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a8bcccaba1
Implement FETCH-OP atomic primitives, these are very similar to the existing OP-RETURN primitives we already have, except they return the value of the atomic variable _before_ modification. This is especially useful for irreversible operations -- such as bitops (because it becomes impossible to reconstruct the state prior to modification). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
349 lines
8.3 KiB
C
349 lines
8.3 KiB
C
#ifndef _ASM_X86_ATOMIC64_32_H
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#define _ASM_X86_ATOMIC64_32_H
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#include <linux/compiler.h>
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#include <linux/types.h>
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//#include <asm/cmpxchg.h>
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/* An 64bit atomic type */
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typedef struct {
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u64 __aligned(8) counter;
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} atomic64_t;
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#define ATOMIC64_INIT(val) { (val) }
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#define __ATOMIC64_DECL(sym) void atomic64_##sym(atomic64_t *, ...)
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#ifndef ATOMIC64_EXPORT
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#define ATOMIC64_DECL_ONE __ATOMIC64_DECL
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#else
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#define ATOMIC64_DECL_ONE(sym) __ATOMIC64_DECL(sym); \
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ATOMIC64_EXPORT(atomic64_##sym)
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#endif
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#ifdef CONFIG_X86_CMPXCHG64
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#define __alternative_atomic64(f, g, out, in...) \
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asm volatile("call %P[func]" \
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: out : [func] "i" (atomic64_##g##_cx8), ## in)
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#define ATOMIC64_DECL(sym) ATOMIC64_DECL_ONE(sym##_cx8)
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#else
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#define __alternative_atomic64(f, g, out, in...) \
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alternative_call(atomic64_##f##_386, atomic64_##g##_cx8, \
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X86_FEATURE_CX8, ASM_OUTPUT2(out), ## in)
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#define ATOMIC64_DECL(sym) ATOMIC64_DECL_ONE(sym##_cx8); \
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ATOMIC64_DECL_ONE(sym##_386)
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ATOMIC64_DECL_ONE(add_386);
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ATOMIC64_DECL_ONE(sub_386);
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ATOMIC64_DECL_ONE(inc_386);
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ATOMIC64_DECL_ONE(dec_386);
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#endif
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#define alternative_atomic64(f, out, in...) \
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__alternative_atomic64(f, f, ASM_OUTPUT2(out), ## in)
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ATOMIC64_DECL(read);
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ATOMIC64_DECL(set);
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ATOMIC64_DECL(xchg);
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ATOMIC64_DECL(add_return);
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ATOMIC64_DECL(sub_return);
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ATOMIC64_DECL(inc_return);
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ATOMIC64_DECL(dec_return);
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ATOMIC64_DECL(dec_if_positive);
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ATOMIC64_DECL(inc_not_zero);
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ATOMIC64_DECL(add_unless);
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#undef ATOMIC64_DECL
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#undef ATOMIC64_DECL_ONE
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#undef __ATOMIC64_DECL
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#undef ATOMIC64_EXPORT
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/**
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* atomic64_cmpxchg - cmpxchg atomic64 variable
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* @v: pointer to type atomic64_t
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* @o: expected value
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* @n: new value
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*
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* Atomically sets @v to @n if it was equal to @o and returns
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* the old value.
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*/
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static inline long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n)
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{
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return cmpxchg64(&v->counter, o, n);
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}
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/**
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* atomic64_xchg - xchg atomic64 variable
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* @v: pointer to type atomic64_t
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* @n: value to assign
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*
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* Atomically xchgs the value of @v to @n and returns
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* the old value.
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*/
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static inline long long atomic64_xchg(atomic64_t *v, long long n)
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{
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long long o;
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unsigned high = (unsigned)(n >> 32);
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unsigned low = (unsigned)n;
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alternative_atomic64(xchg, "=&A" (o),
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"S" (v), "b" (low), "c" (high)
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: "memory");
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return o;
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}
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/**
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* atomic64_set - set atomic64 variable
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* @v: pointer to type atomic64_t
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* @i: value to assign
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*
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* Atomically sets the value of @v to @n.
