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Thomas Gleixner457c8992019-05-19 13:08:55 +01001// SPDX-License-Identifier: GPL-2.0-only
Linus Torvalds1da177e2005-04-16 15:20:36 -07002/*
3 * linux/kernel/profile.c
4 * Simple profiling. Manages a direct-mapped profile hit count buffer,
5 * with configurable resolution, support for restricting the cpus on
6 * which profiling is done, and switching between cpu time and
7 * schedule() calls via kernel command line parameters passed at boot.
8 *
9 * Scheduler profiling support, Arjan van de Ven and Ingo Molnar,
10 * Red Hat, July 2004
11 * Consolidation of architecture support code for profiling,
Nadia Yvette Chambers6d49e352012-12-06 10:39:54 +010012 * Nadia Yvette Chambers, Oracle, July 2004
Linus Torvalds1da177e2005-04-16 15:20:36 -070013 * Amortized hit count accounting via per-cpu open-addressed hashtables
Nadia Yvette Chambers6d49e352012-12-06 10:39:54 +010014 * to resolve timer interrupt livelocks, Nadia Yvette Chambers,
15 * Oracle, 2004
Linus Torvalds1da177e2005-04-16 15:20:36 -070016 */
17
Paul Gortmaker9984de12011-05-23 14:51:41 -040018#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <linux/profile.h>
Mike Rapoport57c8a662018-10-30 15:09:49 -070020#include <linux/memblock.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#include <linux/notifier.h>
22#include <linux/mm.h>
23#include <linux/cpumask.h>
24#include <linux/cpu.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#include <linux/highmem.h>
Arjan van de Ven97d1f152006-03-23 03:00:24 -080026#include <linux/mutex.h>
Dave Hansen22b8ce92008-10-15 22:01:46 -070027#include <linux/slab.h>
28#include <linux/vmalloc.h>
Ingo Molnar3905f9a2017-02-05 12:07:04 +010029#include <linux/sched/stat.h>
30
Linus Torvalds1da177e2005-04-16 15:20:36 -070031#include <asm/sections.h>
David Howells7d12e782006-10-05 14:55:46 +010032#include <asm/irq_regs.h>
Alexey Dobriyane8edc6e2007-05-21 01:22:52 +040033#include <asm/ptrace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
35struct profile_hit {
36 u32 pc, hits;
37};
38#define PROFILE_GRPSHIFT 3
39#define PROFILE_GRPSZ (1 << PROFILE_GRPSHIFT)
40#define NR_PROFILE_HIT (PAGE_SIZE/sizeof(struct profile_hit))
41#define NR_PROFILE_GRP (NR_PROFILE_HIT/PROFILE_GRPSZ)
42
Linus Torvalds1da177e2005-04-16 15:20:36 -070043static atomic_t *prof_buffer;
Pavel Skripkin2d186af2021-09-07 19:58:21 -070044static unsigned long prof_len;
45static unsigned short int prof_shift;
Ingo Molnar07031e12007-01-10 23:15:38 -080046
Ingo Molnarece8a682006-12-06 20:37:24 -080047int prof_on __read_mostly;
Ingo Molnar07031e12007-01-10 23:15:38 -080048EXPORT_SYMBOL_GPL(prof_on);
49
Rusty Russellc309b912009-01-01 10:12:27 +103050static cpumask_var_t prof_cpu_mask;
Arnd Bergmannade356b2016-03-22 14:27:26 -070051#if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS)
Linus Torvalds1da177e2005-04-16 15:20:36 -070052static DEFINE_PER_CPU(struct profile_hit *[2], cpu_profile_hits);
53static DEFINE_PER_CPU(int, cpu_profile_flip);
