Merge tag 'locking-core-2023-06-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking updates from Ingo Molnar:

 - Introduce cmpxchg128() -- aka. the demise of cmpxchg_double()

   The cmpxchg128() family of functions is basically & functionally the
   same as cmpxchg_double(), but with a saner interface.

   Instead of a 6-parameter horror that forced u128 - u64/u64-halves
   layout details on the interface and exposed users to complexity,
   fragility & bugs, use a natural 3-parameter interface with u128
   types.

 - Restructure the generated atomic headers, and add kerneldoc comments
   for all of the generic atomic{,64,_long}_t operations.

   The generated definitions are much cleaner now, and come with
   documentation.

 - Implement lock_set_cmp_fn() on lockdep, for defining an ordering when
   taking multiple locks of the same type.

   This gets rid of one use of lockdep_set_novalidate_class() in the
   bcache code.

 - Fix raw_cpu_generic_try_cmpxchg() bug due to an unintended variable
   shadowing generating garbage code on Clang on certain ARM builds.

* tag 'locking-core-2023-06-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (43 commits)
  locking/atomic: scripts: fix ${atomic}_dec_if_positive() kerneldoc
  percpu: Fix self-assignment of __old in raw_cpu_generic_try_cmpxchg()
  locking/atomic: treewide: delete arch_atomic_*() kerneldoc
  locking/atomic: docs: Add atomic operations to the driver basic API documentation
  locking/atomic: scripts: generate kerneldoc comments
  docs: scripts: kernel-doc: accept bitwise negation like ~@var
  locking/atomic: scripts: simplify raw_atomic*() definitions
  locking/atomic: scripts: simplify raw_atomic_long*() definitions
  locking/atomic: scripts: split pfx/name/sfx/order
  locking/atomic: scripts: restructure fallback ifdeffery
  locking/atomic: scripts: build raw_atomic_long*() directly
  locking/atomic: treewide: use raw_atomic*_<op>()
  locking/atomic: scripts: add trivial raw_atomic*_<op>()
  locking/atomic: scripts: factor out order template generation
  locking/atomic: scripts: remove leftover "${mult}"
  locking/atomic: scripts: remove bogus order parameter
  locking/atomic: xtensa: add preprocessor symbols
  locking/atomic: x86: add preprocessor symbols
  locking/atomic: sparc: add preprocessor symbols
  locking/atomic: sh: add preprocessor symbols
  ...

Author: torvalds

Documentation/core-api/this_cpu_ops.rst

@@ -53,7 +53,6 @@ preemption and interrupts::
 	this_cpu_add_return(pcp, val)
 	this_cpu_xchg(pcp, nval)
 	this_cpu_cmpxchg(pcp, oval, nval)
-	this_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
 	this_cpu_sub(pcp, val)
 	this_cpu_inc(pcp)
 	this_cpu_dec(pcp)
@@ -242,7 +241,6 @@ safe::
 	__this_cpu_add_return(pcp, val)
 	__this_cpu_xchg(pcp, nval)
 	__this_cpu_cmpxchg(pcp, oval, nval)
-	__this_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
 	__this_cpu_sub(pcp, val)
 	__this_cpu_inc(pcp)
 	__this_cpu_dec(pcp)

Documentation/driver-api/basics.rst

@@ -84,7 +84,13 @@ Reference counting
 Atomics
 -------
 
-.. kernel-doc:: arch/x86/include/asm/atomic.h
+.. kernel-doc:: include/linux/atomic/atomic-instrumented.h
+   :internal:
+
+.. kernel-doc:: include/linux/atomic/atomic-arch-fallback.h
+   :internal:
+
+.. kernel-doc:: include/linux/atomic/atomic-long.h
    :internal:
 
 Kernel objects manipulation

arch/alpha/include/asm/atomic.h

@@ -200,25 +200,6 @@ ATOMIC_OPS(xor, xor)
 #undef ATOMIC_OP_RETURN
 #undef ATOMIC_OP
 
-#define arch_atomic64_cmpxchg(v, old, new) \
-	(arch_cmpxchg(&((v)->counter), old, new))
-#define arch_atomic64_xchg(v, new) \
-	(arch_xchg(&((v)->counter), new))
-
-#define arch_atomic_cmpxchg(v, old, new) \
-	(arch_cmpxchg(&((v)->counter), old, new))
-#define arch_atomic_xchg(v, new) \
-	(arch_xchg(&((v)->counter), new))
-
-/**
- * arch_atomic_fetch_add_unless - add unless the number is a given value
- * @v: pointer of type atomic_t
- * @a: the amount to add to v...
- * @u: ...unless v is equal to u.
- *
- * Atomically adds @a to @v, so long as it was not @u.
- * Returns the old value of @v.
- */
 static __inline__ int arch_atomic_fetch_add_unless(atomic_t *v, int a, int u)
 {
 	int c, new, old;
@@ -242,15 +223,6 @@ static __inline__ int arch_atomic_fetch_add_unless(atomic_t *v, int a, int u)
 }
 #define arch_atomic_fetch_add_unless arch_atomic_fetch_add_unless
 
