Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * Performance events callchain code, extracted from core.c:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  *  Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  *  Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  *  Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8)  *  Copyright  ©  2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) #include <linux/perf_event.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) #include <linux/sched/task_stack.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) #include "internal.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) struct callchain_cpus_entries {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) 	struct rcu_head			rcu_head;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) 	struct perf_callchain_entry	*cpu_entries[];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) int sysctl_perf_event_max_stack __read_mostly = PERF_MAX_STACK_DEPTH;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) int sysctl_perf_event_max_contexts_per_stack __read_mostly = PERF_MAX_CONTEXTS_PER_STACK;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) static inline size_t perf_callchain_entry__sizeof(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) 	return (sizeof(struct perf_callchain_entry) +
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 		sizeof(__u64) * (sysctl_perf_event_max_stack +
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) 				 sysctl_perf_event_max_contexts_per_stack));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) static DEFINE_PER_CPU(int, callchain_recursion[PERF_NR_CONTEXTS]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) static atomic_t nr_callchain_events;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) static DEFINE_MUTEX(callchain_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) static struct callchain_cpus_entries *callchain_cpus_entries;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) __weak void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) 				  struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) __weak void perf_callchain_user(struct perf_callchain_entry_ctx *entry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 				struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) static void release_callchain_buffers_rcu(struct rcu_head *head)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 	struct callchain_cpus_entries *entries;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 	int cpu;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 	entries = container_of(head, struct callchain_cpus_entries, rcu_head);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 	for_each_possible_cpu(cpu)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 		kfree(entries->cpu_entries[cpu]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 	kfree(entries);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) static void release_callchain_buffers(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 	struct callchain_cpus_entries *entries;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 	entries = callchain_cpus_entries;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 	RCU_INIT_POINTER(callchain_cpus_entries, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 	call_rcu(&entries->rcu_head, release_callchain_buffers_rcu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) static int alloc_callchain_buffers(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 	int cpu;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 	int size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 	struct callchain_cpus_entries *entries;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 	 * We can't use the percpu allocation API for data that can be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 	 * accessed from NMI. Use a temporary manual per cpu allocation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 	 * until that gets sorted out.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 	size = offsetof(struct callchain_cpus_entries, cpu_entries[nr_cpu_ids]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 	entries = kzalloc(size, GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 	if (!entries)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 		return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 	size = perf_callchain_entry__sizeof() * PERF_NR_CONTEXTS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 	for_each_possible_cpu(cpu) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 		entries->cpu_entries[cpu] = kmalloc_node(size, GFP_KERNEL,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 							 cpu_to_node(cpu));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 		if (!entries->cpu_entries[cpu])
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 			goto fail;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 	rcu_assign_pointer(callchain_cpus_entries, entries);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) fail:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 	for_each_possible_cpu(cpu)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 		kfree(entries->cpu_entries[cpu]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 	kfree(entries);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 	return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) int get_callchain_buffers(int event_max_stack)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 	int err = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 	int count;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 	mutex_lock(&callchain_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 	count = atomic_inc_return(&nr_callchain_events);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 	if (WARN_ON_ONCE(count < 1)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 		err = -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 		goto exit;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 	 * If requesting per event more than the global cap,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 	 * return a different error to help userspace figure
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 	 * this out.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 	 * And also do it here so that we have &callchain_mutex held.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 	if (event_max_stack > sysctl_perf_event_max_stack) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 		err = -EOVERFLOW;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 		goto exit;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 	if (count == 1)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 		err = alloc_callchain_buffers();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) exit:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 	if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 		atomic_dec(&nr_callchain_events);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 	mutex_unlock(&callchain_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 	return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) void put_callchain_buffers(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 	if (atomic_dec_and_mutex_lock(&nr_callchain_events, &callchain_mutex)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 		release_callchain_buffers();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 		mutex_unlock(&callchain_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) struct perf_callchain_entry *get_callchain_entry(int *rctx)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 	int cpu;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 	struct callchain_cpus_entries *entries;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 	*rctx = get_recursion_context(this_cpu_ptr(callchain_recursion));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 	if (*rctx == -1)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 		return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 	entries = rcu_dereference(callchain_cpus_entries);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 	if (!entries) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 		put_recursion_context(this_cpu_ptr(callchain_recursion), *rctx);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 		return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	cpu = smp_processor_id();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 	return (((void *)entries->cpu_entries[cpu]) +
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 		(*rctx * perf_callchain_entry__sizeof()));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) void
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) put_callchain_entry(int rctx)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 	put_recursion_context(this_cpu_ptr(callchain_recursion), rctx);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) struct perf_callchain_entry *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 		   u32 max_stack, bool crosstask, bool add_mark)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 	struct perf_callchain_entry *entry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 	struct perf_callchain_entry_ctx ctx;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 	int rctx;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 	entry = get_callchain_entry(&rctx);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 	if (!entry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 		return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 	ctx.entry     = entry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 	ctx.max_stack = max_stack;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 	ctx.nr	      = entry->nr = init_nr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 	ctx.contexts       = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 	ctx.contexts_maxed = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 	if (kernel && !user_mode(regs)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 		if (add_mark)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 			perf_callchain_store_context(&ctx, PERF_CONTEXT_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 		perf_callchain_kernel(&ctx, regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 	if (user) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 		if (!user_mode(regs)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 			if  (current->mm)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 				regs = task_pt_regs(current);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 			else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 				regs = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 		if (regs) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 			mm_segment_t fs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 			if (crosstask)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 				goto exit_put;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 			if (add_mark)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 				perf_callchain_store_context(&ctx, PERF_CONTEXT_USER);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 			fs = force_uaccess_begin();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 			perf_callchain_user(&ctx, regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 			force_uaccess_end(fs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) exit_put:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) 	put_callchain_entry(rctx);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) 	return entry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233)  * Used for sysctl_perf_event_max_stack and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234)  * sysctl_perf_event_max_contexts_per_stack.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) int perf_event_max_stack_handler(struct ctl_table *table, int write,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) 				 void *buffer, size_t *lenp, loff_t *ppos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) 	int *value = table->data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) 	int new_value = *value, ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) 	struct ctl_table new_table = *table;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) 	new_table.data = &new_value;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) 	ret = proc_dointvec_minmax(&new_table, write, buffer, lenp, ppos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) 	if (ret || !write)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) 		return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 	mutex_lock(&callchain_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 	if (atomic_read(&nr_callchain_events))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 		ret = -EBUSY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 	else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) 		*value = new_value;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) 	mutex_unlock(&callchain_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) }