From: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Subject: arm: port KCOV to arm KCOV is code coverage collection facility used, in particular, by syzkaller system call fuzzer. There is some interest in using syzkaller on arm devices. So port KCOV to arm. On implementation level this merely declares that KCOV is supported and disables instrumentation of 3 special cases. Reasons for disabling are commented in code. Tested with qemu-system-arm/vexpress-a15. Link: http://lkml.kernel.org/r/20180511143248.112484-1-dvyukov@xxxxxxxxxx Signed-off-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Acked-by: Mark Rutland <mark.rutland@xxxxxxx> Cc: Russell King <linux@xxxxxxxxxxxxxxx> Cc: Abbott Liu <liuwenliang@xxxxxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Koguchi Takuo <takuo.koguchi.sw@xxxxxxxxxxx> Cc: <syzkaller@xxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/arm/Kconfig | 3 ++- arch/arm/boot/compressed/Makefile | 3 +++ arch/arm/kvm/hyp/Makefile | 8 ++++++++ arch/arm/vdso/Makefile | 3 +++ 4 files changed, 16 insertions(+), 1 deletion(-) diff -puN arch/arm/boot/compressed/Makefile~arm-port-kcov-to-arm arch/arm/boot/compressed/Makefile --- a/arch/arm/boot/compressed/Makefile~arm-port-kcov-to-arm +++ a/arch/arm/boot/compressed/Makefile @@ -25,6 +25,9 @@ endif GCOV_PROFILE := n +# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in. +KCOV_INSTRUMENT := n + # # Architecture dependencies # diff -puN arch/arm/Kconfig~arm-port-kcov-to-arm arch/arm/Kconfig --- a/arch/arm/Kconfig~arm-port-kcov-to-arm +++ a/arch/arm/Kconfig @@ -8,9 +8,10 @@ config ARM select ARCH_HAS_DEVMEM_IS_ALLOWED select ARCH_HAS_ELF_RANDOMIZE select ARCH_HAS_FORTIFY_SOURCE + select ARCH_HAS_KCOV select ARCH_HAS_PTE_SPECIAL if ARM_LPAE - select ARCH_HAS_SET_MEMORY select ARCH_HAS_PHYS_TO_DMA + select ARCH_HAS_SET_MEMORY select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL select ARCH_HAS_STRICT_MODULE_RWX if MMU select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST diff -puN arch/arm/kvm/hyp/Makefile~arm-port-kcov-to-arm arch/arm/kvm/hyp/Makefile --- a/arch/arm/kvm/hyp/Makefile~arm-port-kcov-to-arm +++ a/arch/arm/kvm/hyp/Makefile @@ -23,3 +23,11 @@ obj-$(CONFIG_KVM_ARM_HOST) += hyp-entry. obj-$(CONFIG_KVM_ARM_HOST) += switch.o CFLAGS_switch.o += $(CFLAGS_ARMV7VE) obj-$(CONFIG_KVM_ARM_HOST) += s2-setup.o + +# KVM code is run at a different exception code with a different map, so +# compiler instrumentation that inserts callbacks or checks into the code may +# cause crashes. Just disable it. +GCOV_PROFILE := n +KASAN_SANITIZE := n +UBSAN_SANITIZE := n +KCOV_INSTRUMENT := n diff -puN arch/arm/vdso/Makefile~arm-port-kcov-to-arm arch/arm/vdso/Makefile --- a/arch/arm/vdso/Makefile~arm-port-kcov-to-arm +++ a/arch/arm/vdso/Makefile @@ -30,6 +30,9 @@ CFLAGS_vgettimeofday.o = -O2 # Disable gcov profiling for VDSO code GCOV_PROFILE := n +# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in. +KCOV_INSTRUMENT := n + # Force dependency $(obj)/vdso.o : $(obj)/vdso.so _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
