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Message-ID: <20061221002242.GS28643@Krystal>
Date: Wed, 20 Dec 2006 19:22:42 -0500
From: Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>
To: linux-kernel@...r.kernel.org, Andrew Morton <akpm@...l.org>,
Ingo Molnar <mingo@...hat.com>,
Greg Kroah-Hartman <gregkh@...e.de>,
Christoph Hellwig <hch@...radead.org>
Cc: ltt-dev@...fik.org, systemtap@...rces.redhat.com,
Douglas Niehaus <niehaus@...s.ku.edu>,
"Martin J. Bligh" <mbligh@...igh.org>,
Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH 3/10] local_t : i386
i386 architecture local_t extension.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>
--- a/include/asm-i386/system.h
+++ b/include/asm-i386/system.h
@@ -274,6 +274,9 @@ #define cmpxchg(ptr,o,n)\
#define sync_cmpxchg(ptr,o,n)\
((__typeof__(*(ptr)))__sync_cmpxchg((ptr),(unsigned long)(o),\
(unsigned long)(n),sizeof(*(ptr))))
+#define cmpxchg_local(ptr,o,n)\
+ ((__typeof__(*(ptr)))__cmpxchg_local((ptr),(unsigned long)(o),\
+ (unsigned long)(n),sizeof(*(ptr))))
#endif
static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
@@ -336,6 +339,33 @@ static inline unsigned long __sync_cmpxc
return old;
}
+static inline unsigned long __cmpxchg_local(volatile void *ptr,
+ unsigned long old, unsigned long new, int size)
+{
+ unsigned long prev;
+ switch (size) {
+ case 1:
+ __asm__ __volatile__("cmpxchgb %b1,%2"
+ : "=a"(prev)
+ : "q"(new), "m"(*__xg(ptr)), "0"(old)
+ : "memory");
+ return prev;
+ case 2:
+ __asm__ __volatile__("cmpxchgw %w1,%2"
+ : "=a"(prev)
+ : "r"(new), "m"(*__xg(ptr)), "0"(old)
+ : "memory");
+ return prev;
+ case 4:
+ __asm__ __volatile__("cmpxchgl %1,%2"
+ : "=a"(prev)
+ : "r"(new), "m"(*__xg(ptr)), "0"(old)
+ : "memory");
+ return prev;
+ }
+ return old;
+}
+
#ifndef CONFIG_X86_CMPXCHG
/*
* Building a kernel capable running on 80386. It may be necessary to
@@ -372,6 +402,17 @@ ({ \
(unsigned long)(n), sizeof(*(ptr))); \
__ret; \
})
+#define cmpxchg_local(ptr,o,n) \
+({ \
+ __typeof__(*(ptr)) __ret; \
+ if (likely(boot_cpu_data.x86 > 3)) \
+ __ret = __cmpxchg_local((ptr), (unsigned long)(o), \
+ (unsigned long)(n), sizeof(*(ptr))); \
+ else \
+ __ret = cmpxchg_386((ptr), (unsigned long)(o), \
+ (unsigned long)(n), sizeof(*(ptr))); \
+ __ret; \
+})
#endif
#ifdef CONFIG_X86_CMPXCHG64
@@ -390,10 +431,26 @@ static inline unsigned long long __cmpxc
return prev;
}
+static inline unsigned long long __cmpxchg64_local(volatile void *ptr,
+ unsigned long long old, unsigned long long new)
+{
+ unsigned long long prev;
+ __asm__ __volatile__("cmpxchg8b %3"
+ : "=A"(prev)
+ : "b"((unsigned long)new),
+ "c"((unsigned long)(new >> 32)),
+ "m"(*__xg(ptr)),
+ "0"(old)
+ : "memory");
+ return prev;
+}
+
#define cmpxchg64(ptr,o,n)\
((__typeof__(*(ptr)))__cmpxchg64((ptr),(unsigned long long)(o),\
(unsigned long long)(n)))
-
+#define cmpxchg64_local(ptr,o,n)\
+ ((__typeof__(*(ptr)))__cmpxchg64_local((ptr),(unsigned long long)(o),\