Arjan van de Ven97d1f152006-03-23 03:00:24 -080054static DEFINE_MUTEX(profile_flip_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070055#endif /* CONFIG_SMP */
56
Dave Hansen22b8ce92008-10-15 22:01:46 -070057int profile_setup(char *str)
Linus Torvalds1da177e2005-04-16 15:20:36 -070058{
Fabian Frederickf3da64d2014-06-06 14:37:30 -070059 static const char schedstr[] = "schedule";
60 static const char sleepstr[] = "sleep";
61 static const char kvmstr[] = "kvm";
wuchi35783cc2022-09-01 08:31:21 +080062 const char *select = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 int par;
64
Ingo Molnarece8a682006-12-06 20:37:24 -080065 if (!strncmp(str, sleepstr, strlen(sleepstr))) {
Mel Gormanb3da2a72007-10-24 18:23:50 +020066#ifdef CONFIG_SCHEDSTATS
Mel Gormancb251762016-02-05 09:08:36 +000067 force_schedstat_enabled();
Ingo Molnarece8a682006-12-06 20:37:24 -080068 prof_on = SLEEP_PROFILING;
wuchi35783cc2022-09-01 08:31:21 +080069 select = sleepstr;
Mel Gormanb3da2a72007-10-24 18:23:50 +020070#else
Fabian Frederickaba871f2014-06-06 14:37:29 -070071 pr_warn("kernel sleep profiling requires CONFIG_SCHEDSTATS\n");
Mel Gormanb3da2a72007-10-24 18:23:50 +020072#endif /* CONFIG_SCHEDSTATS */
Ingo Molnara75acf82007-01-05 16:36:29 -080073 } else if (!strncmp(str, schedstr, strlen(schedstr))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070074 prof_on = SCHED_PROFILING;
wuchi35783cc2022-09-01 08:31:21 +080075 select = schedstr;
Ingo Molnar07031e12007-01-10 23:15:38 -080076 } else if (!strncmp(str, kvmstr, strlen(kvmstr))) {
77 prof_on = KVM_PROFILING;
wuchi35783cc2022-09-01 08:31:21 +080078 select = kvmstr;
William Lee Irwin IIIdfaa9c92005-05-16 21:53:58 -070079 } else if (get_option(&str, &par)) {
Pavel Skripkin2d186af2021-09-07 19:58:21 -070080 prof_shift = clamp(par, 0, BITS_PER_LONG - 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -070081 prof_on = CPU_PROFILING;
Pavel Skripkin2d186af2021-09-07 19:58:21 -070082 pr_info("kernel profiling enabled (shift: %u)\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -070083 prof_shift);
84 }
wuchi35783cc2022-09-01 08:31:21 +080085
86 if (select) {
87 if (str[strlen(select)] == ',')
88 str += strlen(select) + 1;
89 if (get_option(&str, &par))
90 prof_shift = clamp(par, 0, BITS_PER_LONG - 1);
91 pr_info("kernel %s profiling enabled (shift: %u)\n",
92 select, prof_shift);
93 }
94
Linus Torvalds1da177e2005-04-16 15:20:36 -070095 return 1;
96}
97__setup("profile=", profile_setup);
98
99
Paul Mundtce05fcc2008-10-29 14:01:07 -0700100int __ref profile_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101{
Dave Hansen22b8ce92008-10-15 22:01:46 -0700102 int buffer_bytes;
Paolo Ciarrocchi1ad82fd2008-01-25 21:08:33 +0100103 if (!prof_on)
Dave Hansen22b8ce92008-10-15 22:01:46 -0700104 return 0;
Paolo Ciarrocchi1ad82fd2008-01-25 21:08:33 +0100105
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 /* only text is profiled */
107 prof_len = (_etext - _stext) >> prof_shift;
Chen Zhongjin0fe6ee8f2022-05-31 09:28:54 +0800108
109 if (!prof_len) {
110 pr_warn("profiling shift: %u too large\n", prof_shift);
111 prof_on = 0;
112 return -EINVAL;
113 }
