When building pseries_defconfig, building vdso32 errors out: error: unknown target ABI 'elfv1'
This happens because -m32 in clang changes the target to 32-bit, which does not allow the ABI to be changed, as the setABI virtual function is not overridden: https://github.com/llvm/llvm-project/blob/llvmorg-9.0.0-rc2/clang/include/clang/Basic/TargetInfo.h#L1073-L1078 https://github.com/llvm/llvm-project/blob/llvmorg-9.0.0-rc2/clang/lib/Basic/Targets/PPC.h#L327-L365 Commit 4dc831aa8813 ("powerpc: Fix compiling a BE kernel with a powerpc64le toolchain") added these flags to fix building big endian kernels with a little endian GCC. Clang doesn't need -mabi because the target triple controls the default value. -mlittle-endian and -mbig-endian manipulate the triple into either powerpc64-* or powerpc64le-*, which properly sets the default ABI: https://github.com/llvm/llvm-project/blob/llvmorg-9.0.0-rc2/clang/lib/Driver/Driver.cpp#L450-L463 https://github.com/llvm/llvm-project/blob/llvmorg-9.0.0-rc2/llvm/lib/Support/Triple.cpp#L1432-L1516 https://github.com/llvm/llvm-project/blob/llvmorg-9.0.0-rc2/clang/lib/Basic/Targets/PPC.h#L377-L383 Adding a debug print out in the PPC64TargetInfo constructor after line 383 above shows this: $ echo | ./clang -E --target=powerpc64-linux -mbig-endian -o /dev/null - Default ABI: elfv1 $ echo | ./clang -E --target=powerpc64-linux -mlittle-endian -o /dev/null - Default ABI: elfv2 $ echo | ./clang -E --target=powerpc64le-linux -mbig-endian -o /dev/null - Default ABI: elfv1 $ echo | ./clang -E --target=powerpc64le-linux -mlittle-endian -o /dev/null - Default ABI: elfv2 Don't specify -mabi when building with clang to avoid the build error with -m32 and not change any code generation. -mcall-aixdesc is not an implemented flag in clang so it can be safely excluded as well, see commit 238abecde8ad ("powerpc: Don't use gcc specific options on clang"). pseries_defconfig successfully builds after this patch and powernv_defconfig and ppc44x_defconfig don't regress. Link: https://github.com/ClangBuiltLinux/linux/issues/240 Reviewed-by: Daniel Axtens <d...@axtens.net> Signed-off-by: Nathan Chancellor <natechancel...@gmail.com> --- v1 -> v2: * Improve commit message v2 -> v3: * Rebase and merge into a single series. arch/powerpc/Makefile | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index 46ed198a3aa3..150925a2e06e 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -93,11 +93,13 @@ MULTIPLEWORD := -mmultiple endif ifdef CONFIG_PPC64 +ifndef CONFIG_CC_IS_CLANG cflags-$(CONFIG_CPU_BIG_ENDIAN) += $(call cc-option,-mabi=elfv1) cflags-$(CONFIG_CPU_BIG_ENDIAN) += $(call cc-option,-mcall-aixdesc) aflags-$(CONFIG_CPU_BIG_ENDIAN) += $(call cc-option,-mabi=elfv1) aflags-$(CONFIG_CPU_LITTLE_ENDIAN) += -mabi=elfv2 endif +endif ifndef CONFIG_CC_IS_CLANG cflags-$(CONFIG_CPU_LITTLE_ENDIAN) += -mno-strict-align @@ -143,6 +145,7 @@ endif endif CFLAGS-$(CONFIG_PPC64) := $(call cc-option,-mtraceback=no) +ifndef CONFIG_CC_IS_CLANG ifdef CONFIG_CPU_LITTLE_ENDIAN CFLAGS-$(CONFIG_PPC64) += $(call cc-option,-mabi=elfv2,$(call cc-option,-mcall-aixdesc)) AFLAGS-$(CONFIG_PPC64) += $(call cc-option,-mabi=elfv2) @@ -151,6 +154,7 @@ CFLAGS-$(CONFIG_PPC64) += $(call cc-option,-mabi=elfv1) CFLAGS-$(CONFIG_PPC64) += $(call cc-option,-mcall-aixdesc) AFLAGS-$(CONFIG_PPC64) += $(call cc-option,-mabi=elfv1) endif +endif CFLAGS-$(CONFIG_PPC64) += $(call cc-option,-mcmodel=medium,$(call cc-option,-mminimal-toc)) CFLAGS-$(CONFIG_PPC64) += $(call cc-option,-mno-pointers-to-nested-functions) -- 2.23.0
