[RFC patch 08/20] LTTng Kernel Trace Thread Flag ia64

[Mathieu Desnoyers]

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

FIXME : Masami reported that enabling the KERNEL_TRACE thread flag did disable
the gate page for gettimeofday, falling back on a standard system call. More
work would be needed in this area and I don't have the architecture available.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>
CC: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
---
 arch/ia64/include/asm/thread_info.h |   10 +++++++---
 arch/ia64/kernel/entry.S            |    6 ++++--
 2 files changed, 11 insertions(+), 5 deletions(-)

Index: linux-2.6-lttng/arch/ia64/include/asm/thread_info.h
===================================================================
--- linux-2.6-lttng.orig/arch/ia64/include/asm/thread_info.h	2009-04-23 14:56:15.000000000 -0400
+++ linux-2.6-lttng/arch/ia64/include/asm/thread_info.h	2009-04-23 14:56:30.000000000 -0400
@@ -100,6 +100,7 @@ struct thread_info {
 #define TIF_SYSCALL_TRACE	2	/* syscall trace active */
 #define TIF_SYSCALL_AUDIT	3	/* syscall auditing active */
 #define TIF_SINGLESTEP		4	/* restore singlestep on return to user mode */
+#define TIF_KERNEL_TRACE	5	/* kernel trace active */
 #define TIF_NOTIFY_RESUME	6	/* resumption notification requested */
 #define TIF_POLLING_NRFLAG	16	/* true if poll_idle() is polling TIF_NEED_RESCHED */
 #define TIF_MEMDIE		17
@@ -111,7 +112,9 @@ struct thread_info {
 #define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
 #define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
 #define _TIF_SINGLESTEP		(1 << TIF_SINGLESTEP)
-#define _TIF_SYSCALL_TRACEAUDIT	(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP)
+#define _TIF_KERNEL_TRACE	(1 << TIF_KERNEL_TRACE)
+#define _TIF_SYSCALL_TRACEAUDIT	(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|\
+	_TIF_SINGLESTEP|_TIF_KERNEL_TRACE)
 #define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
 #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
 #define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
@@ -124,8 +127,9 @@ struct thread_info {
 /* "work to do on user-return" bits */
 #define TIF_ALLWORK_MASK	(_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SYSCALL_AUDIT|\
 				 _TIF_NEED_RESCHED|_TIF_SYSCALL_TRACE)
-/* like TIF_ALLWORK_BITS but sans TIF_SYSCALL_TRACE or TIF_SYSCALL_AUDIT */
-#define TIF_WORK_MASK		(TIF_ALLWORK_MASK&~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT))
+/* like TIF_ALLWORK_BITS but sans TIF_SYSCALL_TRACE, TIF_KERNEL_TRACE or TIF_SYSCALL_AUDIT */
+#define TIF_WORK_MASK		(TIF_ALLWORK_MASK&~(_TIF_SYSCALL_TRACE|_TIF_KERNEL_TRACE|\
+					_TIF_SYSCALL_AUDIT))
 
 #define TS_POLLING		1 	/* true if in idle loop and not sleeping */
 #define TS_RESTORE_SIGMASK	2	/* restore signal mask in do_signal() */
Index: linux-2.6-lttng/arch/ia64/kernel/entry.S
===================================================================
--- linux-2.6-lttng.orig/arch/ia64/kernel/entry.S	2009-04-23 14:56:15.000000000 -0400
+++ linux-2.6-lttng/arch/ia64/kernel/entry.S	2009-04-23 14:56:30.000000000 -0400
@@ -635,9 +635,11 @@ GLOBAL_ENTRY(ia64_ret_from_clone)
 	;;
 	ld4 r2=[r2]
 	;;
+	movl r8=_TIF_SYSCALL_TRACEAUDIT
+	;;					// added stop bits to prevent r8 dependency
+	and r2=r8,r2
 	mov r8=0
-	and r2=_TIF_SYSCALL_TRACEAUDIT,r2
-	;;
+	;;					// added stop bits to prevent r2 dependency
 	cmp.ne p6,p0=r2,r0
 (p6)	br.cond.spnt .strace_check_retval
 	;;					// added stop bits to prevent r8 dependency

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