K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 1 | /* |
| 2 | * This program is free software; you can redistribute it and/or modify |
| 3 | * it under the terms of the GNU General Public License as published by |
| 4 | * the Free Software Foundation; either version 2 of the License, or |
| 5 | * (at your option) any later version. |
| 6 | * |
| 7 | * This program is distributed in the hope that it will be useful, |
| 8 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 9 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 10 | * GNU General Public License for more details. |
| 11 | * |
| 12 | * You should have received a copy of the GNU General Public License |
| 13 | * along with this program; if not, write to the Free Software |
| 14 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 15 | * |
| 16 | * Copyright (C) 2007 Alan Stern |
| 17 | * Copyright (C) IBM Corporation, 2009 |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 18 | * Copyright (C) 2009, Frederic Weisbecker <fweisbec@gmail.com> |
Frederic Weisbecker | ba1c813 | 2009-09-10 09:26:21 +0200 | [diff] [blame] | 19 | * |
| 20 | * Thanks to Ingo Molnar for his many suggestions. |
K.Prasad | ba6909b | 2009-11-23 21:17:13 +0530 | [diff] [blame] | 21 | * |
| 22 | * Authors: Alan Stern <stern@rowland.harvard.edu> |
| 23 | * K.Prasad <prasad@linux.vnet.ibm.com> |
| 24 | * Frederic Weisbecker <fweisbec@gmail.com> |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 25 | */ |
| 26 | |
| 27 | /* |
| 28 | * HW_breakpoint: a unified kernel/user-space hardware breakpoint facility, |
| 29 | * using the CPU's debug registers. |
| 30 | * This file contains the arch-independent routines. |
| 31 | */ |
| 32 | |
| 33 | #include <linux/irqflags.h> |
| 34 | #include <linux/kallsyms.h> |
| 35 | #include <linux/notifier.h> |
| 36 | #include <linux/kprobes.h> |
| 37 | #include <linux/kdebug.h> |
| 38 | #include <linux/kernel.h> |
| 39 | #include <linux/module.h> |
| 40 | #include <linux/percpu.h> |
| 41 | #include <linux/sched.h> |
| 42 | #include <linux/init.h> |
| 43 | #include <linux/smp.h> |
| 44 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 45 | #include <linux/hw_breakpoint.h> |
| 46 | |
Frederic Weisbecker | ba1c813 | 2009-09-10 09:26:21 +0200 | [diff] [blame] | 47 | /* |
| 48 | * Constraints data |
| 49 | */ |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 50 | |
Frederic Weisbecker | ba1c813 | 2009-09-10 09:26:21 +0200 | [diff] [blame] | 51 | /* Number of pinned cpu breakpoints in a cpu */ |
| 52 | static DEFINE_PER_CPU(unsigned int, nr_cpu_bp_pinned); |
| 53 | |
| 54 | /* Number of pinned task breakpoints in a cpu */ |
| 55 | static DEFINE_PER_CPU(unsigned int, task_bp_pinned[HBP_NUM]); |
| 56 | |
| 57 | /* Number of non-pinned cpu/task breakpoints in a cpu */ |
| 58 | static DEFINE_PER_CPU(unsigned int, nr_bp_flexible); |
| 59 | |
| 60 | /* Gather the number of total pinned and un-pinned bp in a cpuset */ |
| 61 | struct bp_busy_slots { |
| 62 | unsigned int pinned; |
| 63 | unsigned int flexible; |
| 64 | }; |
| 65 | |
| 66 | /* Serialize accesses to the above constraints */ |
| 67 | static DEFINE_MUTEX(nr_bp_mutex); |
| 68 | |
| 69 | /* |
| 70 | * Report the maximum number of pinned breakpoints a task |
| 71 | * have in this cpu |
| 72 | */ |
| 73 | static unsigned int max_task_bp_pinned(int cpu) |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 74 | { |
