[patch 12/23] local_t m32r use architecture specific cmpxchg_local

Mathieu Desnoyers
2007-08-20T20:20:49Z

[-- Attachment #1: local_t_m32r_optimized.patch --]
[-- Type: text/plain, Size: 10239 bytes --]

On m32r, use the new cmpxchg_local as primitive for the local_cmpxchg
operation.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
CC: takata@linux-m32r.org
CC: linux-m32r@ml.linux-m32r.org
---
include/asm-m32r/local.h | 362 ++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 361 insertions(+), 1 deletion(-)

Index: linux-2.6-lttng/include/asm-m32r/local.h
===================================================================
--- linux-2.6-lttng.orig/include/asm-m32r/local.h 2007-07-20 17:29:08.000000000 -0400
+++ linux-2.6-lttng/include/asm-m32r/local.h 2007-07-20 17:43:28.000000000 -0400
@@ -1,6 +1,366 @@
#ifndef __M32R_LOCAL_H
#define __M32R_LOCAL_H

-#include <asm-generic/local.h>
+/*
+ * linux/include/asm-m32r/local.h
+ *
+ * M32R version:
+ * Copyright (C) 2001, 2002 Hitoshi Yamamoto
+ * Copyright (C) 2004 Hirokazu Takata <takata at linux-m32r.org>
+ * Copyright (C) 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ */
+
+#include <linux/percpu.h>
+#include <asm/assembler.h>
+#include <asm/system.h>
+#include <asm/local.h>
+
+/*
+ * Atomic operations that C can't guarantee us. Useful for
+ * resource counting etc..
+ */
+
+/*
+ * Make sure gcc doesn't try to be clever and move things around
+ * on us. We need to use _exactly_ the address the user gave us,
+ * not some alias that contains the same information.
+ */
+typedef struct { volatile int counter; } local_t;
+
+#define LOCAL_INIT(i) { (i) }
+
+/**
+ * local_read - read local variable
+ * @l: pointer of type local_t
+ *
+ * Atomically reads the value of @l.
+ */
+#define local_read(l) ((l)->counter)
+
+/**
+ * local_set - set local variable
+ * @l: pointer of type local_t
+ * @i: required value
+ *
+ * Atomically sets the value of @l to @i.
+ */
+#define local_set(l,i) (((l)->counter) = (i))
+
+/**
+ * local_add_return - add long to local variable and return it
+ * @i: long value to add
+ * @l: pointer of type local_t
+ *
+ * Atomically adds @i to @l and return (@i + @l).
+ */
+static __inline__ long local_add_return(long i, local_t *l)
+{
+ unsigned long flags;
+ long result;
+
+ local_irq_save(flags);
+ __asm__ __volatile__ (
+ "# local_add_return \n\t"
+ DCACHE_CLEAR("%0", "r4", "%1")
+ "ld %0, @%1; \n\t"
+ "add %0, %2; \n\t"
+ "st %0, @%1; \n\t"
+ : "=&r" (result)
+ : "r" (&l->counter), "r" (i)
+ : "memory"
+#ifdef CONFIG_CHIP_M32700_TS1
+ , "r4"
+#endif /* CONFIG_CHIP_M32700_TS1 */
+ );
+ local_irq_restore(flags);
+
+ return result;
+}
+
+/**
+ * local_sub_return - subtract long from local variable and return it
+ * @i: long value to subtract
+ * @l: pointer of type local_t
+ *
+ * Atomically subtracts @i from @l and return (@l - @i).
+ */
+static __inline__ long local_sub_return(long i, local_t *l)
+{
+ unsigned long flags;
+ long result;
+
+ local_irq_save(flags);
+ __asm__ __volatile__ (
+ "# local_sub_return \n\t"
+ DCACHE_CLEAR("%0", "r4", "%1")
+ "ld %0, @%1; \n\t"
+ "sub %0, %2; \n\t"
+ "st %0, @%1; \n\t"
+ : "=&r" (result)
+ : "r" (&l->counter), "r" (i)
+ : "memory"
+#ifdef CONFIG_CHIP_M32700_TS1
+ , "r4"
+#endif /* CONFIG_CHIP_M32700_TS1 */
+ );
+ local_irq_restore(flags);
+
+ return result;
+}
+
+/**
+ * local_add - add long to local variable
+ * @i: long value to add
+ * @l: pointer of type local_t
+ *
+ * Atomically adds @i to @l.
+ */
+#define local_add(i,l) ((void) local_add_return((i), (l)))
+
+/**
+ * local_sub - subtract the local variable
+ * @i: long value to subtract
+ * @l: pointer of type local_t
+ *
+ * Atomically subtracts @i from @l.
+ */
+#define local_sub(i,l) ((void) local_sub_return((i), (l)))
+
+/**
+ * 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.
+ */
