From: Kim Phillips kim.phillips@amd.com
commit 0ee9073000e8791f8b134a8ded31bcc767f7f232 upstream.
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: Kim Phillips kim.phillips@amd.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Borislav Petkov bp@suse.de Reviewed-by: Josh Poimboeuf jpoimboe@kernel.org Signed-off-by: Borislav Petkov bp@suse.de Signed-off-by: Thadeu Lima de Souza Cascardo cascardo@canonical.com Signed-off-by: Ben Hutchings ben@decadent.org.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/mm/mem_encrypt_boot.S | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/arch/x86/mm/mem_encrypt_boot.S +++ b/arch/x86/mm/mem_encrypt_boot.S @@ -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)