+ if (IS_ERR(path))
+ return (char **)path;
+
+ strings = xs_single(t, XS_DIRECTORY, path, &len);
+ kfree(path);
+ if (IS_ERR(strings))
+ return (char **)strings;
+
+ return split(strings, len, num);
+}
+EXPORT_SYMBOL_GPL(xenbus_directory);
+
+/* Check if a path exists. Return 1 if it does. */
+int xenbus_exists(struct xenbus_transaction t,
+ const char *dir, const char *node)
+{
+ char **d;
+ int dir_n;
+
+ d = xenbus_directory(t, dir, node, &dir_n);
+ if (IS_ERR(d))
+ return 0;
+ kfree(d);
+ return 1;
+}
+EXPORT_SYMBOL_GPL(xenbus_exists);
+
+/* Get the value of a single file.
+ * Returns a kmalloced value: call free() on it after use.
+ * len indicates length in bytes.
+ */
+void *xenbus_read(struct xenbus_transaction t,
+ const char *dir, const char *node, unsigned int *len)
+{
+ char *path;
+ void *ret;
+
+ path = join(dir, node);
+ if (IS_ERR(path))
+ return (void *)path;
+
+ ret = xs_single(t, XS_READ, path, len);
+ kfree(path);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(xenbus_read);
+
+/* Write the value of a single file.
+ * Returns -err on failure.
+ */
+int xenbus_write(struct xenbus_transaction t,
+ const char *dir, const char *node, const char *string)
+{
+ const char *path;
+ struct kvec iovec[2];
+ int ret;
+
+ path = join(dir, node);
+ if (IS_ERR(path))
+ return PTR_ERR(path);
+
+ iovec[0].iov_base = (void *)path;
+ iovec[0].iov_len = strlen(path) + 1;
+ iovec[1].iov_base = (void *)string;
+ iovec[1].iov_len = strlen(string);
+
+ ret = xs_error(xs_talkv(t, XS_WRITE, iovec, ARRAY_SIZE(iovec), NULL));
+ kfree(path);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(xenbus_write);
+
+/* Create a new directory. */
+int xenbus_mkdir(struct xenbus_transaction t,
+ const char *dir, const char *node)
+{
+ char *path;
+ int ret;
+
+ path = join(dir, node);
+ if (IS_ERR(path))
+ return PTR_ERR(path);
+
+ ret = xs_error(xs_single(t, XS_MKDIR, path, NULL));
+ kfree(path);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(xenbus_mkdir);
+
+/* Destroy a file or directory (directories must be empty). */
+int xenbus_rm(struct xenbus_transaction t, const char *dir, const char *node)
+{
+ char *path;
+ int ret;
+
+ path = join(dir, node);
+ if (IS_ERR(path))
+ return PTR_ERR(path);
+
+ ret = xs_error(xs_single(t, XS_RM, path, NULL));
+ kfree(path);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(xenbus_rm);
+
+/* Start a transaction: changes by others will not be seen during this
+ * transaction, and changes will not be visible to others until end.
+ */
+int xenbus_transaction_start(struct xenbus_transaction *t)
+{
+ char *id_str;
+
+ id_str = xs_single(XBT_NIL, XS_TRANSACTION_START, "", NULL);
+ if (IS_ERR(id_str))
+ return PTR_ERR(id_str);
+
+ t->id = simple_strtoul(id_str, NULL, 0);
+ kfree(id_str);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(xenbus_transaction_start);
+
+/* End a transaction.
+ * If abandon is true, transaction is discarded instead of committed.
+ */
+int xenbus_transaction_end(struct xenbus_transaction t, int abort)
+{
+ char abortstr[2];
+
+ if (abort)
+ strcpy(abortstr, "F");
+ else
+ strcpy(abortstr, "T");
+
+ return xs_error(xs_single(t, XS_TRANSACTION_END, abortstr, NULL));
+}
+EXPORT_SYMBOL_GPL(xenbus_transaction_end);
+
+/* Single read and scanf: returns -errno or num scanned. */
+int xenbus_scanf(struct xenbus_transaction t,
+ const char *dir, const char *node, const char *fmt, ...)
+{
+ va_list ap;
+ int ret;
+ char *val;
+
+ val = xenbus_read(t, dir, node, NULL);
+ if (IS_ERR(val))
+ return PTR_ERR(val);
+
+ va_start(ap, fmt);
+ ret = vsscanf(val, fmt, ap);
+ va_end(ap);
+ kfree(val);
+ /* Distinctive errno. */
+ if (ret == 0)
+ return -ERANGE;
+ return ret;
+}
+EXPORT_SYMBOL_GPL(xenbus_scanf);
+
+/* Read an (optional) unsigned value. */
+unsigned int xenbus_read_unsigned(const char *dir, const char *node,
+ unsigned int default_val)
+{
+ unsigned int val;
+ int ret;
+
+ ret = xenbus_scanf(XBT_NIL, dir, node, "%u", &val);
+ if (ret <= 0)
+ val = default_val;
+
+ return val;
+}
+EXPORT_SYMBOL_GPL(xenbus_read_unsigned);
+
+/* Single printf and write: returns -errno or 0. */
+int xenbus_printf(struct xenbus_transaction t,
+ const char *dir, const char *node, const char *fmt, ...)
