powerpc: Fix error path in kernel_thread function
The powerpc 32-bit and 64-bit kernel_thread functions don't properly
propagate errors being returned by the clone syscall. (In the case of
error, the syscall exit code returns a positive errno in r3 and sets
the CR0[SO] bit.)
This patch fixes that by negating r3 if CR0[SO] is set after the syscall.
Signed-off-by: Josh Poimboeuf <jpoimboe@us.ibm.com>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S
index 4dd70cf..3053fe5 100644
--- a/arch/powerpc/kernel/misc_64.S
+++ b/arch/powerpc/kernel/misc_64.S
@@ -426,8 +426,10 @@
li r4,0 /* new sp (unused) */
li r0,__NR_clone
sc
- cmpdi 0,r3,0 /* parent or child? */
- bne 1f /* return if parent */
+ bns+ 1f /* did system call indicate error? */
+ neg r3,r3 /* if so, make return code negative */
+1: cmpdi 0,r3,0 /* parent or child? */
+ bne 2f /* return if parent */
li r0,0
stdu r0,-STACK_FRAME_OVERHEAD(r1)
ld r2,8(r29)
@@ -438,7 +440,7 @@
li r0,__NR_exit /* exit after child exits */
li r3,0
sc
-1: addi r1,r1,STACK_FRAME_OVERHEAD
+2: addi r1,r1,STACK_FRAME_OVERHEAD
ld r29,-24(r1)
ld r30,-16(r1)
blr
