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From: Will Deacon <will@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org, Will Deacon <will@kernel.org>,
	Arnd Bergmann <arnd@arndb.de>, Ard Biesheuvel <ardb@kernel.org>,
	Eric Biggers <ebiggers@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Oliver Upton <oupton@kernel.org>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Marc Zyngier <maz@kernel.org>
Subject: [PATCH 11/12] arm64: image: Remove endianness handling for generating image header
Date: Tue, 11 Aug 2026 15:01:30 +0100	[thread overview]
Message-ID: <20260811140132.22778-12-will@kernel.org> (raw)
In-Reply-To: <20260811140132.22778-1-will@kernel.org>

Since big-endian support for arm64 depends on BROKEN, we don't need to
bother jumping through hoops to generate a little-endian kernel image
header for a big-endian target. We can just ignore the possibility
instead.

Signed-off-by: Will Deacon <will@kernel.org>
---
 arch/arm64/include/asm/assembler.h | 11 -----------
 arch/arm64/kernel/head.S           |  4 ++--
 arch/arm64/kernel/image.h          | 24 ++----------------------
 3 files changed, 4 insertions(+), 35 deletions(-)

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 45279e577ff5..d3ce96c7b8ec 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -525,17 +525,6 @@ alternative_else_nop_endif
 #define EXPORT_SYMBOL_NOKASAN(name)	EXPORT_SYMBOL(name)
 #endif
 
-	/*
-	 * Emit a 64-bit absolute little endian symbol reference in a way that
-	 * ensures that it will be resolved at build time, even when building a
-	 * PIE binary. This requires cooperation from the linker script, which
-	 * must emit the lo32/hi32 halves individually.
-	 */
-	.macro	le64sym, sym
-	.long	\sym\()_lo32
-	.long	\sym\()_hi32
-	.endm
-
 	/*
 	 * mov_q - move an immediate constant into a 64-bit register using
 	 *         between 2 and 4 movz/movk instructions (depending on the
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 8951ce693552..684896390258 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -61,8 +61,8 @@
 	efi_signature_nop			// special NOP to identity as PE/COFF executable
 	b	primary_entry			// branch to kernel start, magic
 	.quad	0				// Image load offset from start of RAM, little-endian
-	le64sym	_kernel_size_le			// Effective size of kernel image, little-endian
-	le64sym	_kernel_flags_le		// Informative flags, little-endian
+	.quad	_kernel_size_le			// Effective size of kernel image, little-endian
+	.quad	_kernel_flags_le		// Informative flags, little-endian
 	.quad	0				// reserved
 	.quad	0				// reserved
 	.quad	0				// reserved
diff --git a/arch/arm64/kernel/image.h b/arch/arm64/kernel/image.h
index 5c10ca773363..208843f96b4d 100644
--- a/arch/arm64/kernel/image.h
+++ b/arch/arm64/kernel/image.h
@@ -13,21 +13,6 @@
 
 #include <asm/image.h>
 
-/*
- * There aren't any ELF relocations we can use to endian-swap values known only
- * at link time (e.g. the subtraction of two symbol addresses), so we must get
- * the linker to endian-swap certain values before emitting them.
- *
- * Note that, in order for this to work when building the ELF64 PIE executable
- * (for KASLR), these values should not be referenced via R_AARCH64_ABS64
- * relocations, since these are fixed up at runtime rather than at build time
- * when PIE is in effect. So we need to split them up in 32-bit high and low
- * words.
- */
-#define DEFINE_IMAGE_LE64(sym, data)				\
-	sym##_lo32 = (data) & 0xffffffff;			\
-	sym##_hi32 = (data) >> 32
-
 #define __HEAD_FLAG(field)	(__HEAD_FLAG_##field << \
 					ARM64_IMAGE_FLAG_##field##_SHIFT)
 
@@ -41,13 +26,8 @@
 				 __HEAD_FLAG(PAGE_SIZE) | \
 				 __HEAD_FLAG(PHYS_BASE))
 
-/*
- * These will output as part of the Image header, which should be little-endian
- * regardless of the endianness of the kernel. While constant values could be
- * endian swapped in head.S, all are done here for consistency.
- */
 #define HEAD_SYMBOLS						\
-	DEFINE_IMAGE_LE64(_kernel_size_le, _end - _text);	\
-	DEFINE_IMAGE_LE64(_kernel_flags_le, __HEAD_FLAGS);
+	_kernel_size_le		=  _end - _text;		\
+	_kernel_flags_le	= __HEAD_FLAGS;
 
 #endif /* __ARM64_KERNEL_IMAGE_H */
-- 
2.55.0.679.g6767b8d81c-goog



  parent reply	other threads:[~2026-08-11 14:02 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-11 14:01 [PATCH 00/12] arm64: Remove unused big-endian support Will Deacon
2026-08-11 14:01 ` [PATCH 01/12] selftests/arm64: Remove " Will Deacon
2026-08-11 14:01 ` [PATCH 02/12] arm64: bpf: Remove big-endian support from the JIT compiler Will Deacon
2026-08-11 14:01 ` [PATCH 03/12] arm64: crypto: Assume a little-endian kernel Will Deacon
2026-08-11 14:01 ` [PATCH 04/12] arm64: lib: Assume a little-endian kernel in custom library routines Will Deacon
2026-08-11 14:01 ` [PATCH 05/12] arm64: lib: Assume a little-endian kernel in optimised string routines Will Deacon
2026-08-11 14:01 ` [PATCH 06/12] arm64: assembler: Remove endianness helper macros Will Deacon
2026-08-11 15:04   ` Ard Biesheuvel
2026-08-11 14:01 ` [PATCH 07/12] arm64: vdso32: Always build compat vDSO object as little-endian Will Deacon
2026-08-11 14:01 ` [PATCH 08/12] KVM: arm64: Remove support for a big-endian hypervisor object Will Deacon
2026-08-11 14:01 ` [PATCH 09/12] arm64: Remove all usage of CONFIG_CPU_BIG_ENDIAN Will Deacon
2026-08-11 14:49   ` Marc Zyngier
2026-08-11 14:01 ` [PATCH 10/12] arm64: Remove all usage of __AARCH64EB__ Will Deacon
2026-08-11 14:01 ` Will Deacon [this message]
2026-08-11 14:01 ` [PATCH 12/12] arm64: Kbuild: Remove vestigial big-endian support Will Deacon
2026-08-11 14:54 ` [PATCH 00/12] arm64: Remove unused " Marc Zyngier
2026-08-11 15:11 ` Arnd Bergmann
2026-08-11 15:43 ` Catalin Marinas

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