Commit 0ee90730 authored by Kim Phillips's avatar Kim Phillips Committed by Borislav Petkov
Browse files

x86/sev: Avoid using __x86_return_thunk 



Specifically, it's because __enc_copy() encrypts the kernel after
being relocated outside the kernel in sme_encrypt_execute(), and the
RET macro's jmp offset isn't amended prior to execution.

Signed-off-by: default avatarKim Phillips <kim.phillips@amd.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
parent 15583e51

arch/x86/mm/mem_encrypt_boot.S

+6 −2
Original line number Diff line number Diff line
@@ -65,7 +65,9 @@ SYM_FUNC_START(sme_encrypt_execute) 
	movq	%rbp, %rsp		/* Restore original stack pointer */

	pop	%rbp



	RET

	/* Offset to __x86_return_thunk would be wrong here */

	ret

	int3

SYM_FUNC_END(sme_encrypt_execute)



SYM_FUNC_START(__enc_copy)
@@ -151,6 +153,8 @@ SYM_FUNC_START(__enc_copy) 
	pop	%r12

	pop	%r15



	RET

	/* Offset to __x86_return_thunk would be wrong here */

	ret

	int3

.L__enc_copy_end:

SYM_FUNC_END(__enc_copy)