Commit 0c289ff8 authored Mar 10, 2021 by Joerg Roedel Committed by Borislav Petkov Mar 18, 2021

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

parent eab696d8

arch/x86/boot/compressed/head_64.S

+8 −1

Original line number	Diff line number	Diff line
		@@ -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