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*/
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static inline void atomic64_set(atomic64_t *v, long long i)
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{
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unsigned high = (unsigned)(i >> 32);
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unsigned low = (unsigned)i;
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alternative_atomic64(set, /* no output */,
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"S" (v), "b" (low), "c" (high)
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: "eax", "edx", "memory");
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}
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/**
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* atomic64_read - read atomic64 variable
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* @v: pointer to type atomic64_t
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*
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* Atomically reads the value of @v and returns it.
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*/
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static inline long long atomic64_read(const atomic64_t *v)
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{
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long long r;
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alternative_atomic64(read, "=&A" (r), "c" (v) : "memory");
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return r;
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}
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/**
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* atomic64_add_return - add and return
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* @i: integer value to add
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* @v: pointer to type atomic64_t
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*
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* Atomically adds @i to @v and returns @i + *@v
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*/
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static inline long long atomic64_add_return(long long i, atomic64_t *v)
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{
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alternative_atomic64(add_return,
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ASM_OUTPUT2("+A" (i), "+c" (v)),
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ASM_NO_INPUT_CLOBBER("memory"));
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return i;
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}
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/*
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* Other variants with different arithmetic operators:
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*/
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static inline long long atomic64_sub_return(long long i, atomic64_t *v)
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{
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alternative_atomic64(sub_return,
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ASM_OUTPUT2("+A" (i), "+c" (v)),
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ASM_NO_INPUT_CLOBBER("memory"));
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return i;
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}
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static inline long long atomic64_inc_return(atomic64_t *v)
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{
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long long a;
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alternative_atomic64(inc_return, "=&A" (a),
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"S" (v) : "memory", "ecx");
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return a;
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}
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static inline long long atomic64_dec_return(atomic64_t *v)
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{
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long long a;
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alternative_atomic64(dec_return, "=&A" (a),
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"S" (v) : "memory", "ecx");
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return a;
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}
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/**
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* atomic64_add - add integer to atomic64 variable
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* @i: integer value to add
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* @v: pointer to type atomic64_t
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*
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* Atomically adds @i to @v.
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*/
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static inline long long atomic64_add(long long i, atomic64_t *v)
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{
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__alternative_atomic64(add, add_return,
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ASM_OUTPUT2("+A" (i), "+c" (v)),
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ASM_NO_INPUT_CLOBBER("memory"));
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return i;
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}
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/**
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* atomic64_sub - subtract the atomic64 variable
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* @i: integer value to subtract
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* @v: pointer to type atomic64_t
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*
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* Atomically subtracts @i from @v.
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*/
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static inline long long atomic64_sub(long long i, atomic64_t *v)
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{
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__alternative_atomic64(sub, sub_return,
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ASM_OUTPUT2("+A" (i), "+c" (v)),
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ASM_NO_INPUT_CLOBBER("memory"));
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return i;
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}
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/**
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* atomic64_sub_and_test - subtract value from variable and test result
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* @i: integer value to subtract
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* @v: pointer to type atomic64_t
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*
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* Atomically subtracts @i from @v and returns
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* true if the result is zero, or false for all
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* other cases.
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*/
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static inline int atomic64_sub_and_test(long long i, atomic64_t *v)
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{
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return atomic64_sub_return(i, v) == 0;
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}
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/**
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* atomic64_inc - increment atomic64 variable
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* @v: pointer to type atomic64_t
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*
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* Atomically increments @v by 1.
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*/
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static inline void atomic64_inc(atomic64_t *v)
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{
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__alternative_atomic64(inc, inc_return, /* no output */,
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"S" (v) : "memory", "eax", "ecx", "edx");
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}
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/**
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* atomic64_dec - decrement atomic64 variable
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* @v: pointer to type atomic64_t
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*
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* Atomically decrements @v by 1.