+#define local_sub_and_test(i,l) (local_sub_return((i), (l)) == 0)
+
+/**
+ * local_inc_return - increment local variable and return it
+ * @l: pointer of type local_t
+ *
+ * Atomically increments @l by 1 and returns the result.
+ */
+static __inline__ long local_inc_return(local_t *l)
+{
+ unsigned long flags;
+ long result;
+
+ local_irq_save(flags);
+ __asm__ __volatile__ (
+ "# local_inc_return \n\t"
+ DCACHE_CLEAR("%0", "r4", "%1")
+ "ld %0, @%1; \n\t"
+ "addi %0, #1; \n\t"
+ "st %0, @%1; \n\t"
+ : "=&r" (result)
+ : "r" (&l->counter)
+ : "memory"
+#ifdef CONFIG_CHIP_M32700_TS1
+ , "r4"
+#endif /* CONFIG_CHIP_M32700_TS1 */
+ );
+ local_irq_restore(flags);
+
+ return result;
+}
+
+/**
+ * local_dec_return - decrement local variable and return it
+ * @l: pointer of type local_t
+ *
+ * Atomically decrements @l by 1 and returns the result.
+ */
+static __inline__ long local_dec_return(local_t *l)
+{
+ unsigned long flags;
+ long result;
+
+ local_irq_save(flags);
+ __asm__ __volatile__ (
+ "# local_dec_return \n\t"
+ DCACHE_CLEAR("%0", "r4", "%1")
+ "ld %0, @%1; \n\t"
+ "addi %0, #-1; \n\t"
+ "st %0, @%1; \n\t"
+ : "=&r" (result)
+ : "r" (&l->counter)
+ : "memory"
+#ifdef CONFIG_CHIP_M32700_TS1
+ , "r4"
+#endif /* CONFIG_CHIP_M32700_TS1 */
+ );
+ local_irq_restore(flags);
+
+ return result;
+}
+
+/**
+ * local_inc - increment local variable
+ * @l: pointer of type local_t
+ *
+ * Atomically increments @l by 1.
+ */
+#define local_inc(l) ((void)local_inc_return(l))
+
+/**
+ * local_dec - decrement local variable
+ * @l: pointer of type local_t
+ *
+ * Atomically decrements @l by 1.
+ */
+#define local_dec(l) ((void)local_dec_return(l))
+
+/**
+ * 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)
+
+/**
+ * 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.
+ */
+#define local_dec_and_test(l) (local_dec_return(l) == 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.
+ */
+#define local_add_negative(i,l) (local_add_return((i), (l)) < 0)
+
+#define local_cmpxchg(l, o, n) (cmpxchg_local(&((l)->counter), (o), (n)))
+#define local_xchg(v, new) (xchg_local(&((l)->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.
+ */
+static __inline__ int local_add_unless(local_t *l, long a, long 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;
+ }
+ return c != (u);
+}
+
+#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
+
+static __inline__ void local_clear_mask(unsigned long mask, local_t *addr)
+{
+ unsigned long flags;
+ unsigned long tmp;
+
+ local_irq_save(flags);
+ __asm__ __volatile__ (
+ "# local_clear_mask \n\t"
+ DCACHE_CLEAR("%0", "r5", "%1")
+ "ld %0, @%1; \n\t"
+ "and %0, %2; \n\t"
+ "st %0, @%1; \n\t"
+ : "=&r" (tmp)
+ : "r" (addr), "r" (~mask)
+ : "memory"
+#ifdef CONFIG_CHIP_M32700_TS1
+ , "r5"
+#endif /* CONFIG_CHIP_M32700_TS1 */
+ );
+ local_irq_restore(flags);
+}
+
+static __inline__ void local_set_mask(unsigned long mask, local_t *addr)
+{
+ unsigned long flags;
+ unsigned long tmp;
+
+ local_irq_save(flags);
+ __asm__ __volatile__ (
+ "# local_set_mask \n\t"
+ DCACHE_CLEAR("%0", "r5", "%1")
+ "ld %0, @%1; \n\t"
+ "or %0, %2; \n\t"
+ "st %0, @%1; \n\t"
+ : "=&r" (tmp)
+ : "r" (addr), "r" (mask)
+ : "memory"
+#ifdef CONFIG_CHIP_M32700_TS1
+ , "r5"
+#endif /* CONFIG_CHIP_M32700_TS1 */
+ );
+ local_irq_restore(flags);
+}
+
+/* Atomic operations are already serializing on m32r */
+#define smp_mb__before_local_dec() barrier()
+#define smp_mb__after_local_dec() barrier()
+#define smp_mb__before_local_inc() barrier()
+#define smp_mb__after_local_inc() barrier()
+
+/* 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))
+
+/* 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.
+ */
+
+/* Need to disable preemption for the cpu local counters otherwise we could
+ still access a variable of a previous CPU in a non local 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 /* __M32R_LOCAL_H */