Merge tag 'clang-features-v5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull clang feature updates from Kees Cook:

 - Add CC_HAS_NO_PROFILE_FN_ATTR in preparation for PGO support in the
   face of the noinstr attribute, paving the way for PGO and fixing
   GCOV. (Nick Desaulniers)

 - x86_64 LTO coverage is expanded to 32-bit x86. (Nathan Chancellor)

 - Small fixes to CFI. (Mark Rutland, Nathan Chancellor)

* tag 'clang-features-v5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  qemu_fw_cfg: Make fw_cfg_rev_attr a proper kobj_attribute
  Kconfig: Introduce ARCH_WANTS_NO_INSTR and CC_HAS_NO_PROFILE_FN_ATTR
  compiler_attributes.h: cleanups for GCC 4.9+
  compiler_attributes.h: define __no_profile, add to noinstr
  x86, lto: Enable Clang LTO for 32-bit as well
  CFI: Move function_nocfi() into compiler.h
  MAINTAINERS: Add Clang CFI section

6 files changed, 28 insertions, 18 deletions

diff --git a/arch/Kconfig b/arch/Kconfig
index c45b770d3579..129df498a8e1 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -285,6 +285,13 @@ config ARCH_THREAD_STACK_ALLOCATOR
 config ARCH_WANTS_DYNAMIC_TASK_STRUCT
 	bool
 
+config ARCH_WANTS_NO_INSTR
+	bool
+	help
+	  An architecture should select this if the noinstr macro is being used on
+	  functions to denote that the toolchain should avoid instrumenting such
+	  functions and is required for correctness.
+
 config ARCH_32BIT_OFF_T
 	bool
 	depends on !64BIT
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index a6a09cb95cc7..be9083882f97 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -93,6 +93,7 @@ config ARM64
 	select ARCH_WANT_FRAME_POINTERS
 	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
 	select ARCH_WANT_LD_ORPHAN_WARN
+	select ARCH_WANTS_NO_INSTR
 	select ARCH_HAS_UBSAN_SANITIZE_ALL
 	select ARM_AMBA
 	select ARM_ARCH_TIMER
diff --git a/arch/arm64/include/asm/compiler.h b/arch/arm64/include/asm/compiler.h
index 6fb2e6bcc392..dc3ea4080e2e 100644
--- a/arch/arm64/include/asm/compiler.h
+++ b/arch/arm64/include/asm/compiler.h
@@ -23,4 +23,20 @@
 #define __builtin_return_address(val)					\
 	(void *)(ptrauth_clear_pac((unsigned long)__builtin_return_address(val)))
 
+#ifdef CONFIG_CFI_CLANG
+/*
+ * With CONFIG_CFI_CLANG, the compiler replaces function address
+ * references with the address of the function's CFI jump table
+ * entry. The function_nocfi macro always returns the address of the
+ * actual function instead.
+ */
+#define function_nocfi(x) ({						\
+	void *addr;							\
+	asm("adrp %0, " __stringify(x) "\n\t"				\
+	    "add  %0, %0, :lo12:" __stringify(x)			\
+	    : "=r" (addr));						\
+	addr;								\
+})
+#endif
+
 #endif /* __ASM_COMPILER_H */
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 7b360960cc35..1a35a4473598 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -321,22 +321,6 @@ static inline void *phys_to_virt(phys_addr_t x)
 #define virt_to_pfn(x)		__phys_to_pfn(__virt_to_phys((unsigned long)(x)))
 #define sym_to_pfn(x)		__phys_to_pfn(__pa_symbol(x))
 
-#ifdef CONFIG_CFI_CLANG
-/*
- * With CONFIG_CFI_CLANG, the compiler replaces function address
- * references with the address of the function's CFI jump table
- * entry. The function_nocfi macro always returns the address of the
- * actual function instead.
- */
-#define function_nocfi(x) ({						\
-	void *addr;							\
-	asm("adrp %0, " __stringify(x) "\n\t"				\
-	    "add  %0, %0, :lo12:" __stringify(x)			\
-	    : "=r" (addr));						\
-	addr;								\
-})
-#endif
-
 /*
  *  virt_to_page(x)	convert a _valid_ virtual address to struct page *
  *  virt_addr_valid(x)	indicates whether a virtual address is valid
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 707afbcd81c2..a49971647f81 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -117,6 +117,7 @@ config S390
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_CMPXCHG_LOCKREF
 	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
+	select ARCH_WANTS_NO_INSTR
 	select ARCH_WANT_DEFAULT_BPF_JIT
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select BUILDTIME_TABLE_SORT
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 49ffb69e34dd..867e7936dbc5 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -103,8 +103,8 @@ config X86
 	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
 	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
 	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
-	select ARCH_SUPPORTS_LTO_CLANG		if X86_64
-	select ARCH_SUPPORTS_LTO_CLANG_THIN	if X86_64
+	select ARCH_SUPPORTS_LTO_CLANG
+	select ARCH_SUPPORTS_LTO_CLANG_THIN
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_MEMTEST
 	select ARCH_USE_QUEUED_RWLOCKS
@@ -113,6 +113,7 @@ config X86
 	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
 	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
 	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
+	select ARCH_WANTS_NO_INSTR
 	select ARCH_WANT_HUGE_PMD_SHARE
 	select ARCH_WANT_LD_ORPHAN_WARN
 	select ARCH_WANTS_THP_SWAP		if X86_64