This is a note to let you know that I've just added the patch titled
powerpc/vdso: Improve linker flags
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
powerpc-vdso-improve-linker-flags.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 71230a744a26de5d1bc5f2f738ec9be0599068a8
Author: Nathan Chancellor <nathan@xxxxxxxxxx>
Date: Wed Jan 11 20:05:04 2023 -0700
powerpc/vdso: Improve linker flags
[ Upstream commit f0a42fbab447ed9f55bbd99751183e71f3a1f6ec ]
When clang's -Qunused-arguments is dropped from KBUILD_CPPFLAGS, there
are several warnings in the PowerPC vDSO:
clang-16: error: -Wl,-soname=linux-vdso32.so.1: 'linker' input unused [-Werror,-Wunused-command-line-argument]
clang-16: error: -Wl,--hash-style=both: 'linker' input unused [-Werror,-Wunused-command-line-argument]
clang-16: error: argument unused during compilation: '-shared' [-Werror,-Wunused-command-line-argument]
clang-16: error: argument unused during compilation: '-nostdinc' [-Werror,-Wunused-command-line-argument]
clang-16: error: argument unused during compilation: '-Wa,-maltivec' [-Werror,-Wunused-command-line-argument]
The first group of warnings point out that linker flags were being added
to all invocations of $(CC), even though they will only be used during
the final vDSO link. Move those flags to ldflags-y.
The second group of warnings are compiler or assembler flags that will
be unused during linking. Filter them out from KBUILD_CFLAGS so that
they are not used during linking.
Additionally, '-z noexecstack' was added directly to the ld_and_check
rule in commit 1d53c0192b15 ("powerpc/vdso: link with -z noexecstack")
but now that there is a common ldflags variable, it can be moved there.
Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Tested-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>
Tested-by: Anders Roxell <anders.roxell@xxxxxxxxxx>
Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Stable-dep-of: d677ce521334 ("powerpc/vdso: Drop -mstack-protector-guard flags in 32-bit files with clang")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/powerpc/kernel/vdso/Makefile b/arch/powerpc/kernel/vdso/Makefile
index 45c0cc5d34b64..d4023bceec348 100644
--- a/arch/powerpc/kernel/vdso/Makefile
+++ b/arch/powerpc/kernel/vdso/Makefile
@@ -47,13 +47,17 @@ KCOV_INSTRUMENT := n
UBSAN_SANITIZE := n
KASAN_SANITIZE := n
-ccflags-y := -shared -fno-common -fno-builtin -nostdlib -Wl,--hash-style=both
-ccflags-$(CONFIG_LD_IS_LLD) += $(call cc-option,--ld-path=$(LD),-fuse-ld=lld)
-
-CC32FLAGS := -Wl,-soname=linux-vdso32.so.1 -m32
+ccflags-y := -fno-common -fno-builtin
+ldflags-y := -Wl,--hash-style=both -nostdlib -shared -z noexecstack
+ldflags-$(CONFIG_LD_IS_LLD) += $(call cc-option,--ld-path=$(LD),-fuse-ld=lld)
+# Filter flags that clang will warn are unused for linking
+ldflags-y += $(filter-out $(CC_FLAGS_FTRACE) -Wa$(comma)%, $(KBUILD_CFLAGS))
+
+CC32FLAGS := -m32
+LD32FLAGS := -Wl,-soname=linux-vdso32.so.1
AS32FLAGS := -D__VDSO32__
-CC64FLAGS := -Wl,-soname=linux-vdso64.so.1
+LD64FLAGS := -Wl,-soname=linux-vdso64.so.1
AS64FLAGS := -D__VDSO64__
targets += vdso32.lds
@@ -92,15 +96,15 @@ include/generated/vdso64-offsets.h: $(obj)/vdso64.so.dbg FORCE
# actual build commands
quiet_cmd_vdso32ld_and_check = VDSO32L $@
- cmd_vdso32ld_and_check = $(VDSOCC) $(c_flags) $(CC32FLAGS) -o $@ -Wl,-T$(filter %.lds,$^) $(filter %.o,$^) -z noexecstack ; $(cmd_vdso_check)
+ cmd_vdso32ld_and_check = $(VDSOCC) $(ldflags-y) $(CC32FLAGS) $(LD32FLAGS) -o $@ -Wl,-T$(filter %.lds,$^) $(filter %.o,$^); $(cmd_vdso_check)
quiet_cmd_vdso32as = VDSO32A $@
cmd_vdso32as = $(VDSOCC) $(a_flags) $(CC32FLAGS) $(AS32FLAGS) -c -o $@ $<
quiet_cmd_vdso32cc = VDSO32C $@
cmd_vdso32cc = $(VDSOCC) $(c_flags) $(CC32FLAGS) -c -o $@ $<
quiet_cmd_vdso64ld_and_check = VDSO64L $@
- cmd_vdso64ld_and_check = $(VDSOCC) $(c_flags) $(CC64FLAGS) -o $@ -Wl,-T$(filter %.lds,$^) $(filter %.o,$^) -z noexecstack ; $(cmd_vdso_check)
+ cmd_vdso64ld_and_check = $(VDSOCC) $(ldflags-y) $(LD64FLAGS) -o $@ -Wl,-T$(filter %.lds,$^) $(filter %.o,$^); $(cmd_vdso_check)
quiet_cmd_vdso64as = VDSO64A $@
- cmd_vdso64as = $(VDSOCC) $(a_flags) $(CC64FLAGS) $(AS64FLAGS) -c -o $@ $<
+ cmd_vdso64as = $(VDSOCC) $(a_flags) $(AS64FLAGS) -c -o $@ $<
OBJECT_FILES_NON_STANDARD := y
