Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Debug Store support |
| 3 | * |
| 4 | * This provides a low-level interface to the hardware's Debug Store |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 5 | * feature that is used for branch trace store (BTS) and |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 6 | * precise-event based sampling (PEBS). |
| 7 | * |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 8 | * It manages: |
| 9 | * - per-thread and per-cpu allocation of BTS and PEBS |
| 10 | * - buffer memory allocation (optional) |
| 11 | * - buffer overflow handling |
| 12 | * - buffer access |
| 13 | * |
| 14 | * It assumes: |
| 15 | * - get_task_struct on all parameter tasks |
| 16 | * - current is allowed to trace parameter tasks |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 17 | * |
| 18 | * |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 19 | * Copyright (C) 2007-2008 Intel Corporation. |
| 20 | * Markus Metzger <markus.t.metzger@intel.com>, 2007-2008 |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 21 | */ |
| 22 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 23 | |
| 24 | #ifdef CONFIG_X86_DS |
| 25 | |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 26 | #include <asm/ds.h> |
| 27 | |
| 28 | #include <linux/errno.h> |
| 29 | #include <linux/string.h> |
| 30 | #include <linux/slab.h> |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 31 | #include <linux/sched.h> |
Ingo Molnar | 3c933904 | 2008-07-25 11:32:36 +0200 | [diff] [blame] | 32 | #include <linux/mm.h> |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 33 | |
| 34 | |
| 35 | /* |
| 36 | * The configuration for a particular DS hardware implementation. |
| 37 | */ |
| 38 | struct ds_configuration { |
| 39 | /* the size of the DS structure in bytes */ |
| 40 | unsigned char sizeof_ds; |
| 41 | /* the size of one pointer-typed field in the DS structure in bytes; |
| 42 | this covers the first 8 fields related to buffer management. */ |
| 43 | unsigned char sizeof_field; |
| 44 | /* the size of a BTS/PEBS record in bytes */ |
| 45 | unsigned char sizeof_rec[2]; |
| 46 | }; |
| 47 | static struct ds_configuration ds_cfg; |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 48 | |
| 49 | |
| 50 | /* |
| 51 | * Debug Store (DS) save area configuration (see Intel64 and IA32 |
| 52 | * Architectures Software Developer's Manual, section 18.5) |
| 53 | * |
| 54 | * The DS configuration consists of the following fields; different |
| 55 | * architetures vary in the size of those fields. |
| 56 | * - double-word aligned base linear address of the BTS buffer |
| 57 | * - write pointer into the BTS buffer |
| 58 | * - end linear address of the BTS buffer (one byte beyond the end of |
| 59 | * the buffer) |
| 60 | * - interrupt pointer into BTS buffer |
| 61 | * (interrupt occurs when write pointer passes interrupt pointer) |
| 62 | * - double-word aligned base linear address of the PEBS buffer |
| 63 | * - write pointer into the PEBS buffer |
| 64 | * - end linear address of the PEBS buffer (one byte beyond the end of |
| 65 | * the buffer) |
| 66 | * - interrupt pointer into PEBS buffer |
| 67 | * (interrupt occurs when write pointer passes interrupt pointer) |
| 68 | * - value to which counter is reset following counter overflow |
| 69 | * |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 70 | * Later architectures use 64bit pointers throughout, whereas earlier |
| 71 | * architectures use 32bit pointers in 32bit mode. |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 72 | * |
| 73 | * |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 74 | * We compute the base address for the first 8 fields based on: |
| 75 | * - the field size stored in the DS configuration |
| 76 | * - the relative field position |
| 77 | * - an offset giving the start of the respective region |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 78 | * |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 79 | * This offset is further used to index various arrays holding |
| 80 | * information for BTS and PEBS at the respective index. |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 81 | * |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 82 | * On later 32bit processors, we only access the lower 32bit of the |
| 83 | * 64bit pointer fields. The upper halves will be zeroed out. |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 84 | */ |
