linux-kernel - [PATCH 0/5] ARM: findbit assembly updates

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Message-ID: <Y1wHlSE0S5QZ+QCI@shell.armlinux.org.uk>
Date:   Fri, 28 Oct 2022 17:47:17 +0100
From:   "Russell King (Oracle)" <linux@...linux.org.uk>
To:     Yury Norov <yury.norov@...il.com>
Cc:     Catalin Marinas <catalin.marinas@....com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        linux-arm-kernel@...ts.infradead.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Mark Rutland <mark.rutland@....com>,
        Will Deacon <will@...nel.org>
Subject: [PATCH 0/5] ARM: findbit assembly updates

Hi,

This series updates the arm32 assembly versions of the findbit
operations:

- Document ARMv5 code that calculates the bit offset
- Provide an updated ARMv7 implementation using the rbit instruction
- Switch to use macros instead of duplicating mostly identical code
- Switch to using word loads rather than byte loads
- Add unwinder information for backtracing

I've had it sitting around in-use for some time, and no issues have
arisen. Tested also outside the kernel tree in userspace and results
are the same with the previous implementation.

Testing with the find_bit benchmark module shows that these operations
coded in assembly are faster than the generic versions (previously
posted), so I believe they're worth keeping.

 arch/arm/include/asm/assembler.h |   6 +
 arch/arm/lib/findbit.S           | 230 +++++++++++++++------------------------
 2 files changed, 94 insertions(+), 142 deletions(-)

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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