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>
This commit is contained in:
Dmitry Vyukov 2018-06-14 15:27:44 -07:00 committed by Linus Torvalds
parent 0ed557aa81
commit 758517202b
4 changed files with 16 additions and 1 deletions

View File

@ -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

View File

@ -25,6 +25,9 @@ endif
GCOV_PROFILE := n
# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
KCOV_INSTRUMENT := n
#
# Architecture dependencies
#

View File

@ -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

View File

@ -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