kernel/2.6.29.6-aldebaran-rt/arch/x86/include/asm/ds.h

   1 /*
   2  * Debug Store (DS) support
   3  *
   4  * This provides a low-level interface to the hardware's Debug Store
   5  * feature that is used for branch trace store (BTS) and
   6  * precise-event based sampling (PEBS).
   7  *
   8  * It manages:
   9  * - DS and BTS hardware configuration
  10  * - buffer overflow handling (to be done)
  11  * - buffer access
  12  *
  13  * It does not do:
  14  * - security checking (is the caller allowed to trace the task)
  15  * - buffer allocation (memory accounting)
  16  *
  17  *
  18  * Copyright (C) 2007-2008 Intel Corporation.
  19  * Markus Metzger <markus.t.metzger@intel.com>, 2007-2008
  20  */
  21
  22 #ifndef _ASM_X86_DS_H
  23 #define _ASM_X86_DS_H
  24
  25
  26 #include <linux/types.h>
  27 #include <linux/init.h>
  28 #include <linux/err.h>
  29
  30
  31 #ifdef CONFIG_X86_DS
  32
  33 struct task_struct;
  34 struct ds_context;
  35 struct ds_tracer;
  36 struct bts_tracer;
  37 struct pebs_tracer;
  38
  39 typedef void (*bts_ovfl_callback_t)(struct bts_tracer *);
  40 typedef void (*pebs_ovfl_callback_t)(struct pebs_tracer *);
  41
  42
  43 /*
  44  * A list of features plus corresponding macros to talk about them in
  45  * the ds_request function's flags parameter.
  46  *
  47  * We use the enum to index an array of corresponding control bits;
  48  * we use the macro to index a flags bit-vector.
  49  */
  50 enum ds_feature {
  51         dsf_bts = 0,
  52         dsf_bts_kernel,
  53 #define BTS_KERNEL (1 << dsf_bts_kernel)
  54         /* trace kernel-mode branches */
  55
  56         dsf_bts_user,
  57 #define BTS_USER (1 << dsf_bts_user)
  58         /* trace user-mode branches */
  59
  60         dsf_bts_overflow,
  61         dsf_bts_max,
  62         dsf_pebs = dsf_bts_max,
  63
  64         dsf_pebs_max,
  65         dsf_ctl_max = dsf_pebs_max,
  66         dsf_bts_timestamps = dsf_ctl_max,
  67 #define BTS_TIMESTAMPS (1 << dsf_bts_timestamps)
  68         /* add timestamps into BTS trace */
  69
  70 #define BTS_USER_FLAGS (BTS_KERNEL | BTS_USER | BTS_TIMESTAMPS)
  71 };
  72
  73
  74 /*
  75  * Request BTS or PEBS
  76  *
  77  * Due to alignement constraints, the actual buffer may be slightly
  78  * smaller than the requested or provided buffer.
  79  *
  80  * Returns a pointer to a tracer structure on success, or
  81  * ERR_PTR(errcode) on failure.
  82  *
  83  * The interrupt threshold is independent from the overflow callback
  84  * to allow users to use their own overflow interrupt handling mechanism.
  85  *
  86  * task: the task to request recording for;
  87  *       NULL for per-cpu recording on the current cpu
  88  * base: the base pointer for the (non-pageable) buffer;
  89  * size: the size of the provided buffer in bytes
  90  * ovfl: pointer to a function to be called on buffer overflow;
  91  *       NULL if cyclic buffer requested
  92  * th: the interrupt threshold in records from the end of the buffer;
  93  *     -1 if no interrupt threshold is requested.
  94  * flags: a bit-mask of the above flags
  95  */
  96 extern struct bts_tracer *ds_request_bts(struct task_struct *task,
  97                                          void *base, size_t size,
  98                                          bts_ovfl_callback_t ovfl,
  99                                          size_t th, unsigned int flags);
 100 extern struct pebs_tracer *ds_request_pebs(struct task_struct *task,
 101                                            void *base, size_t size,
 102                                            pebs_ovfl_callback_t ovfl,
 103                                            size_t th, unsigned int flags);
 104
 105 /*
 106  * Release BTS or PEBS resources
 107  * Suspend and resume BTS or PEBS tracing
 108  *
 109  * tracer: the tracer handle returned from ds_request_~()
 110  */
 111 extern void ds_release_bts(struct bts_tracer *tracer);
 112 extern void ds_suspend_bts(struct bts_tracer *tracer);
 113 extern void ds_resume_bts(struct bts_tracer *tracer);
 114 extern void ds_release_pebs(struct pebs_tracer *tracer);
 115 extern void ds_suspend_pebs(struct pebs_tracer *tracer);
 116 extern void ds_resume_pebs(struct pebs_tracer *tracer);
 117
 118
 119 /*
 120  * The raw DS buffer state as it is used for BTS and PEBS recording.
 121  *
 122  * This is the low-level, arch-dependent interface for working
 123  * directly on the raw trace data.
