v4.19.13 snapshot.
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
new file mode 100644
index 0000000..dc43fa9
--- /dev/null
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -0,0 +1,694 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * xen console driver interface to hvc_console.c
+ *
+ * (c) 2007 Gerd Hoffmann <kraxel@suse.de>
+ */
+
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/irq.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/serial_core.h>
+
+#include <asm/io.h>
+#include <asm/xen/hypervisor.h>
+
+#include <xen/xen.h>
+#include <xen/interface/xen.h>
+#include <xen/hvm.h>
+#include <xen/grant_table.h>
+#include <xen/page.h>
+#include <xen/events.h>
+#include <xen/interface/io/console.h>
+#include <xen/interface/sched.h>
+#include <xen/hvc-console.h>
+#include <xen/xenbus.h>
+
+#include "hvc_console.h"
+
+#define HVC_COOKIE 0x58656e /* "Xen" in hex */
+
+struct xencons_info {
+ struct list_head list;
+ struct xenbus_device *xbdev;
+ struct xencons_interface *intf;
+ unsigned int evtchn;
+ struct hvc_struct *hvc;
+ int irq;
+ int vtermno;
+ grant_ref_t gntref;
+};
+
+static LIST_HEAD(xenconsoles);
+static DEFINE_SPINLOCK(xencons_lock);
+
+/* ------------------------------------------------------------------ */
+
+static struct xencons_info *vtermno_to_xencons(int vtermno)
+{
+ struct xencons_info *entry, *n, *ret = NULL;
+
+ if (list_empty(&xenconsoles))
+ return NULL;
+
+ list_for_each_entry_safe(entry, n, &xenconsoles, list) {
+ if (entry->vtermno == vtermno) {
+ ret = entry;
+ break;
+ }
+ }
+
+ return ret;
+}
+
+static inline int xenbus_devid_to_vtermno(int devid)
+{
+ return devid + HVC_COOKIE;
+}
+
+static inline void notify_daemon(struct xencons_info *cons)
+{
+ /* Use evtchn: this is called early, before irq is set up. */
+ notify_remote_via_evtchn(cons->evtchn);
+}
+
+static int __write_console(struct xencons_info *xencons,
+ const char *data, int len)
+{
+ XENCONS_RING_IDX cons, prod;
+ struct xencons_interface *intf = xencons->intf;
+ int sent = 0;
+
+ cons = intf->out_cons;
+ prod = intf->out_prod;
+ mb(); /* update queue values before going on */
+ BUG_ON((prod - cons) > sizeof(intf->out));
+
+ while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
+ intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];
+
+ wmb(); /* write ring before updating pointer */
+ intf->out_prod = prod;
+
+ if (sent)
+ notify_daemon(xencons);
+ return sent;
+}
+
+static int domU_write_console(uint32_t vtermno, const char *data, int len)
+{
+ int ret = len;
+ struct xencons_info *cons = vtermno_to_xencons(vtermno);
+ if (cons == NULL)
+ return -EINVAL;
+
+ /*
+ * Make sure the whole buffer is emitted, polling if
+ * necessary. We don't ever want to rely on the hvc daemon
+ * because the most interesting console output is when the
+ * kernel is crippled.
