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-rw-r--r--kernel/hw_breakpoint.c457
1 files changed, 0 insertions, 457 deletions
diff --git a/kernel/hw_breakpoint.c b/kernel/hw_breakpoint.c
deleted file mode 100644
index 50dbd599958..00000000000
--- a/kernel/hw_breakpoint.c
+++ /dev/null
@@ -1,457 +0,0 @@
-/*
- * 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) 2007 Alan Stern
- * Copyright (C) IBM Corporation, 2009
- * Copyright (C) 2009, Frederic Weisbecker <fweisbec@gmail.com>
- *
- * Thanks to Ingo Molnar for his many suggestions.
- *
- * Authors: Alan Stern <stern@rowland.harvard.edu>
- * K.Prasad <prasad@linux.vnet.ibm.com>
- * Frederic Weisbecker <fweisbec@gmail.com>
- */
-
-/*
- * HW_breakpoint: a unified kernel/user-space hardware breakpoint facility,
- * using the CPU's debug registers.
- * This file contains the arch-independent routines.
- */
-
-#include <linux/irqflags.h>
-#include <linux/kallsyms.h>
-#include <linux/notifier.h>
-#include <linux/kprobes.h>
-#include <linux/kdebug.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/percpu.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/cpu.h>
-#include <linux/smp.h>
-
-#include <linux/hw_breakpoint.h>
-
-/*
- * Constraints data
- */
-
-/* Number of pinned cpu breakpoints in a cpu */
-static DEFINE_PER_CPU(unsigned int, nr_cpu_bp_pinned);
-
-/* Number of pinned task breakpoints in a cpu */
-static DEFINE_PER_CPU(unsigned int, nr_task_bp_pinned[HBP_NUM]);
-
-/* Number of non-pinned cpu/task breakpoints in a cpu */
-static DEFINE_PER_CPU(unsigned int, nr_bp_flexible);
-
-/* Gather the number of total pinned and un-pinned bp in a cpuset */
-struct bp_busy_slots {
- unsigned int pinned;
- unsigned int flexible;
-};
-
-/* Serialize accesses to the above constraints */
-static DEFINE_MUTEX(nr_bp_mutex);
-
-/*
- * Report the maximum number of pinned breakpoints a task
- * have in this cpu
- */
-static unsigned int max_task_bp_pinned(int cpu)
-{
- int i;
- unsigned int *tsk_pinned = per_cpu(nr_task_bp_pinned, cpu);
-
- for (i = HBP_NUM -1; i >= 0; i--) {
- if (tsk_pinned[i] > 0)
- return i + 1;
- }
-
- return 0;
-}
-
-static int task_bp_pinned(struct task_struct *tsk)
-{
- struct perf_event_context *ctx = tsk->perf_event_ctxp;
- struct list_head *list;
- struct perf_event *bp;
- unsigned long flags;
- int count = 0;
-
- if (WARN_ONCE(!ctx, "No perf context for this task"))
- return 0;
-
- list = &ctx->event_list;
-
- raw_spin_lock_irqsave(&ctx->lock, flags);
-
- /*
- * The current breakpoint counter is not included in the list
- * at the open() callback time
- */
- list_for_each_entry(bp, list, event_entry) {
- if (bp->attr.type == PERF_TYPE_BREAKPOINT)
- count++;
- }
-
- raw_spin_unlock_irqrestore(&ctx->lock, flags);
-
- return count;
-}
-
-/*
- * Report the number of pinned/un-pinned breakpoints we have in
- * a given cpu (cpu > -1) or in all of them (cpu = -1).
