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Message-ID: <20180723095757.stwepqrnefsoncgv@lakrids.cambridge.arm.com>
Date: Mon, 23 Jul 2018 10:57:58 +0100
From: Mark Rutland <mark.rutland@....com>
To: mingo@...nel.org, mingo@...hat.com
Cc: andy.shevchenko@...il.com, arnd@...db.de, aryabinin@...tuozzo.com,
boqun.feng@...il.com, catalin.marinas@....com, dvyukov@...gle.com,
glider@...gle.com, hpa@...or.com, linux-kernel@...r.kernel.org,
parri.andrea@...il.com, peter@...leysoftware.com,
peterz@...radead.org, tglx@...utronix.de, will.deacon@....com,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCHv4 00/12] atomics: generate atomic headers / instrument
arm64
On Mon, Jul 16, 2018 at 12:30:05PM +0100, Mark Rutland wrote:
> Hi Ingo,
Sorry to ping, but are you happy to pick this up?
Mark.
> Are you happy to pick this series? Both Will and Peter are happy with v3, and
> since then I've only made a minor cleanup to the commit messages for patches
> 8-10 (as requested by Peter), and added Will's Acked-by tags.
>
> This series scripts the generation of the various atomic headers, to ensure
> that the various atomic APIs remain consistent, reducing the risk of human
> error, and simplifying future rework. This fleshes out the instrumented atomics
> such that arm64 can be migrated over to them.
>
> Since v1 [1]:
> * Use 'p' instead of 'I' for pointer to base int type
> * Use Peter's patch for ldsem
> * Rename atomic acquire/release barriers
> * Handle xchg/cmpxchg variants
> * Typo fixes
> * Migrate arm64 to instrumented atomics
>
> Since v2 [2]:
> * Drop undefs for __atomic_*_fence()
> * Rename __atomic_{pre,post}_fence => __atomic_{pre,post}_full_fence()
> * Restore atomic_long_cond_read_relaxed()
> * Add Kbuild step to verify atomic headers are up-to-date
> * Rework arm64 atomic naming
> * Commit message cleanups
> * Accumulate acks
>
> Since v3 [3]:
> * Add Will's Acked-by tags
> * Clean up rationale for patches 8-10 given we check at kbuild time
>
> The series is based on my atomic API cleanup patches [4], which have been
> queued in the tip locking/core branch.
>
> The first six patches clean up some issues with the existing atomic
> instrumentation, with patch six introducing the header generation
> infrastructure. The subsequent three patches migrate to each generated header
> in turn, with the final patch moving arm64 over to the instrumented atomics.
>
> The scripts themselves are mostly POSIX sh (modulo local), without bashisms,
> and work in dash and bash.
>
> Per Linus request that it is possible to use git grep to inspect the atomic
> headers [3], the headers are committed (and not generated by kbuild). Since we
> now expand the fallback definitions inline, each *should* be easier to find
> with grep. Each header also has a comment at the top with a path to the script
> used to generate it.
>
> That scripting comes to ~900 lines, and replaces ~1700 lines of hand-written
> boilerplate with ~4700 lines of generated code. Some of that increase in line
> count is due to filling in missing portions of the API (e.g. adding all the
> ordering variants to the instrumented atomics), while some of that is due to
> expanding fallbacks in place, and consistently spreading these across multiple
> lines.
>
> I've build-tested this for x86_64 and arm64 (with and without LSE), and given
> this some basic boot testing on an Arm Juno platform.
>
> I've pushed the series out to my atomics/generated branch [5], based atop of
> tip locking/core.
>
> Thanks,
> Mark.
