[PATCHv3 0/6] atomics: generate atomic headers / instrument arm64

Mark Rutland mark.rutland at arm.com
Tue Sep 4 03:48:24 PDT 2018


Hi Ingo,

As previously requested, this is a (trivial) rebase of the remaining generated
atomic patches atop of v4.19-rc2, avoiding any potential conflict with Peter's
ldsem atomic cleanup patch that got taken through the tty tree.

Are you still happy to pick this up? Full blurb below.

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 [4]:
* rebase to v4.19-rc2 to solve potential conflicts with ldsem patch

The series is based on my atomic API cleanup patches [2], 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.

I've pushed the series out to my atomics/generated branch [3], based atop of
v4.19-rc2.

Thanks,
Mark.

[1] https://lkml.kernel.org/r/20180529180746.29684-1-mark.rutland@arm.com
[2] https://lkml.kernel.org/r/20180621121321.4761-1-mark.rutland@arm.com
[3] git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git atomics/generated
[4] https://lkml.kernel.org/r/20180625105952.3756-1-mark.rutland@arm.com

Mark Rutland (6):
  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

 Kbuild                                       |   18 +-
 MAINTAINERS                                  |    1 +
 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 +-
 include/asm-generic/atomic-instrumented.h    | 1688 ++++++++++++++++---
 include/asm-generic/atomic-long.h            | 1173 ++++++++++---
 include/linux/atomic-fallback.h              | 2294 ++++++++++++++++++++++++++
 include/linux/atomic.h                       | 1241 +-------------
 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 ++
 36 files changed, 5909 insertions(+), 1827 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




More information about the linux-arm-kernel mailing list