From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f72.google.com (mail-wm0-f72.google.com [74.125.82.72]) by kanga.kvack.org (Postfix) with ESMTP id 6E03A6B0668 for ; Fri, 11 May 2018 10:32:55 -0400 (EDT) Received: by mail-wm0-f72.google.com with SMTP id b192-v6so1248864wmb.1 for ; Fri, 11 May 2018 07:32:55 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id a139-v6sor351835wma.71.2018.05.11.07.32.53 for (Google Transport Security); Fri, 11 May 2018 07:32:53 -0700 (PDT) From: Dmitry Vyukov Subject: [PATCH v2] arm: port KCOV to arm Date: Fri, 11 May 2018 16:32:48 +0200 Message-Id: <20180511143248.112484-1-dvyukov@google.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux@armlinux.org.uk, mark.rutland@arm.com, liuwenliang@huawei.com, catalin.marinas@arm.com, inux-arm-kernel@lists.infradead.org, linux-mm@kvack.org Cc: Dmitry Vyukov , Koguchi Takuo , linux-arm-kernel@lists.infradead.org, syzkaller@googlegroups.com 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. Signed-off-by: Dmitry Vyukov Cc: Russell King Cc: Mark Rutland Cc: Abbott Liu Cc: Catalin Marinas Cc: Koguchi Takuo Cc: linux-arm-kernel@lists.infradead.org Cc: linux-mm@kvack.org Cc: syzkaller@googlegroups.com --- Changes since v1: - remove disable of instrumentation for arch/arm/mm/fault.c - disable instrumentation of arch/arm/kvm/hyp/* - resort ARCH_HAS_KCOV alphabetically --- 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 --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 3493f840e89c..34591796c36f 100644 --- a/arch/arm/Kconfig +++ b/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 --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile index 6a4e7341ecd3..5f5f081e4879 100644 --- a/arch/arm/boot/compressed/Makefile +++ b/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 --git a/arch/arm/kvm/hyp/Makefile b/arch/arm/kvm/hyp/Makefile index 7fc0638f263a..d2b5ec9c4b92 100644 --- a/arch/arm/kvm/hyp/Makefile +++ b/arch/arm/kvm/hyp/Makefile @@ -23,3 +23,11 @@ obj-$(CONFIG_KVM_ARM_HOST) += hyp-entry.o obj-$(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 --git a/arch/arm/vdso/Makefile b/arch/arm/vdso/Makefile index bb4118213fee..f4efff9d3afb 100644 --- a/arch/arm/vdso/Makefile +++ b/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 -- 2.17.0.441.gb46fe60e1d-goog