This is a note to let you know that I've just added the patch titled powerpc: Don't add -mabi= flags when building with Clang to the 5.4-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-don-t-add-mabi-flags-when-building-with-clan.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit d188a1afeb7d5af752172f09bc71a41d745356d7 Author: Nathan Chancellor <natechancellor@xxxxxxxxx> Date: Mon Nov 18 21:57:10 2019 -0700 powerpc: Don't add -mabi= flags when building with Clang [ Upstream commit 465bfd9c44dea6b55962b5788a23ac87a467c923 ] 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. 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. 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. Reviewed-by: Daniel Axtens <dja@xxxxxxxxxx> Signed-off-by: Nathan Chancellor <natechancellor@xxxxxxxxx> [mpe: Trim clang links in change log] Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20191119045712.39633-2-natechancellor@xxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index 83522c9fc7b6..37ac731a556b 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -91,11 +91,13 @@ 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-$(CONFIG_CPU_LITTLE_ENDIAN) += -mno-strict-align @@ -141,6 +143,7 @@ endif endif CFLAGS-$(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) += $(call cc-option,-mabi=elfv2) @@ -149,6 +152,7 @@ CFLAGS-$(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)