114
Dave Hansen22b8ce92008-10-15 22:01:46 -0700115 buffer_bytes = prof_len*sizeof(atomic_t);
Dave Hansen22b8ce92008-10-15 22:01:46 -0700116
Rusty Russellc309b912009-01-01 10:12:27 +1030117 if (!alloc_cpumask_var(&prof_cpu_mask, GFP_KERNEL))
118 return -ENOMEM;
119
Hugh Dickinsacd89572009-02-09 19:20:50 +0000120 cpumask_copy(prof_cpu_mask, cpu_possible_mask);
121
Mel Gormanb62f4952009-07-29 15:04:09 -0700122 prof_buffer = kzalloc(buffer_bytes, GFP_KERNEL|__GFP_NOWARN);
Dave Hansen22b8ce92008-10-15 22:01:46 -0700123 if (prof_buffer)
124 return 0;
125
Mel Gormanb62f4952009-07-29 15:04:09 -0700126 prof_buffer = alloc_pages_exact(buffer_bytes,
127 GFP_KERNEL|__GFP_ZERO|__GFP_NOWARN);
Dave Hansen22b8ce92008-10-15 22:01:46 -0700128 if (prof_buffer)
129 return 0;
130
Jesper Juhl559fa6e2010-10-30 21:56:26 +0200131 prof_buffer = vzalloc(buffer_bytes);
132 if (prof_buffer)
Dave Hansen22b8ce92008-10-15 22:01:46 -0700133 return 0;
134
Rusty Russellc309b912009-01-01 10:12:27 +1030135 free_cpumask_var(prof_cpu_mask);
Dave Hansen22b8ce92008-10-15 22:01:46 -0700136 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137}
138
Arnd Bergmannade356b2016-03-22 14:27:26 -0700139#if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140/*
141 * Each cpu has a pair of open-addressed hashtables for pending
142 * profile hits. read_profile() IPI's all cpus to request them
143 * to flip buffers and flushes their contents to prof_buffer itself.
144 * Flip requests are serialized by the profile_flip_mutex. The sole
145 * use of having a second hashtable is for avoiding cacheline
146 * contention that would otherwise happen during flushes of pending
147 * profile hits required for the accuracy of reported profile hits
148 * and so resurrect the interrupt livelock issue.
149 *
150 * The open-addressed hashtables are indexed by profile buffer slot
151 * and hold the number of pending hits to that profile buffer slot on
152 * a cpu in an entry. When the hashtable overflows, all pending hits
153 * are accounted to their corresponding profile buffer slots with
154 * atomic_add() and the hashtable emptied. As numerous pending hits
155 * may be accounted to a profile buffer slot in a hashtable entry,
156 * this amortizes a number of atomic profile buffer increments likely
157 * to be far larger than the number of entries in the hashtable,
158 * particularly given that the number of distinct profile buffer
159 * positions to which hits are accounted during short intervals (e.g.
160 * several seconds) is usually very small. Exclusion from buffer
161 * flipping is provided by interrupt disablement (note that for
Ingo Molnarece8a682006-12-06 20:37:24 -0800162 * SCHED_PROFILING or SLEEP_PROFILING profile_hit() may be called from
163 * process context).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 * The hash function is meant to be lightweight as opposed to strong,
165 * and was vaguely inspired by ppc64 firmware-supported inverted
166 * pagetable hash functions, but uses a full hashtable full of finite
167 * collision chains, not just pairs of them.
