v4.19.13 snapshot.
diff --git a/arch/x86/mm/mmio-mod.c b/arch/x86/mm/mmio-mod.c
new file mode 100644
index 0000000..2c1ecf4
--- /dev/null
+++ b/arch/x86/mm/mmio-mod.c
@@ -0,0 +1,477 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) IBM Corporation, 2005
+ * Jeff Muizelaar, 2006, 2007
+ * Pekka Paalanen, 2008 <pq@iki.fi>
+ *
+ * Derived from the read-mod example from relay-examples by Tom Zanussi.
+ */
+
+#define pr_fmt(fmt) "mmiotrace: " fmt
+
+#define DEBUG 1
+
+#include <linux/moduleparam.h>
+#include <linux/debugfs.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
+#include <asm/pgtable.h>
+#include <linux/mmiotrace.h>
+#include <asm/e820/api.h> /* for ISA_START_ADDRESS */
+#include <linux/atomic.h>
+#include <linux/percpu.h>
+#include <linux/cpu.h>
+
+#include "pf_in.h"
+
+struct trap_reason {
+ unsigned long addr;
+ unsigned long ip;
+ enum reason_type type;
+ int active_traces;
+};
+
+struct remap_trace {
+ struct list_head list;
+ struct kmmio_probe probe;
+ resource_size_t phys;
+ unsigned long id;
+};
+
+/* Accessed per-cpu. */
+static DEFINE_PER_CPU(struct trap_reason, pf_reason);
+static DEFINE_PER_CPU(struct mmiotrace_rw, cpu_trace);
+
+static DEFINE_MUTEX(mmiotrace_mutex);
+static DEFINE_SPINLOCK(trace_lock);
+static atomic_t mmiotrace_enabled;
+static LIST_HEAD(trace_list); /* struct remap_trace */
+
+/*
+ * Locking in this file:
+ * - mmiotrace_mutex enforces enable/disable_mmiotrace() critical sections.
+ * - mmiotrace_enabled may be modified only when holding mmiotrace_mutex
+ * and trace_lock.
+ * - Routines depending on is_enabled() must take trace_lock.
+ * - trace_list users must hold trace_lock.
+ * - is_enabled() guarantees that mmio_trace_{rw,mapping} are allowed.
+ * - pre/post callbacks assume the effect of is_enabled() being true.
+ */
+
+/* module parameters */
+static unsigned long filter_offset;
+static bool nommiotrace;
+static bool trace_pc;
+
+module_param(filter_offset, ulong, 0);
+module_param(nommiotrace, bool, 0);
+module_param(trace_pc, bool, 0);
+
+MODULE_PARM_DESC(filter_offset, "Start address of traced mappings.");
+MODULE_PARM_DESC(nommiotrace, "Disable actual MMIO tracing.");
+MODULE_PARM_DESC(trace_pc, "Record address of faulting instructions.");
+
+static bool is_enabled(void)
+{
+ return atomic_read(&mmiotrace_enabled);
+}
+
+static void print_pte(unsigned long address)
+{
+ unsigned int level;
+ pte_t *pte = lookup_address(address, &level);
+
+ if (!pte) {
+ pr_err("Error in %s: no pte for page 0x%08lx\n",
+ __func__, address);
+ return;
+ }
+
+ if (level == PG_LEVEL_2M) {
+ pr_emerg("4MB pages are not currently supported: 0x%08lx\n",
+ address);
+ BUG();
+ }
+ pr_info("pte for 0x%lx: 0x%llx 0x%llx\n",
+ address,
+ (unsigned long long)pte_val(*pte),
+ (unsigned long long)pte_val(*pte) & _PAGE_PRESENT);
+}
+
+/*
+ * For some reason the pre/post pairs have been called in an
+ * unmatched order. Report and die.
