Re: [PATCH v2 00/33] locking/atomic: convert all architectures to ARCH_ATOMIC
From: Randy Dunlap
Date: Sat Jun 05 2021 - 02:03:03 EST
On 5/25/21 7:01 AM, Mark Rutland wrote:
> This series (based on v5.13-rc2) converts all architectures to
> ARCH_ATOMIC. This will allow the use of instrumented atomics on all
> architectures (e.g. for KASAN and similar), and simplifies the core
> atomic code (which should allow for easier rework of the fallbacks and
> other bits in future).
>
> I'm hoping that we can queue this via the tip tree for v5.14.
>
> I've build-tested this with the kernel.org crosstool GCC 10.3.0 binaries
> (all arches except hexagon), and I haven't seen issues with the configs
> I tried, so I'm fairly confident this is solid now. I'd like to get this
> into linux-next ASAP to flush out any remaining issues.
>
> The series is split into three parts:
>
> 1) Some preparatory work is done to prepare architectures and common
> code for the conversion. In this phase h8300 and microblaze are
> converted to use the asm-generic atomics exclusively, and the
> asm-generic implementations are made to function with or without
> ARCH_ATOMIC.
>
> 2) Architectures are converted one-by-one to use the ARCH_ATOMIC
> interface. I've converted each architecture with its own patch (even
> where the conversion is trivial) to make review and bisection easier.
>
> 3) The code handling !ARCH_ATOMIC is removed.
>
> Note: I've generated the patches with:
>
> git format-patch -C -M -D
>
> ... so the preimage of include/linux/atomic-fallback.h is not included
> in the diff when it is deleted.
>
> The series can also be found in my atomics/arch-atomic branch on
> kernel.org:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=atomics/arch-atomic
> git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git atomics/arch-atomic
>
> This version is tagged as arch-atomic-20210525.
>
> Since v1 [1]:
> * Rebase to v5.13-rc2
> * Accumulate Acked-by / Reviewed-by tags
> * Correct missing `arch_` prefixes
> * Fix missing preprocessor glue
>
> [1] https://lore.kernel.org/r/20210510093753.40683-1-mark.rutland@xxxxxxx
>
> Thanks,
> Mark.
>
> Mark Rutland (33):
> locking/atomic: make ARCH_ATOMIC a Kconfig symbol
> locking/atomic: net: use linux/atomic.h for xchg & cmpxchg
> locking/atomic: h8300: use asm-generic exclusively
> locking/atomic: microblaze: use asm-generic exclusively
> locking/atomic: openrisc: avoid asm-generic/atomic.h
> locking/atomic: atomic: remove stale comments
> locking/atomic: atomic: remove redundant include
> locking/atomic: atomic: simplify ifdeffery
> locking/atomic: atomic: support ARCH_ATOMIC
> locking/atomic: atomic64: support ARCH_ATOMIC
> locking/atomic: cmpxchg: make `generic` a prefix
> locking/atomic: cmpxchg: support ARCH_ATOMIC
> locking/atomic: alpha: move to ARCH_ATOMIC
> locking/atomic: arc: move to ARCH_ATOMIC
> locking/atomic: arm: move to ARCH_ATOMIC
> locking/atomic: csky: move to ARCH_ATOMIC
> locking/atomic: h8300: move to ARCH_ATOMIC
> locking/atomic: hexagon: move to ARCH_ATOMIC
> locking/atomic: ia64: move to ARCH_ATOMIC
> locking/atomic: m68k: move to ARCH_ATOMIC
> locking/atomic: microblaze: move to ARCH_ATOMIC
> locking/atomic: mips: move to ARCH_ATOMIC
> locking/atomic: nds32: move to ARCH_ATOMIC
> locking/atomic: nios2: move to ARCH_ATOMIC
> locking/atomic: openrisc: move to ARCH_ATOMIC
> locking/atomic: parisc: move to ARCH_ATOMIC
> locking/atomic: powerpc: move to ARCH_ATOMIC
> locking/atomic: riscv: move to ARCH_ATOMIC
> locking/atomic: sh: move to ARCH_ATOMIC
> locking/atomic: sparc: move to ARCH_ATOMIC
> locking/atomic: xtensa: move to ARCH_ATOMIC
> locking/atomic: delete !ARCH_ATOMIC remnants
> locking/atomics: atomic-instrumented: simplify ifdeffery