168 *
Nadia Yvette Chambers6d49e352012-12-06 10:39:54 +0100169 * -- nyc
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 */
171static void __profile_flip_buffers(void *unused)
172{
173 int cpu = smp_processor_id();
174
175 per_cpu(cpu_profile_flip, cpu) = !per_cpu(cpu_profile_flip, cpu);
176}
177
178static void profile_flip_buffers(void)
179{
180 int i, j, cpu;
181
Arjan van de Ven97d1f152006-03-23 03:00:24 -0800182 mutex_lock(&profile_flip_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 j = per_cpu(cpu_profile_flip, get_cpu());
184 put_cpu();
Jens Axboe15c8b6c2008-05-09 09:39:44 +0200185 on_each_cpu(__profile_flip_buffers, NULL, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 for_each_online_cpu(cpu) {
187 struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[j];
188 for (i = 0; i < NR_PROFILE_HIT; ++i) {
189 if (!hits[i].hits) {
190 if (hits[i].pc)
191 hits[i].pc = 0;
192 continue;
193 }
194 atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
195 hits[i].hits = hits[i].pc = 0;
196 }
197 }
Arjan van de Ven97d1f152006-03-23 03:00:24 -0800198 mutex_unlock(&profile_flip_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199}
200
201static void profile_discard_flip_buffers(void)
202{
203 int i, cpu;
204
Arjan van de Ven97d1f152006-03-23 03:00:24 -0800205 mutex_lock(&profile_flip_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 i = per_cpu(cpu_profile_flip, get_cpu());
207 put_cpu();
Jens Axboe15c8b6c2008-05-09 09:39:44 +0200208 on_each_cpu(__profile_flip_buffers, NULL, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 for_each_online_cpu(cpu) {
210 struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[i];
211 memset(hits, 0, NR_PROFILE_HIT*sizeof(struct profile_hit));
212 }
Arjan van de Ven97d1f152006-03-23 03:00:24 -0800213 mutex_unlock(&profile_flip_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214}
215
Rakib Mullick6f7bd762011-05-26 16:26:00 -0700216static void do_profile_hits(int type, void *__pc, unsigned int nr_hits)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217{
218 unsigned long primary, secondary, flags, pc = (unsigned long)__pc;
219 int i, j, cpu;
220 struct profile_hit *hits;
221
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222 pc = min((pc - (unsigned long)_stext) >> prof_shift, prof_len - 1);
223 i = primary = (pc & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
224 secondary = (~(pc << 1) & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
225 cpu = get_cpu();
226 hits = per_cpu(cpu_profile_hits, cpu)[per_cpu(cpu_profile_flip, cpu)];
227 if (!hits) {
228 put_cpu();
229 return;
230 }
Ingo Molnarece8a682006-12-06 20:37:24 -0800231 /*
232 * We buffer the global profiler buffer into a per-CPU
233 * queue and thus reduce the number of global (and possibly
234 * NUMA-alien) accesses. The write-queue is self-coalescing:
235 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 local_irq_save(flags);
237 do {
238 for (j = 0; j < PROFILE_GRPSZ; ++j) {
239 if (hits[i + j].pc == pc) {
Ingo Molnarece8a682006-12-06 20:37:24 -0800240 hits[i + j].hits += nr_hits;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241 goto out;
242 } else if (!hits[i + j].hits) {
243 hits[i + j].pc = pc;
Ingo Molnarece8a682006-12-06 20:37:24 -0800244 hits[i + j].hits = nr_hits;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 goto out;
246 }
247 }
248 i = (i + secondary) & (NR_PROFILE_HIT - 1);
249 } while (i != primary);
Ingo Molnarece8a682006-12-06 20:37:24 -0800250
251 /*
252 * Add the current hit(s) and flush the write-queue out
253 * to the global buffer:
254 */
255 atomic_add(nr_hits, &prof_buffer[pc]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 for (i = 0; i < NR_PROFILE_HIT; ++i) {
257 atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
258 hits[i].pc = hits[i].hits = 0;
259 }
260out:
261 local_irq_restore(flags);
262 put_cpu();
263}
264