+ */
+ while (len) {
+ int sent = __write_console(cons, data, len);
+
+ data += sent;
+ len -= sent;
+
+ if (unlikely(len))
+ HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
+ }
+
+ return ret;
+}
+
+static int domU_read_console(uint32_t vtermno, char *buf, int len)
+{
+ struct xencons_interface *intf;
+ XENCONS_RING_IDX cons, prod;
+ int recv = 0;
+ struct xencons_info *xencons = vtermno_to_xencons(vtermno);
+ if (xencons == NULL)
+ return -EINVAL;
+ intf = xencons->intf;
+
+ cons = intf->in_cons;
+ prod = intf->in_prod;
+ mb(); /* get pointers before reading ring */
+ BUG_ON((prod - cons) > sizeof(intf->in));
+
+ while (cons != prod && recv < len)
+ buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];
+
+ mb(); /* read ring before consuming */
+ intf->in_cons = cons;
+
+ notify_daemon(xencons);
+ return recv;
+}
+
+static const struct hv_ops domU_hvc_ops = {
+ .get_chars = domU_read_console,
+ .put_chars = domU_write_console,
+ .notifier_add = notifier_add_irq,
+ .notifier_del = notifier_del_irq,
+ .notifier_hangup = notifier_hangup_irq,
+};
+
+static int dom0_read_console(uint32_t vtermno, char *buf, int len)
+{
+ return HYPERVISOR_console_io(CONSOLEIO_read, len, buf);
+}
+
+/*
+ * Either for a dom0 to write to the system console, or a domU with a
+ * debug version of Xen
+ */
+static int dom0_write_console(uint32_t vtermno, const char *str, int len)
+{
+ int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str);
+ if (rc < 0)
+ return rc;
+
+ return len;
+}
+
+static const struct hv_ops dom0_hvc_ops = {
+ .get_chars = dom0_read_console,
+ .put_chars = dom0_write_console,
+ .notifier_add = notifier_add_irq,
+ .notifier_del = notifier_del_irq,
+ .notifier_hangup = notifier_hangup_irq,
+};
+
+static int xen_hvm_console_init(void)
+{
+ int r;
+ uint64_t v = 0;
+ unsigned long gfn;
+ struct xencons_info *info;
+
+ if (!xen_hvm_domain())
+ return -ENODEV;
+
+ info = vtermno_to_xencons(HVC_COOKIE);
+ if (!info) {
+ info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
+ if (!info)
+ return -ENOMEM;
+ } else if (info->intf != NULL) {
+ /* already configured */
+ return 0;
+ }
+ /*
+ * If the toolstack (or the hypervisor) hasn't set these values, the
+ * default value is 0. Even though gfn = 0 and evtchn = 0 are
+ * theoretically correct values, in practice they never are and they
+ * mean that a legacy toolstack hasn't initialized the pv console correctly.
+ */
+ r = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
+ if (r < 0 || v == 0)
+ goto err;
+ info->evtchn = v;
+ v = 0;
+ r = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
+ if (r < 0 || v == 0)
+ goto err;
+ gfn = v;
+ info->intf = xen_remap(gfn << XEN_PAGE_SHIFT, XEN_PAGE_SIZE);
+ if (info->intf == NULL)
+ goto err;
+ info->vtermno = HVC_COOKIE;
+
+ spin_lock(&xencons_lock);
+ list_add_tail(&info->list, &xenconsoles);
+ spin_unlock(&xencons_lock);
+
+ return 0;
+err:
+ kfree(info);
+ return -ENODEV;
+}
+
+static int xencons_info_pv_init(struct xencons_info *info, int vtermno)
+{
+ info->evtchn = xen_start_info->console.domU.evtchn;
+ /* GFN == MFN for PV guest */
+ info->intf = gfn_to_virt(xen_start_info->console.domU.mfn);
+ info->vtermno = vtermno;
+
+ list_add_tail(&info->list, &xenconsoles);
+
+ return 0;
+}
+
+static int xen_pv_console_init(void)
+{
