From 71ff44ac6cfaa1d8d3dff6c73636f4fb97b2be10 Mon Sep 17 00:00:00 2001 From: Arvind Sankar Date: Sun, 8 Mar 2020 09:08:41 +0100 Subject: efi/x86: Respect 32-bit ABI in efi32_pe_entry() verify_cpu() clobbers BX and DI. In case we have to return error, we need to preserve them to respect the 32-bit calling convention. Signed-off-by: Arvind Sankar Signed-off-by: Ard Biesheuvel Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20200301230436.2246909-3-nivedita@alum.mit.edu Link: https://lore.kernel.org/r/20200308080859.21568-11-ardb@kernel.org --- arch/x86/boot/compressed/head_64.S | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/x86/boot/compressed/head_64.S') diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 8105e8348607..920daf62dac2 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 -- cgit v1.2.3