Merge tag 'kbuild-v4.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull more Kbuild updates from Masahiro Yamada:

 - fix some bugs introduced by the recent Kconfig syntax extension

 - add some symbols about compiler information in Kconfig, such as
   CC_IS_GCC, CC_IS_CLANG, GCC_VERSION, etc.

 - test compiler capability for the stack protector in Kconfig, and
   clean-up Makefile

 - test compiler capability for GCC-plugins in Kconfig, and clean-up
   Makefile

 - allow to enable GCC-plugins for COMPILE_TEST

 - test compiler capability for KCOV in Kconfig and correct dependency

 - remove auto-detect mode of the GCOV format, which is now more nicely
   handled in Kconfig

 - test compiler capability for mprofile-kernel on PowerPC, and clean-up
   Makefile

 - misc cleanups

* tag 'kbuild-v4.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  linux/linkage.h: replace VMLINUX_SYMBOL_STR() with __stringify()
  kconfig: fix localmodconfig
  sh: remove no-op macro VMLINUX_SYMBOL()
  powerpc/kbuild: move -mprofile-kernel check to Kconfig
  Documentation: kconfig: add recommended way to describe compiler support
  gcc-plugins: disable GCC_PLUGIN_STRUCTLEAK_BYREF_ALL for COMPILE_TEST
  gcc-plugins: allow to enable GCC_PLUGINS for COMPILE_TEST
  gcc-plugins: test plugin support in Kconfig and clean up Makefile
  gcc-plugins: move GCC version check for PowerPC to Kconfig
  kcov: test compiler capability in Kconfig and correct dependency
  gcov: remove CONFIG_GCOV_FORMAT_AUTODETECT
  arm64: move GCC version check for ARCH_SUPPORTS_INT128 to Kconfig
  kconfig: add CC_IS_CLANG and CLANG_VERSION
  kconfig: add CC_IS_GCC and GCC_VERSION
  stack-protector: test compiler capability in Kconfig and drop AUTO mode
  kbuild: fix endless syncconfig in case arch Makefile sets CROSS_COMPILE

11 files changed, 47 insertions, 69 deletions

diff --git a/arch/Kconfig b/arch/Kconfig
index 86ae4c4edd6f..ebbb45096191 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -405,6 +405,15 @@ config SECCOMP_FILTER
 
 	  See Documentation/prctl/seccomp_filter.txt for details.
 
+preferred-plugin-hostcc := $(if-success,[ $(gcc-version) -ge 40800 ],$(HOSTCXX),$(HOSTCC))
+
+config PLUGIN_HOSTCC
+	string
+	default "$(shell,$(srctree)/scripts/gcc-plugin.sh "$(preferred-plugin-hostcc)" "$(HOSTCXX)" "$(CC)")"
+	help
+	  Host compiler used to build GCC plugins.  This can be $(HOSTCXX),
+	  $(HOSTCC), or a null string if GCC plugin is unsupported.
+
 config HAVE_GCC_PLUGINS
 	bool
 	help
@@ -414,7 +423,7 @@ config HAVE_GCC_PLUGINS
 menuconfig GCC_PLUGINS
 	bool "GCC plugins"
 	depends on HAVE_GCC_PLUGINS
-	depends on !COMPILE_TEST
+	depends on PLUGIN_HOSTCC != ""
 	help
 	  GCC plugins are loadable modules that provide extra features to the
 	  compiler. They are useful for runtime instrumentation and static analysis.
@@ -424,7 +433,7 @@ menuconfig GCC_PLUGINS
 config GCC_PLUGIN_CYC_COMPLEXITY
 	bool "Compute the cyclomatic complexity of a function" if EXPERT
 	depends on GCC_PLUGINS
-	depends on !COMPILE_TEST
+	depends on !COMPILE_TEST	# too noisy
 	help
 	  The complexity M of a function's control flow graph is defined as:
 	   M = E - N + 2P
@@ -484,6 +493,7 @@ config GCC_PLUGIN_STRUCTLEAK
 config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL
 	bool "Force initialize all struct type variables passed by reference"
 	depends on GCC_PLUGIN_STRUCTLEAK
+	depends on !COMPILE_TEST
 	help
 	  Zero initialize any struct type local variable that may be passed by
 	  reference without having been initialized.
@@ -491,7 +501,7 @@ config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL
 config GCC_PLUGIN_STRUCTLEAK_VERBOSE
 	bool "Report forcefully initialized variables"
 	depends on GCC_PLUGIN_STRUCTLEAK
-	depends on !COMPILE_TEST
+	depends on !COMPILE_TEST	# too noisy
 	help
 	  This option will cause a warning to be printed each time the
 	  structleak plugin finds a variable it thinks needs to be
@@ -531,7 +541,7 @@ config GCC_PLUGIN_RANDSTRUCT
 config GCC_PLUGIN_RANDSTRUCT_PERFORMANCE
 	bool "Use cacheline-aware structure randomization"
 	depends on GCC_PLUGIN_RANDSTRUCT
-	depends on !COMPILE_TEST
+	depends on !COMPILE_TEST	# do not reduce test coverage
 	help
 	  If you say Y here, the RANDSTRUCT randomization will make a
 	  best effort at restricting randomization to cacheline-sized
@@ -543,13 +553,16 @@ config HAVE_CC_STACKPROTECTOR
 	bool
 	help
 	  An arch should select this symbol if:
-	  - its compiler supports the -fstack-protector option
 	  - it has implemented a stack canary (e.g. __stack_chk_guard)
 