Frederic Weisbecker | ba1c813 | 2009-09-10 09:26:21 +0200 | [diff] [blame] | 75 | int i; |
| 76 | unsigned int *tsk_pinned = per_cpu(task_bp_pinned, cpu); |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 77 | |
Frederic Weisbecker | ba1c813 | 2009-09-10 09:26:21 +0200 | [diff] [blame] | 78 | for (i = HBP_NUM -1; i >= 0; i--) { |
| 79 | if (tsk_pinned[i] > 0) |
| 80 | return i + 1; |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 81 | } |
| 82 | |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 83 | return 0; |
| 84 | } |
| 85 | |
Frederic Weisbecker | ba1c813 | 2009-09-10 09:26:21 +0200 | [diff] [blame] | 86 | /* |
| 87 | * Report the number of pinned/un-pinned breakpoints we have in |
| 88 | * a given cpu (cpu > -1) or in all of them (cpu = -1). |
| 89 | */ |
| 90 | static void fetch_bp_busy_slots(struct bp_busy_slots *slots, int cpu) |
| 91 | { |
| 92 | if (cpu >= 0) { |
| 93 | slots->pinned = per_cpu(nr_cpu_bp_pinned, cpu); |
| 94 | slots->pinned += max_task_bp_pinned(cpu); |
| 95 | slots->flexible = per_cpu(nr_bp_flexible, cpu); |
| 96 | |
| 97 | return; |
| 98 | } |
| 99 | |
| 100 | for_each_online_cpu(cpu) { |
| 101 | unsigned int nr; |
| 102 | |
| 103 | nr = per_cpu(nr_cpu_bp_pinned, cpu); |
| 104 | nr += max_task_bp_pinned(cpu); |
| 105 | |
| 106 | if (nr > slots->pinned) |
| 107 | slots->pinned = nr; |
| 108 | |
| 109 | nr = per_cpu(nr_bp_flexible, cpu); |
| 110 | |
| 111 | if (nr > slots->flexible) |
| 112 | slots->flexible = nr; |
| 113 | } |
| 114 | } |
| 115 | |
| 116 | /* |
| 117 | * Add a pinned breakpoint for the given task in our constraint table |
| 118 | */ |
| 119 | static void toggle_bp_task_slot(struct task_struct *tsk, int cpu, bool enable) |
| 120 | { |
| 121 | int count = 0; |
| 122 | struct perf_event *bp; |
| 123 | struct perf_event_context *ctx = tsk->perf_event_ctxp; |
Andrew Morton | 11e6635 | 2009-11-25 23:01:50 -0800 | [diff] [blame] | 124 | unsigned int *tsk_pinned; |
Frederic Weisbecker | ba1c813 | 2009-09-10 09:26:21 +0200 | [diff] [blame] | 125 | struct list_head *list; |
| 126 | unsigned long flags; |
| 127 | |
| 128 | if (WARN_ONCE(!ctx, "No perf context for this task")) |
| 129 | return; |
| 130 | |
| 131 | list = &ctx->event_list; |
| 132 | |
| 133 | spin_lock_irqsave(&ctx->lock, flags); |
| 134 | |
| 135 | /* |
| 136 | * The current breakpoint counter is not included in the list |
| 137 | * at the open() callback time |
| 138 | */ |
| 139 | list_for_each_entry(bp, list, event_entry) { |
| 140 | if (bp->attr.type == PERF_TYPE_BREAKPOINT) |
| 141 | count++; |
| 142 | } |
| 143 | |
| 144 | spin_unlock_irqrestore(&ctx->lock, flags); |
| 145 | |
| 146 | if (WARN_ONCE(count < 0, "No breakpoint counter found in the counter list")) |
| 147 | return; |
| 148 | |
Andrew Morton | 11e6635 | 2009-11-25 23:01:50 -0800 | [diff] [blame] | 149 | tsk_pinned = per_cpu(task_bp_pinned, cpu); |
Frederic Weisbecker | ba1c813 | 2009-09-10 09:26:21 +0200 | [diff] [blame] | 150 | if (enable) { |
Andrew Morton | 11e6635 | 2009-11-25 23:01:50 -0800 | [diff] [blame] | 151 | tsk_pinned[count]++; |
Frederic Weisbecker | ba1c813 | 2009-09-10 09:26:21 +0200 | [diff] [blame] | 152 | if (count > 0) |
Andrew Morton | 11e6635 | 2009-11-25 23:01:50 -0800 | [diff] [blame] | 153 | tsk_pinned[count-1]--; |
Frederic Weisbecker | ba1c813 | 2009-09-10 09:26:21 +0200 | [diff] [blame] | 154 | } else { |
Andrew Morton | 11e6635 | 2009-11-25 23:01:50 -0800 | [diff] [blame] | 155 | tsk_pinned[count]--; |
