cregit-Linux how code gets into the kernel

Release 4.14 arch/alpha/include/asm/atomic.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ALPHA_ATOMIC_H

#define _ALPHA_ATOMIC_H

#include <linux/types.h>
#include <asm/barrier.h>
#include <asm/cmpxchg.h>

/*
 * Atomic operations that C can't guarantee us.  Useful for
 * resource counting etc...
 *
 * But use these as seldom as possible since they are much slower
 * than regular operations.
 */



#define ATOMIC_INIT(i)		{ (i) }

#define ATOMIC64_INIT(i)	{ (i) }


#define atomic_read(v)		READ_ONCE((v)->counter)

#define atomic64_read(v)	READ_ONCE((v)->counter)


#define atomic_set(v,i)		WRITE_ONCE((v)->counter, (i))

#define atomic64_set(v,i)	WRITE_ONCE((v)->counter, (i))

/*
 * To get proper branch prediction for the main line, we must branch
 * forward to code at the end of this object's .text section, then
 * branch back to restart the operation.
 */


#define ATOMIC_OP(op, asm_op)						\
static __inline__ void atomic_##op(int i, atomic_t * v)                 \
{                                                                       \
        unsigned long temp;                                             \
        __asm__ __volatile__(                                           \
        "1:     ldl_l %0,%1\n"                                          \
        "       " #asm_op " %0,%2,%0\n"                                 \
        "       stl_c %0,%1\n"                                          \
        "       beq %0,2f\n"                                            \
        ".subsection 2\n"                                               \
        "2:     br 1b\n"                                                \
        ".previous"                                                     \
        :"=&r" (temp), "=m" (v->counter)                                \
        :"Ir" (i), "m" (v->counter));                                   \
}                                                                       \

#define ATOMIC_OP_RETURN(op, asm_op)                                    \
static inline int atomic_##op##_return_relaxed(int i, atomic_t *v)      \
{                                                                       \
        long temp, result;                                              \
        __asm__ __volatile__(                                           \
        "1:     ldl_l %0,%1\n"                                          \
        "       " #asm_op " %0,%3,%2\n"                                 \
        "       " #asm_op " %0,%3,%0\n"                                 \
        "       stl_c %0,%1\n"                                          \
        "       beq %0,2f\n"                                            \
        ".subsection 2\n"                                               \
        "2:     br 1b\n"                                                \
        ".previous"                                                     \
        :"=&r" (temp), "=m" (v->counter), "=&r" (result)                \
        :"Ir" (i), "m" (v->counter) : "memory");                        \
        return result;                                                  \
}


#define ATOMIC_FETCH_OP(op, asm_op)					\
static inline int atomic_fetch_##op##_relaxed(int i, atomic_t *v)       \
{                                                                       \
        long temp, result;                                              \
        __asm__ __volatile__(                                           \
        "1:     ldl_l %2,%1\n"                                          \
        "       " #asm_op " %2,%3,%0\n"                                 \
        "       stl_c %0,%1\n"                                          \
        "       beq %0,2f\n"                                            \
        ".subsection 2\n"                                               \
        "2:     br 1b\n"                                                \
        ".previous"                                                     \
        :"=&r" (temp), "=m" (v->counter), "=&r" (result)                \
        :"Ir" (i), "m" (v->counter) : "memory");                        \
        return result;                                                  \
}


#define ATOMIC64_OP(op, asm_op)						\
static __inline__ void atomic64_##op(long i, atomic64_t * v)            \
{                                                                       \
        unsigned long temp;                                             \
        __asm__ __volatile__(                                           \
        "1:     ldq_l %0,%1\n"                                          \
        "       " #asm_op " %0,%2,%0\n"                                 \
        "       stq_c %0,%1\n"                                          \
        "       beq %0,2f\n"                                            \
        ".subsection 2\n"                                               \
        "2:     br 1b\n"                                                \
        ".previous"                                                     \
        :"=&r" (temp), "=m" (v->counter)                                \
        :"Ir" (i), "m" (v->counter));                                   \
}                                                                       \

#define ATOMIC64_OP_RETURN(op, asm_op)                                  \
static __inline__ long atomic64_##op##_return_relaxed(long i, atomic64_t * v)   \
{                                                                       \
        long temp, result;                                              \
        __asm__ __volatile__(                                           \
        "1:     ldq_l %0,%1\n"                                          \
        "       " #asm_op " %0,%3,%2\n"                                 \
        "       " #asm_op " %0,%3,%0\n"                                 \
        "       stq_c %0,%1\n"                                          \
        "       beq %0,2f\n"                                            \
        ".subsection 2\n"                                               \
        "2:     br 1b\n"                                                \
        ".previous"                                                     \
        :"=&r" (temp), "=m" (v->counter), "=&r" (result)                \
        :"Ir" (i), "m" (v->counter) : "memory");                        \
        return result;                                                  \
}