| 85 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 86 | enum ds_field { |
| 87 | ds_buffer_base = 0, |
| 88 | ds_index, |
| 89 | ds_absolute_maximum, |
| 90 | ds_interrupt_threshold, |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 91 | }; |
| 92 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 93 | enum ds_qualifier { |
| 94 | ds_bts = 0, |
| 95 | ds_pebs |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 96 | }; |
| 97 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 98 | static inline unsigned long ds_get(const unsigned char *base, |
| 99 | enum ds_qualifier qual, enum ds_field field) |
| 100 | { |
| 101 | base += (ds_cfg.sizeof_field * (field + (4 * qual))); |
| 102 | return *(unsigned long *)base; |
| 103 | } |
| 104 | |
| 105 | static inline void ds_set(unsigned char *base, enum ds_qualifier qual, |
| 106 | enum ds_field field, unsigned long value) |
| 107 | { |
| 108 | base += (ds_cfg.sizeof_field * (field + (4 * qual))); |
| 109 | (*(unsigned long *)base) = value; |
| 110 | } |
| 111 | |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 112 | |
| 113 | /* |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 114 | * Locking is done only for allocating BTS or PEBS resources and for |
| 115 | * guarding context and buffer memory allocation. |
| 116 | * |
| 117 | * Most functions require the current task to own the ds context part |
| 118 | * they are going to access. All the locking is done when validating |
| 119 | * access to the context. |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 120 | */ |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 121 | static spinlock_t ds_lock = __SPIN_LOCK_UNLOCKED(ds_lock); |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 122 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 123 | /* |
| 124 | * Validate that the current task is allowed to access the BTS/PEBS |
| 125 | * buffer of the parameter task. |
| 126 | * |
| 127 | * Returns 0, if access is granted; -Eerrno, otherwise. |
| 128 | */ |
| 129 | static inline int ds_validate_access(struct ds_context *context, |
| 130 | enum ds_qualifier qual) |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 131 | { |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 132 | if (!context) |
| 133 | return -EPERM; |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 134 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 135 | if (context->owner[qual] == current) |
Markus Metzger | a95d67f | 2008-01-30 13:31:20 +0100 | [diff] [blame] | 136 | return 0; |
| 137 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 138 | return -EPERM; |
Markus Metzger | a95d67f | 2008-01-30 13:31:20 +0100 | [diff] [blame] | 139 | } |
| 140 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 141 | |
| 142 | /* |
| 143 | * We either support (system-wide) per-cpu or per-thread allocation. |
| 144 | * We distinguish the two based on the task_struct pointer, where a |
| 145 | * NULL pointer indicates per-cpu allocation for the current cpu. |
| 146 | * |
| 147 | * Allocations are use-counted. As soon as resources are allocated, |
| 148 | * further allocations must be of the same type (per-cpu or |
| 149 | * per-thread). We model this by counting allocations (i.e. the number |
| 150 | * of tracers of a certain type) for one type negatively: |
| 151 | * =0 no tracers |
| 152 | * >0 number of per-thread tracers |
| 153 | * <0 number of per-cpu tracers |
| 154 | * |
| 155 | * The below functions to get and put tracers and to check the |
| 156 | * allocation type require the ds_lock to be held by the caller. |
| 157 | * |
| 158 | * Tracers essentially gives the number of ds contexts for a certain |
| 159 | * type of allocation. |
| 160 | */ |
| 161 | static long tracers; |
| 162 | |
| 163 | static inline void get_tracer(struct task_struct *task) |
Markus Metzger | a95d67f | 2008-01-30 13:31:20 +0100 | [diff] [blame] | 164 | { |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 165 | tracers += (task ? 1 : -1); |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 166 | } |
| 167 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 168 | static inline void put_tracer(struct task_struct *task) |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 169 | { |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 170 | tracers -= (task ? 1 : -1); |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 171 | } |