Frederic Weisbecker | ba1c813 | 2009-09-10 09:26:21 +0200 | [diff] [blame] | 156 | if (count > 0) |
Andrew Morton | 11e6635 | 2009-11-25 23:01:50 -0800 | [diff] [blame] | 157 | tsk_pinned[count-1]++; |
Frederic Weisbecker | ba1c813 | 2009-09-10 09:26:21 +0200 | [diff] [blame] | 158 | } |
| 159 | } |
| 160 | |
| 161 | /* |
| 162 | * Add/remove the given breakpoint in our constraint table |
| 163 | */ |
| 164 | static void toggle_bp_slot(struct perf_event *bp, bool enable) |
| 165 | { |
| 166 | int cpu = bp->cpu; |
| 167 | struct task_struct *tsk = bp->ctx->task; |
| 168 | |
| 169 | /* Pinned counter task profiling */ |
| 170 | if (tsk) { |
| 171 | if (cpu >= 0) { |
| 172 | toggle_bp_task_slot(tsk, cpu, enable); |
| 173 | return; |
| 174 | } |
| 175 | |
| 176 | for_each_online_cpu(cpu) |
| 177 | toggle_bp_task_slot(tsk, cpu, enable); |
| 178 | return; |
| 179 | } |
| 180 | |
| 181 | /* Pinned counter cpu profiling */ |
| 182 | if (enable) |
| 183 | per_cpu(nr_cpu_bp_pinned, bp->cpu)++; |
| 184 | else |
| 185 | per_cpu(nr_cpu_bp_pinned, bp->cpu)--; |
| 186 | } |
| 187 | |
| 188 | /* |
| 189 | * Contraints to check before allowing this new breakpoint counter: |
| 190 | * |
| 191 | * == Non-pinned counter == (Considered as pinned for now) |
| 192 | * |
| 193 | * - If attached to a single cpu, check: |
| 194 | * |
| 195 | * (per_cpu(nr_bp_flexible, cpu) || (per_cpu(nr_cpu_bp_pinned, cpu) |
| 196 | * + max(per_cpu(task_bp_pinned, cpu)))) < HBP_NUM |
| 197 | * |
| 198 | * -> If there are already non-pinned counters in this cpu, it means |
| 199 | * there is already a free slot for them. |
| 200 | * Otherwise, we check that the maximum number of per task |
| 201 | * breakpoints (for this cpu) plus the number of per cpu breakpoint |
| 202 | * (for this cpu) doesn't cover every registers. |
| 203 | * |
| 204 | * - If attached to every cpus, check: |
| 205 | * |
| 206 | * (per_cpu(nr_bp_flexible, *) || (max(per_cpu(nr_cpu_bp_pinned, *)) |
| 207 | * + max(per_cpu(task_bp_pinned, *)))) < HBP_NUM |
| 208 | * |
| 209 | * -> This is roughly the same, except we check the number of per cpu |
| 210 | * bp for every cpu and we keep the max one. Same for the per tasks |
| 211 | * breakpoints. |
| 212 | * |
| 213 | * |
| 214 | * == Pinned counter == |
| 215 | * |
| 216 | * - If attached to a single cpu, check: |
| 217 | * |
| 218 | * ((per_cpu(nr_bp_flexible, cpu) > 1) + per_cpu(nr_cpu_bp_pinned, cpu) |
| 219 | * + max(per_cpu(task_bp_pinned, cpu))) < HBP_NUM |
| 220 | * |
| 221 | * -> Same checks as before. But now the nr_bp_flexible, if any, must keep |
| 222 | * one register at least (or they will never be fed). |
| 223 | * |
| 224 | * - If attached to every cpus, check: |
| 225 | * |
| 226 | * ((per_cpu(nr_bp_flexible, *) > 1) + max(per_cpu(nr_cpu_bp_pinned, *)) |
| 227 | * + max(per_cpu(task_bp_pinned, *))) < HBP_NUM |
| 228 | */ |
| 229 | int reserve_bp_slot(struct perf_event *bp) |
| 230 | { |
| 231 | struct bp_busy_slots slots = {0}; |
| 232 | int ret = 0; |
| 233 | |
| 234 | mutex_lock(&nr_bp_mutex); |
| 235 | |
| 236 | fetch_bp_busy_slots(&slots, bp->cpu); |
| 237 | |
| 238 | /* Flexible counters need to keep at least one slot */ |
| 239 | if (slots.pinned + (!!slots.flexible) == HBP_NUM) { |
| 240 | ret = -ENOSPC; |
| 241 | goto end; |
| 242 | } |
| 243 | |
| 244 | toggle_bp_slot(bp, true); |
| 245 | |
| 246 | end: |
