On Wed, Aug 28, 2019 at 11:26:35PM -0700, Nathan Chancellor wrote: > Currently, multi_v7_defconfig + CONFIG_FUNCTION_TRACER fails to build > with clang: > > arm-linux-gnueabi-ld: kernel/softirq.o: in function `_local_bh_enable': > softirq.c:(.text+0x504): undefined reference to `mcount' > arm-linux-gnueabi-ld: kernel/softirq.o: in function `__local_bh_enable_ip': > softirq.c:(.text+0x58c): undefined reference to `mcount' > arm-linux-gnueabi-ld: kernel/softirq.o: in function `do_softirq': > softirq.c:(.text+0x6c8): undefined reference to `mcount' > arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_enter': > softirq.c:(.text+0x75c): undefined reference to `mcount' > arm-linux-gnueabi-ld: kernel/softirq.o: in function `irq_exit': > softirq.c:(.text+0x840): undefined reference to `mcount' > arm-linux-gnueabi-ld: kernel/softirq.o:softirq.c:(.text+0xa50): more > undefined references to `mcount' follow > > clang can emit a working mcount symbol, __gnu_mcount_nc, when > '-meabi gnu' is passed to it. Until r369147 in LLVM, this was > broken and caused the kernel not to boot because the calling > convention was not correct. Now that it is fixed, add this to > the command line when clang is 10.0.0 or newer so everything > works properly. > > Link: https://github.com/ClangBuiltLinux/linux/issues/35 > Link: https://bugs.llvm.org/show_bug.cgi?id=33845 > Link: > https://github.com/llvm/llvm-project/commit/16fa8b09702378bacfa3d07081afe6b353b99e60 > Signed-off-by: Nathan Chancellor <[email protected]> > --- > arch/arm/Makefile | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/arch/arm/Makefile b/arch/arm/Makefile > index c3624ca6c0bc..7b5a26a866fc 100644 > --- a/arch/arm/Makefile > +++ b/arch/arm/Makefile > @@ -112,6 +112,12 @@ ifeq ($(CONFIG_ARM_UNWIND),y) > CFLAGS_ABI +=-funwind-tables > endif > > +ifeq ($(CONFIG_CC_IS_CLANG),y) > +ifeq ($(shell test $(CONFIG_CLANG_VERSION) -ge 100000; echo $$?),0) > +CFLAGS_ABI +=-meabi gnu > +endif > +endif
Is this also correct/needed when CONFIG_AEABI is not set?
