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| author | Mark Rutland <mark.rutland@arm.com> | 2021-06-07 10:46:23 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-07-14 17:06:25 +0200 |
| commit | b8ce443813d553d6303b761312ebdf0d116053d6 (patch) | |
| tree | f99391d0e6af7d0ea052f59230b128edabfdb156 /arch | |
| parent | 6a8665574f6b7b1d54d328c6a98fa49ea741c73e (diff) | |
arm64: entry: don't instrument entry code with KCOV
[ Upstream commit bf6fa2c0dda751863c3446aa64d733013bec4a19 ]
The code in entry-common.c runs at exception entry and return
boundaries, where portions of the kernel environment aren't available.
For example, RCU may not be watching, and lockdep state may be
out-of-sync with the hardware. Due to this, it is not sound to
instrument this code.
We generally avoid instrumentation by marking the entry functions as
`noinstr`, but currently this doesn't inhibit KCOV instrumentation.
Prevent this by disabling KCOV for the entire compilation unit.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210607094624.34689-20-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/kernel/Makefile | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index 6cc97730790e..787c3c83edd7 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -14,6 +14,11 @@ CFLAGS_REMOVE_return_address.o = $(CC_FLAGS_FTRACE) CFLAGS_REMOVE_syscall.o = -fstack-protector -fstack-protector-strong CFLAGS_syscall.o += -fno-stack-protector +# It's not safe to invoke KCOV when portions of the kernel environment aren't +# available or are out-of-sync with HW state. Since `noinstr` doesn't always +# inhibit KCOV instrumentation, disable it for the entire compilation unit. +KCOV_INSTRUMENT_entry.o := n + # Object file lists. obj-y := debug-monitors.o entry.o irq.o fpsimd.o \ entry-common.o entry-fpsimd.o process.o ptrace.o \ |