Messages in this thread | | | Date | Tue, 14 Jun 2022 11:20:07 +0800 | Subject | Re: [PATCH v4 2/2] arm64: kcsan: Support detecting more missing memory barriers | From | Kefeng Wang <> |
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Hi Will and Catalin, kindly ping...
On 2022/5/23 22:16, Mark Rutland wrote: > On Mon, May 23, 2022 at 07:31:26PM +0800, Kefeng Wang wrote: >> As "kcsan: Support detecting a subset of missing memory barriers"[1] >> introduced KCSAN_STRICT/KCSAN_WEAK_MEMORY which make kcsan detects >> more missing memory barrier, but arm64 don't have KCSAN instrumentation >> for barriers, so the new selftest test_barrier() and test cases for >> memory barrier instrumentation in kcsan_test module will fail, even >> panic on selftest. >> >> Let's prefix all barriers with __ on arm64, as asm-generic/barriers.h >> defined the final instrumented version of these barriers, which will >> fix the above issues. >> >> Note, barrier instrumentation that can be disabled via __no_kcsan with >> appropriate compiler-support (and not just with objtool help), see >> commit bd3d5bd1a0ad ("kcsan: Support WEAK_MEMORY with Clang where no >> objtool support exists"), it adds disable_sanitizer_instrumentation to >> __no_kcsan attribute which will remove all sanitizer instrumentation fully >> (with Clang 14.0). Meanwhile, GCC does the same thing with no_sanitize. >> >> [1] https://lore.kernel.org/linux-mm/20211130114433.2580590-1-elver@google.com/ >> >> Acked-by: Marco Elver <elver@google.com> >> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> > Having built this with GCC 12.1.0 and LLVM 14.0.0, I think this patch itself > doesn't introduce any new problems, and logically makes sense. With that in > mind: > > Acked-by: Mark Rutland <mark.rutland@arm.com> > > As an aside, having scanned the resulting vmlinux with objdump, there are > plenty of latent issues where we get KCSAN instrumentation where we don't want > it (e.g. early/late in arm64's entry-common.o). The bulk of those are due to > missing `nonistr` or `__always_inline`, which we'll need to fix up. > > Thanks, > Mark. > >> --- >> arch/arm64/include/asm/barrier.h | 12 ++++++------ >> 1 file changed, 6 insertions(+), 6 deletions(-) >> >> diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h >> index 9f3e2c3d2ca0..2cfc4245d2e2 100644 >> --- a/arch/arm64/include/asm/barrier.h >> +++ b/arch/arm64/include/asm/barrier.h >> @@ -50,13 +50,13 @@ >> #define pmr_sync() do {} while (0) >> #endif >> >> -#define mb() dsb(sy) >> -#define rmb() dsb(ld) >> -#define wmb() dsb(st) >> +#define __mb() dsb(sy) >> +#define __rmb() dsb(ld) >> +#define __wmb() dsb(st) >> >> -#define dma_mb() dmb(osh) >> -#define dma_rmb() dmb(oshld) >> -#define dma_wmb() dmb(oshst) >> +#define __dma_mb() dmb(osh) >> +#define __dma_rmb() dmb(oshld) >> +#define __dma_wmb() dmb(oshst) >> >> #define io_stop_wc() dgh() >> >> -- >> 2.35.3 >> > .
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