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From: ard.biesheuvel@linaro.org (Ard Biesheuvel)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 4/7] arm64: efi: ensure that the PE/COFF header pointer appears at offset 0x3c
Date: Mon,  6 Feb 2017 16:24:32 +0000	[thread overview]
Message-ID: <1486398275-3966-5-git-send-email-ard.biesheuvel@linaro.org> (raw)
In-Reply-To: <1486398275-3966-1-git-send-email-ard.biesheuvel@linaro.org>

Use a .org directive to ensure that the PE/COFF header pointer appears
at offset 0x3c. Since the EFI header is now emitted using a macro, this
helps ensure that the invocation of the macro remains at the correct
offset.

At the same time, collapse two adjacent #ifdef CONFIG_EFI blocks into one,
and replace .word with .long (which are equivalent, but the former is
never used elsewhere)

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/arm64/kernel/efi-header.S | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kernel/efi-header.S b/arch/arm64/kernel/efi-header.S
index 8c8cd0a8192b..74a25c09a1b8 100644
--- a/arch/arm64/kernel/efi-header.S
+++ b/arch/arm64/kernel/efi-header.S
@@ -22,14 +22,16 @@
 	.endm
 
 	.macro	__EFI_HEADER
-#ifdef CONFIG_EFI
-	.long	pe_header - _head		// Offset to the PE header.
+#ifndef CONFIG_EFI
+	.long	0				// reserved
 #else
-	.word	0				// reserved
-#endif
+	/*
+	 * PE/COFF requires the offset to the PE header
+	 * to be stored at offset 0x3c into the file.
+	 */
+	.org	_head + 0x3c
+	.long	pe_header - _head		// Offset to the PE header.
 
-#ifdef CONFIG_EFI
-	.align 3
 pe_header:
 	.ascii	"PE"
 	.short 	0
-- 
2.7.4

  parent reply	other threads:[~2017-02-06 16:24 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-06 16:24 [PATCH 0/7] arm64: efi: PE/COFF cleanup/hardening Ard Biesheuvel
2017-02-06 16:24 ` [PATCH 1/7] include: pe.h: allow for use in assembly Ard Biesheuvel
2017-02-06 16:33   ` Mark Rutland
2017-02-06 16:40     ` Ard Biesheuvel
2017-02-06 16:24 ` [PATCH 2/7] include: pe.h: add some missing definitions Ard Biesheuvel
2017-02-06 16:24 ` [PATCH 3/7] arm64: efi: move EFI header and related data to a separate .S file Ard Biesheuvel
2017-02-06 17:03   ` Mark Rutland
2017-02-06 17:07     ` Ard Biesheuvel
2017-02-06 16:24 ` Ard Biesheuvel [this message]
2017-02-06 17:05   ` [PATCH 4/7] arm64: efi: ensure that the PE/COFF header pointer appears at offset 0x3c Mark Rutland
2017-02-06 16:24 ` [PATCH 5/7] arm64: efi: remove pointless dummy .reloc section Ard Biesheuvel
2017-02-06 17:06   ` Mark Rutland
2017-02-07 18:30   ` Peter Jones
2017-02-06 16:24 ` [PATCH 6/7] arm64: efi: replace open coded constants with symbolic ones Ard Biesheuvel
2017-02-06 17:13   ` Mark Rutland
2017-02-06 16:24 ` [PATCH 7/7] arm64: efi: split Image code and data into separate PE/COFF sections Ard Biesheuvel

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