+ */
+static void die_kmmio_nesting_error(struct pt_regs *regs, unsigned long addr)
+{
+ const struct trap_reason *my_reason = &get_cpu_var(pf_reason);
+ pr_emerg("unexpected fault for address: 0x%08lx, last fault for address: 0x%08lx\n",
+ addr, my_reason->addr);
+ print_pte(addr);
+ pr_emerg("faulting IP is at %pS\n", (void *)regs->ip);
+ pr_emerg("last faulting IP was at %pS\n", (void *)my_reason->ip);
+#ifdef __i386__
+ pr_emerg("eax: %08lx ebx: %08lx ecx: %08lx edx: %08lx\n",
+ regs->ax, regs->bx, regs->cx, regs->dx);
+ pr_emerg("esi: %08lx edi: %08lx ebp: %08lx esp: %08lx\n",
+ regs->si, regs->di, regs->bp, regs->sp);
+#else
+ pr_emerg("rax: %016lx rcx: %016lx rdx: %016lx\n",
+ regs->ax, regs->cx, regs->dx);
+ pr_emerg("rsi: %016lx rdi: %016lx rbp: %016lx rsp: %016lx\n",
+ regs->si, regs->di, regs->bp, regs->sp);
+#endif
+ put_cpu_var(pf_reason);
+ BUG();
+}
+
+static void pre(struct kmmio_probe *p, struct pt_regs *regs,
+ unsigned long addr)
+{
+ struct trap_reason *my_reason = &get_cpu_var(pf_reason);
+ struct mmiotrace_rw *my_trace = &get_cpu_var(cpu_trace);
+ const unsigned long instptr = instruction_pointer(regs);
+ const enum reason_type type = get_ins_type(instptr);
+ struct remap_trace *trace = p->private;
+
+ /* it doesn't make sense to have more than one active trace per cpu */
+ if (my_reason->active_traces)
+ die_kmmio_nesting_error(regs, addr);
+ else
+ my_reason->active_traces++;
+
+ my_reason->type = type;
+ my_reason->addr = addr;
+ my_reason->ip = instptr;
+
+ my_trace->phys = addr - trace->probe.addr + trace->phys;
+ my_trace->map_id = trace->id;
+
+ /*
+ * Only record the program counter when requested.
+ * It may taint clean-room reverse engineering.
+ */
+ if (trace_pc)
+ my_trace->pc = instptr;
+ else
+ my_trace->pc = 0;
+
+ /*
+ * XXX: the timestamp recorded will be *after* the tracing has been
+ * done, not at the time we hit the instruction. SMP implications
+ * on event ordering?
+ */
+
+ switch (type) {
+ case REG_READ:
+ my_trace->opcode = MMIO_READ;
+ my_trace->width = get_ins_mem_width(instptr);
+ break;
+ case REG_WRITE:
+ my_trace->opcode = MMIO_WRITE;
+ my_trace->width = get_ins_mem_width(instptr);
+ my_trace->value = get_ins_reg_val(instptr, regs);
+ break;
+ case IMM_WRITE:
+ my_trace->opcode = MMIO_WRITE;
+ my_trace->width = get_ins_mem_width(instptr);
+ my_trace->value = get_ins_imm_val(instptr);
+ break;
+ default:
+ {
+ unsigned char *ip = (unsigned char *)instptr;
+ my_trace->opcode = MMIO_UNKNOWN_OP;
+ my_trace->width = 0;
+ my_trace->value = (*ip) << 16 | *(ip + 1) << 8 |
+ *(ip + 2);
+ }
+ }
+ put_cpu_var(cpu_trace);
+ put_cpu_var(pf_reason);
+}
+
+static void post(struct kmmio_probe *p, unsigned long condition,
+ struct pt_regs *regs)
+{
+ struct trap_reason *my_reason = &get_cpu_var(pf_reason);
+ struct mmiotrace_rw *my_trace = &get_cpu_var(cpu_trace);
+
+ /* this should always return the active_trace count to 0 */
+ my_reason->active_traces--;
+ if (my_reason->active_traces) {
+ pr_emerg("unexpected post handler");
+ BUG();
+ }
+
+ switch (my_reason->type) {
+ case REG_READ:
+ my_trace->value = get_ins_reg_val(my_reason->ip, regs);
