Re: [PATCH 3/3] arm64: vdso32: require CROSS_COMPILE_COMPAT for gcc+bfd
From: Nathan Chancellor <nathan@kernel.org>
Date: 2021-10-18 22:58:56
Also in:
lkml, llvm
On Tue, Oct 12, 2021 at 04:46:06PM -0700, Nick Desaulniers wrote:
Similar to
commit 231ad7f409f1 ("Makefile: infer --target from ARCH for CC=clang")
There really is no point in setting --target based on
$CROSS_COMPILE_COMPAT for clang when the integrated assembler is being
used.
It might be nice to mention commit ef94340583ee ("arm64: vdso32: drop
-no-integrated-as flag") here, as that is what flipped on the integrated
assembler for this Makefile (and it cannot be turned off).
Allows COMPAT_VDSO to be selected without setting $CROSS_COMPILE_COMPAT when using clang and lld together. Before: $ ARCH=arm64 CROSS_COMPILE_COMPAT=arm-linux-gnueabi- make -j72 LLVM=1 defconfig $ grep CONFIG_COMPAT_VDSO .config CONFIG_COMPAT_VDSO=y $ ARCH=arm64 make -j72 LLVM=1 defconfig $ grep CONFIG_COMPAT_VDSO .config $ After: $ ARCH=arm64 CROSS_COMPILE_COMPAT=arm-linux-gnueabi- make -j72 LLVM=1 defconfig $ grep CONFIG_COMPAT_VDSO .config CONFIG_COMPAT_VDSO=y $ ARCH=arm64 make -j72 LLVM=1 defconfig $ grep CONFIG_COMPAT_VDSO .config CONFIG_COMPAT_VDSO=y Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Modulo these two nits, this works for me too. Reviewed-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org>
quoted hunk ↗ jump to hunk
--- arch/arm64/Kconfig | 3 ++- arch/arm64/kernel/vdso32/Makefile | 17 +++++------------ 2 files changed, 7 insertions(+), 13 deletions(-)diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 5c7ae4c3954b..7b28dad2fb80 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig@@ -1264,7 +1264,8 @@ config KUSER_HELPERS config COMPAT_VDSO bool "Enable vDSO for 32-bit applications" - depends on !CPU_BIG_ENDIAN && "$(CROSS_COMPILE_COMPAT)" != "" + depends on !CPU_BIG_ENDIAN + depends on CC_IS_CLANG && LD_IS_LLD || "$(CROSS_COMPILE_COMPAT)" != ""
It works fine as is but it might be nice to add parentheses around the new condition for ease of understanding.
quoted hunk ↗ jump to hunk
select GENERIC_COMPAT_VDSO default y helpdiff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile index d24b12318f4c..376261d3791f 100644 --- a/arch/arm64/kernel/vdso32/Makefile +++ b/arch/arm64/kernel/vdso32/Makefile@@ -10,18 +10,15 @@ include $(srctree)/lib/vdso/Makefile # Same as cc-*option, but using CC_COMPAT instead of CC ifeq ($(CONFIG_CC_IS_CLANG), y) -CC_COMPAT_CLANG_FLAGS := --target=$(notdir $(CROSS_COMPILE_COMPAT:%-=%)) - CC_COMPAT ?= $(CC) -CC_COMPAT += $(CC_COMPAT_CLANG_FLAGS) - -ifneq ($(LLVM),) -LD_COMPAT ?= $(LD) +CC_COMPAT += --target=arm-linux-gnueabi else -LD_COMPAT ?= $(CROSS_COMPILE_COMPAT)ld +CC_COMPAT ?= $(CROSS_COMPILE_COMPAT)gcc endif + +ifeq ($(CONFIG_LD_IS_LLD), y) +LD_COMPAT ?= $(LD) else -CC_COMPAT ?= $(CROSS_COMPILE_COMPAT)gcc LD_COMPAT ?= $(CROSS_COMPILE_COMPAT)ld endif@@ -44,10 +41,6 @@ VDSO_CPPFLAGS += $(LINUXINCLUDE) # Common C and assembly flags # From top-level Makefile VDSO_CAFLAGS = $(VDSO_CPPFLAGS) -ifneq ($(shell $(CC_COMPAT) --version 2>&1 | head -n 1 | grep clang),) -VDSO_CAFLAGS += --target=$(notdir $(CROSS_COMPILE_COMPAT:%-=%)) -endif - VDSO_CAFLAGS += $(call cc32-option,-fno-PIE) ifdef CONFIG_DEBUG_INFO VDSO_CAFLAGS += -g-- 2.33.0.882.g93a45727a2-goog
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