diff options
| author | Joerg Roedel <jroedel@suse.de> | 2020-09-07 15:15:33 +0200 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2020-09-07 21:44:01 +0200 |
| commit | 3add38cb96a1ae7d152db69ab4329e809c2af2d4 (patch) | |
| tree | ec2c4e3701a9ea8c7da447f935dd99fd99045f5f /arch/x86/kernel/head_64.S | |
| parent | 7b99819dfb60268cc1c75f83c949bc4a09221bea (diff) | |
x86/head/64: Switch to initial stack earlier
Make sure there is a stack once the kernel runs from virtual addresses.
At this stage any secondary CPU which boots will have lost its stack
because the kernel switched to a new page-table which does not map the
real-mode stack anymore.
This is needed for handling early #VC exceptions caused by instructions
like CPUID.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20200907131613.12703-33-joro@8bytes.org
Diffstat (limited to 'arch/x86/kernel/head_64.S')
| -rw-r--r-- | arch/x86/kernel/head_64.S | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index f402087a02ac..83050c9e54d9 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -192,6 +192,12 @@ SYM_CODE_START(secondary_startup_64) movl initial_gs+4(%rip),%edx wrmsr + /* + * Setup a boot time stack - Any secondary CPU will have lost its stack + * by now because the cr3-switch above unmaps the real-mode stack + */ + movq initial_stack(%rip), %rsp + /* Check if nx is implemented */ movl $0x80000001, %eax cpuid @@ -212,9 +218,6 @@ SYM_CODE_START(secondary_startup_64) /* Make changes effective */ movq %rax, %cr0 - /* Setup a boot time stack */ - movq initial_stack(%rip), %rsp - /* zero EFLAGS after setting rsp */ pushq $0 popfq |