- */
-static void
-fetch_bp_busy_slots(struct bp_busy_slots *slots, struct perf_event *bp)
-{
- int cpu = bp->cpu;
- struct task_struct *tsk = bp->ctx->task;
-
- if (cpu >= 0) {
- slots->pinned = per_cpu(nr_cpu_bp_pinned, cpu);
- if (!tsk)
- slots->pinned += max_task_bp_pinned(cpu);
- else
- slots->pinned += task_bp_pinned(tsk);
- slots->flexible = per_cpu(nr_bp_flexible, cpu);
-
- return;
- }
-
- for_each_online_cpu(cpu) {
- unsigned int nr;
-
- nr = per_cpu(nr_cpu_bp_pinned, cpu);
- if (!tsk)
- nr += max_task_bp_pinned(cpu);
- else
- nr += task_bp_pinned(tsk);
-
- if (nr > slots->pinned)
- slots->pinned = nr;
-
- nr = per_cpu(nr_bp_flexible, cpu);
-
- if (nr > slots->flexible)
- slots->flexible = nr;
- }
-}
-
-/*
- * Add a pinned breakpoint for the given task in our constraint table
- */
-static void toggle_bp_task_slot(struct task_struct *tsk, int cpu, bool enable)
-{
- unsigned int *tsk_pinned;
- int count = 0;
-
- count = task_bp_pinned(tsk);
-
- tsk_pinned = per_cpu(nr_task_bp_pinned, cpu);
- if (enable) {
- tsk_pinned[count]++;
- if (count > 0)
- tsk_pinned[count-1]--;
- } else {
- tsk_pinned[count]--;
- if (count > 0)
- tsk_pinned[count-1]++;
- }
-}
-
-/*
- * Add/remove the given breakpoint in our constraint table
- */
-static void toggle_bp_slot(struct perf_event *bp, bool enable)
-{
- int cpu = bp->cpu;
- struct task_struct *tsk = bp->ctx->task;
-
- /* Pinned counter task profiling */
- if (tsk) {
- if (cpu >= 0) {
- toggle_bp_task_slot(tsk, cpu, enable);
- return;
- }
-
- for_each_online_cpu(cpu)
- toggle_bp_task_slot(tsk, cpu, enable);
- return;
- }
-
- /* Pinned counter cpu profiling */
- if (enable)
- per_cpu(nr_cpu_bp_pinned, bp->cpu)++;
- else
- per_cpu(nr_cpu_bp_pinned, bp->cpu)--;
-}
-
-/*
- * Contraints to check before allowing this new breakpoint counter:
- *
- * == Non-pinned counter == (Considered as pinned for now)
- *
- * - If attached to a single cpu, check:
- *
- * (per_cpu(nr_bp_flexible, cpu) || (per_cpu(nr_cpu_bp_pinned, cpu)
- * + max(per_cpu(nr_task_bp_pinned, cpu)))) < HBP_NUM
- *
- * -> If there are already non-pinned counters in this cpu, it means
- * there is already a free slot for them.
- * Otherwise, we check that the maximum number of per task
- * breakpoints (for this cpu) plus the number of per cpu breakpoint
- * (for this cpu) doesn't cover every registers.
- *
- * - If attached to every cpus, check:
- *
- * (per_cpu(nr_bp_flexible, *) || (max(per_cpu(nr_cpu_bp_pinned, *))
- * + max(per_cpu(nr_task_bp_pinned, *)))) < HBP_NUM
- *
- * -> This is roughly the same, except we check the number of per cpu
- * bp for every cpu and we keep the max one. Same for the per tasks
- * breakpoints.
- *
- *
- * == Pinned counter ==
- *
- * - If attached to a single cpu, check:
- *
- * ((per_cpu(nr_bp_flexible, cpu) > 1) + per_cpu(nr_cpu_bp_pinned, cpu)
- * + max(per_cpu(nr_task_bp_pinned, cpu))) < HBP_NUM
- *
- * -> Same checks as before. But now the nr_bp_flexible, if any, must keep
- * one register at least (or they will never be fed).
- *
- * - If attached to every cpus, check:
- *
- * ((per_cpu(nr_bp_flexible, *) > 1) + max(per_cpu(nr_cpu_bp_pinned, *))
- * + max(per_cpu(nr_task_bp_pinned, *))) < HBP_NUM
- */
-int reserve_bp_slot(struct perf_event *bp)
-{
- struct bp_busy_slots slots = {0};
- int ret = 0;
-
- mutex_lock(&nr_bp_mutex);
-
- fetch_bp_busy_slots(&slots, bp);
-
- /* Flexible counters need to keep at least one slot */
- if (slots.pinned + (!!slots.flexible) == HBP_NUM) {
- ret = -ENOSPC;
- goto end;
- }
-
- toggle_bp_slot(bp, true);
-
-end:
- mutex_unlock(&nr_bp_mutex);
-
- return ret;
-}
-
-void release_bp_slot(struct perf_event *bp)
-{
- mutex_lock(&nr_bp_mutex);
-
- toggle_bp_slot(bp, false);
-
- mutex_unlock(&nr_bp_mutex);
-}
-
-
-int register_perf_hw_breakpoint(struct perf_event *bp)
-{
- int ret;
-
- ret = reserve_bp_slot(bp);
- if (ret)
- return ret;
-
- /*
- * Ptrace breakpoints can be temporary perf events only
- * meant to reserve a slot. In this case, it is created disabled and
- * we don't want to check the params right now (as we put a null addr)
- * But perf tools create events as disabled and we want to check
- * the params for them.