+ struct xencons_info *info;
+
+ if (!xen_pv_domain())
+ return -ENODEV;
+
+ if (!xen_start_info->console.domU.evtchn)
+ return -ENODEV;
+
+ info = vtermno_to_xencons(HVC_COOKIE);
+ if (!info) {
+ info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
+ if (!info)
+ return -ENOMEM;
+ } else if (info->intf != NULL) {
+ /* already configured */
+ return 0;
+ }
+ spin_lock(&xencons_lock);
+ xencons_info_pv_init(info, HVC_COOKIE);
+ spin_unlock(&xencons_lock);
+
+ return 0;
+}
+
+static int xen_initial_domain_console_init(void)
+{
+ struct xencons_info *info;
+
+ if (!xen_initial_domain())
+ return -ENODEV;
+
+ info = vtermno_to_xencons(HVC_COOKIE);
+ if (!info) {
+ info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
+ if (!info)
+ return -ENOMEM;
+ }
+
+ info->irq = bind_virq_to_irq(VIRQ_CONSOLE, 0, false);
+ info->vtermno = HVC_COOKIE;
+
+ spin_lock(&xencons_lock);
+ list_add_tail(&info->list, &xenconsoles);
+ spin_unlock(&xencons_lock);
+
+ return 0;
+}
+
+static void xen_console_update_evtchn(struct xencons_info *info)
+{
+ if (xen_hvm_domain()) {
+ uint64_t v = 0;
+ int err;
+
+ err = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
+ if (!err && v)
+ info->evtchn = v;
+ } else
+ info->evtchn = xen_start_info->console.domU.evtchn;
+}
+
+void xen_console_resume(void)
+{
+ struct xencons_info *info = vtermno_to_xencons(HVC_COOKIE);
+ if (info != NULL && info->irq) {
+ if (!xen_initial_domain())
+ xen_console_update_evtchn(info);
+ rebind_evtchn_irq(info->evtchn, info->irq);
+ }
+}
+
+#ifdef CONFIG_HVC_XEN_FRONTEND
+static void xencons_disconnect_backend(struct xencons_info *info)
+{
+ if (info->irq > 0)
+ unbind_from_irqhandler(info->irq, NULL);
+ info->irq = 0;
+ if (info->evtchn > 0)
+ xenbus_free_evtchn(info->xbdev, info->evtchn);
+ info->evtchn = 0;
+ if (info->gntref > 0)
+ gnttab_free_grant_references(info->gntref);
+ info->gntref = 0;
+ if (info->hvc != NULL)
+ hvc_remove(info->hvc);
+ info->hvc = NULL;
+}
+
+static void xencons_free(struct xencons_info *info)
+{
+ free_page((unsigned long)info->intf);
+ info->intf = NULL;
+ info->vtermno = 0;
+ kfree(info);
+}
+
+static int xen_console_remove(struct xencons_info *info)
+{
+ xencons_disconnect_backend(info);
+ spin_lock(&xencons_lock);
+ list_del(&info->list);
+ spin_unlock(&xencons_lock);
+ if (info->xbdev != NULL)
+ xencons_free(info);
+ else {
+ if (xen_hvm_domain())
+ iounmap(info->intf);
+ kfree(info);
+ }
+ return 0;
+}
+
+static int xencons_remove(struct xenbus_device *dev)
+{
+ return xen_console_remove(dev_get_drvdata(&dev->dev));
+}
+
+static int xencons_connect_backend(struct xenbus_device *dev,
+ struct xencons_info *info)
+{
+ int ret, evtchn, devid, ref, irq;
+ struct xenbus_transaction xbt;
+ grant_ref_t gref_head;
+
+ ret = xenbus_alloc_evtchn(dev, &evtchn);
+ if (ret)
+ return ret;
+ info->evtchn = evtchn;
+ irq = bind_evtchn_to_irq(evtchn);
+ if (irq < 0)
+ return irq;
+ info->irq = irq;
+ devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
+ info->hvc = hvc_alloc(xenbus_devid_to_vtermno(devid),
+ irq, &domU_hvc_ops, 256);
+ if (IS_ERR(info->hvc))
+ return PTR_ERR(info->hvc);
+ ret = gnttab_alloc_grant_references(1, &gref_head);
+ if (ret < 0)
+ return ret;
+ info->gntref = gref_head;
+ ref = gnttab_claim_grant_reference(&gref_head);
+ if (ref < 0)
+ return ref;