>
> arch/alpha/include/asm/atomic.h | 88 +-
> arch/alpha/include/asm/cmpxchg.h | 12 +-
> arch/arc/include/asm/atomic.h | 60 +-
> arch/arc/include/asm/cmpxchg.h | 10 +-
> arch/arm/include/asm/atomic.h | 96 +-
> arch/arm/include/asm/cmpxchg.h | 20 +-
> arch/arm/include/asm/sync_bitops.h | 2 +-
> arch/arm64/include/asm/atomic.h | 2 -
> arch/csky/include/asm/cmpxchg.h | 8 +-
> arch/h8300/include/asm/Kbuild | 1 +
> arch/h8300/include/asm/atomic.h | 97 --
> arch/h8300/include/asm/cmpxchg.h | 66 -
> arch/hexagon/include/asm/atomic.h | 28 +-
> arch/hexagon/include/asm/cmpxchg.h | 4 +-
> arch/ia64/include/asm/atomic.h | 74 +-
> arch/ia64/include/asm/cmpxchg.h | 16 +
> arch/ia64/include/uapi/asm/cmpxchg.h | 10 +-
> arch/m68k/include/asm/atomic.h | 60 +-
> arch/m68k/include/asm/cmpxchg.h | 10 +-
> arch/m68k/include/asm/mmu_context.h | 2 +-
> arch/microblaze/include/asm/Kbuild | 1 +
> arch/microblaze/include/asm/atomic.h | 28 -
> arch/microblaze/include/asm/cmpxchg.h | 9 -
> arch/mips/include/asm/atomic.h | 55 +-
> arch/mips/include/asm/cmpxchg.h | 22 +-
> arch/mips/kernel/cmpxchg.c | 4 +-
> arch/openrisc/include/asm/atomic.h | 42 +-
> arch/openrisc/include/asm/cmpxchg.h | 4 +-
> arch/parisc/include/asm/atomic.h | 34 +-
> arch/parisc/include/asm/cmpxchg.h | 14 +-
> arch/powerpc/include/asm/atomic.h | 140 +-
> arch/powerpc/include/asm/cmpxchg.h | 30 +-
> arch/powerpc/include/asm/qspinlock.h | 2 +-
> arch/riscv/include/asm/atomic.h | 128 +-
> arch/riscv/include/asm/cmpxchg.h | 34 +-
> arch/s390/include/asm/atomic.h | 2 -
> arch/sh/include/asm/atomic-grb.h | 6 +-
> arch/sh/include/asm/atomic-irq.h | 6 +-
> arch/sh/include/asm/atomic-llsc.h | 6 +-
> arch/sh/include/asm/atomic.h | 8 +-
> arch/sh/include/asm/cmpxchg.h | 4 +-
> arch/sparc/include/asm/atomic_32.h | 38 +-
> arch/sparc/include/asm/atomic_64.h | 36 +-
> arch/sparc/include/asm/cmpxchg_32.h | 12 +-
> arch/sparc/include/asm/cmpxchg_64.h | 12 +-
> arch/sparc/lib/atomic32.c | 24 +-
> arch/sparc/lib/atomic_64.S | 42 +-
> arch/x86/include/asm/atomic.h | 2 -
> arch/xtensa/include/asm/atomic.h | 26 +-
> arch/xtensa/include/asm/cmpxchg.h | 14 +-
> include/asm-generic/atomic-instrumented.h | 498 +-----
> include/asm-generic/atomic.h | 118 +-
> include/asm-generic/atomic64.h | 45 +-
> include/asm-generic/cmpxchg-local.h | 4 +-
> include/asm-generic/cmpxchg.h | 42 +-
> include/linux/atomic-fallback.h | 2595 -----------------------------
> include/linux/atomic.h | 4 -
> lib/atomic64.c | 36 +-
> net/core/filter.c | 2 +-
> net/sunrpc/xprtmultipath.c | 2 +-
> scripts/atomic/check-atomics.sh | 1 -
> scripts/atomic/gen-atomic-instrumented.sh | 51 +-
> scripts/atomic/gen-atomics.sh | 1 -
> 63 files changed, 756 insertions(+), 4094 deletions(-)
> delete mode 100644 arch/h8300/include/asm/atomic.h
> delete mode 100644 arch/h8300/include/asm/cmpxchg.h
> create mode 100644 arch/ia64/include/asm/cmpxchg.h
> delete mode 100644 arch/microblaze/include/asm/atomic.h
> delete mode 100644 arch/microblaze/include/asm/cmpxchg.h
> delete mode 100644 include/linux/atomic-fallback.h
>
Hi Mark,
Sorry for the late reply. I was just trying to update a patch
to arch/sh/include/asm/cmpxchg.h, in its xchg() macro:
https://lore.kernel.org/lkml/20210602231443.4670-2-rdunlap@xxxxxxxxxxxxx/
The patch simply converts xchg() to a GCC statement expression to
eliminate a build warning.
Arnd has done this for m68k and I have done it for sparc in the past.
Is there any (good) reason that all versions of arch_xchg() are not
statement expressions? In this patch series, they seem to be quite
mixed (as they were before this patch series). I count 11 arches
that use a statement expression and 4 that do not (including arch/sh/).
thanks.
--
~Randy