Messages in this thread | | | Date | Wed, 4 Jul 2018 17:37:23 +0100 | From | Mark Rutland <> | Subject | Re: [PATCHv2 11/11] arm64: use instrumented atomics |
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On Wed, Jul 04, 2018 at 04:24:22PM +0100, Will Deacon wrote: > On Mon, Jun 25, 2018 at 11:59:52AM +0100, Mark Rutland wrote: > > Now that the generic atomic headers provide instrumented wrappers of all > > the atomics implemented by arm64, let's migrate arm64 over to these. > > > > The additional instrumentation will help to find bugs (e.g. when fuzzing > > with Syzkaller). > > > > Mostly this change involes adding an arch_ prefix to a number of > > function names and macro definitions. Due to the way we call the LL/SC > > atomics via the LSE atomic wrappers, this requires adding an arch_ > > prefix to some arm64-specific atomic primitives. > > > > Some unusual whitespace in the cmpxchg wrappers is fixed up as part of > > the change. > > > > Signed-off-by: Mark Rutland <mark.rutland@arm.com> > > Cc: Catalin Marinas <catalin.marinas@arm.com> > > Cc: Will Deacon <will.deacon@arm.com> > > --- > > arch/arm64/include/asm/atomic.h | 237 ++++++++++++++++++----------------- > > arch/arm64/include/asm/atomic_lse.h | 51 ++++---- > > arch/arm64/include/asm/cmpxchg.h | 106 ++++++++-------- > > arch/arm64/include/asm/lse.h | 2 +- > > arch/arm64/include/asm/sync_bitops.h | 16 +-- > > 5 files changed, 212 insertions(+), 200 deletions(-) > > This is mostly straightforward, but the cmpxchg/cmpxchg_double cases grow > an 'arch' prefix which suggests that they're part of the API with the core > atomics and also makes them horribly ugly.
I agree this isn't nice.
> This just looks to be an artifact of __LL_SC_CALL pasting that in. Can > you drop that auto pasting of 'arch', and instead change the > non-cmpxchg-case callers of the macro to include the arch prefix > instead, please?
That leads to having an arch___llsc_ prefix in some cases, which is equally hideous.
How about I remove the prefix mangling entirely, and always give functions an __llsc_ or __lse_ prefix. Then, unify the two in our atomic.h with:
#ifdef CONFIG_ARM64_LSE #define ATOMIC_PFX __lse_ #else #define ATOMIC_PFX __ll_sc_ #endif
#define arch_atomic_foo ATOMIC_PFX##atomic_foo #define arch_atomic_bar ATOMIC_PFX##atomic_bar
... which clearly delineates the implementation from core API.
Does that sound ok to you?
Thanks, Mark.
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