x86, ptrace: support for branch trace store(BTS)

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Changes to the last version:
- split implementation into two layers: ds/bts and ptrace
- renamed TIF's
- save/restore ds save area msr in __switch_to_xtra()
- make block-stepping only look at BTF bit

Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 10 insertions, 2 deletions

diff --git a/include/asm-x86/thread_info_32.h b/include/asm-x86/thread_info_32.h
index 306fc80800e1..5bd508260ffb 100644
--- a/include/asm-x86/thread_info_32.h
+++ b/include/asm-x86/thread_info_32.h
@@ -140,6 +140,8 @@ static inline struct thread_info *current_thread_info(void)
 #define TIF_NOTSC               20      /* TSC is not accessible in userland */
 #define TIF_FORCED_TF           21      /* true if TF in eflags artificially */
 #define TIF_DEBUGCTLMSR         22      /* uses thread_struct.debugctlmsr */
+#define TIF_DS_AREA_MSR         23      /* uses thread_struct.ds_area_msr */
+#define TIF_BTS_TRACE_TS        24      /* record scheduling event timestamps */
 
 #define _TIF_SYSCALL_TRACE      (1<<TIF_SYSCALL_TRACE)
 #define _TIF_SIGPENDING         (1<<TIF_SIGPENDING)
@@ -157,6 +159,8 @@ static inline struct thread_info *current_thread_info(void)
 #define _TIF_NOTSC              (1<<TIF_NOTSC)
 #define _TIF_FORCED_TF          (1<<TIF_FORCED_TF)
 #define _TIF_DEBUGCTLMSR        (1<<TIF_DEBUGCTLMSR)
+#define _TIF_DS_AREA_MSR        (1<<TIF_DS_AREA_MSR)
+#define _TIF_BTS_TRACE_TS       (1<<TIF_BTS_TRACE_TS)
 
 /* work to do on interrupt/exception return */
 #define _TIF_WORK_MASK \
@@ -166,8 +170,12 @@ static inline struct thread_info *current_thread_info(void)
 #define _TIF_ALLWORK_MASK       (0x0000FFFF & ~_TIF_SECCOMP)
 
 /* flags to check in __switch_to() */
-#define _TIF_WORK_CTXSW_NEXT (_TIF_IO_BITMAP | _TIF_NOTSC | _TIF_DEBUG | _TIF_DEBUGCTLMSR)
-#define _TIF_WORK_CTXSW_PREV (_TIF_IO_BITMAP | _TIF_NOTSC | _TIF_DEBUGCTLMSR)
+#define _TIF_WORK_CTXSW \
+    (_TIF_IO_BITMAP | _TIF_NOTSC | _TIF_DEBUGCTLMSR | \
+     _TIF_DS_AREA_MSR | _TIF_BTS_TRACE_TS)
+#define _TIF_WORK_CTXSW_PREV _TIF_WORK_CTXSW
+#define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW | _TIF_DEBUG)
+
 
 /*
  * Thread-synchronous status.