Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Debug Store (DS) 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 | |
Vegard Nossum | 77ef50a | 2008-06-18 17:08:48 +0200 | [diff] [blame] | 23 | #ifndef ASM_X86__DS_H |
| 24 | #define ASM_X86__DS_H |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 25 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 26 | #ifdef CONFIG_X86_DS |
| 27 | |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 28 | #include <linux/types.h> |
| 29 | #include <linux/init.h> |
| 30 | |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 31 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 32 | struct task_struct; |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 33 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 34 | /* |
| 35 | * Request BTS or PEBS |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 36 | * |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 37 | * Due to alignement constraints, the actual buffer may be slightly |
| 38 | * smaller than the requested or provided buffer. |
| 39 | * |
| 40 | * Returns 0 on success; -Eerrno otherwise |
| 41 | * |
| 42 | * task: the task to request recording for; |
| 43 | * NULL for per-cpu recording on the current cpu |
| 44 | * base: the base pointer for the (non-pageable) buffer; |
| 45 | * NULL if buffer allocation requested |
| 46 | * size: the size of the requested or provided buffer |
| 47 | * ovfl: pointer to a function to be called on buffer overflow; |
| 48 | * NULL if cyclic buffer requested |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 49 | */ |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 50 | typedef void (*ds_ovfl_callback_t)(struct task_struct *); |
| 51 | extern int ds_request_bts(struct task_struct *task, void *base, size_t size, |
| 52 | ds_ovfl_callback_t ovfl); |
| 53 | extern int ds_request_pebs(struct task_struct *task, void *base, size_t size, |
| 54 | ds_ovfl_callback_t ovfl); |
| 55 | |
| 56 | /* |
| 57 | * Release BTS or PEBS resources |
| 58 | * |
| 59 | * Frees buffers allocated on ds_request. |
| 60 | * |
| 61 | * Returns 0 on success; -Eerrno otherwise |
| 62 | * |
| 63 | * task: the task to release resources for; |
| 64 | * NULL to release resources for the current cpu |
| 65 | */ |
| 66 | extern int ds_release_bts(struct task_struct *task); |
| 67 | extern int ds_release_pebs(struct task_struct *task); |
| 68 | |
| 69 | /* |
| 70 | * Return the (array) index of the write pointer. |
| 71 | * (assuming an array of BTS/PEBS records) |
| 72 | * |
| 73 | * Returns -Eerrno on error |
| 74 | * |
| 75 | * task: the task to access; |
| 76 | * NULL to access the current cpu |
| 77 | * pos (out): if not NULL, will hold the result |
| 78 | */ |
| 79 | extern int ds_get_bts_index(struct task_struct *task, size_t *pos); |
| 80 | extern int ds_get_pebs_index(struct task_struct *task, size_t *pos); |
| 81 | |
| 82 | /* |
| 83 | * Return the (array) index one record beyond the end of the array. |
| 84 | * (assuming an array of BTS/PEBS records) |
| 85 | * |
| 86 | * Returns -Eerrno on error |
| 87 | * |
| 88 | * task: the task to access; |
| 89 | * NULL to access the current cpu |
| 90 | * pos (out): if not NULL, will hold the result |
| 91 | */ |
| 92 | extern int ds_get_bts_end(struct task_struct *task, size_t *pos); |
| 93 | extern int ds_get_pebs_end(struct task_struct *task, size_t *pos); |
| 94 | |
| 95 | /* |
| 96 | * Provide a pointer to the BTS/PEBS record at parameter index. |
| 97 | * (assuming an array of BTS/PEBS records) |
| 98 | * |
| 99 | * The pointer points directly into the buffer. The user is |
| 100 | * responsible for copying the record. |
| 101 | * |
| 102 | * Returns the size of a single record on success; -Eerrno on error |
| 103 | * |
| 104 | * task: the task to access; |
| 105 | * NULL to access the current cpu |
| 106 | * index: the index of the requested record |
| 107 | * record (out): pointer to the requested record |
| 108 | */ |
| 109 | extern int ds_access_bts(struct task_struct *task, |
| 110 | size_t index, const void **record); |
| 111 | extern int ds_access_pebs(struct task_struct *task, |
| 112 | size_t index, const void **record); |
| 113 | |
| 114 | /* |
| 115 | * Write one or more BTS/PEBS records at the write pointer index and |
| 116 | * advance the write pointer. |
| 117 | * |
| 118 | * If size is not a multiple of the record size, trailing bytes are |
| 119 | * zeroed out. |
| 120 | * |
| 121 | * May result in one or more overflow notifications. |
| 122 | * |
| 123 | * If called during overflow handling, that is, with index >= |
| 124 | * interrupt threshold, the write will wrap around. |
| 125 | * |