+ break;
+ default:
+ break;
+ }
+
+ mmio_trace_rw(my_trace);
+ put_cpu_var(cpu_trace);
+ put_cpu_var(pf_reason);
+}
+
+static void ioremap_trace_core(resource_size_t offset, unsigned long size,
+ void __iomem *addr)
+{
+ static atomic_t next_id;
+ struct remap_trace *trace = kmalloc(sizeof(*trace), GFP_KERNEL);
+ /* These are page-unaligned. */
+ struct mmiotrace_map map = {
+ .phys = offset,
+ .virt = (unsigned long)addr,
+ .len = size,
+ .opcode = MMIO_PROBE
+ };
+
+ if (!trace) {
+ pr_err("kmalloc failed in ioremap\n");
+ return;
+ }
+
+ *trace = (struct remap_trace) {
+ .probe = {
+ .addr = (unsigned long)addr,
+ .len = size,
+ .pre_handler = pre,
+ .post_handler = post,
+ .private = trace
+ },
+ .phys = offset,
+ .id = atomic_inc_return(&next_id)
+ };
+ map.map_id = trace->id;
+
+ spin_lock_irq(&trace_lock);
+ if (!is_enabled()) {
+ kfree(trace);
+ goto not_enabled;
+ }
+
+ mmio_trace_mapping(&map);
+ list_add_tail(&trace->list, &trace_list);
+ if (!nommiotrace)
+ register_kmmio_probe(&trace->probe);
+
+not_enabled:
+ spin_unlock_irq(&trace_lock);
+}
+
+void mmiotrace_ioremap(resource_size_t offset, unsigned long size,
+ void __iomem *addr)
+{
+ if (!is_enabled()) /* recheck and proper locking in *_core() */
+ return;
+
+ pr_debug("ioremap_*(0x%llx, 0x%lx) = %p\n",
+ (unsigned long long)offset, size, addr);
+ if ((filter_offset) && (offset != filter_offset))
+ return;
+ ioremap_trace_core(offset, size, addr);
+}
+
+static void iounmap_trace_core(volatile void __iomem *addr)
+{
+ struct mmiotrace_map map = {
+ .phys = 0,
+ .virt = (unsigned long)addr,
+ .len = 0,
+ .opcode = MMIO_UNPROBE
+ };
+ struct remap_trace *trace;
+ struct remap_trace *tmp;
+ struct remap_trace *found_trace = NULL;
+
+ pr_debug("Unmapping %p.\n", addr);
+
+ spin_lock_irq(&trace_lock);
+ if (!is_enabled())
+ goto not_enabled;
+
+ list_for_each_entry_safe(trace, tmp, &trace_list, list) {
+ if ((unsigned long)addr == trace->probe.addr) {
+ if (!nommiotrace)
+ unregister_kmmio_probe(&trace->probe);
+ list_del(&trace->list);
+ found_trace = trace;
+ break;
+ }
+ }
+ map.map_id = (found_trace) ? found_trace->id : -1;
+ mmio_trace_mapping(&map);
+
+not_enabled:
+ spin_unlock_irq(&trace_lock);
+ if (found_trace) {
+ synchronize_rcu(); /* unregister_kmmio_probe() requirement */
+ kfree(found_trace);
+ }
+}
+
+void mmiotrace_iounmap(volatile void __iomem *addr)
+{
+ might_sleep();
+ if (is_enabled()) /* recheck and proper locking in *_core() */
+ iounmap_trace_core(addr);
+}
+
+int mmiotrace_printk(const char *fmt, ...)
+{
+ int ret = 0;
+ va_list args;
+ unsigned long flags;
+ va_start(args, fmt);
+
+ spin_lock_irqsave(&trace_lock, flags);
+ if (is_enabled())
+ ret = mmio_trace_printk(fmt, args);
+ spin_unlock_irqrestore(&trace_lock, flags);
+
+ va_end(args);
+ return ret;
+}
+EXPORT_SYMBOL(mmiotrace_printk);
+
+static void clear_trace_list(void)
+{
+ struct remap_trace *trace;
+ struct remap_trace *tmp;
+
+ /*
+ * No locking required, because the caller ensures we are in a
+ * critical section via mutex, and is_enabled() is false,
+ * i.e. nothing can traverse or modify this list.
