x86/boot/compressed/64: Reload CS in startup_32

Exception handling in the startup_32 boot path requires the CS
selector to be correctly set up. Reload it from the current GDT.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210312123824.306-4-joro@8bytes.org
This commit is contained in:
Joerg Roedel 2021-03-10 09:43:20 +01:00 committed by Borislav Petkov
parent eab696d8e8
commit 0c289ff81c

View file

@ -107,9 +107,16 @@ SYM_FUNC_START(startup_32)
movl %eax, %gs
movl %eax, %ss
/* setup a stack and make sure cpu supports long mode. */
/* Setup a stack and load CS from current GDT */
leal rva(boot_stack_end)(%ebp), %esp
pushl $__KERNEL32_CS
leal rva(1f)(%ebp), %eax
pushl %eax
lretl
1:
/* Make sure cpu supports long mode. */
call verify_cpu
testl %eax, %eax
jnz .Lno_longmode