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authorDmitry Vyukov <dvyukov@google.com>2018-06-15 01:27:44 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-06-15 01:55:24 +0300
commit758517202bd2e427664857c9f2aa59da36848aca (patch)
tree550ace0c2101cf557526c0ac07c04dc2f938c7e1 /arch/arm
parent0ed557aa813922f6f32adec69e266532091c895b (diff)
downloadlinux-758517202bd2e427664857c9f2aa59da36848aca.tar.xz
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@google.com Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Abbott Liu <liuwenliang@huawei.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Koguchi Takuo <takuo.koguchi.sw@hitachi.com> Cc: <syzkaller@googlegroups.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/arm')
-rw-r--r--arch/arm/Kconfig3
-rw-r--r--arch/arm/boot/compressed/Makefile3
-rw-r--r--arch/arm/kvm/hyp/Makefile8
-rw-r--r--arch/arm/vdso/Makefile3
4 files changed, 16 insertions, 1 deletions
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 2a78bdef9a24..47eb26dc2427 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 a3c5fbcad4ab..1f5a5ffe7fcf 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