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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2017-07-15 17:23:13 +0100
committerMark Rutland <mark.rutland@arm.com>2017-08-15 18:35:47 +0100
commit8ea41b11ef746e1ac97f8c90911e5c61f8bd5cc0 (patch)
tree68ad3c4487ce3ae68ae2b4b6f32519ca60ccf19c /arch/arm64/include
parentarm64: factor out entry stack manipulation (diff)
downloadlinux-dev-8ea41b11ef746e1ac97f8c90911e5c61f8bd5cc0.tar.xz
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arm64: assembler: allow adr_this_cpu to use the stack pointer
Given that adr_this_cpu already requires a temp register in addition to the destination register, tweak the instruction sequence so that sp may be used as well. This will simplify switching to per-cpu stacks in subsequent patches. While this limits the range of adr_this_cpu, to +/-4GiB, we don't currently use adr_this_cpu in modules, and this is not problematic for the main kernel image. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> [Mark: add more commit text] Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Will Deacon <will.deacon@arm.com> Tested-by: Laura Abbott <labbott@redhat.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com>
Diffstat (limited to 'arch/arm64/include')
-rw-r--r--arch/arm64/include/asm/assembler.h8
1 files changed, 7 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 610a42018241..2f2bd5192b5e 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -230,12 +230,18 @@ lr .req x30 // link register
.endm
/*
- * @dst: Result of per_cpu(sym, smp_processor_id())
+ * @dst: Result of per_cpu(sym, smp_processor_id()), can be SP for
+ * non-module code
* @sym: The name of the per-cpu variable
* @tmp: scratch register
*/
.macro adr_this_cpu, dst, sym, tmp
+#ifndef MODULE
+ adrp \tmp, \sym
+ add \dst, \tmp, #:lo12:\sym
+#else
adr_l \dst, \sym
+#endif
mrs \tmp, tpidr_el1
add \dst, \dst, \tmp
.endm