cregit-Linux how code gets into the kernel

Release 4.14 arch/arm64/include/asm/cmpxchg.h

/*
 * Based on arch/arm/include/asm/cmpxchg.h
 *
 * Copyright (C) 2012 ARM Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#ifndef __ASM_CMPXCHG_H

#define __ASM_CMPXCHG_H

#include <linux/bug.h>

#include <asm/atomic.h>
#include <asm/barrier.h>
#include <asm/lse.h>

/*
 * We need separate acquire parameters for ll/sc and lse, since the full
 * barrier case is generated as release+dmb for the former and
 * acquire+release for the latter.
 */

#define __XCHG_CASE(w, sz, name, mb, nop_lse, acq, acq_lse, rel, cl)	\
static inline unsigned long __xchg_case_##name(unsigned long x,         \
                                               volatile void *ptr)      \
{                                                                       \
        unsigned long ret, tmp;                                         \
                                                                        \
        asm volatile(ARM64_LSE_ATOMIC_INSN(                             \
	/* LL/SC */							\
        "       prfm    pstl1strm, %2\n"                                \
        "1:     ld" #acq "xr" #sz "\t%" #w "0, %2\n"                    \
        "       st" #rel "xr" #sz "\t%w1, %" #w "3, %2\n"               \
        "       cbnz    %w1, 1b\n"                                      \
        "       " #mb,                                                  \
	/* LSE atomics */						\
        "       swp" #acq_lse #rel #sz "\t%" #w "3, %" #w "0, %2\n"     \
                __nops(3)                                               \
        "       " #nop_lse)                                             \
        : "=&r" (ret), "=&r" (tmp), "+Q" (*(unsigned long *)ptr)        \
        : "r" (x)                                                       \
        : cl);                                                          \
                                                                        \
        return ret;                                                     \
}

__XCHG_CASE(w, b,     1,        ,    ,  ,  ,  ,         )
__XCHG_CASE(w, h,     2,        ,    ,  ,  ,  ,         )
__XCHG_CASE(w,  ,     4,        ,    ,  ,  ,  ,         )
__XCHG_CASE( ,  ,     8,        ,    ,  ,  ,  ,         )
__XCHG_CASE(w, b, acq_1,        ,    , a, a,  , "memory")
__XCHG_CASE(w, h, acq_2,        ,    , a, a,  , "memory")
__XCHG_CASE(w,  , acq_4,        ,    , a, a,  , "memory")
__XCHG_CASE( ,  , acq_8,        ,    , a, a,  , "memory")
__XCHG_CASE(w, b, rel_1,        ,    ,  ,  , l, "memory")
__XCHG_CASE(w, h, rel_2,        ,    ,  ,  , l, "memory")
__XCHG_CASE(w,  , rel_4,        ,    ,  ,  , l, "memory")
__XCHG_CASE( ,  , rel_8,        ,    ,  ,  , l, "memory")
__XCHG_CASE(w, b,  mb_1, dmb ish, nop,  , a, l, "memory")
__XCHG_CASE(w, h,  mb_2, dmb ish, nop,  , a, l, "memory")
__XCHG_CASE(w,  ,  mb_4, dmb ish, nop,  , a, l, "memory")
__XCHG_CASE( ,  ,  mb_8, dmb ish, nop,  , a, l, "memory")


#undef __XCHG_CASE


#define __XCHG_GEN(sfx)							\
static inline unsigned long __xchg##sfx(unsigned long x,                \
                                        volatile void *ptr,             \
                                        int size)                       \
{                                                                       \
        switch (size) {                                                 \
        case 1:                                                         \
                return __xchg_case##sfx##_1(x, ptr);                    \
        case 2:                                                         \
                return __xchg_case##sfx##_2(x, ptr);                    \
        case 4:                                                         \
                return __xchg_case##sfx##_4(x, ptr);                    \
        case 8:                                                         \
                return __xchg_case##sfx##_8(x, ptr);                    \
        default:                                                        \
                BUILD_BUG();                                            \
        }                                                               \
                                                                        \
        unreachable();                                                  \
}

