diff options
| author | Nathan Chancellor <nathan@kernel.org> | 2026-03-11 17:39:56 -0700 |
|---|---|---|
| committer | Madhavan Srinivasan <maddy@linux.ibm.com> | 2026-05-06 07:45:59 +0530 |
| commit | 60c71369ee356d11ad845ddeb28ceb70ec6cd70e (patch) | |
| tree | 6dfa850a00fd2efb7cad5e0cc8e8071ef16d5362 | |
| parent | 4052b932041614675fa2dbf48f725557c23ebf05 (diff) | |
powerpc/vdso: Drop -DCC_USING_PATCHABLE_FUNCTION_ENTRY from 32-bit flags with clang
After commit 73cdf24e81e4 ("powerpc64: make clang cross-build
friendly"), building 64-bit little endian + CONFIG_COMPAT=y with clang
results in many warnings along the lines of:
$ cat arch/powerpc/configs/compat.config
CONFIG_COMPAT=y
$ make -skj"$(nproc)" ARCH=powerpc LLVM=1 ppc64le_defconfig compat.config arch/powerpc/kernel/vdso/
...
In file included from <built-in>:4:
In file included from lib/vdso/gettimeofday.c:6:
In file included from include/vdso/datapage.h:15:
In file included from include/vdso/cache.h:5:
arch/powerpc/include/asm/cache.h:77:8: warning: unknown attribute 'patchable_function_entry' ignored [-Wunknown-attributes]
77 | static inline u32 l1_icache_bytes(void)
| ^~~~~~
include/linux/compiler_types.h:235:58: note: expanded from macro 'inline'
235 | #define inline inline __gnu_inline __inline_maybe_unused notrace
| ^~~~~~~
include/linux/compiler_types.h:215:34: note: expanded from macro 'notrace'
215 | #define notrace __attribute__((patchable_function_entry(0, 0)))
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...
arch/powerpc/Makefile adds -DCC_USING_PATCHABLE_FUNCTION_ENTRY to
KBUILD_CPPFLAGS, which is inherited by the 32-bit vDSO. However, the
32-bit little endian target does not support
'-fpatchable-function-entry', resulting in the warnings above.
Remove -DCC_USING_PATCHABLE_FUNCTION_ENTRY from the 32-bit vDSO flags
when building with clang to avoid the warnings.
Fixes: 73cdf24e81e4 ("powerpc64: make clang cross-build friendly")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20260311-ppc-vdso-drop-cc-using-pfe-define-clang-v1-1-66c790e22650@kernel.org
| -rw-r--r-- | arch/powerpc/kernel/vdso/Makefile | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/vdso/Makefile b/arch/powerpc/kernel/vdso/Makefile index 8834dfe9d727..368759f81708 100644 --- a/arch/powerpc/kernel/vdso/Makefile +++ b/arch/powerpc/kernel/vdso/Makefile @@ -62,6 +62,12 @@ CC32FLAGSREMOVE += -fno-stack-clash-protection # 32-bit one. clang validates the values passed to these arguments during # parsing, even when -fno-stack-protector is passed afterwards. CC32FLAGSREMOVE += -mstack-protector-guard% +# ftrace is disabled for the vdso but arch/powerpc/Makefile adds this define to +# KBUILD_CPPFLAGS, which enables use of the 'patchable_function_entry' +# attribute in the 'inline' define via 'notrace'. This attribute is not +# supported for the powerpcle target, resulting in many instances of +# -Wunknown-attributes. +CC32FLAGSREMOVE += -DCC_USING_PATCHABLE_FUNCTION_ENTRY endif LD32FLAGS := -Wl,-soname=linux-vdso32.so.1 AS32FLAGS := -D__VDSO32__ |