Merge tag 'locking_urgent_for_v5.18_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking fixes from Borislav Petkov:

 - Allow the compiler to optimize away unused percpu accesses and change
   the local_lock_* macros back to inline functions

 - A couple of fixes to static call insn patching

* tag 'locking_urgent_for_v5.18_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Revert "mm/page_alloc: mark pagesets as __maybe_unused"
  Revert "locking/local_lock: Make the empty local_lock_*() function a macro."
  x86/percpu: Remove volatile from arch_raw_cpu_ptr().
  static_call: Remove __DEFINE_STATIC_CALL macro
  static_call: Properly initialise DEFINE_STATIC_CALL_RET0()
  static_call: Don't make __static_call_return0 static
  x86,static_call: Fix __static_call_return0 for i386

arch/powerpc/include/asm/static_call.h

@@ -24,5 +24,6 @@
 
 #define ARCH_DEFINE_STATIC_CALL_TRAMP(name, func)	__PPC_SCT(name, "b " #func)
 #define ARCH_DEFINE_STATIC_CALL_NULL_TRAMP(name)	__PPC_SCT(name, "blr")
+#define ARCH_DEFINE_STATIC_CALL_RET0_TRAMP(name)	__PPC_SCT(name, "b .+20")
 
 #endif /* _ASM_POWERPC_STATIC_CALL_H */

arch/x86/include/asm/percpu.h

@@ -38,9 +38,9 @@
 #define arch_raw_cpu_ptr(ptr)				\
 ({							\
 	unsigned long tcp_ptr__;			\
-	asm volatile("add " __percpu_arg(1) ", %0"	\
-		     : "=r" (tcp_ptr__)			\
-		     : "m" (this_cpu_off), "0" (ptr));	\
+	asm ("add " __percpu_arg(1) ", %0"		\
+	     : "=r" (tcp_ptr__)				\
+	     : "m" (this_cpu_off), "0" (ptr));		\
 	(typeof(*(ptr)) __kernel __force *)tcp_ptr__;	\
 })
 #else

arch/x86/include/asm/static_call.h

@@ -38,6 +38,8 @@
 #define ARCH_DEFINE_STATIC_CALL_NULL_TRAMP(name)			\
 	__ARCH_DEFINE_STATIC_CALL_TRAMP(name, "ret; int3; nop; nop; nop")
 
+#define ARCH_DEFINE_STATIC_CALL_RET0_TRAMP(name)			\
+	ARCH_DEFINE_STATIC_CALL_TRAMP(name, __static_call_return0)
 
 #define ARCH_ADD_TRAMP_KEY(name)					\
 	asm(".pushsection .static_call_tramp_key, \"a\"		\n"	\

arch/x86/kernel/static_call.c

@@ -12,10 +12,9 @@ enum insn_type {
 };
 
 /*
- * data16 data16 xorq %rax, %rax - a single 5 byte instruction that clears %rax
- * The REX.W cancels the effect of any data16.
+ * cs cs cs xorl %eax, %eax - a single 5 byte instruction that clears %[er]ax
  */
-static const u8 xor5rax[] = { 0x66, 0x66, 0x48, 0x31, 0xc0 };
+static const u8 xor5rax[] = { 0x2e, 0x2e, 0x2e, 0x31, 0xc0 };
 
 static const u8 retinsn[] = { RET_INSN_OPCODE, 0xcc, 0xcc, 0xcc, 0xcc };
 

include/linux/local_lock_internal.h

@@ -44,9 +44,9 @@ static inline void local_lock_debug_init(local_lock_t *l)
 }
 #else /* CONFIG_DEBUG_LOCK_ALLOC */
 # define LOCAL_LOCK_DEBUG_INIT(lockname)
-# define local_lock_acquire(__ll)  do { typecheck(local_lock_t *, __ll); } while (0)
-# define local_lock_release(__ll)  do { typecheck(local_lock_t *, __ll); } while (0)
-# define local_lock_debug_init(__ll)  do { typecheck(local_lock_t *, __ll); } while (0)
+static inline void local_lock_acquire(local_lock_t *l) { }
+static inline void local_lock_release(local_lock_t *l) { }
+static inline void local_lock_debug_init(local_lock_t *l) { }
 #endif /* !CONFIG_DEBUG_LOCK_ALLOC */
 
 #define INIT_LOCAL_LOCK(lockname)	{ LOCAL_LOCK_DEBUG_INIT(lockname) }

include/linux/static_call.h

@@ -180,13 +180,13 @@ extern int static_call_text_reserved(void *start, void *end);
 
 extern long __static_call_return0(void);
 
-#define __DEFINE_STATIC_CALL(name, _func, _func_init)			\
+#define DEFINE_STATIC_CALL(name, _func)					\
 	DECLARE_STATIC_CALL(name, _func);				\
 	struct static_call_key STATIC_CALL_KEY(name) = {		\
-		.func = _func_init,					\
+		.func = _func,						\
 		.type = 1,						\
 	};								\
-	ARCH_DEFINE_STATIC_CALL_TRAMP(name, _func_init)
+	ARCH_DEFINE_STATIC_CALL_TRAMP(name, _func)
 
