From 050438ed5a05b25cdf287f5691e56a58c2606997 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Thu, 14 Jul 2011 09:34:37 +0800 Subject: [PATCH] kexec, x86: Fix incorrect jump back address if not preserving context In kexec jump support, jump back address passed to the kexeced kernel via function calling ABI, that is, the function call return address is the jump back entry. Furthermore, jump back entry == 0 should be used to signal that the jump back or preserve context is not enabled in the original kernel. But in the current implementation the stack position used for function call return address is not cleared context preservation is disabled. The patch fixes this bug. Reported-and-tested-by: Yin Kangkai Signed-off-by: Huang Ying Cc: Eric W. Biederman Cc: Vivek Goyal Cc: Link: http://lkml.kernel.org/r/1310607277-25029-1-git-send-email-ying.huang@intel.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/relocate_kernel_32.S | 2 ++ arch/x86/kernel/relocate_kernel_64.S | 2 ++ 2 files changed, 4 insertions(+) diff --git a/arch/x86/kernel/relocate_kernel_32.S b/arch/x86/kernel/relocate_kernel_32.S index 41235531b11c..36818f8ec2be 100644 --- a/arch/x86/kernel/relocate_kernel_32.S +++ b/arch/x86/kernel/relocate_kernel_32.S @@ -97,6 +97,8 @@ relocate_kernel: ret identity_mapped: + /* set return address to 0 if not preserving context */ + pushl $0 /* store the start address on the stack */ pushl %edx diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S index 4de8f5b3d476..7a6f3b3be3cf 100644 --- a/arch/x86/kernel/relocate_kernel_64.S +++ b/arch/x86/kernel/relocate_kernel_64.S @@ -100,6 +100,8 @@ relocate_kernel: ret identity_mapped: + /* set return address to 0 if not preserving context */ + pushq $0 /* store the start address on the stack */ pushq %rdx -- 2.39.2