From 097a0788df71b0f3328c70ab5f4e41c27ee66817 Mon Sep 17 00:00:00 2001 From: Glauber Costa Date: Thu, 14 Aug 2008 17:33:12 -0300 Subject: x86: set bp field in pt_regs properly Save rbp twice: One is for marking the stack frame, as usual (already there), and the other, to fill pt_regs properly. This is because bx comes right before the last saved register in that structure, and not bp. If the base pointer were in the place bx is today, this would not be needed. Signed-off-by: Glauber Costa Signed-off-by: Ingo Molnar --- arch/x86/kernel/entry_64.S | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'arch') diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index cf3a0b2d005..25bb3f9b255 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -667,6 +667,13 @@ END(stub_rt_sigreturn) SAVE_ARGS leaq -ARGOFFSET(%rsp),%rdi # arg1 for handler pushq %rbp + /* + * Save rbp twice: One is for marking the stack frame, as usual, and the + * other, to fill pt_regs properly. This is because bx comes right + * before the last saved register in that structure, and not bp. If the + * base pointer were in the place bx is today, this would not be needed. + */ + movq %rbp, -8(%rsp) CFI_ADJUST_CFA_OFFSET 8 CFI_REL_OFFSET rbp, 0 movq %rsp,%rbp -- cgit v1.2.3-70-g09d2