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_32.S b/arch/powerpc/kernel/misc_32.S
index e9c8ab6..6a9b4bf 100644
--- a/arch/powerpc/kernel/misc_32.S
+++ b/arch/powerpc/kernel/misc_32.S
@@ -900,8 +900,10 @@
li r4,0 /* new sp (unused) */
li r0,__NR_clone
sc
- cmpwi 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: cmpwi 0,r3,0 /* parent or child? */
+ bne 2f /* return if parent */
li r0,0 /* make top-level stack frame */
stwu r0,-16(r1)
mtlr r30 /* fn addr in lr */
@@ -911,7 +913,7 @@
li r0,__NR_exit /* exit if function returns */
li r3,0
sc
-1: lwz r30,8(r1)
+2: lwz r30,8(r1)
lwz r31,12(r1)
addi r1,r1,16
blr