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Subject[patch 14/28] New cmpxchg_local (optimized for UP case) for m32r
Add __xchg_local, xchg_local (define), __cmpxchg_local_u32, __cmpxchg_local,
cmpxchg_local(macro).

cmpxchg_local and cmpxchg64_local will use the architecture specific
__cmpxchg_local_u32 for 32 bits arguments, and use the generic
__cmpxchg_local_generic for 8, 16 and 64 bits arguments.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: Hirokazu Takata <takata@linux-m32r.org>
CC: clameter@sgi.com
CC: linux-m32r@ml.linux-m32r.org
---
include/asm-m32r/system.h | 103 +++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 97 insertions(+), 6 deletions(-)
Index: linux-2.6-lttng/include/asm-m32r/system.h
===================================================================
--- linux-2.6-lttng.orig/include/asm-m32r/system.h 2007-08-07 14:31:52.000000000 -0400
+++ linux-2.6-lttng/include/asm-m32r/system.h 2007-08-07 14:55:02.000000000 -0400
@@ -123,6 +123,9 @@ static inline void local_irq_disable(voi

#define xchg(ptr,x) \
((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
+#define xchg_local(ptr,x) \
+ ((__typeof__(*(ptr)))__xchg_local((unsigned long)(x),(ptr), \
+ sizeof(*(ptr))))

#ifdef CONFIG_SMP
extern void __xchg_called_with_bad_pointer(void);
@@ -196,6 +199,42 @@ __xchg(unsigned long x, volatile void *
return (tmp);
}

+static __always_inline unsigned long
+__xchg_local(unsigned long x, volatile void * ptr, int size)
+{
+ unsigned long flags;
+ unsigned long tmp = 0;
+
+ local_irq_save(flags);
+
+ switch (size) {
+ case 1:
+ __asm__ __volatile__ (
+ "ldb %0, @%2 \n\t"
+ "stb %1, @%2 \n\t"
+ : "=&r" (tmp) : "r" (x), "r" (ptr) : "memory");
+ break;
+ case 2:
+ __asm__ __volatile__ (
+ "ldh %0, @%2 \n\t"
+ "sth %1, @%2 \n\t"
+ : "=&r" (tmp) : "r" (x), "r" (ptr) : "memory");
+ break;
+ case 4:
+ __asm__ __volatile__ (
+ "ld %0, @%2 \n\t"
+ "st %1, @%2 \n\t"
+ : "=&r" (tmp) : "r" (x), "r" (ptr) : "memory");
+ break;
+ default:
+ __xchg_called_with_bad_pointer();
+ }
+
+ local_irq_restore(flags);
+
+ return (tmp);
+}
+
#define __HAVE_ARCH_CMPXCHG 1

static inline unsigned long
@@ -228,6 +267,37 @@ __cmpxchg_u32(volatile unsigned int *p,
return retval;
}

+static inline unsigned long
+__cmpxchg_local_u32(volatile unsigned int *p, unsigned int old,
+ unsigned int new)
+{
+ unsigned long flags;
+ unsigned int retval;
+
+ local_irq_save(flags);
+ __asm__ __volatile__ (
+ DCACHE_CLEAR("%0", "r4", "%1")
+ "ld %0, @%1; \n"
+ " bne %0, %2, 1f; \n"
+ "st %3, @%1; \n"
+ " bra 2f; \n"
+ " .fillinsn \n"
+ "1:"
+ "st %0, @%1; \n"
+ " .fillinsn \n"
+ "2:"
+ : "=&r" (retval)
+ : "r" (p), "r" (old), "r" (new)
+ : "cbit", "memory"
+#ifdef CONFIG_CHIP_M32700_TS1
+ , "r4"
+#endif /* CONFIG_CHIP_M32700_TS1 */
+ );
+ local_irq_restore(flags);
+
+ return retval;
+}
+
/* This function doesn't exist, so you'll get a linker error
if something tries to do an invalid cmpxchg(). */
extern void __cmpxchg_called_with_bad_pointer(void);
@@ -248,12 +318,33 @@ __cmpxchg(volatile void *ptr, unsigned l
}

#define cmpxchg(ptr,o,n) \
- ({ \
- __typeof__(*(ptr)) _o_ = (o); \
- __typeof__(*(ptr)) _n_ = (n); \
- (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \
- (unsigned long)_n_, sizeof(*(ptr))); \
- })
+ (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)(o), \
+ (unsigned long)(n), sizeof(*(ptr)))
+
+#include <asm-generic/cmpxchg-local.h>
+
+static inline unsigned long __cmpxchg_local(volatile void *ptr,
+ unsigned long old,
+ unsigned long new, int size)
+{
+ switch (size) {
+ case 4:
+ return __cmpxchg_local_u32(ptr, old, new);
+ default:
+ return __cmpxchg_local_generic(ptr, old, new, size);
+ }
+
+ return old;
+}
+
+/*
+ * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
+ * them available.
+ */
+#define cmpxchg_local(ptr,o,n) \
+ (__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
+ (unsigned long)(n), sizeof(*(ptr)))
+#define cmpxchg64_local(ptr,o,n) __cmpxchg64_local_generic((ptr), (o), (n))

#endif /* __KERNEL__ */

--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
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