| 247 | mutex_unlock(&nr_bp_mutex); |
| 248 | |
| 249 | return ret; |
| 250 | } |
| 251 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 252 | void release_bp_slot(struct perf_event *bp) |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 253 | { |
Frederic Weisbecker | ba1c813 | 2009-09-10 09:26:21 +0200 | [diff] [blame] | 254 | mutex_lock(&nr_bp_mutex); |
| 255 | |
| 256 | toggle_bp_slot(bp, false); |
| 257 | |
| 258 | mutex_unlock(&nr_bp_mutex); |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 259 | } |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 260 | |
Frederic Weisbecker | ba1c813 | 2009-09-10 09:26:21 +0200 | [diff] [blame] | 261 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 262 | int __register_perf_hw_breakpoint(struct perf_event *bp) |
| 263 | { |
| 264 | int ret; |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 265 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 266 | ret = reserve_bp_slot(bp); |
| 267 | if (ret) |
| 268 | return ret; |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 269 | |
Frederic Weisbecker | fdf6bc9 | 2009-11-23 15:42:33 +0100 | [diff] [blame] | 270 | /* |
| 271 | * Ptrace breakpoints can be temporary perf events only |
| 272 | * meant to reserve a slot. In this case, it is created disabled and |
| 273 | * we don't want to check the params right now (as we put a null addr) |
| 274 | * But perf tools create events as disabled and we want to check |
| 275 | * the params for them. |
| 276 | * This is a quick hack that will be removed soon, once we remove |
| 277 | * the tmp breakpoints from ptrace |
| 278 | */ |
| 279 | if (!bp->attr.disabled || bp->callback == perf_bp_event) |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 280 | ret = arch_validate_hwbkpt_settings(bp, bp->ctx->task); |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 281 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 282 | return ret; |
| 283 | } |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 284 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 285 | int register_perf_hw_breakpoint(struct perf_event *bp) |
| 286 | { |
| 287 | bp->callback = perf_bp_event; |
| 288 | |
| 289 | return __register_perf_hw_breakpoint(bp); |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 290 | } |
| 291 | |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 292 | /** |
| 293 | * register_user_hw_breakpoint - register a hardware breakpoint for user space |
Frederic Weisbecker | 5fa10b2 | 2009-11-27 04:55:53 +0100 | [diff] [blame] | 294 | * @attr: breakpoint attributes |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 295 | * @triggered: callback to trigger when we hit the breakpoint |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 296 | * @tsk: pointer to 'task_struct' of the process to which the address belongs |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 297 | */ |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 298 | struct perf_event * |
Frederic Weisbecker | 5fa10b2 | 2009-11-27 04:55:53 +0100 | [diff] [blame] | 299 | register_user_hw_breakpoint(struct perf_event_attr *attr, |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 300 | perf_callback_t triggered, |
Frederic Weisbecker | 5fa10b2 | 2009-11-27 04:55:53 +0100 | [diff] [blame] | 301 | struct task_struct *tsk) |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 302 | { |