+ gnttab_grant_foreign_access_ref(ref, info->xbdev->otherend_id,
+ virt_to_gfn(info->intf), 0);
+
+ again:
+ ret = xenbus_transaction_start(&xbt);
+ if (ret) {
+ xenbus_dev_fatal(dev, ret, "starting transaction");
+ return ret;
+ }
+ ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", ref);
+ if (ret)
+ goto error_xenbus;
+ ret = xenbus_printf(xbt, dev->nodename, "port", "%u",
+ evtchn);
+ if (ret)
+ goto error_xenbus;
+ ret = xenbus_transaction_end(xbt, 0);
+ if (ret) {
+ if (ret == -EAGAIN)
+ goto again;
+ xenbus_dev_fatal(dev, ret, "completing transaction");
+ return ret;
+ }
+
+ xenbus_switch_state(dev, XenbusStateInitialised);
+ return 0;
+
+ error_xenbus:
+ xenbus_transaction_end(xbt, 1);
+ xenbus_dev_fatal(dev, ret, "writing xenstore");
+ return ret;
+}
+
+static int xencons_probe(struct xenbus_device *dev,
+ const struct xenbus_device_id *id)
+{
+ int ret, devid;
+ struct xencons_info *info;
+
+ devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
+ if (devid == 0)
+ return -ENODEV;
+
+ info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
+ if (!info)
+ return -ENOMEM;
+ dev_set_drvdata(&dev->dev, info);
+ info->xbdev = dev;
+ info->vtermno = xenbus_devid_to_vtermno(devid);
+ info->intf = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+ if (!info->intf)
+ goto error_nomem;
+
+ ret = xencons_connect_backend(dev, info);
+ if (ret < 0)
+ goto error;
+ spin_lock(&xencons_lock);
+ list_add_tail(&info->list, &xenconsoles);
+ spin_unlock(&xencons_lock);
+
+ return 0;
+
+ error_nomem:
+ ret = -ENOMEM;
+ xenbus_dev_fatal(dev, ret, "allocating device memory");
+ error:
+ xencons_disconnect_backend(info);
+ xencons_free(info);
+ return ret;
+}
+
+static int xencons_resume(struct xenbus_device *dev)
+{
+ struct xencons_info *info = dev_get_drvdata(&dev->dev);
+
+ xencons_disconnect_backend(info);
+ memset(info->intf, 0, XEN_PAGE_SIZE);
+ return xencons_connect_backend(dev, info);
+}
+
+static void xencons_backend_changed(struct xenbus_device *dev,
+ enum xenbus_state backend_state)
+{
+ switch (backend_state) {
+ case XenbusStateReconfiguring:
+ case XenbusStateReconfigured:
+ case XenbusStateInitialising:
+ case XenbusStateInitialised:
+ case XenbusStateUnknown:
+ break;
+
+ case XenbusStateInitWait:
+ break;
+
+ case XenbusStateConnected:
+ xenbus_switch_state(dev, XenbusStateConnected);
+ break;
+
+ case XenbusStateClosed:
+ if (dev->state == XenbusStateClosed)
+ break;
+ /* Missed the backend's CLOSING state -- fallthrough */
+ case XenbusStateClosing:
+ xenbus_frontend_closed(dev);
+ break;
+ }
+}
+
+static const struct xenbus_device_id xencons_ids[] = {
+ { "console" },
+ { "" }
+};
+
+static struct xenbus_driver xencons_driver = {
+ .name = "xenconsole",
+ .ids = xencons_ids,
+ .probe = xencons_probe,
+ .remove = xencons_remove,
+ .resume = xencons_resume,
+ .otherend_changed = xencons_backend_changed,
+};
+#endif /* CONFIG_HVC_XEN_FRONTEND */
+
+static int __init xen_hvc_init(void)
+{
+ int r;
+ struct xencons_info *info;
+ const struct hv_ops *ops;
+
+ if (!xen_domain())
+ return -ENODEV;
+
+ if (xen_initial_domain()) {
+ ops = &dom0_hvc_ops;
+ r = xen_initial_domain_console_init();
+ if (r < 0)
+ return r;
+ info = vtermno_to_xencons(HVC_COOKIE);
+ } else {
+ ops = &domU_hvc_ops;
+ if (xen_hvm_domain())
+ r = xen_hvm_console_init();