__XCHG_GEN()
__XCHG_GEN(_acq)
__XCHG_GEN(_rel)
__XCHG_GEN(_mb)


#undef __XCHG_GEN


#define __xchg_wrapper(sfx, ptr, x)					\
({                                                                      \
        __typeof__(*(ptr)) __ret;                                       \
        __ret = (__typeof__(*(ptr)))                                    \
                __xchg##sfx((unsigned long)(x), (ptr), sizeof(*(ptr))); \
        __ret;                                                          \
})

/* xchg */

#define xchg_relaxed(...)	__xchg_wrapper(    , __VA_ARGS__)

#define xchg_acquire(...)	__xchg_wrapper(_acq, __VA_ARGS__)

#define xchg_release(...)	__xchg_wrapper(_rel, __VA_ARGS__)

#define xchg(...)		__xchg_wrapper( _mb, __VA_ARGS__)


#define __CMPXCHG_GEN(sfx)						\
static inline unsigned long __cmpxchg##sfx(volatile void *ptr,          \
                                           unsigned long old,           \
                                           unsigned long new,           \
                                           int size)                    \
{                                                                       \
        switch (size) {                                                 \
        case 1:                                                         \
                return __cmpxchg_case##sfx##_1(ptr, (u8)old, new);      \
        case 2:                                                         \
                return __cmpxchg_case##sfx##_2(ptr, (u16)old, new);     \
        case 4:                                                         \
                return __cmpxchg_case##sfx##_4(ptr, old, new);          \
        case 8:                                                         \
                return __cmpxchg_case##sfx##_8(ptr, old, new);          \
        default:                                                        \
                BUILD_BUG();                                            \
        }                                                               \
                                                                        \
        unreachable();                                                  \
}

__CMPXCHG_GEN()
__CMPXCHG_GEN(_acq)
__CMPXCHG_GEN(_rel)
__CMPXCHG_GEN(_mb)


#undef __CMPXCHG_GEN


#define __cmpxchg_wrapper(sfx, ptr, o, n)				\
({                                                                      \
        __typeof__(*(ptr)) __ret;                                       \
        __ret = (__typeof__(*(ptr)))                                    \
                __cmpxchg##sfx((ptr), (unsigned long)(o),               \
                                (unsigned long)(n), sizeof(*(ptr)));    \
        __ret;                                                          \
})

/* cmpxchg */

#define cmpxchg_relaxed(...)	__cmpxchg_wrapper(    , __VA_ARGS__)

#define cmpxchg_acquire(...)	__cmpxchg_wrapper(_acq, __VA_ARGS__)

#define cmpxchg_release(...)	__cmpxchg_wrapper(_rel, __VA_ARGS__)

#define cmpxchg(...)		__cmpxchg_wrapper( _mb, __VA_ARGS__)

#define cmpxchg_local		cmpxchg_relaxed

/* cmpxchg64 */

#define cmpxchg64_relaxed	cmpxchg_relaxed

#define cmpxchg64_acquire	cmpxchg_acquire

#define cmpxchg64_release	cmpxchg_release

#define cmpxchg64		cmpxchg

#define cmpxchg64_local		cmpxchg_local

/* cmpxchg_double */

#define system_has_cmpxchg_double()     1


#define __cmpxchg_double_check(ptr1, ptr2)					\
({                                                                              \
        if (sizeof(*(ptr1)) != 8)                                               \
                BUILD_BUG();                                                    \
        VM_BUG_ON((unsigned long *)(ptr2) - (unsigned long *)(ptr1) != 1);      \
})


#define cmpxchg_double(ptr1, ptr2, o1, o2, n1, n2) \
({\
        int __ret;\
        __cmpxchg_double_check(ptr1, ptr2); \
        __ret = !__cmpxchg_double_mb((unsigned long)(o1), (unsigned long)(o2), \
                                     (unsigned long)(n1), (unsigned long)(n2), \
                                     ptr1); \
        __ret; \
})


