x86, ptrace: new ptrace BTS API
Here's the new ptrace BTS API that supports two different overflow handling mechanisms (wrap-around and buffer-full-signal) to support two different use cases (debugging and profiling).
It further combines buffer allocation and configuration.
Opens:
- memory rlimit
- overflow signal
What would be the right signal to use?
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/asm-x86/ptrace-abi.h b/include/asm-x86/ptrace-abi.h
index b473ad4..cf2fe46 100644
--- a/include/asm-x86/ptrace-abi.h
+++ b/include/asm-x86/ptrace-abi.h
@@ -80,51 +80,53 @@
#define PTRACE_SINGLEBLOCK 33 /* resume execution until next branch */
-/* Return maximal BTS buffer size in number of records,
- if successuf; -1, otherwise.
- EOPNOTSUPP...processor does not support bts tracing */
-#define PTRACE_BTS_MAX_BUFFER_SIZE 40
+/* configuration/status structure used in PTRACE_BTS_CONFIG and
+ PTRACE_BTS_STATUS commands.
+*/
+struct ptrace_bts_config {
+ /* requested or actual size of BTS buffer in bytes */
+ unsigned long size;
+ /* bitmask of below flags */
+ unsigned long flags;
+};
-/* Allocate new bts buffer (free old one, if exists) of size DATA bts records;
- parameter ADDR is ignored.
- Return 0, if successful; -1, otherwise.
- EOPNOTSUPP...processor does not support bts tracing
- EINVAL.......invalid size in records
- ENOMEM.......out of memory */
-#define PTRACE_BTS_ALLOCATE_BUFFER 41
+#define PTRACE_BTS_O_TRACE 0x1 /* branch trace */
+#define PTRACE_BTS_O_SCHED 0x2 /* scheduling events w/ jiffies */
+#define PTRACE_BTS_O_SIGNAL 0x4 /* send SIG? on buffer overflow
+ instead of wrapping around */
+#define PTRACE_BTS_O_CUT_SIZE 0x8 /* cut requested size to max available
+ instead of failing */
-/* Return the size of the bts buffer in number of bts records,
- if successful; -1, otherwise.
- EOPNOTSUPP...processor does not support bts tracing
- ENXIO........no buffer allocated */
-#define PTRACE_BTS_GET_BUFFER_SIZE 42
-
-/* Read the DATA'th bts record into a ptrace_bts_record buffer
- provided in ADDR.
- Records are ordered from newest to oldest.
- Return 0, if successful; -1, otherwise
- EOPNOTSUPP...processor does not support bts tracing
- ENXIO........no buffer allocated
- EINVAL.......invalid index */
-#define PTRACE_BTS_READ_RECORD 43
-
-/* Configure last branch trace; the configuration is given as a bit-mask of
- PTRACE_BTS_O_* options in DATA; parameter ADDR is ignored.
- Return 0, if successful; -1, otherwise
- EOPNOTSUPP...processor does not support bts tracing
- ENXIO........no buffer allocated */
-#define PTRACE_BTS_CONFIG 44
-
-/* Return the configuration as bit-mask of PTRACE_BTS_O_* options
- if successful; -1, otherwise.
- EOPNOTSUPP...processor does not support bts tracing
- ENXIO........no buffer allocated */
-#define PTRACE_BTS_STATUS 45
-
-/* Trace configuration options */
-/* Collect last branch trace */
-#define PTRACE_BTS_O_TRACE_TASK 0x1
-/* Take timestamps when the task arrives and departs */
-#define PTRACE_BTS_O_TIMESTAMPS 0x2
+#define PTRACE_BTS_CONFIG 40
+/* Configure branch trace recording.
+ DATA is ignored, ADDR points to a struct ptrace_bts_config.
+ A new buffer is allocated, iff the size changes.
+*/
+#define PTRACE_BTS_STATUS 41
+/* Return the current configuration.
+ DATA is ignored, ADDR points to a struct ptrace_bts_config
+ that will contain the result.
+*/
+#define PTRACE_BTS_SIZE 42
+/* Return the number of available BTS records.
+ DATA and ADDR are ignored.
+*/
+#define PTRACE_BTS_GET 43
+/* Get a single BTS record.
+ DATA defines the index into the BTS array, where 0 is the newest
+ entry, and higher indices refer to older entries.
+ ADDR is pointing to struct bts_struct (see asm/ds.h).
+*/
+#define PTRACE_BTS_CLEAR 44
+/* Clear the BTS buffer.
+ DATA and ADDR are ignored.
+*/
+#define PTRACE_BTS_DRAIN 45
+/* Read all available BTS records and clear the buffer.
+ DATA is ignored. ADDR points to an array of struct bts_struct of
+ suitable size.
+ BTS records are read from oldest to newest.
+ Returns number of BTS records drained.
+*/
#endif