[SPARC64]: Fix ptrace/strace
Don't clobber register %l0 while checking TI_SYS_NOERROR value in
syscall return path. This bug was introduced by:
db7d9a4eb700be766cc9f29241483dbb1e748832
Problem narrowed down by Luis F. Ortiz and Richard Mortimer.
I tried using %l2 as suggested by Luis and that works for me.
Looking at the code I wonder if it makes sense to simplify the code
a little bit. The following works for me but I'm not sure how to
exercise the "NOERROR" codepath.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc64/kernel/entry.S b/arch/sparc64/kernel/entry.S
index 11a8484..7100029 100644
--- a/arch/sparc64/kernel/entry.S
+++ b/arch/sparc64/kernel/entry.S
@@ -1657,13 +1657,10 @@
/* Check if force_successful_syscall_return()
* was invoked.
*/
- ldub [%curptr + TI_SYS_NOERROR], %l0
- brz,pt %l0, 1f
- nop
- ba,pt %xcc, 80f
+ ldub [%curptr + TI_SYS_NOERROR], %l2
+ brnz,a,pn %l2, 80f
stb %g0, [%curptr + TI_SYS_NOERROR]
-1:
cmp %o0, -ERESTART_RESTARTBLOCK
bgeu,pn %xcc, 1f
andcc %l0, (_TIF_SYSCALL_TRACE|_TIF_SECCOMP|_TIF_SYSCALL_AUDIT), %l6