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- /*
- * Atomic operations that C can't guarantee us. Useful for
- * resource counting etc..
- *
- * But use these as seldom as possible since they are much more slower
- * than regular operations.
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License. See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Copyright (C) 1996, 97, 99, 2000, 03, 04, 06 by Ralf Baechle
- */
- #ifndef _ASM_ATOMIC_H
- #define _ASM_ATOMIC_H
- #include <linux/irqflags.h>
- #include <linux/types.h>
- #include <asm/asm.h>
- #include <asm/barrier.h>
- #include <asm/compiler.h>
- #include <asm/cpu-features.h>
- #include <asm/cmpxchg.h>
- #include <asm/sync.h>
- #define ATOMIC_OPS(pfx, type) \
- static __always_inline type arch_##pfx##_read(const pfx##_t *v) \
- { \
- return READ_ONCE(v->counter); \
- } \
- \
- static __always_inline void arch_##pfx##_set(pfx##_t *v, type i) \
- { \
- WRITE_ONCE(v->counter, i); \
- } \
- \
- static __always_inline type \
- arch_##pfx##_cmpxchg(pfx##_t *v, type o, type n) \
- { \
- return arch_cmpxchg(&v->counter, o, n); \
- } \
- \
- static __always_inline type arch_##pfx##_xchg(pfx##_t *v, type n) \
- { \
- return arch_xchg(&v->counter, n); \
- }
- ATOMIC_OPS(atomic, int)
- #ifdef CONFIG_64BIT
- # define ATOMIC64_INIT(i) { (i) }
- ATOMIC_OPS(atomic64, s64)
- #endif
- #define ATOMIC_OP(pfx, op, type, c_op, asm_op, ll, sc) \
- static __inline__ void arch_##pfx##_##op(type i, pfx##_t * v) \
- { \
- type temp; \
- \
- if (!kernel_uses_llsc) { \
- unsigned long flags; \
- \
- raw_local_irq_save(flags); \
- v->counter c_op i; \
- raw_local_irq_restore(flags); \
- return; \
- } \
- \
- __asm__ __volatile__( \
- " .set push \n" \
- " .set " MIPS_ISA_LEVEL " \n" \
- " " __SYNC(full, loongson3_war) " \n" \
- "1: " #ll " %0, %1 # " #pfx "_" #op " \n" \
- " " #asm_op " %0, %2 \n" \
- " " #sc " %0, %1 \n" \
- "\t" __stringify(SC_BEQZ) " %0, 1b \n" \
- " .set pop \n" \
- : "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (v->counter) \
- : "Ir" (i) : __LLSC_CLOBBER); \
- }
- #define ATOMIC_OP_RETURN(pfx, op, type, c_op, asm_op, ll, sc) \
- static __inline__ type \
- arch_##pfx##_##op##_return_relaxed(type i, pfx##_t * v) \
- { \
- type temp, result; \
- \
- if (!kernel_uses_llsc) { \
- unsigned long flags; \
- \
- raw_local_irq_save(flags); \
- result = v->counter; \
- result c_op i; \
- v->counter = result; \
- raw_local_irq_restore(flags); \
- return result; \
- } \
- \
- __asm__ __volatile__( \
- " .set push \n" \
- " .set " MIPS_ISA_LEVEL " \n" \
- " " __SYNC(full, loongson3_war) " \n" \
- "1: " #ll " %1, %2 # " #pfx "_" #op "_return\n" \
- " " #asm_op " %0, %1, %3 \n" \
- " " #sc " %0, %2 \n" \
- "\t" __stringify(SC_BEQZ) " %0, 1b \n" \
- " " #asm_op " %0, %1, %3 \n" \
- " .set pop \n" \
- : "=&r" (result), "=&r" (temp), \
- "+" GCC_OFF_SMALL_ASM() (v->counter) \
- : "Ir" (i) : __LLSC_CLOBBER); \
- \
- return result; \
- }
- #define ATOMIC_FETCH_OP(pfx, op, type, c_op, asm_op, ll, sc) \
- static __inline__ type \
- arch_##pfx##_fetch_##op##_relaxed(type i, pfx##_t * v) \
- { \
- int temp, result; \
- \
- if (!kernel_uses_llsc) { \
- unsigned long flags; \
- \
- raw_local_irq_save(flags); \
- result = v->counter; \
- v->counter c_op i; \
- raw_local_irq_restore(flags); \
- return result; \
- } \
- \
- __asm__ __volatile__( \
- " .set push \n" \
- " .set " MIPS_ISA_LEVEL " \n" \
- " " __SYNC(full, loongson3_war) " \n" \
- "1: " #ll " %1, %2 # " #pfx "_fetch_" #op "\n" \
- " " #asm_op " %0, %1, %3 \n" \
- " " #sc " %0, %2 \n" \
- "\t" __stringify(SC_BEQZ) " %0, 1b \n" \
- " .set pop \n" \
- " move %0, %1 \n" \
- : "=&r" (result), "=&r" (temp), \
- "+" GCC_OFF_SMALL_ASM() (v->counter) \
- : "Ir" (i) : __LLSC_CLOBBER); \
- \
- return result; \
- }
- #undef ATOMIC_OPS
- #define ATOMIC_OPS(pfx, op, type, c_op, asm_op, ll, sc) \
- ATOMIC_OP(pfx, op, type, c_op, asm_op, ll, sc) \
- ATOMIC_OP_RETURN(pfx, op, type, c_op, asm_op, ll, sc) \