#define cmpxchg_double_local(ptr1, ptr2, o1, o2, n1, n2) \
({\
        int __ret;\
        __cmpxchg_double_check(ptr1, ptr2); \
        __ret = !__cmpxchg_double((unsigned long)(o1), (unsigned long)(o2), \
                                  (unsigned long)(n1), (unsigned long)(n2), \
                                  ptr1); \
        __ret; \
})

/* this_cpu_cmpxchg */

#define _protect_cmpxchg_local(pcp, o, n)			\
({                                                              \
        typeof(*raw_cpu_ptr(&(pcp))) __ret;                     \
        preempt_disable();                                      \
        __ret = cmpxchg_local(raw_cpu_ptr(&(pcp)), o, n);       \
        preempt_enable();                                       \
        __ret;                                                  \
})


#define this_cpu_cmpxchg_1(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)

#define this_cpu_cmpxchg_2(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)

#define this_cpu_cmpxchg_4(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)

#define this_cpu_cmpxchg_8(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)


#define this_cpu_cmpxchg_double_8(ptr1, ptr2, o1, o2, n1, n2)		\
({                                                                      \
        int __ret;                                                      \
        preempt_disable();                                              \
        __ret = cmpxchg_double_local(   raw_cpu_ptr(&(ptr1)),           \
                                        raw_cpu_ptr(&(ptr2)),           \
                                        o1, o2, n1, n2);                \
        preempt_enable();                                               \
        __ret;                                                          \
})


#define __CMPWAIT_CASE(w, sz, name)					\
static inline void __cmpwait_case_##name(volatile void *ptr,            \
                                         unsigned long val)             \
{                                                                       \
        unsigned long tmp;                                              \
                                                                        \
        asm volatile(                                                   \
        "       ldxr" #sz "\t%" #w "[tmp], %[v]\n"              \
        "       eor     %" #w "[tmp], %" #w "[tmp], %" #w "[val]\n"     \
        "       cbnz    %" #w "[tmp], 1f\n"                             \
        "       wfe\n"                                                  \
        "1:"                                                            \
        : [tmp] "=&r" (tmp), [v] "+Q" (*(unsigned long *)ptr)           \
        : [val] "r" (val));                                             \
}

__CMPWAIT_CASE(w, b, 1);
__CMPWAIT_CASE(w, h, 2);
__CMPWAIT_CASE(w,  , 4);
__CMPWAIT_CASE( ,  , 8);


#undef __CMPWAIT_CASE


#define __CMPWAIT_GEN(sfx)						\
static inline void __cmpwait##sfx(volatile void *ptr,                   \
                                  unsigned long val,                    \
                                  int size)                             \
{                                                                       \
        switch (size) {                                                 \
        case 1:                                                         \
                return __cmpwait_case##sfx##_1(ptr, (u8)val);           \
        case 2:                                                         \
                return __cmpwait_case##sfx##_2(ptr, (u16)val);          \
        case 4:                                                         \
                return __cmpwait_case##sfx##_4(ptr, val);               \
        case 8:                                                         \
                return __cmpwait_case##sfx##_8(ptr, val);               \
        default:                                                        \
                BUILD_BUG();                                            \
        }                                                               \
                                                                        \
        unreachable();                                                  \
}

__CMPWAIT_GEN()


#undef __CMPWAIT_GEN


#define __cmpwait_relaxed(ptr, val) \
	__cmpwait((ptr), (unsigned long)(val), sizeof(*(ptr)))

#endif	/* __ASM_CMPXCHG_H */

Overall Contributors

PersonTokensPropCommitsCommitProp
Will Deacon49675.61%550.00%
Steve Capper10816.46%330.00%
Catalin Marinas517.77%110.00%
Mark Rutland10.15%110.00%
Total656100.00%10100.00%
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