powerpc: Make syscall tracing use tracehook.h helpers

This changes powerpc syscall tracing to use the new tracehook.h entry
points.  There is no change, only cleanup.

In addition, the assembly changes allow do_syscall_trace_enter() to
abort the syscall without losing the information about the original
r0 value.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 6 insertions, 1 deletions

diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index d7369243ae44..79c089e97ce4 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -214,7 +214,12 @@ syscall_dotrace:
         bl      .save_nvgprs
         addi    r3,r1,STACK_FRAME_OVERHEAD
         bl      .do_syscall_trace_enter
-        ld      r0,GPR0(r1)     /* Restore original registers */
+        /*
+         * Restore argument registers possibly just changed.
+         * We use the return value of do_syscall_trace_enter
+         * for the call number to look up in the table (r0).
+         */
+        mr      r0,r3
         ld      r3,GPR3(r1)
         ld      r4,GPR4(r1)
         ld      r5,GPR5(r1)