On Thu, Apr 15, 2021 at 6:31 AM Vincenzo Frascino <vincenzo.frasc...@arm.com> wrote: > > > > On 4/14/21 10:45 PM, Nick Desaulniers wrote: > > Clang can assemble these files just fine; this is a relic from the top > > level Makefile conditionally adding this. We no longer need --prefix, > > --gcc-toolchain, or -Qunused-arguments flags either with this change, so > > remove those too. > > > > To test building: > > $ ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- \ > > CROSS_COMPILE_COMPAT=arm-linux-gnueabi- make LLVM=1 LLVM_IAS=1 \ > > defconfig arch/arm64/kernel/vdso32/ > > > > Suggested-by: Nathan Chancellor <nat...@kernel.org> > > Signed-off-by: Nick Desaulniers <ndesaulni...@google.com> > > The patch looks fine, but I have one question: the kernel requires as a > minimum > Clang/LLVM version 10.0.1. Did you verify that with that version compat vDSOs > still builds and works correctly?
Hi Vincenzo, Great question, let's check. $ cd path/to/llvm-project $ git checkout origin/release/10.x $ cd llvm/build && ninja $ cd path/to/linux $ b4 am https://lore.kernel.org/lkml/20210413230609.3114365-1-ndesaulni...@google.com/ -o - | git am -3 We can't generally build ARCH=arm64 defconfig with LLVM_IAS=1 with clang-10, but dropping LLVM_IAS=1 it looks like we can still build without that. $ ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- CROSS_COMPILE_COMPAT=arm-linux-gnueabi- make LLVM=1 -j72 defconfig clean all $ ls -l arch/arm64/kernel/vdso32 total 116 -rw-r----- 1 ndesaulniers primarygroup 7534 Apr 14 14:41 Makefile -rw-r----- 1 ndesaulniers primarygroup 387 Mar 31 10:47 note.c -rw-r----- 1 ndesaulniers primarygroup 2544 Apr 15 09:48 note.o -rw-r----- 1 ndesaulniers primarygroup 4552 Apr 15 09:48 vdso.lds -rw-r----- 1 ndesaulniers primarygroup 1587 Apr 1 12:55 vdso.lds.S -rw------- 1 ndesaulniers primarygroup 3576 Apr 15 09:48 vdso.so -rw------- 1 ndesaulniers primarygroup 24380 Apr 15 09:48 vdso.so.dbg -rwxr-x--- 1 ndesaulniers primarygroup 24380 Apr 15 09:48 vdso.so.raw -rw-r----- 1 ndesaulniers primarygroup 828 Apr 1 12:55 vgettimeofday.c -rw-r----- 1 ndesaulniers primarygroup 29084 Apr 15 09:48 vgettimeofday.o FWIW, clang-10 was missing support for R_AARCH64_PREL32, which affects building arch/arm64/kvm/hyp/nvhe/hyp-reloc.S. > > Otherwise: > > Reviewed-by: Vincenzo Frascino <vincenzo.frasc...@arm.com> > > > --- > > Changes V1 -> V2: > > * Remove --prefix, --gcc-toolchain, COMPAT_GCC_TOOLCHAIN, and > > COMPAT_GCC_TOOLCHAIN_DIR as per Nathan. > > * Credit Nathan with Suggested-by tag. > > * Remove -Qunused-arguments. > > * Update commit message. > > > > arch/arm64/kernel/vdso32/Makefile | 8 -------- > > 1 file changed, 8 deletions(-) > > > > diff --git a/arch/arm64/kernel/vdso32/Makefile > > b/arch/arm64/kernel/vdso32/Makefile > > index 789ad420f16b..3dba0c4f8f42 100644 > > --- a/arch/arm64/kernel/vdso32/Makefile > > +++ b/arch/arm64/kernel/vdso32/Makefile > > @@ -10,15 +10,7 @@ include $(srctree)/lib/vdso/Makefile > > > > # Same as cc-*option, but using CC_COMPAT instead of CC > > ifeq ($(CONFIG_CC_IS_CLANG), y) > > -COMPAT_GCC_TOOLCHAIN_DIR := $(dir $(shell which > > $(CROSS_COMPILE_COMPAT)elfedit)) > > -COMPAT_GCC_TOOLCHAIN := $(realpath $(COMPAT_GCC_TOOLCHAIN_DIR)/..) > > - > > CC_COMPAT_CLANG_FLAGS := --target=$(notdir $(CROSS_COMPILE_COMPAT:%-=%)) > > -CC_COMPAT_CLANG_FLAGS += --prefix=$(COMPAT_GCC_TOOLCHAIN_DIR)$(notdir > > $(CROSS_COMPILE_COMPAT)) > > -CC_COMPAT_CLANG_FLAGS += -no-integrated-as -Qunused-arguments > > -ifneq ($(COMPAT_GCC_TOOLCHAIN),) > > -CC_COMPAT_CLANG_FLAGS += --gcc-toolchain=$(COMPAT_GCC_TOOLCHAIN) > > -endif > > > > CC_COMPAT ?= $(CC) > > CC_COMPAT += $(CC_COMPAT_CLANG_FLAGS) > > > > -- > Regards, > Vincenzo -- Thanks, ~Nick Desaulniers
