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Subject[PATCH 07/10] local_t : powerpc extension
Date
local_t : powerpc extension

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>

--- a/include/asm-powerpc/local.h
+++ b/include/asm-powerpc/local.h
@@ -1 +1,342 @@
-#include <asm-generic/local.h>
+#ifndef _ARCH_POWERPC_LOCAL_H
+#define _ARCH_POWERPC_LOCAL_H
+
+#include <linux/percpu.h>
+#include <asm/atomic.h>
+
+typedef struct
+{
+ atomic_long_t a;
+} local_t;
+
+#define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }
+
+#define local_read(l) atomic_long_read(&(l)->a)
+#define local_set(l,i) atomic_long_set(&(l)->a, (i))
+
+#define local_add(i,l) atomic_long_add((i),(&(l)->a))
+#define local_sub(i,l) atomic_long_sub((i),(&(l)->a))
+#define local_inc(l) atomic_long_inc(&(l)->a)
+#define local_dec(l) atomic_long_dec(&(l)->a)
+
+#ifndef __powerpc64__
+
+static __inline__ int local_add_return(int a, local_t *l)
+{
+ int t;
+
+ __asm__ __volatile__(
+"1: lwarx %0,0,%2 # local_add_return\n\
+ add %0,%1,%0\n"
+ PPC405_ERR77(0,%2)
+" stwcx. %0,0,%2 \n\
+ bne- 1b"
+ : "=&r" (t)
+ : "r" (a), "r" (&(l->a.counter))
+ : "cc", "memory");
+
+ return t;
+}
+
+#define local_add_negative(a, l) (local_add_return((a), (l)) < 0)
+
+static __inline__ int local_sub_return(int a, local_t *l)
+{
+ int t;
+
+ __asm__ __volatile__(
+"1: lwarx %0,0,%2 # local_sub_return\n\
+ subf %0,%1,%0\n"
+ PPC405_ERR77(0,%2)
+" stwcx. %0,0,%2 \n\
+ bne- 1b"
+ : "=&r" (t)
+ : "r" (a), "r" (&(l->a.counter))
+ : "cc", "memory");
+
+ return t;
+}
+
+static __inline__ int local_inc_return(local_t *l)
+{
+ int t;
+
+ __asm__ __volatile__(
+"1: lwarx %0,0,%1 # local_inc_return\n\
+ addic %0,%0,1\n"
+ PPC405_ERR77(0,%1)
+" stwcx. %0,0,%1 \n\
+ bne- 1b"
+ : "=&r" (t)
+ : "r" (&(l->a.counter))
+ : "cc", "memory");
+
+ return t;
+}
+
+/*
+ * 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.
+ */
+#define local_inc_and_test(l) (local_inc_return(l) == 0)
+
+static __inline__ int local_dec_return(local_t *l)
+{
+ int t;
+
+ __asm__ __volatile__(
+"1: lwarx %0,0,%1 # local_dec_return\n\
+ addic %0,%0,-1\n"
+ PPC405_ERR77(0,%1)
+" stwcx. %0,0,%1\n\
+ bne- 1b"
+ : "=&r" (t)
+ : "r" (&(l->a.counter))
+ : "cc", "memory");
+
+ return t;
+}
+
+#define local_cmpxchg(l, o, n) \
+ (cmpxchg_local(&((l)->a.counter), (o), (n)))
+#define local_xchg(l, n) (xchg_local(&((l)->a.counter), (n)))
+
+/**
+ * local_add_unless - add unless the number is a given value
+ * @l: pointer of type local_t
+ * @a: the amount to add to v...
+ * @u: ...unless v 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.
+ */
+static __inline__ int local_add_unless(local_t *l, int a, int u)
+{
+ int t;
+
+ __asm__ __volatile__ (
+"1: lwarx %0,0,%1 # local_add_unless\n\
+ cmpw 0,%0,%3 \n\
+ beq- 2f \n\
+ add %0,%2,%0 \n"
+ PPC405_ERR77(0,%2)
+" stwcx. %0,0,%1 \n\
+ bne- 1b \n"
+" subf %0,%2,%0 \n\
+2:"
+ : "=&r" (t)
+ : "r" (&(l->a.counter)), "r" (a), "r" (u)
+ : "cc", "memory");
+
+ return t != u;
+}
+
+#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
+
+#define local_sub_and_test(a, l) (local_sub_return((a), (l)) == 0)
+#define local_dec_and_test(l) (local_dec_return((l)) == 0)
+
+/*
+ * Atomically test *l and decrement if it is greater than 0.
+ * The function returns the old value of *l minus 1.
+ */
+static __inline__ int local_dec_if_positive(local_t *l)
+{
+ int t;
+
+ __asm__ __volatile__(
+"1: lwarx %0,0,%1 # local_dec_if_positive\n\
+ cmpwi %0,1\n\
+ addi %0,%0,-1\n\
+ blt- 2f\n"
