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>
This commit is contained in:
Josh Poimboeuf 2008-10-07 06:10:03 +00:00 коммит произвёл Benjamin Herrenschmidt
Родитель 99c840668c
Коммит 41c2e949cb
2 изменённых файлов: 10 добавлений и 6 удалений

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@ -900,8 +900,10 @@ _GLOBAL(kernel_thread)
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 @@ _GLOBAL(kernel_thread)
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

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@ -426,8 +426,10 @@ _GLOBAL(kernel_thread)
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 @@ _GLOBAL(kernel_thread)
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