 124  */
 125 struct ds_trace {
 126         /* the number of bts/pebs records */
 127         size_t n;
 128         /* the size of a bts/pebs record in bytes */
 129         size_t size;
 130         /* pointers into the raw buffer:
 131            - to the first entry */
 132         void *begin;
 133         /* - one beyond the last entry */
 134         void *end;
 135         /* - one beyond the newest entry */
 136         void *top;
 137         /* - the interrupt threshold */
 138         void *ith;
 139         /* flags given on ds_request() */
 140         unsigned int flags;
 141 };
 142
 143 /*
 144  * An arch-independent view on branch trace data.
 145  */
 146 enum bts_qualifier {
 147         bts_invalid,
 148 #define BTS_INVALID bts_invalid
 149
 150         bts_branch,
 151 #define BTS_BRANCH bts_branch
 152
 153         bts_task_arrives,
 154 #define BTS_TASK_ARRIVES bts_task_arrives
 155
 156         bts_task_departs,
 157 #define BTS_TASK_DEPARTS bts_task_departs
 158
 159         bts_qual_bit_size = 4,
 160         bts_qual_max = (1 << bts_qual_bit_size),
 161 };
 162
 163 struct bts_struct {
 164         __u64 qualifier;
 165         union {
 166                 /* BTS_BRANCH */
 167                 struct {
 168                         __u64 from;
 169                         __u64 to;
 170                 } lbr;
 171                 /* BTS_TASK_ARRIVES or BTS_TASK_DEPARTS */
 172                 struct {
 173                         __u64 jiffies;
 174                         pid_t pid;
 175                 } timestamp;
 176         } variant;
 177 };
 178
 179
 180 /*
 181  * The BTS state.
 182  *
 183  * This gives access to the raw DS state and adds functions to provide
 184  * an arch-independent view of the BTS data.
 185  */
 186 struct bts_trace {
 187         struct ds_trace ds;
 188
 189         int (*read)(struct bts_tracer *tracer, const void *at,
 190                     struct bts_struct *out);
 191         int (*write)(struct bts_tracer *tracer, const struct bts_struct *in);
 192 };
 193
 194
 195 /*
 196  * The PEBS state.
 197  *
 198  * This gives access to the raw DS state and the PEBS-specific counter
 199  * reset value.
 200  */
 201 struct pebs_trace {
 202         struct ds_trace ds;
 203
 204         /* the PEBS reset value */
 205         unsigned long long reset_value;
 206 };
 207
 208
 209 /*
 210  * Read the BTS or PEBS trace.
 211  *
 212  * Returns a view on the trace collected for the parameter tracer.
 213  *
 214  * The view remains valid as long as the traced task is not running or
 215  * the tracer is suspended.
 216  * Writes into the trace buffer are not reflected.
 217  *
 218  * tracer: the tracer handle returned from ds_request_~()
 219  */
 220 extern const struct bts_trace *ds_read_bts(struct bts_tracer *tracer);
 221 extern const struct pebs_trace *ds_read_pebs(struct pebs_tracer *tracer);
 222
 223
 224 /*
 225  * Reset the write pointer of the BTS/PEBS buffer.
 226  *
 227  * Returns 0 on success; -Eerrno on error
 228  *
 229  * tracer: the tracer handle returned from ds_request_~()
 230  */
 231 extern int ds_reset_bts(struct bts_tracer *tracer);
 232 extern int ds_reset_pebs(struct pebs_tracer *tracer);
 233
 234 /*
 235  * Set the PEBS counter reset value.
 236  *
 237  * Returns 0 on success; -Eerrno on error
 238  *
 239  * tracer: the tracer handle returned from ds_request_pebs()
 240  * value: the new counter reset value
 241  */
 242 extern int ds_set_pebs_reset(struct pebs_tracer *tracer, u64 value);
 243
 244 /*
 245  * Initialization
 246  */
 247 struct cpuinfo_x86;
 248 extern void __cpuinit ds_init_intel(struct cpuinfo_x86 *);
 249
 250 /*
 251  * Context switch work
 252  */
 253 extern void ds_switch_to(struct task_struct *prev, struct task_struct *next);
 254
 255 /*
 256  * Task clone/init and cleanup work
 257  */
 258 extern void ds_copy_thread(struct task_struct *tsk, struct task_struct *father);
 259 extern void ds_exit_thread(struct task_struct *tsk);
 260
 261 #else /* CONFIG_X86_DS */
 262
 263 struct cpuinfo_x86;
 264 static inline void __cpuinit ds_init_intel(struct cpuinfo_x86 *ignored) {}
 265 static inline void ds_switch_to(struct task_struct *prev,
 266                                 struct task_struct *next) {}
 267 static inline void ds_copy_thread(struct task_struct *tsk,
 268                                   struct task_struct *father) {}
 269 static inline void ds_exit_thread(struct task_struct *tsk) {}
 270
 271 #endif /* CONFIG_X86_DS */
 272 #endif /* _ASM_X86_DS_H */