#define ATOMIC64_FETCH_OP(op, asm_op)					\
static __inline__ long atomic64_fetch_##op##_relaxed(long i, atomic64_t * v)    \
{                                                                       \
        long temp, result;                                              \
        __asm__ __volatile__(                                           \
        "1:     ldq_l %2,%1\n"                                          \
        "       " #asm_op " %2,%3,%0\n"                                 \
        "       stq_c %0,%1\n"                                          \
        "       beq %0,2f\n"                                            \
        ".subsection 2\n"                                               \
        "2:     br 1b\n"                                                \
        ".previous"                                                     \
        :"=&r" (temp), "=m" (v->counter), "=&r" (result)                \
        :"Ir" (i), "m" (v->counter) : "memory");                        \
        return result;                                                  \
}


#define ATOMIC_OPS(op)							\
	ATOMIC_OP(op, op##l)                                            \
        ATOMIC_OP_RETURN(op, op##l)                                     \
        ATOMIC_FETCH_OP(op, op##l)                                      \
        ATOMIC64_OP(op, op##q)                                          \
        ATOMIC64_OP_RETURN(op, op##q)                                   \
        ATOMIC64_FETCH_OP(op, op##q)

ATOMIC_OPS(add)
ATOMIC_OPS(sub)


#define atomic_add_return_relaxed	atomic_add_return_relaxed

#define atomic_sub_return_relaxed	atomic_sub_return_relaxed

#define atomic_fetch_add_relaxed	atomic_fetch_add_relaxed

#define atomic_fetch_sub_relaxed	atomic_fetch_sub_relaxed


#define atomic64_add_return_relaxed	atomic64_add_return_relaxed

#define atomic64_sub_return_relaxed	atomic64_sub_return_relaxed

#define atomic64_fetch_add_relaxed	atomic64_fetch_add_relaxed

#define atomic64_fetch_sub_relaxed	atomic64_fetch_sub_relaxed


#define atomic_andnot atomic_andnot

#define atomic64_andnot atomic64_andnot


#undef ATOMIC_OPS

#define ATOMIC_OPS(op, asm)						\
	ATOMIC_OP(op, asm)                                              \
        ATOMIC_FETCH_OP(op, asm)                                        \
        ATOMIC64_OP(op, asm)                                            \
        ATOMIC64_FETCH_OP(op, asm)

ATOMIC_OPS(and, and)
ATOMIC_OPS(andnot, bic)
ATOMIC_OPS(or, bis)
ATOMIC_OPS(xor, xor)


#define atomic_fetch_and_relaxed	atomic_fetch_and_relaxed

#define atomic_fetch_andnot_relaxed	atomic_fetch_andnot_relaxed

#define atomic_fetch_or_relaxed		atomic_fetch_or_relaxed

#define atomic_fetch_xor_relaxed	atomic_fetch_xor_relaxed


#define atomic64_fetch_and_relaxed	atomic64_fetch_and_relaxed

#define atomic64_fetch_andnot_relaxed	atomic64_fetch_andnot_relaxed

#define atomic64_fetch_or_relaxed	atomic64_fetch_or_relaxed

#define atomic64_fetch_xor_relaxed	atomic64_fetch_xor_relaxed


#undef ATOMIC_OPS

#undef ATOMIC64_FETCH_OP

#undef ATOMIC64_OP_RETURN

#undef ATOMIC64_OP

#undef ATOMIC_FETCH_OP

#undef ATOMIC_OP_RETURN

#undef ATOMIC_OP


#define atomic64_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), old, new))

#define atomic64_xchg(v, new) (xchg(&((v)->counter), new))


#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), old, new))

#define atomic_xchg(v, new) (xchg(&((v)->counter), new))

