mirror of https://gitee.com/openkylin/linux.git
locking/atomic, arch/arc: Implement atomic_fetch_{add,sub,and,andnot,or,xor}()
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> Acked-by: Vineet Gupta <vgupta@synopsys.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Noam Camus <noamc@ezchip.com> 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 Cc: linux-snps-arc@lists.infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra
Ingo Molnar
parent
1f51dee7ca
commit
fbffe892e5
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@ -67,6 +67,37 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \
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return val; \
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}
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#define ATOMIC_FETCH_OP(op, c_op, asm_op) \
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static inline int atomic_fetch_##op(int i, atomic_t *v) \
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{ \
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unsigned int val, orig; \
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SCOND_FAIL_RETRY_VAR_DEF \
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\
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/* \
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* Explicit full memory barrier needed before/after as \
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* LLOCK/SCOND thmeselves don't provide any such semantics \
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*/ \
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smp_mb(); \
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\
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__asm__ __volatile__( \
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"1: llock %[orig], [%[ctr]] \n" \
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" " #asm_op " %[val], %[orig], %[i] \n" \
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" scond %[val], [%[ctr]] \n" \
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" \n" \
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SCOND_FAIL_RETRY_ASM \
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\
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: [val] "=&r" (val), \
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[orig] "=&r" (orig) \
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SCOND_FAIL_RETRY_VARS \
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: [ctr] "r" (&v->counter), \
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[i] "ir" (i) \
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: "cc"); \
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\
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smp_mb(); \
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\
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return orig; \
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}
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#else /* !CONFIG_ARC_HAS_LLSC */
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#ifndef CONFIG_SMP
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@ -129,21 +160,46 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \
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return temp; \
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}
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#define ATOMIC_FETCH_OP(op, c_op, asm_op) \
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static inline int atomic_fetch_##op(int i, atomic_t *v) \
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{ \
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unsigned long flags; \
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unsigned long orig; \
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\
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/* \
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* spin lock/unlock provides the needed smp_mb() before/after \
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*/ \
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atomic_ops_lock(flags); \
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orig = v->counter; \
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v->counter c_op i; \
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atomic_ops_unlock(flags); \
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\
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return orig; \
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}
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#endif /* !CONFIG_ARC_HAS_LLSC */
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#define ATOMIC_OPS(op, c_op, asm_op) \
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ATOMIC_OP(op, c_op, asm_op) \
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ATOMIC_OP_RETURN(op, c_op, asm_op)
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ATOMIC_OP_RETURN(op, c_op, asm_op) \
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ATOMIC_FETCH_OP(op, c_op, asm_op)
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ATOMIC_OPS(add, +=, add)
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ATOMIC_OPS(sub, -=, sub)
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#define atomic_andnot atomic_andnot
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ATOMIC_OP(and, &=, and)
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ATOMIC_OP(andnot, &= ~, bic)
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ATOMIC_OP(or, |=, or)
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ATOMIC_OP(xor, ^=, xor)
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#define atomic_fetch_or atomic_fetch_or
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#undef ATOMIC_OPS
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#define ATOMIC_OPS(op, c_op, asm_op) \
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ATOMIC_OP(op, c_op, asm_op) \
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ATOMIC_FETCH_OP(op, c_op, asm_op)
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ATOMIC_OPS(and, &=, and)
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ATOMIC_OPS(andnot, &= ~, bic)
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ATOMIC_OPS(or, |=, or)
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ATOMIC_OPS(xor, ^=, xor)
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#undef SCOND_FAIL_RETRY_VAR_DEF
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#undef SCOND_FAIL_RETRY_ASM
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@ -208,22 +264,51 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \
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return temp; \
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}
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#define ATOMIC_FETCH_OP(op, c_op, asm_op) \
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static inline int atomic_fetch_##op(int i, atomic_t *v) \
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{ \
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unsigned int temp = i; \
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\
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/* Explicit full memory barrier needed before/after */ \
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smp_mb(); \
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\
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__asm__ __volatile__( \
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" mov r2, %0\n" \
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" mov r3, %1\n" \
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" .word %2\n" \
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" mov %0, r2" \
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: "+r"(temp) \
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: "r"(&v->counter), "i"(asm_op) \
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: "r2", "r3", "memory"); \
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\
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smp_mb(); \
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\
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return temp; \
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}
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#define ATOMIC_OPS(op, c_op, asm_op) \
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ATOMIC_OP(op, c_op, asm_op) \
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ATOMIC_OP_RETURN(op, c_op, asm_op)
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ATOMIC_OP_RETURN(op, c_op, asm_op) \
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ATOMIC_FETCH_OP(op, c_op, asm_op)
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ATOMIC_OPS(add, +=, CTOP_INST_AADD_DI_R2_R2_R3)
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#define atomic_sub(i, v) atomic_add(-(i), (v))
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#define atomic_sub_return(i, v) atomic_add_return(-(i), (v))
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ATOMIC_OP(and, &=, CTOP_INST_AAND_DI_R2_R2_R3)
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#undef ATOMIC_OPS
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#define ATOMIC_OPS(op, c_op, asm_op) \
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ATOMIC_OP(op, c_op, asm_op) \
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ATOMIC_FETCH_OP(op, c_op, asm_op)
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ATOMIC_OPS(and, &=, CTOP_INST_AAND_DI_R2_R2_R3)
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#define atomic_andnot(mask, v) atomic_and(~(mask), (v))
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ATOMIC_OP(or, |=, CTOP_INST_AOR_DI_R2_R2_R3)
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ATOMIC_OP(xor, ^=, CTOP_INST_AXOR_DI_R2_R2_R3)
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ATOMIC_OPS(or, |=, CTOP_INST_AOR_DI_R2_R2_R3)
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ATOMIC_OPS(xor, ^=, CTOP_INST_AXOR_DI_R2_R2_R3)
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#endif /* CONFIG_ARC_PLAT_EZNPS */
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#undef ATOMIC_OPS
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#undef ATOMIC_FETCH_OP
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#undef ATOMIC_OP_RETURN
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#undef ATOMIC_OP
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