>
> [1] https://lkml.kernel.org/r/20180529180746.29684-1-mark.rutland@arm.com
> [2] https://lkml.kernel.org/r/20180625105952.3756-1-mark.rutland@arm.com
> [3] https://lkml.kernel.org/r/20180705164053.10073-1-mark.rutland@arm.com
> [4] https://lkml.kernel.org/r/20180621121321.4761-1-mark.rutland@arm.com
> [5] git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git atomics/generated
>
> Mark Rutland (11):
> atomics/x86: reduce arch_cmpxchg64*() instrumentation
> atomics: simplify cmpxchg() instrumentation
> atomics/treewide: instrument xchg()
> atomics: instrument cmpxchg_double*()
> atomics/treewide: rework ordering barriers
> atomics: add common header generation files
> atomics: switch to generated fallbacks
> atomics: switch to generated atomic-long
> atomics: switch to generated instrumentation
> atomics: check generated headers are up-to-date
> arm64: use instrumented atomics
>
> Peter Zijlstra (1):
> atomic/tty: Fix up atomic abuse in ldsem
>
> Kbuild | 18 +-
> MAINTAINERS | 1 +
> arch/alpha/include/asm/atomic.h | 8 +-
> arch/arm64/include/asm/atomic.h | 237 +--
> arch/arm64/include/asm/atomic_ll_sc.h | 28 +-
> arch/arm64/include/asm/atomic_lse.h | 38 +-
> arch/arm64/include/asm/cmpxchg.h | 60 +-
> arch/arm64/include/asm/sync_bitops.h | 16 +-
> arch/powerpc/include/asm/atomic.h | 17 +-
> arch/riscv/include/asm/atomic.h | 17 +-
> arch/x86/include/asm/atomic.h | 2 +-
> arch/x86/include/asm/atomic64_64.h | 2 +-
> arch/x86/include/asm/cmpxchg.h | 2 +-
> arch/x86/include/asm/cmpxchg_64.h | 4 +-
> drivers/tty/tty_ldsem.c | 82 +-
> include/asm-generic/atomic-instrumented.h | 1770 +++++++++++++++++---
> include/asm-generic/atomic-long.h | 1173 ++++++++++---
> include/linux/atomic-fallback.h | 2294 ++++++++++++++++++++++++++
> include/linux/atomic.h | 1279 +-------------
> include/linux/tty_ldisc.h | 4 +-
> scripts/atomic/atomic-tbl.sh | 186 +++
> scripts/atomic/atomics.tbl | 41 +
> scripts/atomic/check-atomics.sh | 19 +
> scripts/atomic/fallbacks/acquire | 9 +
> scripts/atomic/fallbacks/add_negative | 16 +
> scripts/atomic/fallbacks/add_unless | 16 +
> scripts/atomic/fallbacks/andnot | 7 +
> scripts/atomic/fallbacks/dec | 7 +
> scripts/atomic/fallbacks/dec_and_test | 15 +
> scripts/atomic/fallbacks/dec_if_positive | 15 +
> scripts/atomic/fallbacks/dec_unless_positive | 14 +
> scripts/atomic/fallbacks/fence | 11 +
> scripts/atomic/fallbacks/fetch_add_unless | 23 +
> scripts/atomic/fallbacks/inc | 7 +
> scripts/atomic/fallbacks/inc_and_test | 15 +
> scripts/atomic/fallbacks/inc_not_zero | 14 +
> scripts/atomic/fallbacks/inc_unless_negative | 14 +
> scripts/atomic/fallbacks/read_acquire | 7 +
> scripts/atomic/fallbacks/release | 8 +
> scripts/atomic/fallbacks/set_release | 7 +
> scripts/atomic/fallbacks/sub_and_test | 16 +
> scripts/atomic/fallbacks/try_cmpxchg | 11 +
> scripts/atomic/gen-atomic-fallback.sh | 181 ++
> scripts/atomic/gen-atomic-instrumented.sh | 182 ++
> scripts/atomic/gen-atomic-long.sh | 101 ++
> 45 files changed, 5994 insertions(+), 2000 deletions(-)
> create mode 100644 include/linux/atomic-fallback.h
> create mode 100755 scripts/atomic/atomic-tbl.sh
> create mode 100644 scripts/atomic/atomics.tbl
> create mode 100755 scripts/atomic/check-atomics.sh
> create mode 100644 scripts/atomic/fallbacks/acquire
> create mode 100644 scripts/atomic/fallbacks/add_negative
> create mode 100644 scripts/atomic/fallbacks/add_unless
> create mode 100644 scripts/atomic/fallbacks/andnot
> create mode 100644 scripts/atomic/fallbacks/dec
> create mode 100644 scripts/atomic/fallbacks/dec_and_test
> create mode 100644 scripts/atomic/fallbacks/dec_if_positive
> create mode 100644 scripts/atomic/fallbacks/dec_unless_positive
> create mode 100644 scripts/atomic/fallbacks/fence
> create mode 100644 scripts/atomic/fallbacks/fetch_add_unless
> create mode 100644 scripts/atomic/fallbacks/inc
> create mode 100644 scripts/atomic/fallbacks/inc_and_test
> create mode 100644 scripts/atomic/fallbacks/inc_not_zero
> create mode 100644 scripts/atomic/fallbacks/inc_unless_negative
> create mode 100644 scripts/atomic/fallbacks/read_acquire
> create mode 100644 scripts/atomic/fallbacks/release
> create mode 100644 scripts/atomic/fallbacks/set_release
> create mode 100644 scripts/atomic/fallbacks/sub_and_test
> create mode 100644 scripts/atomic/fallbacks/try_cmpxchg
> create mode 100755 scripts/atomic/gen-atomic-fallback.sh
> create mode 100755 scripts/atomic/gen-atomic-instrumented.sh
> create mode 100755 scripts/atomic/gen-atomic-long.sh
>
> --
> 2.11.0
>
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