Sebastian Andrzej Siewiore722d8d2016-07-13 17:16:59 +0000265static int profile_dead_cpu(unsigned int cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266{
Sebastian Andrzej Siewiore722d8d2016-07-13 17:16:59 +0000267 struct page *page;
268 int i;
269
Nathan Chancelloref70eff2019-12-04 16:50:50 -0800270 if (cpumask_available(prof_cpu_mask))
Sebastian Andrzej Siewiore722d8d2016-07-13 17:16:59 +0000271 cpumask_clear_cpu(cpu, prof_cpu_mask);
272
273 for (i = 0; i < 2; i++) {
274 if (per_cpu(cpu_profile_hits, cpu)[i]) {
275 page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[i]);
276 per_cpu(cpu_profile_hits, cpu)[i] = NULL;
277 __free_page(page);
278 }
279 }
280 return 0;
281}
282
283static int profile_prepare_cpu(unsigned int cpu)
284{
285 int i, node = cpu_to_mem(cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286 struct page *page;
287
Sebastian Andrzej Siewiore722d8d2016-07-13 17:16:59 +0000288 per_cpu(cpu_profile_flip, cpu) = 0;
289
290 for (i = 0; i < 2; i++) {
291 if (per_cpu(cpu_profile_hits, cpu)[i])
292 continue;
293
294 page = __alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
295 if (!page) {
296 profile_dead_cpu(cpu);
297 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298 }
Sebastian Andrzej Siewiore722d8d2016-07-13 17:16:59 +0000299 per_cpu(cpu_profile_hits, cpu)[i] = page_address(page);
300
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301 }
Sebastian Andrzej Siewiore722d8d2016-07-13 17:16:59 +0000302 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303}
Sebastian Andrzej Siewiore722d8d2016-07-13 17:16:59 +0000304
305static int profile_online_cpu(unsigned int cpu)
306{
Nathan Chancelloref70eff2019-12-04 16:50:50 -0800307 if (cpumask_available(prof_cpu_mask))
Sebastian Andrzej Siewiore722d8d2016-07-13 17:16:59 +0000308 cpumask_set_cpu(cpu, prof_cpu_mask);
309
310 return 0;
311}
312
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313#else /* !CONFIG_SMP */
314#define profile_flip_buffers() do { } while (0)
315#define profile_discard_flip_buffers() do { } while (0)
316
Rakib Mullick6f7bd762011-05-26 16:26:00 -0700317static void do_profile_hits(int type, void *__pc, unsigned int nr_hits)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318{
319 unsigned long pc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 pc = ((unsigned long)__pc - (unsigned long)_stext) >> prof_shift;
Ingo Molnarece8a682006-12-06 20:37:24 -0800321 atomic_add(nr_hits, &prof_buffer[min(pc, prof_len - 1)]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322}
323#endif /* !CONFIG_SMP */
Rakib Mullick6f7bd762011-05-26 16:26:00 -0700324
325void profile_hits(int type, void *__pc, unsigned int nr_hits)
326{
327 if (prof_on != type || !prof_buffer)
328 return;
329 do_profile_hits(type, __pc, nr_hits);
330}
Andrew Mortonbbe1a59b2007-01-22 20:40:33 -0800331EXPORT_SYMBOL_GPL(profile_hits);
332
David Howells7d12e782006-10-05 14:55:46 +0100333void profile_tick(int type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334{
David Howells7d12e782006-10-05 14:55:46 +0100335 struct pt_regs *regs = get_irq_regs();
336
Nathan Chancelloref70eff2019-12-04 16:50:50 -0800337 if (!user_mode(regs) && cpumask_available(prof_cpu_mask) &&
Rusty Russellc309b912009-01-01 10:12:27 +1030338 cpumask_test_cpu(smp_processor_id(), prof_cpu_mask))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339 profile_hit(type, (void *)profile_pc(regs));
340}
341
342#ifdef CONFIG_PROC_FS
343#include <linux/proc_fs.h>
Alexey Dobriyan583a22e2009-09-18 12:57:09 -0700344#include <linux/seq_file.h>
Linus Torvalds7c0f6ba2016-12-24 11:46:01 -0800345#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346
Alexey Dobriyan583a22e2009-09-18 12:57:09 -0700347static int prof_cpu_mask_proc_show(struct seq_file *m, void *v)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348{
Tejun Heoccbd59c2015-02-13 14:38:13 -0800349 seq_printf(m, "%*pb\n", cpumask_pr_args(prof_cpu_mask));