+ PPC405_ERR77(0,%1)
+" stwcx. %0,0,%1\n\
+ bne- 1b"
+ "\n\
+2:" : "=&b" (t)
+ : "r" (&(l->a.counter))
+ : "cc", "memory");
+
+ return t;
+}
+
+#else /* __powerpc64__ */
+
+static __inline__ long local_add_return(long a, local_t *l)
+{
+ long t;
+
+ __asm__ __volatile__(
+"1: ldarx %0,0,%2 # local_add_return\n\
+ add %0,%1,%0\n\
+ stdcx. %0,0,%2 \n\
+ bne- 1b"
+ : "=&r" (t)
+ : "r" (a), "r" (&(l->a.counter))
+ : "cc", "memory");
+
+ return t;
+}
+
+#define local_add_negative(a, l) (local_add_return((a), (l)) < 0)
+
+static __inline__ long local_sub_return(long a, local_t *l)
+{
+ long t;
+
+ __asm__ __volatile__(
+"1: ldarx %0,0,%2 # local_sub_return\n\
+ subf %0,%1,%0\n\
+ stdcx. %0,0,%2 \n\
+ bne- 1b"
+ : "=&r" (t)
+ : "r" (a), "r" (&(l->a.counter))
+ : "cc", "memory");
+
+ return t;
+}
+
+static __inline__ long local_inc_return(local_t *l)
+{
+ long t;
+
+ __asm__ __volatile__(
+"1: ldarx %0,0,%1 # local_inc_return\n\
+ addic %0,%0,1\n\
+ stdcx. %0,0,%1 \n\
+ bne- 1b"
+ : "=&r" (t)
+ : "r" (&(l->a.counter))
+ : "cc", "memory");
+
+ return t;
+}
+
+/*
+ * 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.
+ */
+#define local_inc_and_test(l) (local_inc_return(l) == 0)
+
+static __inline__ long local_dec_return(local_t *l)
+{
+ long t;
+
+ __asm__ __volatile__(
+"1: ldarx %0,0,%1 # local_dec_return\n\
+ addic %0,%0,-1\n\
+ stdcx. %0,0,%1\n\
+ bne- 1b"
+ : "=&r" (t)
+ : "r" (&(l->a.counter))
+ : "cc", "memory");
+
+ return t;
+}
+
+#define local_sub_and_test(a, l) (local_sub_return((a), (l)) == 0)
+#define local_dec_and_test(l) (local_dec_return((l)) == 0)
+
+/*
+ * Atomically test *l and decrement if it is greater than 0.
+ * The function returns the old value of *l minus 1.
+ */
+static __inline__ long local_dec_if_positive(local_t *l)
+{
+ long t;
+
+ __asm__ __volatile__(
+"1: ldarx %0,0,%1 # local_dec_if_positive\n\
+ addic. %0,%0,-1\n\
+ blt- 2f\n\
+ stdcx. %0,0,%1\n\
+ bne- 1b"
+ "\n\
+2:" : "=&r" (t)
+ : "r" (&(l->a.counter))
+ : "cc", "memory");
+
+ return t;
+}
+
+#define local_cmpxchg(l, o, n) \
+ ((long)cmpxchg_local(&((l)->a.counter), (o), (n)))
+#define local_xchg(l, (n)) (xchg_local(&((l)->a.counter), (n)))
+
+/**
+ * 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.
+ */
+static __inline__ int local_add_unless(local_t *l, long a, long u)
+{
+ long t;
+
+ __asm__ __volatile__ (
+"1: ldarx %0,0,%1 # local_add_unless\n\
+ cmpd 0,%0,%3 \n\
+ beq- 2f \n\
+ add %0,%2,%0 \n"
+" stdcx. %0,0,%1 \n\
+ bne- 1b \n"
+" subf %0,%2,%0 \n\
+2:"
+ : "=&r" (t)
+ : "r" (&(l->a.counter)), "r" (a), "r" (u)
+ : "cc", "memory");
+
+ return t != u;
+}
+
+#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
+
+#endif /* !__powerpc64__ */
+
+/* Use these for per-cpu local_t variables: on some archs they are
+ * much more efficient than these naive implementations. Note they take
+ * a variable, not an address.
+ */
+
+#define __local_inc(l) ((l)->a.counter++)
+#define __local_dec(l) ((l)->a.counter++)
+#define __local_add(i,l) ((l)->a.counter+=(i))
+#define __local_sub(i,l) ((l)->a.counter-=(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(l) \
+ ({ local_t res__; \
+ preempt_disable(); \
+ res__ = (l); \
+ preempt_enable(); \
+ res__; })
+#define cpu_local_wrap(l) \
+ ({ preempt_disable(); \
+ l; \
+ preempt_enable(); }) \
+
+#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_POWERPC_LOCAL_H */
--- a/include/asm-powerpc/system.h
+++ b/include/asm-powerpc/system.h
@@ -7,7 +7,6 @@
#include <linux/kernel.h>