| 172 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 173 | static inline int check_tracer(struct task_struct *task) |
Markus Metzger | a95d67f | 2008-01-30 13:31:20 +0100 | [diff] [blame] | 174 | { |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 175 | return (task ? (tracers >= 0) : (tracers <= 0)); |
| 176 | } |
| 177 | |
| 178 | |
| 179 | /* |
| 180 | * The DS context is either attached to a thread or to a cpu: |
| 181 | * - in the former case, the thread_struct contains a pointer to the |
| 182 | * attached context. |
| 183 | * - in the latter case, we use a static array of per-cpu context |
| 184 | * pointers. |
| 185 | * |
| 186 | * Contexts are use-counted. They are allocated on first access and |
| 187 | * deallocated when the last user puts the context. |
| 188 | * |
| 189 | * We distinguish between an allocating and a non-allocating get of a |
| 190 | * context: |
| 191 | * - the allocating get is used for requesting BTS/PEBS resources. It |
| 192 | * requires the caller to hold the global ds_lock. |
| 193 | * - the non-allocating get is used for all other cases. A |
| 194 | * non-existing context indicates an error. It acquires and releases |
| 195 | * the ds_lock itself for obtaining the context. |
| 196 | * |
| 197 | * A context and its DS configuration are allocated and deallocated |
| 198 | * together. A context always has a DS configuration of the |
| 199 | * appropriate size. |
| 200 | */ |
| 201 | static DEFINE_PER_CPU(struct ds_context *, system_context); |
| 202 | |
| 203 | #define this_system_context per_cpu(system_context, smp_processor_id()) |
| 204 | |
| 205 | /* |
| 206 | * Returns the pointer to the parameter task's context or to the |
| 207 | * system-wide context, if task is NULL. |
| 208 | * |
| 209 | * Increases the use count of the returned context, if not NULL. |
| 210 | */ |
| 211 | static inline struct ds_context *ds_get_context(struct task_struct *task) |
| 212 | { |
| 213 | struct ds_context *context; |
| 214 | |
| 215 | spin_lock(&ds_lock); |
| 216 | |
| 217 | context = (task ? task->thread.ds_ctx : this_system_context); |
| 218 | if (context) |
| 219 | context->count++; |
| 220 | |
| 221 | spin_unlock(&ds_lock); |
| 222 | |
| 223 | return context; |
| 224 | } |
| 225 | |
| 226 | /* |
| 227 | * Same as ds_get_context, but allocates the context and it's DS |
| 228 | * structure, if necessary; returns NULL; if out of memory. |
| 229 | * |
| 230 | * pre: requires ds_lock to be held |
| 231 | */ |
| 232 | static inline struct ds_context *ds_alloc_context(struct task_struct *task) |
| 233 | { |
| 234 | struct ds_context **p_context = |
| 235 | (task ? &task->thread.ds_ctx : &this_system_context); |
| 236 | struct ds_context *context = *p_context; |
| 237 | |
| 238 | if (!context) { |
Ingo Molnar | 10db4ef | 2008-11-18 15:23:08 +0100 | [diff] [blame] | 239 | spin_unlock(&ds_lock); |
| 240 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 241 | context = kzalloc(sizeof(*context), GFP_KERNEL); |
| 242 | |
Ingo Molnar | 10db4ef | 2008-11-18 15:23:08 +0100 | [diff] [blame] | 243 | if (!context) { |
| 244 | spin_lock(&ds_lock); |
Cyrill Gorcunov | 573da42 | 2008-04-28 23:15:04 +0400 | [diff] [blame] | 245 | return NULL; |
Ingo Molnar | 10db4ef | 2008-11-18 15:23:08 +0100 | [diff] [blame] | 246 | } |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 247 | |
| 248 | context->ds = kzalloc(ds_cfg.sizeof_ds, GFP_KERNEL); |
| 249 | if (!context->ds) { |
| 250 | kfree(context); |
Ingo Molnar | 10db4ef | 2008-11-18 15:23:08 +0100 | [diff] [blame] | 251 | spin_lock(&ds_lock); |
Cyrill Gorcunov | 573da42 | 2008-04-28 23:15:04 +0400 | [diff] [blame] | 252 | return NULL; |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 253 | } |
| 254 | |
Ingo Molnar | 10db4ef | 2008-11-18 15:23:08 +0100 | [diff] [blame] | 255 | spin_lock(&ds_lock); |
| 256 | /* |
| 257 | * Check for race - another CPU could have allocated |
| 258 | * it meanwhile: |
| 259 | */ |
| 260 | if (*p_context) { |
| 261 | kfree(context->ds); |
| 262 | kfree(context); |
| 263 | return *p_context; |
| 264 | } |
| 265 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 266 | *p_context = context; |
| 267 | |
| 268 | context->this = p_context; |
| 269 | context->task = task; |
| 270 | |
| 271 | if (task) |
| 272 | set_tsk_thread_flag(task, TIF_DS_AREA_MSR); |
| 273 | |
| 274 | if (!task || (task == current)) |