Alexey Dobriyan583a22e2009-09-18 12:57:09 -0700350 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351}
352
Alexey Dobriyan583a22e2009-09-18 12:57:09 -0700353static int prof_cpu_mask_proc_open(struct inode *inode, struct file *file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354{
Alexey Dobriyan583a22e2009-09-18 12:57:09 -0700355 return single_open(file, prof_cpu_mask_proc_show, NULL);
356}
357
358static ssize_t prof_cpu_mask_proc_write(struct file *file,
359 const char __user *buffer, size_t count, loff_t *pos)
360{
Rusty Russellc309b912009-01-01 10:12:27 +1030361 cpumask_var_t new_value;
Alexey Dobriyan583a22e2009-09-18 12:57:09 -0700362 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363
Tetsuo Handac5e3a412021-04-01 14:58:23 +0900364 if (!zalloc_cpumask_var(&new_value, GFP_KERNEL))
Rusty Russellc309b912009-01-01 10:12:27 +1030365 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366
Rusty Russellc309b912009-01-01 10:12:27 +1030367 err = cpumask_parse_user(buffer, count, new_value);
368 if (!err) {
Alexey Dobriyan583a22e2009-09-18 12:57:09 -0700369 cpumask_copy(prof_cpu_mask, new_value);
370 err = count;
Rusty Russellc309b912009-01-01 10:12:27 +1030371 }
372 free_cpumask_var(new_value);
373 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374}
375
Alexey Dobriyan97a32532020-02-03 17:37:17 -0800376static const struct proc_ops prof_cpu_mask_proc_ops = {
377 .proc_open = prof_cpu_mask_proc_open,
378 .proc_read = seq_read,
379 .proc_lseek = seq_lseek,
380 .proc_release = single_release,
381 .proc_write = prof_cpu_mask_proc_write,
Alexey Dobriyan583a22e2009-09-18 12:57:09 -0700382};
383
Al Virofbd387a2013-04-01 20:48:34 -0400384void create_prof_cpu_mask(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386 /* create /proc/irq/prof_cpu_mask */
Alexey Dobriyan97a32532020-02-03 17:37:17 -0800387 proc_create("irq/prof_cpu_mask", 0600, NULL, &prof_cpu_mask_proc_ops);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388}
389
390/*
391 * This function accesses profiling information. The returned data is
392 * binary: the sampling step and the actual contents of the profile
393 * buffer. Use of the program readprofile is recommended in order to
394 * get meaningful info out of these data.
395 */
396static ssize_t
397read_profile(struct file *file, char __user *buf, size_t count, loff_t *ppos)
398{
399 unsigned long p = *ppos;
400 ssize_t read;
Paolo Ciarrocchi1ad82fd2008-01-25 21:08:33 +0100401 char *pnt;
Pavel Skripkin2d186af2021-09-07 19:58:21 -0700402 unsigned long sample_step = 1UL << prof_shift;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403
404 profile_flip_buffers();
405 if (p >= (prof_len+1)*sizeof(unsigned int))
406 return 0;
407 if (count > (prof_len+1)*sizeof(unsigned int) - p)
408 count = (prof_len+1)*sizeof(unsigned int) - p;
409 read = 0;
410
411 while (p < sizeof(unsigned int) && count > 0) {
Paolo Ciarrocchi1ad82fd2008-01-25 21:08:33 +0100412 if (put_user(*((char *)(&sample_step)+p), buf))
Heiko Carstens064b0222006-12-06 20:36:37 -0800413 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 buf++; p++; count--; read++;
415 }
416 pnt = (char *)prof_buffer + p - sizeof(atomic_t);
Paolo Ciarrocchi1ad82fd2008-01-25 21:08:33 +0100417 if (copy_to_user(buf, (void *)pnt, count))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 return -EFAULT;
419 read += count;
420 *ppos += read;
421 return read;
422}
423
Ben Dooks787dbea2022-07-21 20:55:09 +0100424/* default is to not implement this call */
425int __weak setup_profiling_timer(unsigned mult)
426{
427 return -EINVAL;
428}
429
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430/*
431 * Writing to /proc/profile resets the counters
432 *
433 * Writing a 'profiling multiplier' value into it also re-sets the profiling
434 * interrupt frequency, on architectures that support this.