#include <asm/hw_irq.h>
-#include <asm/atomic.h>

/*
* Memory barrier.
@@ -226,6 +225,29 @@ __xchg_u32(volatile void *p, unsigned long val)
return prev;
}

+/*
+ * Atomic exchange
+ *
+ * Changes the memory location '*ptr' to be val and returns
+ * the previous value stored there.
+ */
+static __inline__ unsigned long
+__xchg_u32_local(volatile void *p, unsigned long val)
+{
+ unsigned long prev;
+
+ __asm__ __volatile__(
+"1: lwarx %0,0,%2 \n"
+ PPC405_ERR77(0,%2)
+" stwcx. %3,0,%2 \n\
+ bne- 1b"
+ : "=&r" (prev), "+m" (*(volatile unsigned int *)p)
+ : "r" (p), "r" (val)
+ : "cc", "memory");
+
+ return prev;
+}
+
#ifdef CONFIG_PPC64
static __inline__ unsigned long
__xchg_u64(volatile void *p, unsigned long val)
@@ -245,6 +267,23 @@ __xchg_u64(volatile void *p, unsigned long val)

return prev;
}
+
+static __inline__ unsigned long
+__xchg_u64_local(volatile void *p, unsigned long val)
+{
+ unsigned long prev;
+
+ __asm__ __volatile__(
+"1: ldarx %0,0,%2 \n"
+ PPC405_ERR77(0,%2)
+" stdcx. %3,0,%2 \n\
+ bne- 1b"
+ : "=&r" (prev), "+m" (*(volatile unsigned long *)p)
+ : "r" (p), "r" (val)
+ : "cc", "memory");
+
+ return prev;
+}
#endif

/*
@@ -268,12 +307,33 @@ __xchg(volatile void *ptr, unsigned long x, unsigned int size)
return x;
}