+{
+ va_list ap;
+ int ret;
+ char *buf;
+
+ va_start(ap, fmt);
+ buf = kvasprintf(GFP_NOIO | __GFP_HIGH, fmt, ap);
+ va_end(ap);
+
+ if (!buf)
+ return -ENOMEM;
+
+ ret = xenbus_write(t, dir, node, buf);
+
+ kfree(buf);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(xenbus_printf);
+
+/* Takes tuples of names, scanf-style args, and void **, NULL terminated. */
+int xenbus_gather(struct xenbus_transaction t, const char *dir, ...)
+{
+ va_list ap;
+ const char *name;
+ int ret = 0;
+
+ va_start(ap, dir);
+ while (ret == 0 && (name = va_arg(ap, char *)) != NULL) {
+ const char *fmt = va_arg(ap, char *);
+ void *result = va_arg(ap, void *);
+ char *p;
+
+ p = xenbus_read(t, dir, name, NULL);
+ if (IS_ERR(p)) {
+ ret = PTR_ERR(p);
+ break;
+ }
+ if (fmt) {
+ if (sscanf(p, fmt, result) == 0)
+ ret = -EINVAL;
+ kfree(p);
+ } else
+ *(char **)result = p;
+ }
+ va_end(ap);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(xenbus_gather);
+
+static int xs_watch(const char *path, const char *token)
+{
+ struct kvec iov[2];
+
+ iov[0].iov_base = (void *)path;
+ iov[0].iov_len = strlen(path) + 1;
+ iov[1].iov_base = (void *)token;
+ iov[1].iov_len = strlen(token) + 1;
+
+ return xs_error(xs_talkv(XBT_NIL, XS_WATCH, iov,
+ ARRAY_SIZE(iov), NULL));
+}
+
+static int xs_unwatch(const char *path, const char *token)
+{
+ struct kvec iov[2];
+
+ iov[0].iov_base = (char *)path;
+ iov[0].iov_len = strlen(path) + 1;
+ iov[1].iov_base = (char *)token;
+ iov[1].iov_len = strlen(token) + 1;
+
+ return xs_error(xs_talkv(XBT_NIL, XS_UNWATCH, iov,
+ ARRAY_SIZE(iov), NULL));
+}
+
+static struct xenbus_watch *find_watch(const char *token)
+{
+ struct xenbus_watch *i, *cmp;
+
+ cmp = (void *)simple_strtoul(token, NULL, 16);
+
+ list_for_each_entry(i, &watches, list)
+ if (i == cmp)
+ return i;
+
+ return NULL;
+}
+
+int xs_watch_msg(struct xs_watch_event *event)
+{
+ if (count_strings(event->body, event->len) != 2) {
+ kfree(event);
+ return -EINVAL;
+ }
+ event->path = (const char *)event->body;
+ event->token = (const char *)strchr(event->body, '\0') + 1;
+
+ spin_lock(&watches_lock);
+ event->handle = find_watch(event->token);
+ if (event->handle != NULL) {
+ spin_lock(&watch_events_lock);
+ list_add_tail(&event->list, &watch_events);
+ wake_up(&watch_events_waitq);
+ spin_unlock(&watch_events_lock);
+ } else
+ kfree(event);
+ spin_unlock(&watches_lock);
+
+ return 0;
+}
+
+/*
+ * Certain older XenBus toolstack cannot handle reading values that are
+ * not populated. Some Xen 3.4 installation are incapable of doing this
+ * so if we are running on anything older than 4 do not attempt to read
+ * control/platform-feature-xs_reset_watches.