+ (unsigned long long)(n)))
#endif
/*
--- a/include/asm-i386/local.h
+++ b/include/asm-i386/local.h
@@ -2,47 +2,198 @@ #ifndef _ARCH_I386_LOCAL_H
#define _ARCH_I386_LOCAL_H
#include <linux/percpu.h>
+#include <asm/system.h>
+#include <asm/atomic.h>
typedef struct
{
- volatile long counter;
+ atomic_long_t a;
} local_t;
-#define LOCAL_INIT(i) { (i) }
+#define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }
-#define local_read(v) ((v)->counter)
-#define local_set(v,i) (((v)->counter) = (i))
+#define local_read(l) atomic_long_read(&(l)->a)
+#define local_set(l,i) atomic_long_set(&(l)->a, (i))
-static __inline__ void local_inc(local_t *v)
+static __inline__ void local_inc(local_t *l)
{
__asm__ __volatile__(
"incl %0"
- :"+m" (v->counter));
+ :"+m" (l->a.counter));
}
-static __inline__ void local_dec(local_t *v)
+static __inline__ void local_dec(local_t *l)
{
__asm__ __volatile__(
"decl %0"
- :"+m" (v->counter));
+ :"+m" (l->a.counter));
}
-static __inline__ void local_add(long i, local_t *v)
+static __inline__ void local_add(long i, local_t *l)
{
__asm__ __volatile__(
"addl %1,%0"
- :"+m" (v->counter)
+ :"+m" (l->a.counter)
:"ir" (i));
}
-static __inline__ void local_sub(long i, local_t *v)
+static __inline__ void local_sub(long i, local_t *l)
{
__asm__ __volatile__(
"subl %1,%0"
- :"+m" (v->counter)
+ :"+m" (l->a.counter)
:"ir" (i));
}
+/**
+ * local_sub_and_test - subtract value from variable and test result
+ * @i: integer value to subtract
+ * @l: pointer of type local_t
+ *
+ * Atomically subtracts @i from @l and returns
+ * true if the result is zero, or false for all
+ * other cases.
+ */
+static __inline__ int local_sub_and_test(long i, local_t *l)
+{
+ unsigned char c;
+
+ __asm__ __volatile__(
+ "subl %2,%0; sete %1"
+ :"+m" (l->a.counter), "=qm" (c)
+ :"ir" (i) : "memory");
+ return c;
+}
+
+/**
+ * local_dec_and_test - decrement and test
+ * @l: pointer of type local_t
+ *
+ * Atomically decrements @l by 1 and
+ * returns true if the result is 0, or false for all other
+ * cases.
+ */
+static __inline__ int local_dec_and_test(local_t *l)
+{
+ unsigned char c;
+
+ __asm__ __volatile__(
+ "decl %0; sete %1"
+ :"+m" (l->a.counter), "=qm" (c)
+ : : "memory");
+ return c != 0;
+}
+
+/**
+ * local_inc_and_test - increment and test
+ * @l: pointer of type local_t
+ *
+ * Atomically increments @l by 1
+ * and returns true if the result is zero, or false for all
+ * other cases.
+ */
+static __inline__ int local_inc_and_test(local_t *l)
+{
+ unsigned char c;
+
+ __asm__ __volatile__(
+ "incl %0; sete %1"
+ :"+m" (l->a.counter), "=qm" (c)
+ : : "memory");
+ return c != 0;
+}
+
+/**
+ * local_add_negative - add and test if negative
+ * @l: pointer of type local_t
+ * @i: integer value to add
+ *
+ * Atomically adds @i to @l and returns true
+ * if the result is negative, or false when
+ * result is greater than or equal to zero.