| 275 | wrmsr(MSR_IA32_DS_AREA, (unsigned long)context->ds, 0); |
| 276 | |
| 277 | get_tracer(task); |
| 278 | } |
| 279 | |
| 280 | context->count++; |
| 281 | |
| 282 | return context; |
| 283 | } |
| 284 | |
| 285 | /* |
| 286 | * Decreases the use count of the parameter context, if not NULL. |
| 287 | * Deallocates the context, if the use count reaches zero. |
| 288 | */ |
| 289 | static inline void ds_put_context(struct ds_context *context) |
| 290 | { |
| 291 | if (!context) |
| 292 | return; |
| 293 | |
| 294 | spin_lock(&ds_lock); |
| 295 | |
| 296 | if (--context->count) |
| 297 | goto out; |
| 298 | |
Cyrill Gorcunov | 573da42 | 2008-04-28 23:15:04 +0400 | [diff] [blame] | 299 | *(context->this) = NULL; |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 300 | |
| 301 | if (context->task) |
| 302 | clear_tsk_thread_flag(context->task, TIF_DS_AREA_MSR); |
| 303 | |
| 304 | if (!context->task || (context->task == current)) |
| 305 | wrmsrl(MSR_IA32_DS_AREA, 0); |
| 306 | |
| 307 | put_tracer(context->task); |
| 308 | |
| 309 | /* free any leftover buffers from tracers that did not |
| 310 | * deallocate them properly. */ |
| 311 | kfree(context->buffer[ds_bts]); |
| 312 | kfree(context->buffer[ds_pebs]); |
| 313 | kfree(context->ds); |
| 314 | kfree(context); |
| 315 | out: |
| 316 | spin_unlock(&ds_lock); |
| 317 | } |
| 318 | |
| 319 | |
| 320 | /* |
| 321 | * Handle a buffer overflow |
| 322 | * |
| 323 | * task: the task whose buffers are overflowing; |
| 324 | * NULL for a buffer overflow on the current cpu |
| 325 | * context: the ds context |
| 326 | * qual: the buffer type |
| 327 | */ |
| 328 | static void ds_overflow(struct task_struct *task, struct ds_context *context, |
| 329 | enum ds_qualifier qual) |
| 330 | { |
| 331 | if (!context) |
| 332 | return; |
| 333 | |
| 334 | if (context->callback[qual]) |
| 335 | (*context->callback[qual])(task); |
| 336 | |
| 337 | /* todo: do some more overflow handling */ |
| 338 | } |
| 339 | |
| 340 | |
| 341 | /* |
| 342 | * Allocate a non-pageable buffer of the parameter size. |
| 343 | * Checks the memory and the locked memory rlimit. |
| 344 | * |
| 345 | * Returns the buffer, if successful; |
| 346 | * NULL, if out of memory or rlimit exceeded. |
| 347 | * |
| 348 | * size: the requested buffer size in bytes |
| 349 | * pages (out): if not NULL, contains the number of pages reserved |
| 350 | */ |
| 351 | static inline void *ds_allocate_buffer(size_t size, unsigned int *pages) |
| 352 | { |
| 353 | unsigned long rlim, vm, pgsz; |
| 354 | void *buffer; |
| 355 | |
| 356 | pgsz = PAGE_ALIGN(size) >> PAGE_SHIFT; |
| 357 | |
| 358 | rlim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT; |
| 359 | vm = current->mm->total_vm + pgsz; |
| 360 | if (rlim < vm) |
Cyrill Gorcunov | 573da42 | 2008-04-28 23:15:04 +0400 | [diff] [blame] | 361 | return NULL; |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 362 | |
| 363 | rlim = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT; |
| 364 | vm = current->mm->locked_vm + pgsz; |
| 365 | if (rlim < vm) |
Cyrill Gorcunov | 573da42 | 2008-04-28 23:15:04 +0400 | [diff] [blame] | 366 | return NULL; |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 367 | |
| 368 | buffer = kzalloc(size, GFP_KERNEL); |
| 369 | if (!buffer) |
Cyrill Gorcunov | 573da42 | 2008-04-28 23:15:04 +0400 | [diff] [blame] | 370 | return NULL; |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 371 | |
| 372 | current->mm->total_vm += pgsz; |
| 373 | current->mm->locked_vm += pgsz; |
| 374 | |
| 375 | if (pages) |
| 376 | *pages = pgsz; |
| 377 | |
| 378 | return buffer; |
Markus Metzger | a95d67f | 2008-01-30 13:31:20 +0100 | [diff] [blame] | 379 | } |
| 380 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 381 | static int ds_request(struct task_struct *task, void *base, size_t size, |
| 382 | ds_ovfl_callback_t ovfl, enum ds_qualifier qual) |
Markus Metzger | a95d67f | 2008-01-30 13:31:20 +0100 | [diff] [blame] | 383 | { |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 384 | struct ds_context *context; |
| 385 | unsigned long buffer, adj; |
| 386 | const unsigned long alignment = (1 << 3); |
| 387 | int error = 0; |
Markus Metzger | a95d67f | 2008-01-30 13:31:20 +0100 | [diff] [blame] | 388 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 389 | if (!ds_cfg.sizeof_ds) |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 390 | return -EOPNOTSUPP; |