- * This is a quick hack that will be removed soon, once we remove
- * the tmp breakpoints from ptrace
- */
- if (!bp->attr.disabled || !bp->overflow_handler)
- ret = arch_validate_hwbkpt_settings(bp, bp->ctx->task);
-
- return ret;
-}
-
-/**
- * register_user_hw_breakpoint - register a hardware breakpoint for user space
- * @attr: breakpoint attributes
- * @triggered: callback to trigger when we hit the breakpoint
- * @tsk: pointer to 'task_struct' of the process to which the address belongs
- */
-struct perf_event *
-register_user_hw_breakpoint(struct perf_event_attr *attr,
- perf_overflow_handler_t triggered,
- struct task_struct *tsk)
-{
- return perf_event_create_kernel_counter(attr, -1, tsk->pid, triggered);
-}
-EXPORT_SYMBOL_GPL(register_user_hw_breakpoint);
-
-/**
- * modify_user_hw_breakpoint - modify a user-space hardware breakpoint
- * @bp: the breakpoint structure to modify
- * @attr: new breakpoint attributes
- * @triggered: callback to trigger when we hit the breakpoint
- * @tsk: pointer to 'task_struct' of the process to which the address belongs
- */
-int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr)
-{
- u64 old_addr = bp->attr.bp_addr;
- int old_type = bp->attr.bp_type;
- int old_len = bp->attr.bp_len;
- int err = 0;
-
- perf_event_disable(bp);
-
- bp->attr.bp_addr = attr->bp_addr;
- bp->attr.bp_type = attr->bp_type;
- bp->attr.bp_len = attr->bp_len;
-
- if (attr->disabled)
- goto end;
-
- err = arch_validate_hwbkpt_settings(bp, bp->ctx->task);
- if (!err)
- perf_event_enable(bp);
-
- if (err) {
- bp->attr.bp_addr = old_addr;
- bp->attr.bp_type = old_type;
- bp->attr.bp_len = old_len;
- if (!bp->attr.disabled)
- perf_event_enable(bp);
-
- return err;
- }
-
-end:
- bp->attr.disabled = attr->disabled;
-
- return 0;
-}
-EXPORT_SYMBOL_GPL(modify_user_hw_breakpoint);
-
-/**
- * unregister_hw_breakpoint - unregister a user-space hardware breakpoint
- * @bp: the breakpoint structure to unregister
- */
-void unregister_hw_breakpoint(struct perf_event *bp)
-{
- if (!bp)
- return;
- perf_event_release_kernel(bp);
-}
-EXPORT_SYMBOL_GPL(unregister_hw_breakpoint);
-
-/**
- * register_wide_hw_breakpoint - register a wide breakpoint in the kernel
- * @attr: breakpoint attributes
- * @triggered: callback to trigger when we hit the breakpoint
- *
- * @return a set of per_cpu pointers to perf events
- */
-struct perf_event **
-register_wide_hw_breakpoint(struct perf_event_attr *attr,
- perf_overflow_handler_t triggered)
-{
- struct perf_event **cpu_events, **pevent, *bp;
- long err;
- int cpu;
-
- cpu_events = alloc_percpu(typeof(*cpu_events));
- if (!cpu_events)
- return ERR_PTR(-ENOMEM);
-
- get_online_cpus();
- for_each_online_cpu(cpu) {
- pevent = per_cpu_ptr(cpu_events, cpu);
- bp = perf_event_create_kernel_counter(attr, cpu, -1, triggered);
-
- *pevent = bp;
-
- if (IS_ERR(bp)) {
- err = PTR_ERR(bp);
- goto fail;
- }
- }
- put_online_cpus();
-
- return cpu_events;
-
-fail:
- for_each_online_cpu(cpu) {
- pevent = per_cpu_ptr(cpu_events, cpu);
- if (IS_ERR(*pevent))
- break;
- unregister_hw_breakpoint(*pevent);
- }
- put_online_cpus();
-
- free_percpu(cpu_events);
- return ERR_PTR(err);
-}
-EXPORT_SYMBOL_GPL(register_wide_hw_breakpoint);
-
-/**
- * unregister_wide_hw_breakpoint - unregister a wide breakpoint in the kernel
- * @cpu_events: the per cpu set of events to unregister
- */
-void unregister_wide_hw_breakpoint(struct perf_event **cpu_events)
-{
- int cpu;
- struct perf_event **pevent;
-
- for_each_possible_cpu(cpu) {
- pevent = per_cpu_ptr(cpu_events, cpu);
- unregister_hw_breakpoint(*pevent);
- }
- free_percpu(cpu_events);
-}
-EXPORT_SYMBOL_GPL(unregister_wide_hw_breakpoint);
-
-static struct notifier_block hw_breakpoint_exceptions_nb = {
- .notifier_call = hw_breakpoint_exceptions_notify,
- /* we need to be notified first */
- .priority = 0x7fffffff
-};
-
-static int __init init_hw_breakpoint(void)
-{
- return register_die_notifier(&hw_breakpoint_exceptions_nb);
-}
-core_initcall(init_hw_breakpoint);
-
-
-struct pmu perf_ops_bp = {
- .enable = arch_install_hw_breakpoint,
- .disable = arch_uninstall_hw_breakpoint,
- .read = hw_breakpoint_pmu_read,
- .unthrottle = hw_breakpoint_pmu_unthrottle
-};
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