+ */
+static __inline__ int local_add_negative(long i, local_t *l)
+{
+ unsigned char c;
+
+ __asm__ __volatile__(
+ "addl %2,%0; sets %1"
+ :"+m" (l->a.counter), "=qm" (c)
+ :"ir" (i) : "memory");
+ return c;
+}
+
+/**
+ * local_add_return - add and return
+ * @l: pointer of type local_t
+ * @i: integer value to add
+ *
+ * Atomically adds @i to @l and returns @i + @l
+ */
+static __inline__ long local_add_return(long i, local_t *l)
+{
+ long __i;
+#ifdef CONFIG_M386
+ unsigned long flags;
+ if(unlikely(boot_cpu_data.x86==3))
+ goto no_xadd;
+#endif
+ /* Modern 486+ processor */
+ __i = i;
+ __asm__ __volatile__(
+ "xaddl %0, %1;"
+ :"=r"(i)
+ :"m"(l->a.counter), "0"(i));
+ return i + __i;
+
+#ifdef CONFIG_M386
+no_xadd: /* Legacy 386 processor */
+ local_irq_save(flags);
+ __i = local_read(l);
+ local_set(l, i + __i);
+ local_irq_restore(flags);
+ return i + __i;
+#endif
+}
+
+static __inline__ long local_sub_return(long i, local_t *l)
+{
+ return local_add_return(-i,l);
+}
+
+#define local_inc_return(l) (local_add_return(1,l))
+#define local_dec_return(l) (local_sub_return(1,l))
+
+#define local_cmpxchg(l, o, n) \
+ ((long)cmpxchg_local(&((l)->a.counter), (o), (n)))
+/* Always has a lock prefix anyway */
+#define local_xchg(l, new) (xchg(&((l)->a.counter), new))
+
+/**
+ * local_add_unless - add unless the number is a given value
+ * @l: pointer of type local_t
+ * @a: the amount to add to l...
+ * @u: ...unless l is equal to u.
+ *
+ * Atomically adds @a to @l, so long as it was not @u.
+ * Returns non-zero if @l was not @u, and zero otherwise.
+ */
+#define local_add_unless(l, a, u) \
+({ \
+ long c, old; \
+ c = local_read(l); \
+ for (;;) { \
+ if (unlikely(c == (u))) \
+ break; \
+ old = local_cmpxchg((l), c, c + (a)); \
+ if (likely(old == c)) \
+ break; \
+ c = old; \
+ } \
+ c != (u); \
+})
+#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
+
/* On x86, these are no better than the atomic variants. */
#define __local_inc(l) local_inc(l)
#define __local_dec(l) local_dec(l)
@@ -56,27 +207,27 @@ #define __local_sub(i,l) local_sub((i),(
/* Need to disable preemption for the cpu local counters otherwise we could
still access a variable of a previous CPU in a non atomic way. */
-#define cpu_local_wrap_v(v) \
+#define cpu_local_wrap_v(l) \
({ local_t res__; \
preempt_disable(); \
- res__ = (v); \
+ res__ = (l); \
preempt_enable(); \
res__; })
-#define cpu_local_wrap(v) \
+#define cpu_local_wrap(l) \
({ preempt_disable(); \
- v; \
+ l; \
preempt_enable(); }) \
-#define cpu_local_read(v) cpu_local_wrap_v(local_read(&__get_cpu_var(v)))
-#define cpu_local_set(v, i) cpu_local_wrap(local_set(&__get_cpu_var(v), (i)))
-#define cpu_local_inc(v) cpu_local_wrap(local_inc(&__get_cpu_var(v)))
-#define cpu_local_dec(v) cpu_local_wrap(local_dec(&__get_cpu_var(v)))
-#define cpu_local_add(i, v) cpu_local_wrap(local_add((i), &__get_cpu_var(v)))
-#define cpu_local_sub(i, v) cpu_local_wrap(local_sub((i), &__get_cpu_var(v)))
-
-#define __cpu_local_inc(v) cpu_local_inc(v)
-#define __cpu_local_dec(v) cpu_local_dec(v)
-#define __cpu_local_add(i, v) cpu_local_add((i), (v))
-#define __cpu_local_sub(i, v) cpu_local_sub((i), (v))
+#define cpu_local_read(l) cpu_local_wrap_v(local_read(&__get_cpu_var(l)))
+#define cpu_local_set(l, i) cpu_local_wrap(local_set(&__get_cpu_var(l), (i)))
+#define cpu_local_inc(l) cpu_local_wrap(local_inc(&__get_cpu_var(l)))
+#define cpu_local_dec(l) cpu_local_wrap(local_dec(&__get_cpu_var(l)))
+#define cpu_local_add(i, l) cpu_local_wrap(local_add((i), &__get_cpu_var(l)))
+#define cpu_local_sub(i, l) cpu_local_wrap(local_sub((i), &__get_cpu_var(l)))
+
+#define __cpu_local_inc(l) cpu_local_inc(l)
+#define __cpu_local_dec(l) cpu_local_dec(l)
+#define __cpu_local_add(i, l) cpu_local_add((i), (l))
+#define __cpu_local_sub(i, l) cpu_local_sub((i), (l))
#endif /* _ARCH_I386_LOCAL_H */
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