-choice
-	prompt "Stack Protector buffer overflow detection"
+config CC_HAS_STACKPROTECTOR_NONE
+	def_bool $(cc-option,-fno-stack-protector)
+
+config CC_STACKPROTECTOR
+	bool "Stack Protector buffer overflow detection"
 	depends on HAVE_CC_STACKPROTECTOR
-	default CC_STACKPROTECTOR_AUTO
+	depends on $(cc-option,-fstack-protector)
+	default y
 	help
 	  This option turns on the "stack-protector" GCC feature. This
 	  feature puts, at the beginning of functions, a canary value on
@@ -559,14 +572,6 @@ choice
 	  overwrite the canary, which gets detected and the attack is then
 	  neutralized via a kernel panic.
 
-config CC_STACKPROTECTOR_NONE
-	bool "None"
-	help
-	  Disable "stack-protector" GCC feature.
-
-config CC_STACKPROTECTOR_REGULAR
-	bool "Regular"
-	help
 	  Functions will have the stack-protector canary logic added if they
 	  have an 8-byte or larger character array on the stack.
 
@@ -578,7 +583,10 @@ config CC_STACKPROTECTOR_REGULAR
 	  by about 0.3%.
 
 config CC_STACKPROTECTOR_STRONG
-	bool "Strong"
+	bool "Strong Stack Protector"
+	depends on CC_STACKPROTECTOR
+	depends on $(cc-option,-fstack-protector-strong)
+	default y
 	help
 	  Functions will have the stack-protector canary logic added in any
 	  of the following conditions:
@@ -596,14 +604,6 @@ config CC_STACKPROTECTOR_STRONG
 	  about 20% of all kernel functions, which increases the kernel code
 	  size by about 2%.
 
-config CC_STACKPROTECTOR_AUTO
-	bool "Automatic"
-	help
-	  If the compiler supports it, the best available stack-protector
-	  option will be chosen.
-
-endchoice
-
 config HAVE_ARCH_WITHIN_STACK_FRAMES
 	bool
 	help
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 9fd4a8ccce07..14f204c45450 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -46,6 +46,7 @@ config ARM64
 	select ARCH_USE_QUEUED_RWLOCKS
 	select ARCH_SUPPORTS_MEMORY_FAILURE
 	select ARCH_SUPPORTS_ATOMIC_RMW
+	select ARCH_SUPPORTS_INT128 if GCC_VERSION >= 50000 || CC_IS_CLANG
 	select ARCH_SUPPORTS_NUMA_BALANCING
 	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
 	select ARCH_WANT_FRAME_POINTERS
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 3c353b4715dc..45272266dafb 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -56,12 +56,6 @@ KBUILD_AFLAGS	+= $(lseinstr) $(brokengasinst)
 KBUILD_CFLAGS	+= $(call cc-option,-mabi=lp64)
 KBUILD_AFLAGS	+= $(call cc-option,-mabi=lp64)
 