+ * Caller also ensures is_enabled() cannot change.
+ */
+ list_for_each_entry(trace, &trace_list, list) {
+ pr_notice("purging non-iounmapped trace @0x%08lx, size 0x%lx.\n",
+ trace->probe.addr, trace->probe.len);
+ if (!nommiotrace)
+ unregister_kmmio_probe(&trace->probe);
+ }
+ synchronize_rcu(); /* unregister_kmmio_probe() requirement */
+
+ list_for_each_entry_safe(trace, tmp, &trace_list, list) {
+ list_del(&trace->list);
+ kfree(trace);
+ }
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static cpumask_var_t downed_cpus;
+
+static void enter_uniprocessor(void)
+{
+ int cpu;
+ int err;
+
+ if (downed_cpus == NULL &&
+ !alloc_cpumask_var(&downed_cpus, GFP_KERNEL)) {
+ pr_notice("Failed to allocate mask\n");
+ goto out;
+ }
+
+ get_online_cpus();
+ cpumask_copy(downed_cpus, cpu_online_mask);
+ cpumask_clear_cpu(cpumask_first(cpu_online_mask), downed_cpus);
+ if (num_online_cpus() > 1)
+ pr_notice("Disabling non-boot CPUs...\n");
+ put_online_cpus();
+
+ for_each_cpu(cpu, downed_cpus) {
+ err = cpu_down(cpu);
+ if (!err)
+ pr_info("CPU%d is down.\n", cpu);
+ else
+ pr_err("Error taking CPU%d down: %d\n", cpu, err);
+ }
+out:
+ if (num_online_cpus() > 1)
+ pr_warning("multiple CPUs still online, may miss events.\n");
+}
+
+static void leave_uniprocessor(void)
+{
+ int cpu;
+ int err;
+
+ if (downed_cpus == NULL || cpumask_weight(downed_cpus) == 0)
+ return;
+ pr_notice("Re-enabling CPUs...\n");
+ for_each_cpu(cpu, downed_cpus) {
+ err = cpu_up(cpu);
+ if (!err)
+ pr_info("enabled CPU%d.\n", cpu);
+ else
+ pr_err("cannot re-enable CPU%d: %d\n", cpu, err);
+ }
+}
+
+#else /* !CONFIG_HOTPLUG_CPU */
+static void enter_uniprocessor(void)
+{
+ if (num_online_cpus() > 1)
+ pr_warning("multiple CPUs are online, may miss events. "
+ "Suggest booting with maxcpus=1 kernel argument.\n");
+}
+
+static void leave_uniprocessor(void)
+{
+}
+#endif
+
+void enable_mmiotrace(void)
+{
+ mutex_lock(&mmiotrace_mutex);
+ if (is_enabled())
+ goto out;
+
+ if (nommiotrace)
+ pr_info("MMIO tracing disabled.\n");
+ kmmio_init();
+ enter_uniprocessor();
+ spin_lock_irq(&trace_lock);
+ atomic_inc(&mmiotrace_enabled);
+ spin_unlock_irq(&trace_lock);
+ pr_info("enabled.\n");
+out:
+ mutex_unlock(&mmiotrace_mutex);
+}
+
+void disable_mmiotrace(void)
+{
+ mutex_lock(&mmiotrace_mutex);
+ if (!is_enabled())
+ goto out;
+
+ spin_lock_irq(&trace_lock);
+ atomic_dec(&mmiotrace_enabled);
+ BUG_ON(is_enabled());
+ spin_unlock_irq(&trace_lock);
+
+ clear_trace_list(); /* guarantees: no more kmmio callbacks */
+ leave_uniprocessor();
+ kmmio_cleanup();
+ pr_info("disabled.\n");
+out:
+ mutex_unlock(&mmiotrace_mutex);
+}