From: Arvind Sankar <nivedita@xxxxxxxxxxxx> verify_cpu clobbers BX and DI. In case we have to return error, we need to preserve them to respect 32-bit calling convention. Signed-off-by: Arvind Sankar <nivedita@xxxxxxxxxxxx> Link: https://lore.kernel.org/r/20200301230436.2246909-3-nivedita@xxxxxxxxxxxx Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> --- arch/x86/boot/compressed/head_64.S | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 86c97797bf78..25fa763f4e83 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -660,7 +660,11 @@ SYM_DATA(efi_is64, .byte 1) SYM_FUNC_START(efi32_pe_entry) pushl %ebp + pushl %ebx + pushl %edi call verify_cpu // check for long mode support + popl %edi + popl %ebx testl %eax, %eax movl $0x80000003, %eax // EFI_UNSUPPORTED jnz 3f -- 2.17.1