+static __inline__ unsigned long
+__xchg_local(volatile void *ptr, unsigned long x, unsigned int size)
+{
+ switch (size) {
+ case 4:
+ return __xchg_u32_local(ptr, x);
+#ifdef CONFIG_PPC64
+ case 8:
+ return __xchg_u64_local(ptr, x);
+#endif
+ }
+ __xchg_called_with_bad_pointer();
+ return x;
+}
#define xchg(ptr,x) \
({ \
__typeof__(*(ptr)) _x_ = (x); \
(__typeof__(*(ptr))) __xchg((ptr), (unsigned long)_x_, sizeof(*(ptr))); \
})

+#define xchg_local(ptr,x) \
+ ({ \
+ __typeof__(*(ptr)) _x_ = (x); \
+ (__typeof__(*(ptr))) __xchg_local((ptr), \
+ (unsigned long)_x_, sizeof(*(ptr))); \
+ })
+
#define tas(ptr) (xchg((ptr),1))

/*
@@ -305,6 +365,28 @@ __cmpxchg_u32(volatile unsigned int *p, unsigned long old, unsigned long new)
return prev;
}

+static __inline__ unsigned long
+__cmpxchg_u32_local(volatile unsigned int *p, unsigned long old,
+ unsigned long new)
+{
+ unsigned int prev;
+
+ __asm__ __volatile__ (
+"1: lwarx %0,0,%2 # __cmpxchg_u32\n\
+ cmpw 0,%0,%3\n\
+ bne- 2f\n"
+ PPC405_ERR77(0,%2)
+" stwcx. %4,0,%2\n\
+ bne- 1b"
+ "\n\
+2:"
+ : "=&r" (prev), "+m" (*p)
+ : "r" (p), "r" (old), "r" (new)
+ : "cc", "memory");
+
+ return prev;
+}
+
#ifdef CONFIG_PPC64
static __inline__ unsigned long
__cmpxchg_u64(volatile unsigned long *p, unsigned long old, unsigned long new)
@@ -327,6 +409,27 @@ __cmpxchg_u64(volatile unsigned long *p, unsigned long old, unsigned long new)

return prev;
}
+
+static __inline__ unsigned long
+__cmpxchg_u64_local(volatile unsigned long *p, unsigned long old,
+ unsigned long new)
+{
+ unsigned long prev;
+
+ __asm__ __volatile__ (
+"1: ldarx %0,0,%2 # __cmpxchg_u64\n\
+ cmpd 0,%0,%3\n\
+ bne- 2f\n\
+ stdcx. %4,0,%2\n\
+ bne- 1b"
+ "\n\
+2:"
+ : "=&r" (prev), "+m" (*p)
+ : "r" (p), "r" (old), "r" (new)
+ : "cc", "memory");
+
+ return prev;
+}
#endif

/* This function doesn't exist, so you'll get a linker error
@@ -349,6 +452,22 @@ __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new,
return old;
}

+static __inline__ unsigned long
+__cmpxchg_local(volatile void *ptr, unsigned long old, unsigned long new,
+ unsigned int size)
+{
+ switch (size) {
+ case 4:
+ return __cmpxchg_u32_local(ptr, old, new);
+#ifdef CONFIG_PPC64
+ case 8:
+ return __cmpxchg_u64_local(ptr, old, new);
+#endif
+ }
+ __cmpxchg_called_with_bad_pointer();
+ return old;
+}
+
#define cmpxchg(ptr,o,n) \
({ \
__typeof__(*(ptr)) _o_ = (o); \
@@ -357,6 +476,15 @@ __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new,
(unsigned long)_n_, sizeof(*(ptr))); \
})

+
+#define cmpxchg_local(ptr,o,n) \
+ ({ \
+ __typeof__(*(ptr)) _o_ = (o); \
+ __typeof__(*(ptr)) _n_ = (n); \
+ (__typeof__(*(ptr))) __cmpxchg_local((ptr), (unsigned long)_o_, \
+ (unsigned long)_n_, sizeof(*(ptr))); \
+ })
+
#ifdef CONFIG_PPC64
/*
* We handle most unaligned accesses in hardware. On the other hand
-
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