-ifeq ($(cc-name),clang)
-KBUILD_CFLAGS	+= -DCONFIG_ARCH_SUPPORTS_INT128
-else
-KBUILD_CFLAGS	+= $(call cc-ifversion, -ge, 0500, -DCONFIG_ARCH_SUPPORTS_INT128)
-endif
-
 ifeq ($(CONFIG_CPU_BIG_ENDIAN), y)
 KBUILD_CPPFLAGS	+= -mbig-endian
 CHECKFLAGS	+= -D__AARCH64EB__
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index eaba5920234d..9f2b75fe2c2d 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -190,7 +190,7 @@ config PPC
 	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_FUNCTION_TRACER
-	select HAVE_GCC_PLUGINS
+	select HAVE_GCC_PLUGINS			if GCC_VERSION >= 50200   # plugin support on gcc <= 5.1 is buggy on PPC
 	select HAVE_GENERIC_GUP
 	select HAVE_HW_BREAKPOINT		if PERF_EVENTS && (PPC_BOOK3S || PPC_8xx)
 	select HAVE_IDE
@@ -461,23 +461,9 @@ config LD_HEAD_STUB_CATCH
 
 	  If unsure, say "N".
 
-config DISABLE_MPROFILE_KERNEL
-	bool "Disable use of mprofile-kernel for kernel tracing"
-	depends on PPC64 && CPU_LITTLE_ENDIAN
-	default y
-	help
-	  Selecting this options disables use of the mprofile-kernel ABI for
-	  kernel tracing. That will cause options such as live patching
-	  (CONFIG_LIVEPATCH) which depend on CONFIG_DYNAMIC_FTRACE_WITH_REGS to
-	  be disabled also.
-
-	  If you have a toolchain which supports mprofile-kernel, then you can
-	  disable this. Otherwise leave it enabled. If you're not sure, say
-	  "Y".
-
 config MPROFILE_KERNEL
 	depends on PPC64 && CPU_LITTLE_ENDIAN
-	def_bool !DISABLE_MPROFILE_KERNEL
+	def_bool $(success,$(srctree)/arch/powerpc/tools/gcc-check-mprofile-kernel.sh $(CC) -I$(srctree)/include -D__KERNEL__)
 
 config HOTPLUG_CPU
 	bool "Support for enabling/disabling CPUs"
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 9b52e42e581b..bd06a3ccda31 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -161,18 +161,7 @@ CFLAGS-$(CONFIG_GENERIC_CPU) += -mcpu=powerpc64
 endif
 
 ifdef CONFIG_MPROFILE_KERNEL
-    ifeq ($(shell $(srctree)/arch/powerpc/tools/gcc-check-mprofile-kernel.sh $(CC) -I$(srctree)/include -D__KERNEL__),OK)
-        CC_FLAGS_FTRACE := -pg -mprofile-kernel
-        KBUILD_CPPFLAGS += -DCC_USING_MPROFILE_KERNEL
-    else
-        # If the user asked for mprofile-kernel but the toolchain doesn't
-        # support it, emit a warning and deliberately break the build later
-        # with mprofile-kernel-not-supported. We would prefer to make this an
-        # error right here, but then the user would never be able to run
-        # oldconfig to change their configuration.
-        $(warning Compiler does not support mprofile-kernel, set CONFIG_DISABLE_MPROFILE_KERNEL)
-        CC_FLAGS_FTRACE := -mprofile-kernel-not-supported
-    endif
+	CC_FLAGS_FTRACE := -pg -mprofile-kernel
 endif
 
 CFLAGS-$(CONFIG_CELL_CPU) += $(call cc-option,-mcpu=cell)
diff --git a/arch/powerpc/include/asm/module.h b/arch/powerpc/include/asm/module.h
index d8374f984f39..d61b0818e267 100644
--- a/arch/powerpc/include/asm/module.h
+++ b/arch/powerpc/include/asm/module.h
@@ -14,7 +14,7 @@
 #include <asm-generic/module.h>
 
 
-#ifdef CC_USING_MPROFILE_KERNEL
+#ifdef CONFIG_MPROFILE_KERNEL
 #define MODULE_ARCH_VERMAGIC_FTRACE	"mprofile-kernel "
 #else
 #define MODULE_ARCH_VERMAGIC_FTRACE	""
diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
index 1b7419579820..b8d61e019d06 100644
--- a/arch/powerpc/kernel/module_64.c
+++ b/arch/powerpc/kernel/module_64.c
@@ -466,7 +466,7 @@ static unsigned long stub_for_addr(const Elf64_Shdr *sechdrs,
 	return (unsigned long)&stubs[i];
 }
 
