Messages in this thread Patch in this message |  | | From | Masahiro Yamada <> | Date | Sat, 2 Apr 2022 22:31:03 +0900 | Subject | Re: [PATCH 1/3] kbuild: Change CFI_CLANG to depend on __builtin_function_start |
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On Sat, Apr 2, 2022 at 5:19 AM Sami Tolvanen <samitolvanen@google.com> wrote: > > Clang 14 added support for the __builtin_function_start() > built-in function, which allows us to implement function_nocfi() > without architecture-specific inline assembly. This patch changes > CONFIG_CFI_CLANG to depend on the built-in and effectively upgrades > the minimum supported compiler version for CFI to Clang 14.
From this description, I think the straight-forward change would be:
depends on CLANG_VERSION >= 120000 --> depends on CLANG_VERSION >= 140000
Any reason to avoid this?
> > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> > --- > arch/Kconfig | 5 +---- > init/Kconfig | 3 +++ > 2 files changed, 4 insertions(+), 4 deletions(-) > > diff --git a/arch/Kconfig b/arch/Kconfig > index 29b0167c088b..eecfc2809781 100644 > --- a/arch/Kconfig > +++ b/arch/Kconfig > @@ -723,10 +723,7 @@ config ARCH_SUPPORTS_CFI_CLANG > config CFI_CLANG > bool "Use Clang's Control Flow Integrity (CFI)" > depends on LTO_CLANG && ARCH_SUPPORTS_CFI_CLANG > - # Clang >= 12: > - # - https://bugs.llvm.org/show_bug.cgi?id=46258 > - # - https://bugs.llvm.org/show_bug.cgi?id=47479 > - depends on CLANG_VERSION >= 120000 > + depends on CC_HAS_BUILTIN_FUNCTION_START > select KALLSYMS > help > This option enables Clang’s forward-edge Control Flow Integrity > diff --git a/init/Kconfig b/init/Kconfig > index ddcbefe535e9..f024fd353373 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -86,6 +86,9 @@ config CC_HAS_ASM_INLINE > config CC_HAS_NO_PROFILE_FN_ATTR > def_bool $(success,echo '__attribute__((no_profile_instrument_function)) int x();' | $(CC) -x c - -c -o /dev/null -Werror) > > +config CC_HAS_BUILTIN_FUNCTION_START > + def_bool $(success,echo 'void f(void) {}; void *p = __builtin_function_start(f);' | $(CC) -x c - -c -o /dev/null) > + > config PAHOLE_VERSION > int > default $(shell,$(srctree)/scripts/pahole-version.sh $(PAHOLE)) > -- > 2.35.0 >
-- Best Regards Masahiro Yamada
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