+ */
+static bool xen_strict_xenbus_quirk(void)
+{
+#ifdef CONFIG_X86
+ uint32_t eax, ebx, ecx, edx, base;
+
+ base = xen_cpuid_base();
+ cpuid(base + 1, &eax, &ebx, &ecx, &edx);
+
+ if ((eax >> 16) < 4)
+ return true;
+#endif
+ return false;
+
+}
+static void xs_reset_watches(void)
+{
+ int err;
+
+ if (!xen_hvm_domain() || xen_initial_domain())
+ return;
+
+ if (xen_strict_xenbus_quirk())
+ return;
+
+ if (!xenbus_read_unsigned("control",
+ "platform-feature-xs_reset_watches", 0))
+ return;
+
+ err = xs_error(xs_single(XBT_NIL, XS_RESET_WATCHES, "", NULL));
+ if (err && err != -EEXIST)
+ pr_warn("xs_reset_watches failed: %d\n", err);
+}
+
+/* Register callback to watch this node. */
+int register_xenbus_watch(struct xenbus_watch *watch)
+{
+ /* Pointer in ascii is the token. */
+ char token[sizeof(watch) * 2 + 1];
+ int err;
+
+ sprintf(token, "%lX", (long)watch);
+
+ down_read(&xs_watch_rwsem);
+
+ spin_lock(&watches_lock);
+ BUG_ON(find_watch(token));
+ list_add(&watch->list, &watches);
+ spin_unlock(&watches_lock);
+
+ err = xs_watch(watch->node, token);
+
+ if (err) {
+ spin_lock(&watches_lock);
+ list_del(&watch->list);
+ spin_unlock(&watches_lock);
+ }
+
+ up_read(&xs_watch_rwsem);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(register_xenbus_watch);
+
+void unregister_xenbus_watch(struct xenbus_watch *watch)
+{
+ struct xs_watch_event *event, *tmp;
+ char token[sizeof(watch) * 2 + 1];
+ int err;
+
+ sprintf(token, "%lX", (long)watch);
+
+ down_read(&xs_watch_rwsem);
+
+ spin_lock(&watches_lock);
+ BUG_ON(!find_watch(token));
+ list_del(&watch->list);
+ spin_unlock(&watches_lock);
+
+ err = xs_unwatch(watch->node, token);
+ if (err)
+ pr_warn("Failed to release watch %s: %i\n", watch->node, err);
+
+ up_read(&xs_watch_rwsem);
+
+ /* Make sure there are no callbacks running currently (unless
+ its us) */
+ if (current->pid != xenwatch_pid)
+ mutex_lock(&xenwatch_mutex);
+
+ /* Cancel pending watch events. */
+ spin_lock(&watch_events_lock);
+ list_for_each_entry_safe(event, tmp, &watch_events, list) {
+ if (event->handle != watch)
+ continue;
+ list_del(&event->list);
+ kfree(event);
+ }
+ spin_unlock(&watch_events_lock);
+
+ if (current->pid != xenwatch_pid)
+ mutex_unlock(&xenwatch_mutex);
+}
+EXPORT_SYMBOL_GPL(unregister_xenbus_watch);
+
+void xs_suspend(void)
+{
+ xs_suspend_enter();
+
+ down_write(&xs_watch_rwsem);
+ mutex_lock(&xs_response_mutex);
+}
+
+void xs_resume(void)
+{
+ struct xenbus_watch *watch;
+ char token[sizeof(watch) * 2 + 1];
+
+ xb_init_comms();
+
+ mutex_unlock(&xs_response_mutex);
+
+ xs_suspend_exit();
+
+ /* No need for watches_lock: the xs_watch_rwsem is sufficient. */
+ list_for_each_entry(watch, &watches, list) {
+ sprintf(token, "%lX", (long)watch);
+ xs_watch(watch->node, token);
+ }
+
+ up_write(&xs_watch_rwsem);
+}
+
+void xs_suspend_cancel(void)
+{
+ mutex_unlock(&xs_response_mutex);
+ up_write(&xs_watch_rwsem);
+
+ xs_suspend_exit();
+}
+
+static int xenwatch_thread(void *unused)
+{
+ struct list_head *ent;
+ struct xs_watch_event *event;
+
+ xenwatch_pid = current->pid;
+
+ for (;;) {
+ wait_event_interruptible(watch_events_waitq,
+ !list_empty(&watch_events));
+
+ if (kthread_should_stop())
+ break;
+
+ mutex_lock(&xenwatch_mutex);
+
+ spin_lock(&watch_events_lock);
+ ent = watch_events.next;
+ if (ent != &watch_events)
+ list_del(ent);
+ spin_unlock(&watch_events_lock);
+
+ if (ent != &watch_events) {
+ event = list_entry(ent, struct xs_watch_event, list);
+ event->handle->callback(event->handle, event->path,
+ event->token);
+ kfree(event);
+ }
+
+ mutex_unlock(&xenwatch_mutex);
+ }
+
+ return 0;
+}
+
+/*
+ * Wake up all threads waiting for a xenstore reply. In case of shutdown all
+ * pending replies will be marked as "aborted" in order to let the waiters
+ * return in spite of xenstore possibly no longer being able to reply. This
+ * will avoid blocking shutdown by a thread waiting for xenstore but being
+ * necessary for shutdown processing to proceed.
+ */
+static int xs_reboot_notify(struct notifier_block *nb,
+ unsigned long code, void *unused)
+{
+ struct xb_req_data *req;
+
+ mutex_lock(&xb_write_mutex);
+ list_for_each_entry(req, &xs_reply_list, list)
+ wake_up(&req->wq);
+ list_for_each_entry(req, &xb_write_list, list)
+ wake_up(&req->wq);
+ mutex_unlock(&xb_write_mutex);
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block xs_reboot_nb = {
+ .notifier_call = xs_reboot_notify,
+};
+
+int xs_init(void)
+{
+ int err;
+ struct task_struct *task;
+
+ register_reboot_notifier(&xs_reboot_nb);
+
+ /* Initialize the shared memory rings to talk to xenstored */
+ err = xb_init_comms();
+ if (err)
+ return err;
+
+ task = kthread_run(xenwatch_thread, NULL, "xenwatch");
+ if (IS_ERR(task))
+ return PTR_ERR(task);
+
+ /* shutdown watches for kexec boot */
+ xs_reset_watches();
+
+ return 0;
+}