| 391 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 392 | /* we require some space to do alignment adjustments below */ |
| 393 | if (size < (alignment + ds_cfg.sizeof_rec[qual])) |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 394 | return -EINVAL; |
| 395 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 396 | /* buffer overflow notification is not yet implemented */ |
| 397 | if (ovfl) |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 398 | return -EOPNOTSUPP; |
| 399 | |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 400 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 401 | spin_lock(&ds_lock); |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 402 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 403 | error = -ENOMEM; |
| 404 | context = ds_alloc_context(task); |
| 405 | if (!context) |
| 406 | goto out_unlock; |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 407 | |
Ingo Molnar | 10db4ef | 2008-11-18 15:23:08 +0100 | [diff] [blame] | 408 | error = -EPERM; |
| 409 | if (!check_tracer(task)) |
| 410 | goto out_unlock; |
| 411 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 412 | error = -EALREADY; |
| 413 | if (context->owner[qual] == current) |
| 414 | goto out_unlock; |
| 415 | error = -EPERM; |
Cyrill Gorcunov | 573da42 | 2008-04-28 23:15:04 +0400 | [diff] [blame] | 416 | if (context->owner[qual] != NULL) |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 417 | goto out_unlock; |
| 418 | context->owner[qual] = current; |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 419 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 420 | spin_unlock(&ds_lock); |
| 421 | |
| 422 | |
| 423 | error = -ENOMEM; |
| 424 | if (!base) { |
| 425 | base = ds_allocate_buffer(size, &context->pages[qual]); |
| 426 | if (!base) |
| 427 | goto out_release; |
| 428 | |
| 429 | context->buffer[qual] = base; |
| 430 | } |
| 431 | error = 0; |
| 432 | |
| 433 | context->callback[qual] = ovfl; |
| 434 | |
| 435 | /* adjust the buffer address and size to meet alignment |
| 436 | * constraints: |
| 437 | * - buffer is double-word aligned |
| 438 | * - size is multiple of record size |
| 439 | * |
| 440 | * We checked the size at the very beginning; we have enough |
| 441 | * space to do the adjustment. |
| 442 | */ |
| 443 | buffer = (unsigned long)base; |
| 444 | |
| 445 | adj = ALIGN(buffer, alignment) - buffer; |
| 446 | buffer += adj; |
| 447 | size -= adj; |
| 448 | |
| 449 | size /= ds_cfg.sizeof_rec[qual]; |
| 450 | size *= ds_cfg.sizeof_rec[qual]; |
| 451 | |
| 452 | ds_set(context->ds, qual, ds_buffer_base, buffer); |
| 453 | ds_set(context->ds, qual, ds_index, buffer); |
| 454 | ds_set(context->ds, qual, ds_absolute_maximum, buffer + size); |
| 455 | |
| 456 | if (ovfl) { |
| 457 | /* todo: select a suitable interrupt threshold */ |
| 458 | } else |
| 459 | ds_set(context->ds, qual, |
| 460 | ds_interrupt_threshold, buffer + size + 1); |
| 461 | |
| 462 | /* we keep the context until ds_release */ |
| 463 | return error; |
| 464 | |
| 465 | out_release: |
Cyrill Gorcunov | 573da42 | 2008-04-28 23:15:04 +0400 | [diff] [blame] | 466 | context->owner[qual] = NULL; |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 467 | ds_put_context(context); |
| 468 | return error; |
| 469 | |
| 470 | out_unlock: |
| 471 | spin_unlock(&ds_lock); |
| 472 | ds_put_context(context); |
| 473 | return error; |
| 474 | } |
| 475 | |
| 476 | int ds_request_bts(struct task_struct *task, void *base, size_t size, |
| 477 | ds_ovfl_callback_t ovfl) |
| 478 | { |
| 479 | return ds_request(task, base, size, ovfl, ds_bts); |
| 480 | } |
| 481 | |
| 482 | int ds_request_pebs(struct task_struct *task, void *base, size_t size, |
| 483 | ds_ovfl_callback_t ovfl) |
| 484 | { |
| 485 | return ds_request(task, base, size, ovfl, ds_pebs); |
| 486 | } |
| 487 | |
| 488 | static int ds_release(struct task_struct *task, enum ds_qualifier qual) |
| 489 | { |
| 490 | struct ds_context *context; |
| 491 | int error; |
| 492 | |
| 493 | context = ds_get_context(task); |
| 494 | error = ds_validate_access(context, qual); |
| 495 | if (error < 0) |
| 496 | goto out; |
| 497 | |
| 498 | kfree(context->buffer[qual]); |
Harvey Harrison | 493cd91 | 2008-09-23 14:56:44 -0700 | [diff] [blame] | 499 | context->buffer[qual] = NULL; |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 500 | |
| 501 | current->mm->total_vm -= context->pages[qual]; |