Frederic Weisbecker | 5fa10b2 | 2009-11-27 04:55:53 +0100 | [diff] [blame] | 303 | return perf_event_create_kernel_counter(attr, -1, tsk->pid, triggered); |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 304 | } |
| 305 | EXPORT_SYMBOL_GPL(register_user_hw_breakpoint); |
| 306 | |
| 307 | /** |
| 308 | * modify_user_hw_breakpoint - modify a user-space hardware breakpoint |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 309 | * @bp: the breakpoint structure to modify |
Frederic Weisbecker | 5fa10b2 | 2009-11-27 04:55:53 +0100 | [diff] [blame] | 310 | * @attr: new breakpoint attributes |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 311 | * @triggered: callback to trigger when we hit the breakpoint |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 312 | * @tsk: pointer to 'task_struct' of the process to which the address belongs |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 313 | */ |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 314 | struct perf_event * |
Frederic Weisbecker | 5fa10b2 | 2009-11-27 04:55:53 +0100 | [diff] [blame] | 315 | modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr, |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 316 | perf_callback_t triggered, |
Frederic Weisbecker | 5fa10b2 | 2009-11-27 04:55:53 +0100 | [diff] [blame] | 317 | struct task_struct *tsk) |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 318 | { |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 319 | /* |
| 320 | * FIXME: do it without unregistering |
| 321 | * - We don't want to lose our slot |
| 322 | * - If the new bp is incorrect, don't lose the older one |
| 323 | */ |
| 324 | unregister_hw_breakpoint(bp); |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 325 | |
Frederic Weisbecker | 5fa10b2 | 2009-11-27 04:55:53 +0100 | [diff] [blame] | 326 | return perf_event_create_kernel_counter(attr, -1, tsk->pid, triggered); |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 327 | } |
| 328 | EXPORT_SYMBOL_GPL(modify_user_hw_breakpoint); |
| 329 | |
| 330 | /** |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 331 | * unregister_hw_breakpoint - unregister a user-space hardware breakpoint |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 332 | * @bp: the breakpoint structure to unregister |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 333 | */ |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 334 | void unregister_hw_breakpoint(struct perf_event *bp) |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 335 | { |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 336 | if (!bp) |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 337 | return; |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 338 | perf_event_release_kernel(bp); |
| 339 | } |
| 340 | EXPORT_SYMBOL_GPL(unregister_hw_breakpoint); |
| 341 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 342 | /** |
| 343 | * register_wide_hw_breakpoint - register a wide breakpoint in the kernel |
Frederic Weisbecker | dd1853c | 2009-11-27 04:55:54 +0100 | [diff] [blame] | 344 | * @attr: breakpoint attributes |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 345 | * @triggered: callback to trigger when we hit the breakpoint |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 346 | * |
| 347 | * @return a set of per_cpu pointers to perf events |
| 348 | */ |
| 349 | struct perf_event ** |
Frederic Weisbecker | dd1853c | 2009-11-27 04:55:54 +0100 | [diff] [blame] | 350 | register_wide_hw_breakpoint(struct perf_event_attr *attr, |