- ATOMIC_FETCH_OP(pfx, op, type, c_op, asm_op, ll, sc)
- ATOMIC_OPS(atomic, add, int, +=, addu, ll, sc)
- ATOMIC_OPS(atomic, sub, int, -=, subu, ll, sc)
- #define arch_atomic_add_return_relaxed arch_atomic_add_return_relaxed
- #define arch_atomic_sub_return_relaxed arch_atomic_sub_return_relaxed
- #define arch_atomic_fetch_add_relaxed arch_atomic_fetch_add_relaxed
- #define arch_atomic_fetch_sub_relaxed arch_atomic_fetch_sub_relaxed
- #ifdef CONFIG_64BIT
- ATOMIC_OPS(atomic64, add, s64, +=, daddu, lld, scd)
- ATOMIC_OPS(atomic64, sub, s64, -=, dsubu, lld, scd)
- # define arch_atomic64_add_return_relaxed arch_atomic64_add_return_relaxed
- # define arch_atomic64_sub_return_relaxed arch_atomic64_sub_return_relaxed
- # define arch_atomic64_fetch_add_relaxed arch_atomic64_fetch_add_relaxed
- # define arch_atomic64_fetch_sub_relaxed arch_atomic64_fetch_sub_relaxed
- #endif /* CONFIG_64BIT */
- #undef ATOMIC_OPS
- #define ATOMIC_OPS(pfx, op, type, c_op, asm_op, ll, sc) \
- ATOMIC_OP(pfx, op, type, c_op, asm_op, ll, sc) \
- ATOMIC_FETCH_OP(pfx, op, type, c_op, asm_op, ll, sc)
- ATOMIC_OPS(atomic, and, int, &=, and, ll, sc)
- ATOMIC_OPS(atomic, or, int, |=, or, ll, sc)
- ATOMIC_OPS(atomic, xor, int, ^=, xor, ll, sc)
- #define arch_atomic_fetch_and_relaxed arch_atomic_fetch_and_relaxed
- #define arch_atomic_fetch_or_relaxed arch_atomic_fetch_or_relaxed
- #define arch_atomic_fetch_xor_relaxed arch_atomic_fetch_xor_relaxed
- #ifdef CONFIG_64BIT
- ATOMIC_OPS(atomic64, and, s64, &=, and, lld, scd)
- ATOMIC_OPS(atomic64, or, s64, |=, or, lld, scd)
- ATOMIC_OPS(atomic64, xor, s64, ^=, xor, lld, scd)
- # define arch_atomic64_fetch_and_relaxed arch_atomic64_fetch_and_relaxed
- # define arch_atomic64_fetch_or_relaxed arch_atomic64_fetch_or_relaxed
- # define arch_atomic64_fetch_xor_relaxed arch_atomic64_fetch_xor_relaxed
- #endif
- #undef ATOMIC_OPS
- #undef ATOMIC_FETCH_OP
- #undef ATOMIC_OP_RETURN
- #undef ATOMIC_OP
- /*
- * atomic_sub_if_positive - conditionally subtract integer from atomic variable
- * @i: integer value to subtract
- * @v: pointer of type atomic_t
- *
- * Atomically test @v and subtract @i if @v is greater or equal than @i.
- * The function returns the old value of @v minus @i.
- */
- #define ATOMIC_SIP_OP(pfx, type, op, ll, sc) \
- static __inline__ type arch_##pfx##_sub_if_positive(type i, pfx##_t * v) \
- { \
- type temp, result; \
- \
- smp_mb__before_atomic(); \
- \
- if (!kernel_uses_llsc) { \
- unsigned long flags; \
- \
- raw_local_irq_save(flags); \
- result = v->counter; \
- result -= i; \
- if (result >= 0) \
- v->counter = result; \
- raw_local_irq_restore(flags); \
- smp_mb__after_atomic(); \
- return result; \
- } \
- \
- __asm__ __volatile__( \
- " .set push \n" \
- " .set " MIPS_ISA_LEVEL " \n" \
- " " __SYNC(full, loongson3_war) " \n" \
- "1: " #ll " %1, %2 # atomic_sub_if_positive\n" \
- " .set pop \n" \
- " " #op " %0, %1, %3 \n" \
- " move %1, %0 \n" \
- " bltz %0, 2f \n" \
- " .set push \n" \
- " .set " MIPS_ISA_LEVEL " \n" \
- " " #sc " %1, %2 \n" \
- " " __stringify(SC_BEQZ) " %1, 1b \n" \
- "2: " __SYNC(full, loongson3_war) " \n" \
- " .set pop \n" \
- : "=&r" (result), "=&r" (temp), \
- "+" GCC_OFF_SMALL_ASM() (v->counter) \
- : "Ir" (i) \
- : __LLSC_CLOBBER); \
- \
- /* \
- * In the Loongson3 workaround case we already have a \
- * completion barrier at 2: above, which is needed due to the \
- * bltz that can branch to code outside of the LL/SC loop. As \
- * such, we don't need to emit another barrier here. \
- */ \
- if (__SYNC_loongson3_war == 0) \
- smp_mb__after_atomic(); \
- \
- return result; \
- }
- ATOMIC_SIP_OP(atomic, int, subu, ll, sc)
- #define arch_atomic_dec_if_positive(v) arch_atomic_sub_if_positive(1, v)
- #ifdef CONFIG_64BIT
- ATOMIC_SIP_OP(atomic64, s64, dsubu, lld, scd)
- #define arch_atomic64_dec_if_positive(v) arch_atomic64_sub_if_positive(1, v)
- #endif
- #undef ATOMIC_SIP_OP
- #endif /* _ASM_ATOMIC_H */
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