435 */
436static ssize_t write_profile(struct file *file, const char __user *buf,
437 size_t count, loff_t *ppos)
438{
439#ifdef CONFIG_SMP
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440 if (count == sizeof(int)) {
441 unsigned int multiplier;
442
443 if (copy_from_user(&multiplier, buf, sizeof(int)))
444 return -EFAULT;
445
446 if (setup_profiling_timer(multiplier))
447 return -EINVAL;
448 }
449#endif
450 profile_discard_flip_buffers();
451 memset(prof_buffer, 0, prof_len * sizeof(atomic_t));
452 return count;
453}
454
Alexey Dobriyan97a32532020-02-03 17:37:17 -0800455static const struct proc_ops profile_proc_ops = {
456 .proc_read = read_profile,
457 .proc_write = write_profile,
458 .proc_lseek = default_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459};
460
Sebastian Andrzej Siewiore722d8d2016-07-13 17:16:59 +0000461int __ref create_proc_profile(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462{
463 struct proc_dir_entry *entry;
Sebastian Andrzej Siewiore722d8d2016-07-13 17:16:59 +0000464#ifdef CONFIG_SMP
465 enum cpuhp_state online_state;
466#endif
467
Srivatsa S. Bhatc270a812014-03-11 02:12:08 +0530468 int err = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469
470 if (!prof_on)
471 return 0;
Sebastian Andrzej Siewiore722d8d2016-07-13 17:16:59 +0000472#ifdef CONFIG_SMP
473 err = cpuhp_setup_state(CPUHP_PROFILE_PREPARE, "PROFILE_PREPARE",
474 profile_prepare_cpu, profile_dead_cpu);
475 if (err)
476 return err;
Srivatsa S. Bhatc270a812014-03-11 02:12:08 +0530477
Sebastian Andrzej Siewiore722d8d2016-07-13 17:16:59 +0000478 err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "AP_PROFILE_ONLINE",
479 profile_online_cpu, NULL);
480 if (err < 0)
481 goto err_state_prep;
482 online_state = err;
483 err = 0;
484#endif
Denis V. Lunevc33fff02008-04-29 01:02:31 -0700485 entry = proc_create("profile", S_IWUSR | S_IRUGO,
Alexey Dobriyan97a32532020-02-03 17:37:17 -0800486 NULL, &profile_proc_ops);
Paolo Ciarrocchi1ad82fd2008-01-25 21:08:33 +0100487 if (!entry)
Sebastian Andrzej Siewiore722d8d2016-07-13 17:16:59 +0000488 goto err_state_onl;
David Howells271a15e2013-04-12 00:38:51 +0100489 proc_set_size(entry, (1 + prof_len) * sizeof(atomic_t));
Srivatsa S. Bhatc270a812014-03-11 02:12:08 +0530490
Sebastian Andrzej Siewiore722d8d2016-07-13 17:16:59 +0000491 return err;
492err_state_onl:
493#ifdef CONFIG_SMP
494 cpuhp_remove_state(online_state);
495err_state_prep:
496 cpuhp_remove_state(CPUHP_PROFILE_PREPARE);
497#endif
Srivatsa S. Bhatc270a812014-03-11 02:12:08 +0530498 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499}
Paul Gortmakerc96d6662014-04-03 14:48:35 -0700500subsys_initcall(create_proc_profile);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501#endif /* CONFIG_PROC_FS */