| 351 | perf_callback_t triggered) |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 352 | { |
| 353 | struct perf_event **cpu_events, **pevent, *bp; |
| 354 | long err; |
| 355 | int cpu; |
| 356 | |
| 357 | cpu_events = alloc_percpu(typeof(*cpu_events)); |
| 358 | if (!cpu_events) |
| 359 | return ERR_PTR(-ENOMEM); |
| 360 | |
| 361 | for_each_possible_cpu(cpu) { |
| 362 | pevent = per_cpu_ptr(cpu_events, cpu); |
Frederic Weisbecker | dd1853c | 2009-11-27 04:55:54 +0100 | [diff] [blame] | 363 | bp = perf_event_create_kernel_counter(attr, cpu, -1, triggered); |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 364 | |
| 365 | *pevent = bp; |
| 366 | |
Frederic Weisbecker | 605bfae | 2009-11-26 05:35:42 +0100 | [diff] [blame] | 367 | if (IS_ERR(bp)) { |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 368 | err = PTR_ERR(bp); |
| 369 | goto fail; |
| 370 | } |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 371 | } |
| 372 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 373 | return cpu_events; |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 374 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 375 | fail: |
| 376 | for_each_possible_cpu(cpu) { |
| 377 | pevent = per_cpu_ptr(cpu_events, cpu); |
Frederic Weisbecker | 605bfae | 2009-11-26 05:35:42 +0100 | [diff] [blame] | 378 | if (IS_ERR(*pevent)) |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 379 | break; |
| 380 | unregister_hw_breakpoint(*pevent); |
| 381 | } |
| 382 | free_percpu(cpu_events); |
| 383 | /* return the error if any */ |
| 384 | return ERR_PTR(err); |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 385 | } |
Frederic Weisbecker | f60d24d | 2009-11-10 10:17:07 +0100 | [diff] [blame] | 386 | EXPORT_SYMBOL_GPL(register_wide_hw_breakpoint); |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 387 | |
| 388 | /** |
| 389 | * unregister_wide_hw_breakpoint - unregister a wide breakpoint in the kernel |
| 390 | * @cpu_events: the per cpu set of events to unregister |
| 391 | */ |
| 392 | void unregister_wide_hw_breakpoint(struct perf_event **cpu_events) |
| 393 | { |
| 394 | int cpu; |
| 395 | struct perf_event **pevent; |
| 396 | |
| 397 | for_each_possible_cpu(cpu) { |
| 398 | pevent = per_cpu_ptr(cpu_events, cpu); |
| 399 | unregister_hw_breakpoint(*pevent); |
| 400 | } |
| 401 | free_percpu(cpu_events); |
| 402 | } |
Frederic Weisbecker | f60d24d | 2009-11-10 10:17:07 +0100 | [diff] [blame] | 403 | EXPORT_SYMBOL_GPL(unregister_wide_hw_breakpoint); |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 404 | |
| 405 | static struct notifier_block hw_breakpoint_exceptions_nb = { |
| 406 | .notifier_call = hw_breakpoint_exceptions_notify, |
| 407 | /* we need to be notified first */ |
| 408 | .priority = 0x7fffffff |
| 409 | }; |
| 410 | |
| 411 | static int __init init_hw_breakpoint(void) |
| 412 | { |
| 413 | return register_die_notifier(&hw_breakpoint_exceptions_nb); |
| 414 | } |
K.Prasad | 62a038d | 2009-06-01 23:43:33 +0530 | [diff] [blame] | 415 | core_initcall(init_hw_breakpoint); |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 416 | |
| 417 | |
| 418 | struct pmu perf_ops_bp = { |
| 419 | .enable = arch_install_hw_breakpoint, |
| 420 | .disable = arch_uninstall_hw_breakpoint, |
| 421 | .read = hw_breakpoint_pmu_read, |
| 422 | .unthrottle = hw_breakpoint_pmu_unthrottle |
| 423 | }; |