[RFC patch 02/20] LTTng Kernel Trace Thread Flag ARM

[Mathieu Desnoyers]

Add a thread flag to activate system-wide syscall tracing.

folded omap-arm-fix-syscall-exit-trace-flag.patch.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>
---
 arch/arm/include/asm/thread_info.h |    3 +++
 arch/arm/kernel/entry-common.S     |    2 ++
 2 files changed, 5 insertions(+)

Index: linux-2.6-lttng/arch/arm/include/asm/thread_info.h
===================================================================
--- linux-2.6-lttng.orig/arch/arm/include/asm/thread_info.h	2009-03-15 15:58:19.000000000 -0400
+++ linux-2.6-lttng/arch/arm/include/asm/thread_info.h	2009-03-15 15:58:20.000000000 -0400
@@ -124,6 +124,7 @@ extern void iwmmxt_task_switch(struct th
 /*
  * thread information flags:
  *  TIF_SYSCALL_TRACE	- syscall trace active
+ *  TIF_KERNEL_TRACE	- kernel trace active
  *  TIF_SIGPENDING	- signal pending
  *  TIF_NEED_RESCHED	- rescheduling necessary
  *  TIF_USEDFPU		- FPU was used by this task this quantum (SMP)
@@ -131,6 +132,7 @@ extern void iwmmxt_task_switch(struct th
  */
 #define TIF_SIGPENDING		0
 #define TIF_NEED_RESCHED	1
+#define TIF_KERNEL_TRACE	7
 #define TIF_SYSCALL_TRACE	8
 #define TIF_POLLING_NRFLAG	16
 #define TIF_USING_IWMMXT	17
@@ -139,6 +141,7 @@ extern void iwmmxt_task_switch(struct th
 
 #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
 #define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
+#define _TIF_KERNEL_TRACE	(1 << TIF_KERNEL_TRACE)
 #define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
 #define _TIF_POLLING_NRFLAG	(1 << TIF_POLLING_NRFLAG)
 #define _TIF_USING_IWMMXT	(1 << TIF_USING_IWMMXT)
Index: linux-2.6-lttng/arch/arm/kernel/entry-common.S
===================================================================
--- linux-2.6-lttng.orig/arch/arm/kernel/entry-common.S	2009-03-15 16:00:03.000000000 -0400
+++ linux-2.6-lttng/arch/arm/kernel/entry-common.S	2009-03-15 16:00:15.000000000 -0400
@@ -43,6 +43,8 @@ ret_fast_syscall:
  * Ok, we need to do extra processing, enter the slow path.
  */
 fast_work_pending:
+	tst	r1, #_TIF_KERNEL_TRACE		@ flag can be set asynchronously
+	bne	__sys_trace_return
 	str	r0, [sp, #S_R0+S_OFF]!		@ returned r0
 work_pending:
 	tst	r1, #_TIF_NEED_RESCHED

-- 
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
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