Merge branch 'for-next/vdso' into for-next/core

* for-next/vdso:
  arm64: vdso32: require CROSS_COMPILE_COMPAT for gcc+bfd
  arm64: vdso32: suppress error message for 'make mrproper'
  arm64: vdso32: drop test for -march=armv8-a
  arm64: vdso32: drop the test for dmb ishld

Author: willdeacon

arch/arm64/Kconfig

@@ -1379,7 +1379,8 @@ 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)" != ""
 	select GENERIC_COMPAT_VDSO
 	default y
 	help

arch/arm64/include/asm/vdso/compat_barrier.h

@@ -20,16 +20,9 @@
 
 #define dmb(option) __asm__ __volatile__ ("dmb " #option : : : "memory")
 
-#if __LINUX_ARM_ARCH__ >= 8 && defined(CONFIG_AS_DMB_ISHLD)
 #define aarch32_smp_mb()	dmb(ish)
 #define aarch32_smp_rmb()	dmb(ishld)
 #define aarch32_smp_wmb()	dmb(ishst)
-#else
-#define aarch32_smp_mb()	dmb(ish)
-#define aarch32_smp_rmb()	aarch32_smp_mb()
-#define aarch32_smp_wmb()	dmb(ishst)
-#endif
-
 
 #undef smp_mb
 #undef smp_rmb

arch/arm64/kernel/vdso32/Makefile

@@ -10,27 +10,22 @@ 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
 
 cc32-option = $(call try-run,\
         $(CC_COMPAT) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2))
 cc32-disable-warning = $(call try-run,\
 	$(CC_COMPAT) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
-cc32-as-instr = $(call try-run,\
-	printf "%b\n" "$(1)" | $(CC_COMPAT) $(VDSO_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3))
 
 # We cannot use the global flags to compile the vDSO files, the main reason
 # being that the 32-bit compiler may be older than the main (64-bit) compiler
@@ -40,16 +35,13 @@ cc32-as-instr = $(call try-run,\
 # As a result we set our own flags here.
 
 # KBUILD_CPPFLAGS and NOSTDINC_FLAGS from top-level Makefile
-VDSO_CPPFLAGS := -DBUILD_VDSO -D__KERNEL__ -nostdinc -isystem $(shell $(CC_COMPAT) -print-file-name=include)
+VDSO_CPPFLAGS := -DBUILD_VDSO -D__KERNEL__ -nostdinc
+VDSO_CPPFLAGS += -isystem $(shell $(CC_COMPAT) -print-file-name=include 2>/dev/null)
 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
@@ -67,13 +59,7 @@ endif
 # From arm vDSO Makefile
 VDSO_CAFLAGS += -fPIC -fno-builtin -fno-stack-protector
 VDSO_CAFLAGS += -DDISABLE_BRANCH_PROFILING
-
-
-# Try to compile for ARMv8. If the compiler is too old and doesn't support it,
-# fall back to v7. There is no easy way to check for what architecture the code
-# is being compiled, so define a macro specifying that (see arch/arm/Makefile).
-VDSO_CAFLAGS += $(call cc32-option,-march=armv8-a -D__LINUX_ARM_ARCH__=8,\
-                                   -march=armv7-a -D__LINUX_ARM_ARCH__=7)
+VDSO_CAFLAGS += -march=armv8-a
 
 VDSO_CFLAGS := $(VDSO_CAFLAGS)
 VDSO_CFLAGS += -DENABLE_COMPAT_VDSO=1
@@ -113,12 +99,6 @@ endif
 VDSO_AFLAGS := $(VDSO_CAFLAGS)
 VDSO_AFLAGS += -D__ASSEMBLY__
 
-# Check for binutils support for dmb ishld
-dmbinstr := $(call cc32-as-instr,dmb ishld,-DCONFIG_AS_DMB_ISHLD=1)
-
-VDSO_CFLAGS += $(dmbinstr)
-VDSO_AFLAGS += $(dmbinstr)
-
 # From arm vDSO Makefile
 VDSO_LDFLAGS += -Bsymbolic --no-undefined -soname=linux-vdso.so.1
 VDSO_LDFLAGS += -z max-page-size=4096 -z common-page-size=4096