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authorAnton Blanchard <anton@samba.org>2012-09-03 16:49:47 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2012-09-05 16:05:21 +1000
commit1021cb268b3025573c4811f1dee4a11260c4507b (patch)
tree54fee24502e5c8ce2f0a96ef1b5fd62bef2dfc73
parent00ca0de02f80924dfff6b4f630e1dff3db005e35 (diff)
downloadlinux-linaro-stable-1021cb268b3025573c4811f1dee4a11260c4507b.tar.gz
powerpc: Fix DSCR inheritance in copy_thread()
If the default DSCR is non zero we set thread.dscr_inherit in copy_thread() meaning the new thread and all its children will ignore future updates to the default DSCR. This is not intended and is a change in behaviour that a number of our users have hit. We just need to inherit thread.dscr and thread.dscr_inherit from the parent which ends up being much simpler. This was found with the following test case: http://ozlabs.org/~anton/junkcode/dscr_default_test.c Signed-off-by: Anton Blanchard <anton@samba.org> Cc: <stable@kernel.org> # 3.0+ Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
-rw-r--r--arch/powerpc/kernel/process.c12
1 files changed, 2 insertions, 10 deletions
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 710f400476de..1a1f2ddfb581 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -802,16 +802,8 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
#endif /* CONFIG_PPC_STD_MMU_64 */
#ifdef CONFIG_PPC64
if (cpu_has_feature(CPU_FTR_DSCR)) {
- if (current->thread.dscr_inherit) {
- p->thread.dscr_inherit = 1;
- p->thread.dscr = current->thread.dscr;
- } else if (0 != dscr_default) {
- p->thread.dscr_inherit = 1;
- p->thread.dscr = dscr_default;
- } else {
- p->thread.dscr_inherit = 0;
- p->thread.dscr = 0;
- }
+ p->thread.dscr_inherit = current->thread.dscr_inherit;
+ p->thread.dscr = current->thread.dscr;
}
#endif