diff mbox series

[2/5] efi/x86: Respect 32-bit ABI in efi32_pe_entry

Message ID 20200301230436.2246909-3-nivedita@alum.mit.edu
State New
Headers show
Series None | expand

Commit Message

Arvind Sankar March 1, 2020, 11:04 p.m. UTC 
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@alum.mit.edu>
---
 arch/x86/boot/compressed/head_64.S | 4 ++++
 1 file changed, 4 insertions(+)
diff mbox series

Patch

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