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From: Arvind Sankar <nivedita@alum.mit.edu>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: linux-efi@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 2/5] efi/x86: Respect 32-bit ABI in efi32_pe_entry
Date: Sun,  1 Mar 2020 18:04:33 -0500	[thread overview]
Message-ID: <20200301230436.2246909-3-nivedita@alum.mit.edu> (raw)
In-Reply-To: <20200301230436.2246909-1-nivedita@alum.mit.edu>

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 --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
-- 
2.24.1


  parent reply	other threads:[~2020-03-01 23:04 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-01 23:04 [PATCH 0/5] efi/x86 cleanups and one bugfix Arvind Sankar
2020-03-01 23:04 ` [PATCH 1/5] efi/x86: Annotate the LOADED_IMAGE_PROTOCOL_GUID with SYM_DATA Arvind Sankar
2020-03-01 23:04 ` Arvind Sankar [this message]
2020-03-01 23:04 ` [PATCH 3/5] efi/x86: Make efi32_pe_entry more readable Arvind Sankar
2020-03-02  7:49   ` Ard Biesheuvel
2020-03-02 16:54     ` Arvind Sankar
2020-03-02 16:57       ` Ard Biesheuvel
2020-03-02 17:02         ` Arvind Sankar
2020-03-02 17:09           ` Ard Biesheuvel
2020-03-01 23:04 ` [PATCH 4/5] efi/x86: Avoid using code32_start Arvind Sankar
2020-03-01 23:04 ` [PATCH 5/5] x86/boot: Use unsigned comparison for addresses Arvind Sankar
2020-03-02  7:50 ` [PATCH 0/5] efi/x86 cleanups and one bugfix Ard Biesheuvel

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