+ else
+ r = xen_pv_console_init();
+ if (r < 0)
+ return r;
+
+ info = vtermno_to_xencons(HVC_COOKIE);
+ info->irq = bind_evtchn_to_irq(info->evtchn);
+ }
+ if (info->irq < 0)
+ info->irq = 0; /* NO_IRQ */
+ else
+ irq_set_noprobe(info->irq);
+
+ info->hvc = hvc_alloc(HVC_COOKIE, info->irq, ops, 256);
+ if (IS_ERR(info->hvc)) {
+ r = PTR_ERR(info->hvc);
+ spin_lock(&xencons_lock);
+ list_del(&info->list);
+ spin_unlock(&xencons_lock);
+ if (info->irq)
+ unbind_from_irqhandler(info->irq, NULL);
+ kfree(info);
+ return r;
+ }
+
+ r = 0;
+#ifdef CONFIG_HVC_XEN_FRONTEND
+ r = xenbus_register_frontend(&xencons_driver);
+#endif
+ return r;
+}
+device_initcall(xen_hvc_init);
+
+static int xen_cons_init(void)
+{
+ const struct hv_ops *ops;
+
+ if (!xen_domain())
+ return 0;
+
+ if (xen_initial_domain())
+ ops = &dom0_hvc_ops;
+ else {
+ int r;
+ ops = &domU_hvc_ops;
+
+ if (xen_hvm_domain())
+ r = xen_hvm_console_init();
+ else
+ r = xen_pv_console_init();
+ if (r < 0)
+ return r;
+ }
+
+ hvc_instantiate(HVC_COOKIE, 0, ops);
+ return 0;
+}
+console_initcall(xen_cons_init);
+
+#ifdef CONFIG_X86
+static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len)
+{
+ if (xen_cpuid_base())
+ outsb(0xe9, str, len);
+}
+#else
+static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len) { }
+#endif
+
+#ifdef CONFIG_EARLY_PRINTK
+static int __init xenboot_setup_console(struct console *console, char *string)
+{
+ static struct xencons_info xenboot;
+
+ if (xen_initial_domain())
+ return 0;
+ if (!xen_pv_domain())
+ return -ENODEV;
+
+ return xencons_info_pv_init(&xenboot, 0);
+}
+
+static void xenboot_write_console(struct console *console, const char *string,
+ unsigned len)
+{
+ unsigned int linelen, off = 0;
+ const char *pos;
+
+ if (!xen_pv_domain()) {
+ xen_hvm_early_write(0, string, len);
+ return;
+ }
+
+ dom0_write_console(0, string, len);
+
+ if (xen_initial_domain())
+ return;
+
+ domU_write_console(0, "(early) ", 8);
+ while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
+ linelen = pos-string+off;
+ if (off + linelen > len)
+ break;
+ domU_write_console(0, string+off, linelen);
+ domU_write_console(0, "\r\n", 2);
+ off += linelen + 1;
+ }
+ if (off < len)
+ domU_write_console(0, string+off, len-off);
+}
+
+struct console xenboot_console = {
+ .name = "xenboot",
+ .write = xenboot_write_console,
+ .setup = xenboot_setup_console,
+ .flags = CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
+ .index = -1,
+};
+#endif /* CONFIG_EARLY_PRINTK */
+
+void xen_raw_console_write(const char *str)
+{
+ ssize_t len = strlen(str);
+ int rc = 0;
+
+ if (xen_domain()) {
+ rc = dom0_write_console(0, str, len);
+ if (rc != -ENOSYS || !xen_hvm_domain())
+ return;
+ }
+ xen_hvm_early_write(0, str, len);
+}
+
+void xen_raw_printk(const char *fmt, ...)
+{
+ static char buf[512];
+ va_list ap;
+
+ va_start(ap, fmt);
+ vsnprintf(buf, sizeof(buf), fmt, ap);
+ va_end(ap);
+
+ xen_raw_console_write(buf);
+}
+
+static void xenboot_earlycon_write(struct console *console,
+ const char *string,
+ unsigned len)
+{
+ dom0_write_console(0, string, len);
+}
+
+static int __init xenboot_earlycon_setup(struct earlycon_device *device,
+ const char *opt)
+{
+ device->con->write = xenboot_earlycon_write;
+ return 0;
+}
+EARLYCON_DECLARE(xenboot, xenboot_earlycon_setup);