diff mbox series

[v4,7/7] arm: remove redundant section alignments

Message ID 20240315064354.2215266-8-ilias.apalodimas@linaro.org
State New
Headers show
Series Clean up arm linker scripts | expand

Commit Message

Ilias Apalodimas March 15, 2024, 6:43 a.m. UTC 
Previous patches cleaning up linker symbols, also merged any explicit
. = ALIGN(x); into section definitions -- e.g
.bss ALIGN(x) : instead of

. = ALIGN(x);
. bss : {...}

However, if the output address is not specified then one will be chosen
for the section. This address will be adjusted to fit the alignment
requirement of the output section following the strictest alignment of
any input section contained within the output section. So let's get rid
of the redundant ALIGN directives when they are not needed.

While at add comments for the alignment of __bss_start/end since our
C runtime setup assembly assumes that __bss_start - __bss_end will be
a multiple of 4/8 for armv7 and armv8 respectively.

It's worth noting that the alignment is preserved on .rel.dyn for
mach-zynq which was explicitly aligning that section on an 8b
boundary instead of 4b one.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
---
 arch/arm/cpu/armv8/u-boot.lds | 9 ++++++---
 arch/arm/cpu/u-boot.lds       | 8 ++++++--
 arch/arm/mach-zynq/u-boot.lds | 4 ++--
 3 files changed, 14 insertions(+), 7 deletions(-)
diff mbox series

Patch

diff --git a/arch/arm/cpu/armv8/u-boot.lds b/arch/arm/cpu/armv8/u-boot.lds
index 147a6e8028d5..857f44412e07 100644
--- a/arch/arm/cpu/armv8/u-boot.lds
+++ b/arch/arm/cpu/armv8/u-boot.lds
@@ -115,7 +115,7 @@  SECTIONS
 		KEEP(*(SORT(__u_boot_list*)));
 	}
 
-	.efi_runtime_rel ALIGN(8) : {
+	.efi_runtime_rel : {
                 __efi_runtime_rel_start = .;
 		*(.rel*.efi_runtime)
 		*(.rel*.efi_runtime.*)
@@ -125,7 +125,7 @@  SECTIONS
 	. = ALIGN(8);
 	__image_copy_end = .;
 
-	.rela.dyn ALIGN(8) : {
+	.rela.dyn : {
 		__rel_dyn_start = .;
 		*(.rela*)
 		__rel_dyn_end = .;
@@ -133,7 +133,10 @@  SECTIONS
 
 	_end = .;
 
-	.bss ALIGN(8): {
+	/*
+	 * arch/arm/lib/crt0_64.S assumes __bss_start - __bss_end % 8 == 0
+	 */
+	.bss ALIGN(8) : {
 		__bss_start = .;
 		*(.bss*)
 		. = ALIGN(8);
diff --git a/arch/arm/cpu/u-boot.lds b/arch/arm/cpu/u-boot.lds
index 798858e3ed6e..707b19795f08 100644
--- a/arch/arm/cpu/u-boot.lds
+++ b/arch/arm/cpu/u-boot.lds
@@ -43,7 +43,7 @@  SECTIONS
 	}
 
 	/* This needs to come before *(.text*) */
-	.efi_runtime ALIGN(4) : {
+	.efi_runtime : {
 		__efi_runtime_start = .;
 		*(.text.efi_runtime*)
 		*(.rodata.efi_runtime*)
@@ -146,7 +146,7 @@  SECTIONS
 		KEEP(*(SORT(__u_boot_list*)));
 	}
 
-	.efi_runtime_rel ALIGN(4) : {
+	.efi_runtime_rel : {
 		__efi_runtime_rel_start = .;
 		*(.rel*.efi_runtime)
 		*(.rel*.efi_runtime.*)
@@ -156,6 +156,10 @@  SECTIONS
 	. = ALIGN(4);
 	__image_copy_end = .;
 
+	/*
+	 * if CONFIG_USE_ARCH_MEMSET is not selected __bss_end - __bss_start
+	 * needs to be a multiple of 4 and we overlay .bss with .rel.dyn
+	 */
 	.rel.dyn ALIGN(4) : {
 		__rel_dyn_start = .;
 		*(.rel*)
diff --git a/arch/arm/mach-zynq/u-boot.lds b/arch/arm/mach-zynq/u-boot.lds
index f6c99a8ce218..3e0c96c50556 100644
--- a/arch/arm/mach-zynq/u-boot.lds
+++ b/arch/arm/mach-zynq/u-boot.lds
@@ -22,7 +22,7 @@  SECTIONS
 	}
 
 	/* This needs to come before *(.text*) */
-	.efi_runtime ALIGN(4) : {
+	.efi_runtime : {
 		__efi_runtime_start = .;
 		*(.text.efi_runtime*)
 		*(.rodata.efi_runtime*)
@@ -52,7 +52,7 @@  SECTIONS
 		KEEP(*(SORT(__u_boot_list*)));
 	}
 
-	.efi_runtime_rel ALIGN(4) : {
+	.efi_runtime_rel : {
 		__efi_runtime_rel_start = .;
 		*(.rel*.efi_runtime)
 		*(.rel*.efi_runtime.*)