/**
 * __atomic_add_unless - add unless the number is a given value
 * @v: pointer of type atomic_t
 * @a: the amount to add to v...
 * @u: ...unless v is equal to u.
 *
 * Atomically adds @a to @v, so long as it was not @u.
 * Returns the old value of @v.
 */

static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u) { int c, new, old; smp_mb(); __asm__ __volatile__( "1: ldl_l %[old],%[mem]\n" " cmpeq %[old],%[u],%[c]\n" " addl %[old],%[a],%[new]\n" " bne %[c],2f\n" " stl_c %[new],%[mem]\n" " beq %[new],3f\n" "2:\n" ".subsection 2\n" "3: br 1b\n" ".previous" : [old] "=&r"(old), [new] "=&r"(new), [c] "=&r"(c) : [mem] "m"(*v), [a] "rI"(a), [u] "rI"((long)u) : "memory"); smp_mb(); return old; }

Contributors

PersonTokensPropCommitsCommitProp
Mathieu Desnoyers1850.00%125.00%
Richard Henderson1027.78%125.00%
Nicholas Piggin719.44%125.00%
Arun Sharma12.78%125.00%
Total36100.00%4100.00%

/** * atomic64_add_unless - add unless the number is a given value * @v: pointer of type atomic64_t * @a: the amount to add to v... * @u: ...unless v is equal to u. * * Atomically adds @a to @v, so long as it was not @u. * Returns true iff @v was not @u. */
static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u) { long c, tmp; smp_mb(); __asm__ __volatile__( "1: ldq_l %[tmp],%[mem]\n" " cmpeq %[tmp],%[u],%[c]\n" " addq %[tmp],%[a],%[tmp]\n" " bne %[c],2f\n" " stq_c %[tmp],%[mem]\n" " beq %[tmp],3f\n" "2:\n" ".subsection 2\n" "3: br 1b\n" ".previous" : [tmp] "=&r"(tmp), [c] "=&r"(c) : [mem] "m"(*v), [a] "rI"(a), [u] "rI"(u) : "memory"); smp_mb(); return !c; }

Contributors

PersonTokensPropCommitsCommitProp
Mathieu Desnoyers2674.29%266.67%
Richard Henderson925.71%133.33%
Total35100.00%3100.00%

/* * atomic64_dec_if_positive - decrement by 1 if old value positive * @v: pointer of type atomic_t * * The function returns the old value of *v minus 1, even if * the atomic variable, v, was not decremented. */
static inline long atomic64_dec_if_positive(atomic64_t *v) { long old, tmp; smp_mb(); __asm__ __volatile__( "1: ldq_l %[old],%[mem]\n" " subq %[old],1,%[tmp]\n" " ble %[old],2f\n" " stq_c %[tmp],%[mem]\n" " beq %[tmp],3f\n" "2:\n" ".subsection 2\n" "3: br 1b\n" ".previous" : [old] "=&r"(old), [tmp] "=&r"(tmp) : [mem] "m"(*v) : "memory"); smp_mb(); return old - 1; }

Contributors

PersonTokensPropCommitsCommitProp
Richard Henderson30100.00%1100.00%
Total30100.00%1100.00%

#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0) #define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0) #define atomic64_add_negative(a, v) (atomic64_add_return((a), (v)) < 0) #define atomic_dec_return(v) atomic_sub_return(1,(v)) #define atomic64_dec_return(v) atomic64_sub_return(1,(v)) #define atomic_inc_return(v) atomic_add_return(1,(v)) #define atomic64_inc_return(v) atomic64_add_return(1,(v)) #define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0) #define atomic64_sub_and_test(i,v) (atomic64_sub_return((i), (v)) == 0) #define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0) #define atomic64_inc_and_test(v) (atomic64_add_return(1, (v)) == 0) #define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0) #define atomic64_dec_and_test(v) (atomic64_sub_return(1, (v)) == 0) #define atomic_inc(v) atomic_add(1,(v)) #define atomic64_inc(v) atomic64_add(1,(v)) #define atomic_dec(v) atomic_sub(1,(v)) #define atomic64_dec(v) atomic64_sub(1,(v)) #endif /* _ALPHA_ATOMIC_H */

Overall Contributors

PersonTokensPropCommitsCommitProp
Peter Zijlstra18435.11%517.86%
Richard Henderson11722.33%310.71%
Linus Torvalds (pre-git)7915.08%725.00%
Mathieu Desnoyers7414.12%27.14%
Hugh Dickins254.77%13.57%
Nicholas Piggin152.86%27.14%
Andrew Morton101.91%27.14%
Ingo Molnar91.72%13.57%
Paul Gortmaker30.57%13.57%
Matthew Wilcox30.57%13.57%
Arun Sharma20.38%13.57%
Mel Gorman20.38%13.57%
Greg Kroah-Hartman10.19%13.57%
Total524100.00%28100.00%
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