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Commit 41c2e949 authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Benjamin Herrenschmidt
Browse files

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: default avatarJosh Poimboeuf <jpoimboe@us.ibm.com>
Signed-off-by: default avatarJosh Boyer <jwboyer@linux.vnet.ibm.com>
Acked-by: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 99c84066

arch/powerpc/kernel/misc_32.S

+5 −3
Original line number Diff line number Diff line
@@ -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

arch/powerpc/kernel/misc_64.S

+5 −3
Original line number Diff line number Diff line
@@ -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