The patch titled
Subject: arm: port KCOV to arm
has been added to the -mm tree. Its filename is
arm-port-kcov-to-arm.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/arm-port-kcov-to-arm.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/arm-port-kcov-to-arm.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
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------------------------------------------------------
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
_
Patches currently in -mm which might be from dvyukov@xxxxxxxxxx are
kasan-prohibit-kasanstructleak-combination.patch
arm-port-kcov-to-arm.patch
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