powerpc/ftrace: Implement raw syscall tracepoints on PowerPC
This patch implements the raw syscall tracepoints on PowerPC and exports
them for ftrace syscalls to use.
To minimise reworking existing code, I slightly re-ordered the thread
info flags such that the new TIF_SYSCALL_TRACEPOINT bit would still fit
within the 16 bits of the andi. instruction's UI field. The instructions
in question are in /arch/powerpc/kernel/entry_{32,64}.S to and the
_TIF_SYSCALL_T_OR_A with the thread flags to see if system call tracing
is enabled.
In the case of 64bit PowerPC, arch_syscall_addr and
arch_syscall_match_sym_name are overridden to allow ftrace syscalls to
work given the unusual system call table structure and symbol names that
start with a period.
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h
index 37c353e..836f231 100644
--- a/arch/powerpc/include/asm/thread_info.h
+++ b/arch/powerpc/include/asm/thread_info.h
@@ -110,7 +110,8 @@
#define TIF_NOERROR 12 /* Force successful syscall return */
#define TIF_NOTIFY_RESUME 13 /* callback before returning to user */
#define TIF_FREEZE 14 /* Freezing for suspend */
-#define TIF_RUNLATCH 15 /* Is the runlatch enabled? */
+#define TIF_SYSCALL_TRACEPOINT 15 /* syscall tracepoint instrumentation */
+#define TIF_RUNLATCH 16 /* Is the runlatch enabled? */
/* as above, but as bit values */
#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
@@ -127,8 +128,10 @@
#define _TIF_NOERROR (1<<TIF_NOERROR)
#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
#define _TIF_FREEZE (1<<TIF_FREEZE)
+#define _TIF_SYSCALL_TRACEPOINT (1<<TIF_SYSCALL_TRACEPOINT)
#define _TIF_RUNLATCH (1<<TIF_RUNLATCH)
-#define _TIF_SYSCALL_T_OR_A (_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP)
+#define _TIF_SYSCALL_T_OR_A (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
+ _TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT)
#define _TIF_USER_WORK_MASK (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
_TIF_NOTIFY_RESUME)