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authorPeter Zijlstra <peterz@infradead.org>2022-09-15 13:10:47 +0200
committerPeter Zijlstra <peterz@infradead.org>2022-10-17 16:40:58 +0200
commitd49a0626216b95cd4bf696f6acf55f39a16ab0bb (patch)
tree52349000d2ed416b132b74e58c9f005b9a51211c /arch/x86/boot/compressed/head_64.S
parentx86: Sanitize linker script (diff)
downloadlinux-d49a0626216b95cd4bf696f6acf55f39a16ab0bb.tar.xz
linux-d49a0626216b95cd4bf696f6acf55f39a16ab0bb.zip
arch: Introduce CONFIG_FUNCTION_ALIGNMENT
Generic function-alignment infrastructure. Architectures can select FUNCTION_ALIGNMENT_xxB symbols; the FUNCTION_ALIGNMENT symbol is then set to the largest such selected size, 0 otherwise. From this the -falign-functions compiler argument and __ALIGN macro are set. This incorporates the DEBUG_FORCE_FUNCTION_ALIGN_64B knob and future alignment requirements for x86_64 (later in this series) into a single place. NOTE: also removes the 0x90 filler byte from the generic __ALIGN primitive, that value makes no sense outside of x86. NOTE: .balign 0 reverts to a no-op. Requested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20220915111143.719248727@infradead.org
Diffstat (limited to 'arch/x86/boot/compressed/head_64.S')
-rw-r--r--arch/x86/boot/compressed/head_64.S8
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index d33f060900d2..190b803eb787 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -38,6 +38,14 @@
#include "pgtable.h"
/*
+ * Fix alignment at 16 bytes. Following CONFIG_FUNCTION_ALIGNMENT will result
+ * in assembly errors due to trying to move .org backward due to the excessive
+ * alignment.
+ */
+#undef __ALIGN
+#define __ALIGN .balign 16, 0x90
+
+/*
* Locally defined symbols should be marked hidden:
*/
.hidden _bss