diff options
| author | Will Deacon <will@kernel.org> | 2020-06-30 14:02:48 +0100 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-11-09 21:49:34 +0000 |
| commit | e35123d83ee35c31f64ecfbdfabbe5142d3025b8 (patch) | |
| tree | 42cd6bf50f912bbeb4ba2cf8bbe32d98d89ba2c5 /arch/arm64/kernel/vdso32 | |
| parent | 5af76fb4228701bd5377880b09b0216a5fd800ef (diff) | |
arm64: lto: Strengthen READ_ONCE() to acquire when CONFIG_LTO=y
When building with LTO, there is an increased risk of the compiler
converting an address dependency headed by a READ_ONCE() invocation
into a control dependency and consequently allowing for harmful
reordering by the CPU.
Ensure that such transformations are harmless by overriding the generic
READ_ONCE() definition with one that provides acquire semantics when
building with LTO.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/kernel/vdso32')
| -rw-r--r-- | arch/arm64/kernel/vdso32/Makefile | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile index 79280c53b9a6..a1e0f91e6cea 100644 --- a/arch/arm64/kernel/vdso32/Makefile +++ b/arch/arm64/kernel/vdso32/Makefile @@ -48,7 +48,7 @@ cc32-as-instr = $(call try-run,\ # As a result we set our own flags here. # KBUILD_CPPFLAGS and NOSTDINC_FLAGS from top-level Makefile -VDSO_CPPFLAGS := -D__KERNEL__ -nostdinc -isystem $(shell $(CC_COMPAT) -print-file-name=include) +VDSO_CPPFLAGS := -DBUILD_VDSO -D__KERNEL__ -nostdinc -isystem $(shell $(CC_COMPAT) -print-file-name=include) VDSO_CPPFLAGS += $(LINUXINCLUDE) # Common C and assembly flags |