From 3789c122d0a016b947ce5c05d3f1fbafa5db8f26 Mon Sep 17 00:00:00 2001 From: Mark Rutland <mark.rutland@arm.com> Date: Fri, 27 Apr 2018 11:50:36 +0100 Subject: [PATCH] arm64: avoid instrumenting atomic_ll_sc.o Our out-of-line atomics are built with a special calling convention, preventing pointless stack spilling, and allowing us to patch call sites with ARMv8.1 atomic instructions. Instrumentation inserted by the compiler may result in calls to functions not following this special calling convention, resulting in registers being unexpectedly clobbered, and various problems resulting from this. For example, if a kernel is built with KCOV and ARM64_LSE_ATOMICS, the compiler inserts calls to __sanitizer_cov_trace_pc in the prologues of the atomic functions. This has been observed to result in spurious cmpxchg failures, leading to a hang early on in the boot process. This patch avoids such issues by preventing instrumentation of our out-of-line atomics. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> --- arch/arm64/lib/Makefile | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/arm64/lib/Makefile b/arch/arm64/lib/Makefile index 0ead8a1d16795..137710f4dac30 100644 --- a/arch/arm64/lib/Makefile +++ b/arch/arm64/lib/Makefile @@ -19,5 +19,9 @@ CFLAGS_atomic_ll_sc.o := -fcall-used-x0 -ffixed-x1 -ffixed-x2 \ -fcall-saved-x13 -fcall-saved-x14 -fcall-saved-x15 \ -fcall-saved-x18 -fomit-frame-pointer CFLAGS_REMOVE_atomic_ll_sc.o := -pg +GCOV_PROFILE_atomic_ll_sc.o := n +KASAN_SANITIZE_atomic_ll_sc.o := n +KCOV_INSTRUMENT_atomic_ll_sc.o := n +UBSAN_SANITIZE_atomic_ll_sc.o := n lib-$(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) += uaccess_flushcache.o -- GitLab