-/**
- * arch_atomic64_fetch_add_unless - add unless the number is a given value
- * @v: pointer of type atomic64_t
- * @a: the amount to add to v...
- * @u: ...unless v is equal to u.
- *
- * Atomically adds @a to @v, so long as it was not @u.
- * Returns the old value of @v.
- */
 static __inline__ s64 arch_atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
 {
 	s64 c, new, old;
@@ -274,13 +246,6 @@ static __inline__ s64 arch_atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u
 }
 #define arch_atomic64_fetch_add_unless arch_atomic64_fetch_add_unless
 
-/*
- * arch_atomic64_dec_if_positive - decrement by 1 if old value positive
- * @v: pointer of type atomic_t
- *
- * The function returns the old value of *v minus 1, even if
- * the atomic variable, v, was not decremented.
- */
 static inline s64 arch_atomic64_dec_if_positive(atomic64_t *v)
 {
 	s64 old, tmp;

arch/arc/include/asm/atomic-spinlock.h

@@ -81,6 +81,11 @@ static inline int arch_atomic_fetch_##op(int i, atomic_t *v)		\
 ATOMIC_OPS(add, +=, add)
 ATOMIC_OPS(sub, -=, sub)
 
+#define arch_atomic_fetch_add		arch_atomic_fetch_add
+#define arch_atomic_fetch_sub		arch_atomic_fetch_sub
+#define arch_atomic_add_return		arch_atomic_add_return
+#define arch_atomic_sub_return		arch_atomic_sub_return
+
 #undef ATOMIC_OPS
 #define ATOMIC_OPS(op, c_op, asm_op)					\
 	ATOMIC_OP(op, c_op, asm_op)					\
@@ -92,7 +97,11 @@ ATOMIC_OPS(or, |=, or)
 ATOMIC_OPS(xor, ^=, xor)
 
 #define arch_atomic_andnot		arch_atomic_andnot
+
+#define arch_atomic_fetch_and		arch_atomic_fetch_and
 #define arch_atomic_fetch_andnot	arch_atomic_fetch_andnot
+#define arch_atomic_fetch_or		arch_atomic_fetch_or
+#define arch_atomic_fetch_xor		arch_atomic_fetch_xor
 
 #undef ATOMIC_OPS
 #undef ATOMIC_FETCH_OP

arch/arc/include/asm/atomic.h

@@ -22,30 +22,6 @@
 #include <asm/atomic-spinlock.h>
 #endif
 
-#define arch_atomic_cmpxchg(v, o, n)					\
-({									\
-	arch_cmpxchg(&((v)->counter), (o), (n));			\
-})
-
-#ifdef arch_cmpxchg_relaxed
-#define arch_atomic_cmpxchg_relaxed(v, o, n)				\
-({									\
-	arch_cmpxchg_relaxed(&((v)->counter), (o), (n));		\
-})
-#endif
-
-#define arch_atomic_xchg(v, n)						\
-({									\
-	arch_xchg(&((v)->counter), (n));				\
-})
-
-#ifdef arch_xchg_relaxed
-#define arch_atomic_xchg_relaxed(v, n)					\
-({									\
-	arch_xchg_relaxed(&((v)->counter), (n));			\
-})
-#endif
-
 /*
  * 64-bit atomics
  */

arch/arc/include/asm/atomic64-arcv2.h

@@ -159,6 +159,7 @@ arch_atomic64_cmpxchg(atomic64_t *ptr, s64 expected, s64 new)
 
 	return prev;
 }
+#define arch_atomic64_cmpxchg arch_atomic64_cmpxchg
 
 static inline s64 arch_atomic64_xchg(atomic64_t *ptr, s64 new)
 {
@@ -179,14 +180,7 @@ static inline s64 arch_atomic64_xchg(atomic64_t *ptr, s64 new)
 
 	return prev;
 }
-
-/**
- * arch_atomic64_dec_if_positive - decrement by 1 if old value positive
- * @v: pointer of type atomic64_t
- *
- * The function returns the old value of *v minus 1, even if
- * the atomic variable, v, was not decremented.
- */
+#define arch_atomic64_xchg arch_atomic64_xchg
 
 static inline s64 arch_atomic64_dec_if_positive(atomic64_t *v)
 {
@@ -212,15 +206,6 @@ static inline s64 arch_atomic64_dec_if_positive(atomic64_t *v)
 }
 #define arch_atomic64_dec_if_positive arch_atomic64_dec_if_positive
 
