Commit 3763ace7 authored May 14, 2020 by Nathan Chancellor Committed by Alistair Delva May 18, 2020

ANDROID: arm64: vdso: Fix removing SCS flags



Commit 6545d64a ("BACKPORT: arm64: vdso: Substitute gettimeofday()
with C implementation") added an assignment to
CFLAGS_REMOVE_vgettimeofday.o without adjusting the existing one for the
removal of the shadow call stack flags.

Without this patch, the SCS flags do not get filtered:

clang ... -g -fsanitize=shadow-call-stack -Wdeclaration-after-statement
... -c -o arch/arm64/kernel/vdso/.tmp_vgettimeofday.o ...

After this, everything works as it should:

clang ... -g -Wdeclaration-after-statement -Wno-pointer-sign ... -c
-o arch/arm64/kernel/vdso/.tmp_vgettimeofday.o ...

This is an Android specific issue to the backport of the above patch,
this issue will not be present in the mainline version of SCS.

Change-Id: I2ff00e1b407155501ada4c36a961db0b720b80bf
Fixes: 6545d64a ("BACKPORT: arm64: vdso: Substitute gettimeofday() with C implementation")
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>

parent 7502b09f

arch/arm64/kernel/vdso/Makefile

+1 −3

Original line number	Diff line number	Diff line
		@@ -21,14 +21,12 @@ ldflags-y := -shared -nostdlib -soname=linux-vdso.so.1 --hash-style=sysv \
		--build-id -n -T
		ccflags-y += $(DISABLE_LTO)

		CFLAGS_REMOVE_vgettimeofday.o += $(CC_FLAGS_SCS)

		ccflags-y := -fno-common -fno-builtin -fno-stack-protector
		ccflags-y += -DDISABLE_BRANCH_PROFILING

		VDSO_LDFLAGS := -Bsymbolic

		CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os
		CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS)
		KBUILD_CFLAGS += $(DISABLE_LTO)
		KASAN_SANITIZE := n
		UBSAN_SANITIZE := n