-#ifdef CC_USING_MPROFILE_KERNEL
+#ifdef CONFIG_MPROFILE_KERNEL
 static bool is_mprofile_mcount_callsite(const char *name, u32 *instruction)
 {
 	if (strcmp("_mcount", name))
@@ -753,7 +753,7 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
 
 #ifdef CONFIG_DYNAMIC_FTRACE
 
-#ifdef CC_USING_MPROFILE_KERNEL
+#ifdef CONFIG_MPROFILE_KERNEL
 
 #define PACATOC offsetof(struct paca_struct, kernel_toc)
 
diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c
index c076a32093fd..4bfbb54dee51 100644
--- a/arch/powerpc/kernel/trace/ftrace.c
+++ b/arch/powerpc/kernel/trace/ftrace.c
@@ -144,7 +144,7 @@ __ftrace_make_nop(struct module *mod,
 		return -EINVAL;
 	}
 
-#ifdef CC_USING_MPROFILE_KERNEL
+#ifdef CONFIG_MPROFILE_KERNEL
 	/* When using -mkernel_profile there is no load to jump over */
 	pop = PPC_INST_NOP;
 
@@ -188,7 +188,7 @@ __ftrace_make_nop(struct module *mod,
 		pr_err("Expected %08x found %08x\n", PPC_INST_LD_TOC, op);
 		return -EINVAL;
 	}
-#endif /* CC_USING_MPROFILE_KERNEL */
+#endif /* CONFIG_MPROFILE_KERNEL */
 
 	if (patch_instruction((unsigned int *)ip, pop)) {
 		pr_err("Patching NOP failed.\n");
@@ -324,7 +324,7 @@ int ftrace_make_nop(struct module *mod,
  * They should effectively be a NOP, and follow formal constraints,
  * depending on the ABI. Return false if they don't.
  */
-#ifndef CC_USING_MPROFILE_KERNEL
+#ifndef CONFIG_MPROFILE_KERNEL
 static int
 expected_nop_sequence(void *ip, unsigned int op0, unsigned int op1)
 {
diff --git a/arch/powerpc/tools/gcc-check-mprofile-kernel.sh b/arch/powerpc/tools/gcc-check-mprofile-kernel.sh
index a7dd0e5d9f98..137f3376ac2b 100755
--- a/arch/powerpc/tools/gcc-check-mprofile-kernel.sh
+++ b/arch/powerpc/tools/gcc-check-mprofile-kernel.sh
@@ -24,5 +24,4 @@ echo -e "#include <linux/compiler.h>\nnotrace int func() { return 0; }" | \
     2> /dev/null | grep -q "_mcount" && \
     exit 1
 
-echo "OK"
 exit 0
diff --git a/arch/sh/include/asm/vmlinux.lds.h b/arch/sh/include/asm/vmlinux.lds.h
index f312813f39d8..992955685874 100644
--- a/arch/sh/include/asm/vmlinux.lds.h
+++ b/arch/sh/include/asm/vmlinux.lds.h
@@ -7,9 +7,9 @@
 #ifdef CONFIG_DWARF_UNWINDER
 #define DWARF_EH_FRAME							\
 	.eh_frame : AT(ADDR(.eh_frame) - LOAD_OFFSET) {			\
-		  VMLINUX_SYMBOL(__start_eh_frame) = .;			\
+		  __start_eh_frame = .;					\
 		  *(.eh_frame)						\
-		  VMLINUX_SYMBOL(__stop_eh_frame) = .;			\
+		  __stop_eh_frame = .;					\
 	}
 #else
 #define DWARF_EH_FRAME
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 297789aef9fa..455a670ab239 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -130,7 +130,7 @@ config X86
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
 	select HAVE_ARCH_VMAP_STACK		if X86_64
 	select HAVE_ARCH_WITHIN_STACK_FRAMES
-	select HAVE_CC_STACKPROTECTOR
+	select HAVE_CC_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
 	select HAVE_CMPXCHG_DOUBLE
 	select HAVE_CMPXCHG_LOCAL
 	select HAVE_CONTEXT_TRACKING		if X86_64
@@ -346,6 +346,15 @@ config PGTABLE_LEVELS
 	default 2
 
 source "init/Kconfig"
+
+config CC_HAS_SANE_STACKPROTECTOR
+	bool
+	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
+	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
+	help
+	   We have to make sure stack protector is unconditionally disabled if
+	   the compiler produces broken code.
+
 source "kernel/Kconfig.freezer"
 
 menu "Processor type and features"