| 502 | current->mm->locked_vm -= context->pages[qual]; |
| 503 | context->pages[qual] = 0; |
Harvey Harrison | 493cd91 | 2008-09-23 14:56:44 -0700 | [diff] [blame] | 504 | context->owner[qual] = NULL; |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 505 | |
| 506 | /* |
| 507 | * we put the context twice: |
| 508 | * once for the ds_get_context |
| 509 | * once for the corresponding ds_request |
| 510 | */ |
| 511 | ds_put_context(context); |
| 512 | out: |
| 513 | ds_put_context(context); |
| 514 | return error; |
| 515 | } |
| 516 | |
| 517 | int ds_release_bts(struct task_struct *task) |
| 518 | { |
| 519 | return ds_release(task, ds_bts); |
| 520 | } |
| 521 | |
| 522 | int ds_release_pebs(struct task_struct *task) |
| 523 | { |
| 524 | return ds_release(task, ds_pebs); |
| 525 | } |
| 526 | |
| 527 | static int ds_get_index(struct task_struct *task, size_t *pos, |
| 528 | enum ds_qualifier qual) |
| 529 | { |
| 530 | struct ds_context *context; |
| 531 | unsigned long base, index; |
| 532 | int error; |
| 533 | |
| 534 | context = ds_get_context(task); |
| 535 | error = ds_validate_access(context, qual); |
| 536 | if (error < 0) |
| 537 | goto out; |
| 538 | |
| 539 | base = ds_get(context->ds, qual, ds_buffer_base); |
| 540 | index = ds_get(context->ds, qual, ds_index); |
| 541 | |
| 542 | error = ((index - base) / ds_cfg.sizeof_rec[qual]); |
| 543 | if (pos) |
| 544 | *pos = error; |
| 545 | out: |
| 546 | ds_put_context(context); |
| 547 | return error; |
| 548 | } |
| 549 | |
| 550 | int ds_get_bts_index(struct task_struct *task, size_t *pos) |
| 551 | { |
| 552 | return ds_get_index(task, pos, ds_bts); |
| 553 | } |
| 554 | |
| 555 | int ds_get_pebs_index(struct task_struct *task, size_t *pos) |
| 556 | { |
| 557 | return ds_get_index(task, pos, ds_pebs); |
| 558 | } |
| 559 | |
| 560 | static int ds_get_end(struct task_struct *task, size_t *pos, |
| 561 | enum ds_qualifier qual) |
| 562 | { |
| 563 | struct ds_context *context; |
| 564 | unsigned long base, end; |
| 565 | int error; |
| 566 | |
| 567 | context = ds_get_context(task); |
| 568 | error = ds_validate_access(context, qual); |
| 569 | if (error < 0) |
| 570 | goto out; |
| 571 | |
| 572 | base = ds_get(context->ds, qual, ds_buffer_base); |
| 573 | end = ds_get(context->ds, qual, ds_absolute_maximum); |
| 574 | |
| 575 | error = ((end - base) / ds_cfg.sizeof_rec[qual]); |
| 576 | if (pos) |
| 577 | *pos = error; |
| 578 | out: |
| 579 | ds_put_context(context); |
| 580 | return error; |
| 581 | } |
| 582 | |
| 583 | int ds_get_bts_end(struct task_struct *task, size_t *pos) |
| 584 | { |
| 585 | return ds_get_end(task, pos, ds_bts); |
| 586 | } |
| 587 | |
| 588 | int ds_get_pebs_end(struct task_struct *task, size_t *pos) |
| 589 | { |
| 590 | return ds_get_end(task, pos, ds_pebs); |
| 591 | } |
| 592 | |
| 593 | static int ds_access(struct task_struct *task, size_t index, |
| 594 | const void **record, enum ds_qualifier qual) |
| 595 | { |
| 596 | struct ds_context *context; |
| 597 | unsigned long base, idx; |
| 598 | int error; |
| 599 | |
| 600 | if (!record) |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 601 | return -EINVAL; |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 602 | |
| 603 | context = ds_get_context(task); |
| 604 | error = ds_validate_access(context, qual); |
| 605 | if (error < 0) |
| 606 | goto out; |
| 607 | |
| 608 | base = ds_get(context->ds, qual, ds_buffer_base); |
| 609 | idx = base + (index * ds_cfg.sizeof_rec[qual]); |
| 610 | |
| 611 | error = -EINVAL; |
| 612 | if (idx > ds_get(context->ds, qual, ds_absolute_maximum)) |
| 613 | goto out; |
| 614 | |
| 615 | *record = (const void *)idx; |
| 616 | error = ds_cfg.sizeof_rec[qual]; |
| 617 | out: |
| 618 | ds_put_context(context); |
| 619 | return error; |
| 620 | } |
| 621 | |
| 622 | int ds_access_bts(struct task_struct *task, size_t index, const void **record) |
| 623 | { |
| 624 | return ds_access(task, index, record, ds_bts); |
| 625 | } |
| 626 | |
| 627 | int ds_access_pebs(struct task_struct *task, size_t index, const void **record) |
| 628 | { |
| 629 | return ds_access(task, index, record, ds_pebs); |
| 630 | } |
| 631 | |
| 632 | static int ds_write(struct task_struct *task, const void *record, size_t size, |
| 633 | enum ds_qualifier qual, int force) |
| 634 | { |
| 635 | struct ds_context *context; |
| 636 | int error; |
| 637 | |
