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Subject[PATCH 10/14] arm64: assembler: allow adr_this_cpu to use the stack pointer
Date
From: Ard Biesheuvel <ard.biesheuvel@linaro.org>

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>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
---
arch/arm64/include/asm/assembler.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 610a420..4775af5 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -235,7 +235,8 @@
* @tmp: scratch register
*/
.macro adr_this_cpu, dst, sym, tmp
- adr_l \dst, \sym
+ adrp \tmp, \sym
+ add \dst, \tmp, #:lo12:\sym
mrs \tmp, tpidr_el1
add \dst, \dst, \tmp
.endm
--
1.9.1
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