4.2.8-ckt7 -stable review patch. If anyone has any objections, please let me know.
---8<------------------------------------------------------------
From: Vineet Gupta <vgupta@xxxxxxxxxxxx>
commit 2a41b6dc28dc71c1a3f1622612a26edc58f7561e upstream.
commit 80f420842ff42 removed the ARC bitops microoptimization but failed
to prune the comments to same effect
Fixes: 80f420842ff42 ("ARC: Make ARC bitops "safer" (add anti-optimization)")
Signed-off-by: Vineet Gupta <vgupta@xxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
arch/arc/include/asm/bitops.h | 15 ---------------
1 file changed, 15 deletions(-)
diff --git a/arch/arc/include/asm/bitops.h b/arch/arc/include/asm/bitops.h
index 57c1f33..0352fb8 100644
--- a/arch/arc/include/asm/bitops.h
+++ b/arch/arc/include/asm/bitops.h
@@ -35,21 +35,6 @@ static inline void op##_bit(unsigned long nr, volatile unsigned long *m)\
\
m += nr >> 5; \
\
- /* \
- * ARC ISA micro-optimization: \
- * \
- * Instructions dealing with bitpos only consider lower 5 bits \
- * e.g (x << 33) is handled like (x << 1) by ASL instruction \
- * (mem pointer still needs adjustment to point to next word) \
- * \
- * Hence the masking to clamp @nr arg can be elided in general. \
- * \
- * However if @nr is a constant (above assumed in a register), \
- * and greater than 31, gcc can optimize away (x << 33) to 0, \
- * as overflow, given the 32-bit ISA. Thus masking needs to be \
- * done for const @nr, but no code is generated due to gcc \
- * const prop. \
- */ \
nr &= 0x1f; \
\
__asm__ __volatile__( \
--
2.7.4
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html