| 638 | if (!record) |
| 639 | return -EINVAL; |
| 640 | |
| 641 | error = -EPERM; |
| 642 | context = ds_get_context(task); |
| 643 | if (!context) |
| 644 | goto out; |
| 645 | |
| 646 | if (!force) { |
| 647 | error = ds_validate_access(context, qual); |
| 648 | if (error < 0) |
| 649 | goto out; |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 650 | } |
| 651 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 652 | error = 0; |
| 653 | while (size) { |
| 654 | unsigned long base, index, end, write_end, int_th; |
| 655 | unsigned long write_size, adj_write_size; |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 656 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 657 | /* |
| 658 | * write as much as possible without producing an |
| 659 | * overflow interrupt. |
| 660 | * |
| 661 | * interrupt_threshold must either be |
| 662 | * - bigger than absolute_maximum or |
| 663 | * - point to a record between buffer_base and absolute_maximum |
| 664 | * |
| 665 | * index points to a valid record. |
| 666 | */ |
| 667 | base = ds_get(context->ds, qual, ds_buffer_base); |
| 668 | index = ds_get(context->ds, qual, ds_index); |
| 669 | end = ds_get(context->ds, qual, ds_absolute_maximum); |
| 670 | int_th = ds_get(context->ds, qual, ds_interrupt_threshold); |
| 671 | |
| 672 | write_end = min(end, int_th); |
| 673 | |
| 674 | /* if we are already beyond the interrupt threshold, |
| 675 | * we fill the entire buffer */ |
| 676 | if (write_end <= index) |
| 677 | write_end = end; |
| 678 | |
| 679 | if (write_end <= index) |
| 680 | goto out; |
| 681 | |
| 682 | write_size = min((unsigned long) size, write_end - index); |
| 683 | memcpy((void *)index, record, write_size); |
| 684 | |
| 685 | record = (const char *)record + write_size; |
| 686 | size -= write_size; |
| 687 | error += write_size; |
| 688 | |
| 689 | adj_write_size = write_size / ds_cfg.sizeof_rec[qual]; |
| 690 | adj_write_size *= ds_cfg.sizeof_rec[qual]; |
| 691 | |
| 692 | /* zero out trailing bytes */ |
| 693 | memset((char *)index + write_size, 0, |
| 694 | adj_write_size - write_size); |
| 695 | index += adj_write_size; |
| 696 | |
| 697 | if (index >= end) |
| 698 | index = base; |
| 699 | ds_set(context->ds, qual, ds_index, index); |
| 700 | |
| 701 | if (index >= int_th) |
| 702 | ds_overflow(task, context, qual); |
| 703 | } |
| 704 | |
| 705 | out: |
| 706 | ds_put_context(context); |
| 707 | return error; |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 708 | } |
| 709 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 710 | int ds_write_bts(struct task_struct *task, const void *record, size_t size) |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 711 | { |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 712 | return ds_write(task, record, size, ds_bts, /* force = */ 0); |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 713 | } |
| 714 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 715 | int ds_write_pebs(struct task_struct *task, const void *record, size_t size) |
| 716 | { |
| 717 | return ds_write(task, record, size, ds_pebs, /* force = */ 0); |
| 718 | } |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 719 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 720 | int ds_unchecked_write_bts(struct task_struct *task, |
| 721 | const void *record, size_t size) |
| 722 | { |
| 723 | return ds_write(task, record, size, ds_bts, /* force = */ 1); |
| 724 | } |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 725 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 726 | int ds_unchecked_write_pebs(struct task_struct *task, |
| 727 | const void *record, size_t size) |
| 728 | { |
| 729 | return ds_write(task, record, size, ds_pebs, /* force = */ 1); |
| 730 | } |
| 731 | |
| 732 | static int ds_reset_or_clear(struct task_struct *task, |
| 733 | enum ds_qualifier qual, int clear) |
| 734 | { |
| 735 | struct ds_context *context; |
| 736 | unsigned long base, end; |
| 737 | int error; |
| 738 | |
| 739 | context = ds_get_context(task); |
| 740 | error = ds_validate_access(context, qual); |
| 741 | if (error < 0) |
| 742 | goto out; |
| 743 | |
| 744 | base = ds_get(context->ds, qual, ds_buffer_base); |
| 745 | end = ds_get(context->ds, qual, ds_absolute_maximum); |
| 746 | |
| 747 | if (clear) |
| 748 | memset((void *)base, 0, end - base); |
| 749 | |
| 750 | ds_set(context->ds, qual, ds_index, base); |
| 751 | |
