[PATCH 2/3] RISC-V: build: Disable LTO for the vDSO

[Wende Tan]

Disable LTO for the vDSO as done for x86 [1] and arm64 [2].  This also
disables CFI for it [3].

[1] https://patchwork.kernel.org/project/linux-kbuild/patch/20201009161338.657380-28-samitolvanen@google.com/
[2] https://patchwork.kernel.org/project/kernel-hardening/patch/20201211184633.3213045-15-samitolvanen@google.com/
[3] https://lore.kernel.org/bpf/CABCJKucpFHC-9rvT7uNF+E-Jh20fz69zdO49_4p8G_Sb634qmw@mail.gmail.com/

Signed-off-by: Wende Tan <twd2.me at gmail.com>
---
 arch/riscv/kernel/vdso/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile
index 24d936c147cd..4535a77792be 100644
--- a/arch/riscv/kernel/vdso/Makefile
+++ b/arch/riscv/kernel/vdso/Makefile
@@ -30,7 +30,7 @@ obj-y += vdso.o vdso-syms.o
 CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
 
 # Disable -pg to prevent insert call site
-CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os
+CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_LTO)
 
 # Disable profiling and instrumentation for VDSO code
 GCOV_PROFILE := n
-- 
2.25.1