-/**
- * arch_atomic64_fetch_add_unless - add unless the number is a given value
- * @v: pointer of type atomic64_t
- * @a: the amount to add to v...
- * @u: ...unless v is equal to u.
- *
- * Atomically adds @a to @v, if it was not @u.
- * Returns the old value of @v
- */
 static inline s64 arch_atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
 {
 	s64 old, temp;

arch/arm/include/asm/assembler.h

@@ -394,6 +394,23 @@ ALT_UP_B(.L0_\@)
 #endif
 	.endm
 
+/*
+ * Raw SMP data memory barrier
+ */
+	.macro	__smp_dmb mode
+#if __LINUX_ARM_ARCH__ >= 7
+	.ifeqs "\mode","arm"
+	dmb	ish
+	.else
+	W(dmb)	ish
+	.endif
+#elif __LINUX_ARM_ARCH__ == 6
+	mcr	p15, 0, r0, c7, c10, 5	@ dmb
+#else
+	.error "Incompatible SMP platform"
+#endif
+	.endm
+
 #if defined(CONFIG_CPU_V7M)
 	/*
 	 * setmode is used to assert to be in svc mode during boot. For v7-M

arch/arm/include/asm/atomic.h

@@ -197,6 +197,16 @@ static inline int arch_atomic_fetch_##op(int i, atomic_t *v)		\
 	return val;							\
 }
 
+#define arch_atomic_add_return			arch_atomic_add_return
+#define arch_atomic_sub_return			arch_atomic_sub_return
+#define arch_atomic_fetch_add			arch_atomic_fetch_add
+#define arch_atomic_fetch_sub			arch_atomic_fetch_sub
+
+#define arch_atomic_fetch_and			arch_atomic_fetch_and
+#define arch_atomic_fetch_andnot		arch_atomic_fetch_andnot
+#define arch_atomic_fetch_or			arch_atomic_fetch_or
+#define arch_atomic_fetch_xor			arch_atomic_fetch_xor
+
 static inline int arch_atomic_cmpxchg(atomic_t *v, int old, int new)
 {
 	int ret;
@@ -210,8 +220,7 @@ static inline int arch_atomic_cmpxchg(atomic_t *v, int old, int new)
 
 	return ret;
 }
-
-#define arch_atomic_fetch_andnot		arch_atomic_fetch_andnot
+#define arch_atomic_cmpxchg arch_atomic_cmpxchg
 
 #endif /* __LINUX_ARM_ARCH__ */
 
@@ -240,8 +249,6 @@ ATOMIC_OPS(xor, ^=, eor)
 #undef ATOMIC_OP_RETURN
 #undef ATOMIC_OP
 
-#define arch_atomic_xchg(v, new) (arch_xchg(&((v)->counter), new))
-
 #ifndef CONFIG_GENERIC_ATOMIC64
 typedef struct {
 	s64 counter;

arch/arm/include/asm/sync_bitops.h

@@ -14,14 +14,35 @@
  * ops which are SMP safe even on a UP kernel.
  */
 
+/*
+ * Unordered
+ */
+
 #define sync_set_bit(nr, p)		_set_bit(nr, p)
 #define sync_clear_bit(nr, p)		_clear_bit(nr, p)
 #define sync_change_bit(nr, p)		_change_bit(nr, p)
-#define sync_test_and_set_bit(nr, p)	_test_and_set_bit(nr, p)
-#define sync_test_and_clear_bit(nr, p)	_test_and_clear_bit(nr, p)
-#define sync_test_and_change_bit(nr, p)	_test_and_change_bit(nr, p)
 #define sync_test_bit(nr, addr)		test_bit(nr, addr)
-#define arch_sync_cmpxchg		arch_cmpxchg
 
+/*
+ * Fully ordered
+ */
+
+int _sync_test_and_set_bit(int nr, volatile unsigned long * p);
+#define sync_test_and_set_bit(nr, p)	_sync_test_and_set_bit(nr, p)
+
+int _sync_test_and_clear_bit(int nr, volatile unsigned long * p);
+#define sync_test_and_clear_bit(nr, p)	_sync_test_and_clear_bit(nr, p)
+
+int _sync_test_and_change_bit(int nr, volatile unsigned long * p);
+#define sync_test_and_change_bit(nr, p)	_sync_test_and_change_bit(nr, p)
+
+#define arch_sync_cmpxchg(ptr, old, new)				\
+({									\
+	__typeof__(*(ptr)) __ret;					\
+	__smp_mb__before_atomic();					\
+	__ret = arch_cmpxchg_relaxed((ptr), (old), (new));		\
+	__smp_mb__after_atomic();					\
+	__ret;								\
+})
 
