[4.2.y-ckt stable] Patch "ARC: bitops: Remove non relevant comments" has been added to the 4.2.y-ckt tree
Kamal Mostafa
kamal at canonical.com
Wed Mar 30 23:53:59 UTC 2016
This is a note to let you know that I have just added a patch titled
ARC: bitops: Remove non relevant comments
to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue
This patch is scheduled to be released in version 4.2.8-ckt7.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Kamal
---8<------------------------------------------------------------
>From 753ea36aaa50fdcfdfcd515c5ae3f08ddb87e606 Mon Sep 17 00:00:00 2001
From: Vineet Gupta <vgupta at synopsys.com>
Date: Tue, 8 Mar 2016 19:31:24 +0530
Subject: ARC: bitops: Remove non relevant comments
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 at synopsys.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
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
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