linux/kernel/events/callchain.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Performance events callchain code, extracted from core.c:
 *
 *  Copyright (C) 2008 Thomas Gleixner <[email protected]>
 *  Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
 *  Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
 *  Copyright  ©  2009 Paul Mackerras, IBM Corp. <[email protected]>
 */

#include <linux/perf_event.h>
#include <linux/slab.h>
#include <linux/sched/task_stack.h>
#include <linux/uprobes.h>

#include "internal.h"

struct callchain_cpus_entries { … };

int sysctl_perf_event_max_stack __read_mostly = …;
int sysctl_perf_event_max_contexts_per_stack __read_mostly = …;

static inline size_t perf_callchain_entry__sizeof(void)
{ … }

static DEFINE_PER_CPU(u8, callchain_recursion[PERF_NR_CONTEXTS]);
static atomic_t nr_callchain_events;
static DEFINE_MUTEX(callchain_mutex);
static struct callchain_cpus_entries *callchain_cpus_entries;


__weak void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
				  struct pt_regs *regs)
{ … }

__weak void perf_callchain_user(struct perf_callchain_entry_ctx *entry,
				struct pt_regs *regs)
{ … }

static void release_callchain_buffers_rcu(struct rcu_head *head)
{ … }

static void release_callchain_buffers(void)
{ … }

static int alloc_callchain_buffers(void)
{ … }

int get_callchain_buffers(int event_max_stack)
{ … }

void put_callchain_buffers(void)
{ … }

struct perf_callchain_entry *get_callchain_entry(int *rctx)
{ … }

void
put_callchain_entry(int rctx)
{ … }

static void fixup_uretprobe_trampoline_entries(struct perf_callchain_entry *entry,
					       int start_entry_idx)
{ … }

struct perf_callchain_entry *
get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user,
		   u32 max_stack, bool crosstask, bool add_mark)
{ … }

/*
 * Used for sysctl_perf_event_max_stack and
 * sysctl_perf_event_max_contexts_per_stack.
 */
int perf_event_max_stack_handler(const struct ctl_table *table, int write,
				 void *buffer, size_t *lenp, loff_t *ppos)
{ … }