Commit 71ff44ac authored Mar 08, 2020 by Arvind Sankar Committed by Ingo Molnar Mar 08, 2020

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 <nivedita@alum.mit.edu>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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

parent 3cdcd689

arch/x86/boot/compressed/head_64.S

+4 −0

Original line number	Diff line number	Diff line
		@@ -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

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