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*/
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static inline void atomic64_dec(atomic64_t *v)
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{
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__alternative_atomic64(dec, dec_return, /* no output */,
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"S" (v) : "memory", "eax", "ecx", "edx");
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}
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/**
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* atomic64_dec_and_test - decrement and test
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* @v: pointer to type atomic64_t
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*
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* Atomically decrements @v by 1 and
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* returns true if the result is 0, or false for all other
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* cases.
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*/
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static inline int atomic64_dec_and_test(atomic64_t *v)
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{
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return atomic64_dec_return(v) == 0;
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}
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/**
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* atomic64_inc_and_test - increment and test
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* @v: pointer to type atomic64_t
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*
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* Atomically increments @v by 1
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* and returns true if the result is zero, or false for all
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* other cases.
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*/
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static inline int atomic64_inc_and_test(atomic64_t *v)
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{
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return atomic64_inc_return(v) == 0;
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}
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/**
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* atomic64_add_negative - add and test if negative
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* @i: integer value to add
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* @v: pointer to type atomic64_t
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*
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* Atomically adds @i to @v and returns true
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* if the result is negative, or false when
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* result is greater than or equal to zero.
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*/
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static inline int atomic64_add_negative(long long i, atomic64_t *v)
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{
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return atomic64_add_return(i, v) < 0;
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}
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/**
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* atomic64_add_unless - add unless the number is a given value
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* @v: pointer of type atomic64_t
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* @a: the amount to add to v...
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* @u: ...unless v is equal to u.
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*
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* Atomically adds @a to @v, so long as it was not @u.
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* Returns non-zero if the add was done, zero otherwise.
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*/
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static inline int atomic64_add_unless(atomic64_t *v, long long a, long long u)
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{
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unsigned low = (unsigned)u;
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unsigned high = (unsigned)(u >> 32);
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alternative_atomic64(add_unless,
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ASM_OUTPUT2("+A" (a), "+c" (low), "+D" (high)),
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"S" (v) : "memory");
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return (int)a;
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}
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static inline int atomic64_inc_not_zero(atomic64_t *v)
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{
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int r;
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alternative_atomic64(inc_not_zero, "=&a" (r),
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"S" (v) : "ecx", "edx", "memory");
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return r;
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}
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static inline long long atomic64_dec_if_positive(atomic64_t *v)
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{
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long long r;
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alternative_atomic64(dec_if_positive, "=&A" (r),
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"S" (v) : "ecx", "memory");
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return r;
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}
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#undef alternative_atomic64
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#undef __alternative_atomic64
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#define ATOMIC64_OP(op, c_op) \
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static inline void atomic64_##op(long long i, atomic64_t *v) \
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{ \
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long long old, c = 0; \
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while ((old = atomic64_cmpxchg(v, c, c c_op i)) != c) \
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c = old; \
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}
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#define ATOMIC64_FETCH_OP(op, c_op) \
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static inline long long atomic64_fetch_##op(long long i, atomic64_t *v) \
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{ \
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long long old, c = 0; \
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while ((old = atomic64_cmpxchg(v, c, c c_op i)) != c) \
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c = old; \
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return old; \
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}
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ATOMIC64_FETCH_OP(add, +)
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#define atomic64_fetch_sub(i, v) atomic64_fetch_add(-(i), (v))
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#define ATOMIC64_OPS(op, c_op) \
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ATOMIC64_OP(op, c_op) \
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ATOMIC64_FETCH_OP(op, c_op)
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ATOMIC64_OPS(and, &)
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ATOMIC64_OPS(or, |)
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ATOMIC64_OPS(xor, ^)
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#undef ATOMIC64_OPS
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#undef ATOMIC64_FETCH_OP
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#undef ATOMIC64_OP
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#endif /* _ASM_X86_ATOMIC64_32_H */
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