| 126 | * An overflow notification is given if and when the interrupt |
| 127 | * threshold is reached during or after the write. |
| 128 | * |
| 129 | * Returns the number of bytes written or -Eerrno. |
| 130 | * |
| 131 | * task: the task to access; |
| 132 | * NULL to access the current cpu |
| 133 | * buffer: the buffer to write |
| 134 | * size: the size of the buffer |
| 135 | */ |
| 136 | extern int ds_write_bts(struct task_struct *task, |
| 137 | const void *buffer, size_t size); |
| 138 | extern int ds_write_pebs(struct task_struct *task, |
| 139 | const void *buffer, size_t size); |
| 140 | |
| 141 | /* |
| 142 | * Same as ds_write_bts/pebs, but omit ownership checks. |
| 143 | * |
| 144 | * This is needed to have some other task than the owner of the |
| 145 | * BTS/PEBS buffer or the parameter task itself write into the |
| 146 | * respective buffer. |
| 147 | */ |
| 148 | extern int ds_unchecked_write_bts(struct task_struct *task, |
| 149 | const void *buffer, size_t size); |
| 150 | extern int ds_unchecked_write_pebs(struct task_struct *task, |
| 151 | const void *buffer, size_t size); |
| 152 | |
| 153 | /* |
| 154 | * Reset the write pointer of the BTS/PEBS buffer. |
| 155 | * |
| 156 | * Returns 0 on success; -Eerrno on error |
| 157 | * |
| 158 | * task: the task to access; |
| 159 | * NULL to access the current cpu |
| 160 | */ |
| 161 | extern int ds_reset_bts(struct task_struct *task); |
| 162 | extern int ds_reset_pebs(struct task_struct *task); |
| 163 | |
| 164 | /* |
| 165 | * Clear the BTS/PEBS buffer and reset the write pointer. |
| 166 | * The entire buffer will be zeroed out. |
| 167 | * |
| 168 | * Returns 0 on success; -Eerrno on error |
| 169 | * |
| 170 | * task: the task to access; |
| 171 | * NULL to access the current cpu |
| 172 | */ |
| 173 | extern int ds_clear_bts(struct task_struct *task); |
| 174 | extern int ds_clear_pebs(struct task_struct *task); |
| 175 | |
| 176 | /* |
| 177 | * Provide the PEBS counter reset value. |
| 178 | * |
| 179 | * Returns 0 on success; -Eerrno on error |
| 180 | * |
| 181 | * task: the task to access; |
| 182 | * NULL to access the current cpu |
| 183 | * value (out): the counter reset value |
| 184 | */ |
| 185 | extern int ds_get_pebs_reset(struct task_struct *task, u64 *value); |
| 186 | |
| 187 | /* |
| 188 | * Set the PEBS counter reset value. |
| 189 | * |
| 190 | * Returns 0 on success; -Eerrno on error |
| 191 | * |
| 192 | * task: the task to access; |
| 193 | * NULL to access the current cpu |
| 194 | * value: the new counter reset value |
| 195 | */ |
| 196 | extern int ds_set_pebs_reset(struct task_struct *task, u64 value); |
| 197 | |
| 198 | /* |
| 199 | * Initialization |
| 200 | */ |
| 201 | struct cpuinfo_x86; |
| 202 | extern void __cpuinit ds_init_intel(struct cpuinfo_x86 *); |
| 203 | |
| 204 | |
| 205 | |
| 206 | /* |
| 207 | * The DS context - part of struct thread_struct. |
| 208 | */ |
| 209 | struct ds_context { |
| 210 | /* pointer to the DS configuration; goes into MSR_IA32_DS_AREA */ |
| 211 | unsigned char *ds; |
| 212 | /* the owner of the BTS and PEBS configuration, respectively */ |
| 213 | struct task_struct *owner[2]; |
| 214 | /* buffer overflow notification function for BTS and PEBS */ |
| 215 | ds_ovfl_callback_t callback[2]; |
| 216 | /* the original buffer address */ |
| 217 | void *buffer[2]; |
| 218 | /* the number of allocated pages for on-request allocated buffers */ |
| 219 | unsigned int pages[2]; |
| 220 | /* use count */ |
| 221 | unsigned long count; |
| 222 | /* a pointer to the context location inside the thread_struct |
| 223 | * or the per_cpu context array */ |
| 224 | struct ds_context **this; |
| 225 | /* a pointer to the task owning this context, or NULL, if the |
| 226 | * context is owned by a cpu */ |
| 227 | struct task_struct *task; |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 228 | }; |
| 229 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 230 | /* called by exit_thread() to free leftover contexts */ |
| 231 | extern void ds_free(struct ds_context *context); |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 232 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 233 | #else /* CONFIG_X86_DS */ |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 234 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 235 | #define ds_init_intel(config) do {} while (0) |
Markus Metzger | eee3af4 | 2008-01-30 13:31:09 +0100 | [diff] [blame] | 236 | |
Markus Metzger | 93fa763 | 2008-04-08 11:01:58 +0200 | [diff] [blame] | 237 | #endif /* CONFIG_X86_DS */ |
Vegard Nossum | 77ef50a | 2008-06-18 17:08:48 +0200 | [diff] [blame] | 238 | #endif /* ASM_X86__DS_H */ |