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
  ...

1 files changed, 6 insertions, 26 deletions

diff --git a/arch/s390/include/asm/cmpxchg.h b/arch/s390/include/asm/cmpxchg.h
index 06e0e42f4eec..aae0315374de 100644
--- a/arch/s390/include/asm/cmpxchg.h
+++ b/arch/s390/include/asm/cmpxchg.h
@@ -190,38 +190,18 @@ static __always_inline unsigned long __cmpxchg(unsigned long address,
 #define arch_cmpxchg_local	arch_cmpxchg
 #define arch_cmpxchg64_local	arch_cmpxchg
 
-#define system_has_cmpxchg_double()	1
+#define system_has_cmpxchg128()		1
 
-static __always_inline int __cmpxchg_double(unsigned long p1, unsigned long p2,
-					    unsigned long o1, unsigned long o2,
-					    unsigned long n1, unsigned long n2)
+static __always_inline u128 arch_cmpxchg128(volatile u128 *ptr, u128 old, u128 new)
 {
-	union register_pair old = { .even = o1, .odd = o2, };
-	union register_pair new = { .even = n1, .odd = n2, };
-	int cc;
-
 	asm volatile(
 		"	cdsg	%[old],%[new],%[ptr]\n"
-		"	ipm	%[cc]\n"
-		"	srl	%[cc],28\n"
-		: [cc] "=&d" (cc), [old] "+&d" (old.pair)
-		: [new] "d" (new.pair),
-		  [ptr] "QS" (*(unsigned long *)p1), "Q" (*(unsigned long *)p2)
+		: [old] "+d" (old), [ptr] "+QS" (*ptr)
+		: [new] "d" (new)
 		: "memory", "cc");
-	return !cc;
+	return old;
 }
 
-#define arch_cmpxchg_double(p1, p2, o1, o2, n1, n2)			\
-({									\
-	typeof(p1) __p1 = (p1);						\
-	typeof(p2) __p2 = (p2);						\
-									\
-	BUILD_BUG_ON(sizeof(*(p1)) != sizeof(long));			\
-	BUILD_BUG_ON(sizeof(*(p2)) != sizeof(long));			\
-	VM_BUG_ON((unsigned long)((__p1) + 1) != (unsigned long)(__p2));\
-	__cmpxchg_double((unsigned long)__p1, (unsigned long)__p2,	\
-			 (unsigned long)(o1), (unsigned long)(o2),	\
-			 (unsigned long)(n1), (unsigned long)(n2));	\
-})
+#define arch_cmpxchg128		arch_cmpxchg128
 
 #endif /* __ASM_CMPXCHG_H */