| 752 | error = 0; |
| 753 | out: |
| 754 | ds_put_context(context); |
| 755 | return error; |
| 756 | } |
| 757 | |
| 758 | int ds_reset_bts(struct task_struct *task) |
| 759 | { |
| 760 | return ds_reset_or_clear(task, ds_bts, /* clear = */ 0); |
| 761 | } |
| 762 | |
| 763 | int ds_reset_pebs(struct task_struct *task) |
| 764 | { |
| 765 | return ds_reset_or_clear(task, ds_pebs, /* clear = */ 0); |
| 766 | } |
| 767 | |
| 768 | int ds_clear_bts(struct task_struct *task) |
| 769 | { |
| 770 | return ds_reset_or_clear(task, ds_bts, /* clear = */ 1); |
| 771 | } |
| 772 | |
| 773 | int ds_clear_pebs(struct task_struct *task) |
| 774 | { |
| 775 | return ds_reset_or_clear(task, ds_pebs, /* clear = */ 1); |
| 776 | } |
| 777 | |
| 778 | int ds_get_pebs_reset(struct task_struct *task, u64 *value) |
| 779 | { |
| 780 | struct ds_context *context; |
| 781 | int error; |
| 782 | |
| 783 | if (!value) |
| 784 | return -EINVAL; |
| 785 | |
| 786 | context = ds_get_context(task); |
| 787 | error = ds_validate_access(context, ds_pebs); |
| 788 | if (error < 0) |
| 789 | goto out; |
| 790 | |
| 791 | *value = *(u64 *)(context->ds + (ds_cfg.sizeof_field * 8)); |
| 792 | |
| 793 | error = 0; |
| 794 | out: |
| 795 | ds_put_context(context); |
| 796 | return error; |
| 797 | } |
| 798 | |
| 799 | int ds_set_pebs_reset(struct task_struct *task, u64 value) |
| 800 | { |
| 801 | struct ds_context *context; |
| 802 | int error; |
| 803 | |
| 804 | context = ds_get_context(task); |
| 805 | error = ds_validate_access(context, ds_pebs); |
| 806 | if (error < 0) |
| 807 | goto out; |
| 808 | |
| 809 | *(u64 *)(context->ds + (ds_cfg.sizeof_field * 8)) = value; |
| 810 | |
| 811 | error = 0; |
| 812 | out: |
| 813 | ds_put_context(context); |
| 814 | return error; |
| 815 | } |
| 816 | |
| 817 | static const struct ds_configuration ds_cfg_var = { |
| 818 | .sizeof_ds = sizeof(long) * 12, |
| 819 | .sizeof_field = sizeof(long), |
| 820 | .sizeof_rec[ds_bts] = sizeof(long) * 3, |
| 821 | .sizeof_rec[ds_pebs] = sizeof(long) * 10 |
| 822 | }; |
| 823 | static const struct ds_configuration ds_cfg_64 = { |
| 824 | .sizeof_ds = 8 * 12, |
| 825 | .sizeof_field = 8, |
| 826 | .sizeof_rec[ds_bts] = 8 * 3, |
| 827 | .sizeof_rec[ds_pebs] = 8 * 10 |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 828 | }; |
| 829 | |
| 830 | static inline void |
| 831 | ds_configure(const struct ds_configuration *cfg) |
| 832 | { |
| 833 | ds_cfg = *cfg; |
| 834 | } |
| 835 | |
| 836 | void __cpuinit ds_init_intel(struct cpuinfo_x86 *c) |
| 837 | { |
| 838 | switch (c->x86) { |
| 839 | case 0x6: |
| 840 | switch (c->x86_model) { |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 841 | case 0xD: |
| 842 | case 0xE: /* Pentium M */ |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 843 | ds_configure(&ds_cfg_var); |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 844 | break; |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 845 | case 0xF: /* Core2 */ |
Cyrill Gorcunov | 573da42 | 2008-04-28 23:15:04 +0400 | [diff] [blame] | 846 | case 0x1C: /* Atom */ |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 847 | ds_configure(&ds_cfg_64); |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 848 | break; |
| 849 | default: |
| 850 | /* sorry, don't know about them */ |
| 851 | break; |
| 852 | } |
| 853 | break; |
| 854 | case 0xF: |
| 855 | switch (c->x86_model) { |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 856 | case 0x0: |
| 857 | case 0x1: |
| 858 | case 0x2: /* Netburst */ |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 859 | ds_configure(&ds_cfg_var); |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 860 | break; |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 861 | default: |
| 862 | /* sorry, don't know about them */ |
| 863 | break; |
| 864 | } |
| 865 | break; |
| 866 | default: |
| 867 | /* sorry, don't know about them */ |
| 868 | break; |
| 869 | } |
| 870 | } |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 871 | |
| 872 | void ds_free(struct ds_context *context) |
| 873 | { |
| 874 | /* This is called when the task owning the parameter context |
| 875 | * is dying. There should not be any user of that context left |
| 876 | * to disturb us, anymore. */ |
| 877 | unsigned long leftovers = context->count; |
| 878 | while (leftovers--) |
| 879 | ds_put_context(context); |
| 880 | } |
| 881 | #endif /* CONFIG_X86_DS */ |