 #define DEFINE_STATIC_CALL_NULL(name, _func)				\
 	DECLARE_STATIC_CALL(name, _func);				\
@@ -196,6 +196,14 @@ extern long __static_call_return0(void);
 	};								\
 	ARCH_DEFINE_STATIC_CALL_NULL_TRAMP(name)
 
+#define DEFINE_STATIC_CALL_RET0(name, _func)				\
+	DECLARE_STATIC_CALL(name, _func);				\
+	struct static_call_key STATIC_CALL_KEY(name) = {		\
+		.func = __static_call_return0,				\
+		.type = 1,						\
+	};								\
+	ARCH_DEFINE_STATIC_CALL_RET0_TRAMP(name)
+
 #define static_call_cond(name)	(void)__static_call(name)
 
 #define EXPORT_STATIC_CALL(name)					\
@@ -217,12 +225,12 @@ extern long __static_call_return0(void);
 
 static inline int static_call_init(void) { return 0; }
 
-#define __DEFINE_STATIC_CALL(name, _func, _func_init)			\
+#define DEFINE_STATIC_CALL(name, _func)					\
 	DECLARE_STATIC_CALL(name, _func);				\
 	struct static_call_key STATIC_CALL_KEY(name) = {		\
-		.func = _func_init,					\
+		.func = _func,						\
 	};								\
-	ARCH_DEFINE_STATIC_CALL_TRAMP(name, _func_init)
+	ARCH_DEFINE_STATIC_CALL_TRAMP(name, _func)
 
 #define DEFINE_STATIC_CALL_NULL(name, _func)				\
 	DECLARE_STATIC_CALL(name, _func);				\
@@ -231,6 +239,12 @@ static inline int static_call_init(void) { return 0; }
 	};								\
 	ARCH_DEFINE_STATIC_CALL_NULL_TRAMP(name)
 
+#define DEFINE_STATIC_CALL_RET0(name, _func)				\
+	DECLARE_STATIC_CALL(name, _func);				\
+	struct static_call_key STATIC_CALL_KEY(name) = {		\
+		.func = __static_call_return0,				\
+	};								\
+	ARCH_DEFINE_STATIC_CALL_RET0_TRAMP(name)
 
 #define static_call_cond(name)	(void)__static_call(name)
 
@@ -248,10 +262,7 @@ static inline int static_call_text_reserved(void *start, void *end)
 	return 0;
 }
 
-static inline long __static_call_return0(void)
-{
-	return 0;
-}
+extern long __static_call_return0(void);
 
 #define EXPORT_STATIC_CALL(name)					\
 	EXPORT_SYMBOL(STATIC_CALL_KEY(name));				\
@@ -281,11 +292,14 @@ static inline long __static_call_return0(void)
 		.func = _func_init,					\
 	}
 
+#define DEFINE_STATIC_CALL(name, _func)					\
+	__DEFINE_STATIC_CALL(name, _func, _func)
+
 #define DEFINE_STATIC_CALL_NULL(name, _func)				\
-	DECLARE_STATIC_CALL(name, _func);				\
-	struct static_call_key STATIC_CALL_KEY(name) = {		\
-		.func = NULL,						\
-	}
+	__DEFINE_STATIC_CALL(name, _func, NULL)
+
+#define DEFINE_STATIC_CALL_RET0(name, _func)				\
+	__DEFINE_STATIC_CALL(name, _func, __static_call_return0)
 
 static inline void __static_call_nop(void) { }
 
@@ -327,10 +341,4 @@ static inline int static_call_text_reserved(void *start, void *end)
 
 #endif /* CONFIG_HAVE_STATIC_CALL */
 
-#define DEFINE_STATIC_CALL(name, _func)					\
-	__DEFINE_STATIC_CALL(name, _func, _func)
-
-#define DEFINE_STATIC_CALL_RET0(name, _func)				\
-	__DEFINE_STATIC_CALL(name, _func, __static_call_return0)
-
 #endif /* _LINUX_STATIC_CALL_H */

kernel/Makefile

@@ -114,7 +114,8 @@ obj-$(CONFIG_CPU_PM) += cpu_pm.o
 obj-$(CONFIG_BPF) += bpf/
 obj-$(CONFIG_KCSAN) += kcsan/
 obj-$(CONFIG_SHADOW_CALL_STACK) += scs.o
-obj-$(CONFIG_HAVE_STATIC_CALL_INLINE) += static_call.o
+obj-$(CONFIG_HAVE_STATIC_CALL) += static_call.o
+obj-$(CONFIG_HAVE_STATIC_CALL_INLINE) += static_call_inline.o
 obj-$(CONFIG_CFI_CLANG) += cfi.o
 
 obj-$(CONFIG_PERF_EVENTS) += events/

mm/page_alloc.c

@@ -128,7 +128,7 @@ static DEFINE_MUTEX(pcp_batch_high_lock);
 struct pagesets {
 	local_lock_t lock;
 };
-static DEFINE_PER_CPU(struct pagesets, pagesets) __maybe_unused = {
+static DEFINE_PER_CPU(struct pagesets, pagesets) = {
 	.lock = INIT_LOCAL_LOCK(lock),
 };