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authorArd Biesheuvel <ardb@kernel.org>2020-12-09 17:21:43 +0100
committerRussell King <rmk+kernel@armlinux.org.uk>2021-02-01 19:41:30 +0000
commit6468e898c67b905ec0f95d9678929135bcaf7f67 (patch)
tree687e1b123aa0dde8858dd81c3ad731416a1269f6 /arch/arm/include/asm
parent5c8fe583cce542aa0b84adc939ce85293de36e5e (diff)
ARM: 9039/1: assembler: generalize byte swapping macro into rev_l
Take the 4 instruction byte swapping sequence from the decompressor's head.S, and turn it into a rev_l GAS macro for general use. While at it, make it use the 'rev' instruction when compiling for v6 or later. Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Nicolas Pitre <nico@fluxnic.net> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch/arm/include/asm')
-rw-r--r--arch/arm/include/asm/assembler.h17
1 files changed, 17 insertions, 0 deletions
diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h
index 6ed30421f697..e2b1fd558bf3 100644
--- a/arch/arm/include/asm/assembler.h
+++ b/arch/arm/include/asm/assembler.h
@@ -578,4 +578,21 @@ THUMB( orr \reg , \reg , #PSR_T_BIT )
__adldst_l str, \src, \sym, \tmp, \cond
.endm
+ /*
+ * rev_l - byte-swap a 32-bit value
+ *
+ * @val: source/destination register
+ * @tmp: scratch register
+ */
+ .macro rev_l, val:req, tmp:req
+ .if __LINUX_ARM_ARCH__ < 6
+ eor \tmp, \val, \val, ror #16
+ bic \tmp, \tmp, #0x00ff0000
+ mov \val, \val, ror #8
+ eor \val, \val, \tmp, lsr #8
+ .else
+ rev \val, \val
+ .endif
+ .endm
+
#endif /* __ASM_ASSEMBLER_H__ */