From 3eb6f26bcd0d2ce53498deda988e68d663e1c9c2 Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Tue, 20 Dec 2005 15:38:47 +1100 Subject: [PATCH] powerpc: correct register usage in 64-bit syscall exit path Since we don't restore the volatile registers in the syscall exit path, we need to make sure we don't leak any potentially interesting values from the kernel to userspace. This was already the case for all except r11. This makes it use r11 for an MSR value, so r11 will have an (uninteresting) MSR value in it on return to userspace. Signed-off-by: Paul Mackerras --- arch/powerpc/kernel/entry_64.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 2d22bf0..bce33a3 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -183,8 +183,8 @@ syscall_exit_trace_cont: ld r13,GPR13(r1) /* returning to usermode */ 1: ld r2,GPR2(r1) li r12,MSR_RI - andc r10,r10,r12 - mtmsrd r10,1 /* clear MSR.RI */ + andc r11,r10,r12 + mtmsrd r11,1 /* clear MSR.RI */ ld r1,GPR1(r1) mtlr r4 mtcr r5 -- 2.7.4