 #endif

arch/arm/lib/bitops.h

@@ -28,7 +28,7 @@ UNWIND(	.fnend		)
 ENDPROC(\name		)
 	.endm
 
-	.macro	testop, name, instr, store
+	.macro	__testop, name, instr, store, barrier
 ENTRY(	\name		)
 UNWIND(	.fnstart	)
 	ands	ip, r1, #3
@@ -38,7 +38,7 @@ UNWIND(	.fnstart	)
 	mov	r0, r0, lsr #5
 	add	r1, r1, r0, lsl #2	@ Get word offset
 	mov	r3, r2, lsl r3		@ create mask
-	smp_dmb
+	\barrier
 #if __LINUX_ARM_ARCH__ >= 7 && defined(CONFIG_SMP)
 	.arch_extension	mp
 	ALT_SMP(W(pldw)	[r1])
@@ -50,13 +50,21 @@ UNWIND(	.fnstart	)
 	strex	ip, r2, [r1]
 	cmp	ip, #0
 	bne	1b
-	smp_dmb
+	\barrier
 	cmp	r0, #0
 	movne	r0, #1
 2:	bx	lr
 UNWIND(	.fnend		)
 ENDPROC(\name		)
 	.endm
+
+	.macro	testop, name, instr, store
+	__testop \name, \instr, \store, smp_dmb
+	.endm
+
+	.macro	sync_testop, name, instr, store
+	__testop \name, \instr, \store, __smp_dmb
+	.endm
 #else
 	.macro	bitop, name, instr
 ENTRY(	\name		)

arch/arm/lib/testchangebit.S

@@ -10,3 +10,7 @@
                 .text
 
 testop	_test_and_change_bit, eor, str
+
+#if __LINUX_ARM_ARCH__ >= 6
+sync_testop	_sync_test_and_change_bit, eor, str
+#endif

arch/arm/lib/testclearbit.S

@@ -10,3 +10,7 @@
                 .text
 
 testop	_test_and_clear_bit, bicne, strne
+
+#if __LINUX_ARM_ARCH__ >= 6
+sync_testop	_sync_test_and_clear_bit, bicne, strne
+#endif

arch/arm/lib/testsetbit.S

@@ -10,3 +10,7 @@
                 .text
 
 testop	_test_and_set_bit, orreq, streq
+
+#if __LINUX_ARM_ARCH__ >= 6
+sync_testop	_sync_test_and_set_bit, orreq, streq
+#endif

arch/arm64/include/asm/atomic.h

@@ -142,24 +142,6 @@ static __always_inline long arch_atomic64_dec_if_positive(atomic64_t *v)
 #define arch_atomic_fetch_xor_release		arch_atomic_fetch_xor_release
 #define arch_atomic_fetch_xor			arch_atomic_fetch_xor
 
-#define arch_atomic_xchg_relaxed(v, new) \
-	arch_xchg_relaxed(&((v)->counter), (new))
-#define arch_atomic_xchg_acquire(v, new) \
-	arch_xchg_acquire(&((v)->counter), (new))
-#define arch_atomic_xchg_release(v, new) \
-	arch_xchg_release(&((v)->counter), (new))
-#define arch_atomic_xchg(v, new) \
-	arch_xchg(&((v)->counter), (new))
-
-#define arch_atomic_cmpxchg_relaxed(v, old, new) \
-	arch_cmpxchg_relaxed(&((v)->counter), (old), (new))
-#define arch_atomic_cmpxchg_acquire(v, old, new) \
-	arch_cmpxchg_acquire(&((v)->counter), (old), (new))
-#define arch_atomic_cmpxchg_release(v, old, new) \
-	arch_cmpxchg_release(&((v)->counter), (old), (new))
-#define arch_atomic_cmpxchg(v, old, new) \
-	arch_cmpxchg(&((v)->counter), (old), (new))
-
 #define arch_atomic_andnot			arch_atomic_andnot
 
 /*
@@ -209,16 +191,6 @@ static __always_inline long arch_atomic64_dec_if_positive(atomic64_t *v)
 #define arch_atomic64_fetch_xor_release		arch_atomic64_fetch_xor_release
 #define arch_atomic64_fetch_xor			arch_atomic64_fetch_xor
 
-#define arch_atomic64_xchg_relaxed		arch_atomic_xchg_relaxed
-#define arch_atomic64_xchg_acquire		arch_atomic_xchg_acquire
-#define arch_atomic64_xchg_release		arch_atomic_xchg_release
-#define arch_atomic64_xchg			arch_atomic_xchg
-
-#define arch_atomic64_cmpxchg_relaxed		arch_atomic_cmpxchg_relaxed
-#define arch_atomic64_cmpxchg_acquire		arch_atomic_cmpxchg_acquire
-#define arch_atomic64_cmpxchg_release		arch_atomic_cmpxchg_release
-#define arch_atomic64_cmpxchg			arch_atomic_cmpxchg
-
 #define arch_atomic64_andnot			arch_atomic64_andnot
 
 #define arch_atomic64_dec_if_positive		arch_atomic64_dec_if_positive