/* * 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 #include #include #include #include #include #include /* * Using a branch-likely instruction to check the result of an sc instruction * works around a bug present in R10000 CPUs prior to revision 3.0 that could * cause ll-sc sequences to execute non-atomically. */ #if R10000_LLSC_WAR # define __scbeqz "beqzl" #else # define __scbeqz "beqz" #endif #define ATOMIC_INIT(i) { (i) } /* * atomic_read - read atomic variable * @v: pointer of type atomic_t * * Atomically reads the value of @v. */ #define atomic_read(v) READ_ONCE((v)->counter) /* * atomic_set - set atomic variable * @v: pointer of type atomic_t * @i: required value * * Atomically sets the value of @v to @i. */ #define atomic_set(v, i) WRITE_ONCE((v)->counter, (i)) #define ATOMIC_OP(op, c_op, asm_op) \ static __inline__ void atomic_##op(int i, atomic_t * v) \ { \ if (kernel_uses_llsc) { \ int temp; \ \ loongson_llsc_mb(); \ __asm__ __volatile__( \ " .set push \n" \ " .set "MIPS_ISA_LEVEL" \n" \ "1: ll %0, %1 # atomic_" #op " \n" \ " " #asm_op " %0, %2 \n" \ " sc %0, %1 \n" \ "\t" __scbeqz " %0, 1b \n" \ " .set pop \n" \ : "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (v->counter) \ : "Ir" (i)); \ } else { \ unsigned long flags; \ \ raw_local_irq_save(flags); \ v->counter c_op i; \ raw_local_irq_restore(flags); \ } \ } #define ATOMIC_OP_RETURN(op, c_op, asm_op) \ static __inline__ int atomic_##op##_return_relaxed(int i, atomic_t * v) \ { \ int result; \ \ if (kernel_uses_llsc) { \ int temp; \ \ loongson_llsc_mb(); \ __asm__ __volatile__( \ " .set push \n" \ " .set "MIPS_ISA_LEVEL" \n" \ "1: ll %1, %2 # atomic_" #op "_return \n" \ " " #asm_op " %0, %1, %3 \n" \ " sc %0, %2 \n" \ "\t" __scbeqz " %0, 1b \n" \ " " #asm_op " %0, %1, %3 \n" \ " .set pop \n" \ : "=&r" (result), "=&r" (temp), \ "+" GCC_OFF_SMALL_ASM() (v->counter) \ : "Ir" (i)); \ } else { \ 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; \ } #define ATOMIC_FETCH_OP(op, c_op, asm_op) \ static __inline__ int atomic_fetch_##op##_relaxed(int i, atomic_t * v) \ { \ int result; \ \ if (kernel_uses_llsc) { \ int temp; \ \ loongson_llsc_mb(); \ __asm__ __volatile__( \ " .set push \n" \ " .set "MIPS_ISA_LEVEL" \n" \ "1: ll %1, %2 # atomic_fetch_" #op " \n" \ " " #asm_op " %0, %1, %3 \n" \ " sc %0, %2 \n" \ "\t" __scbeqz " %0, 1b \n" \ " .set pop \n" \ " move %0, %1 \n" \ : "=&r" (result), "=&r" (temp), \ "+" GCC_OFF_SMALL_ASM() (v->counter) \ : "Ir" (i)); \ } else { \ unsigned long flags; \ \ raw_local_irq_save(flags); \ result = v->counter; \ v->counter c_op i; \ raw_local_irq_restore(flags); \ } \ \ return result; \ } #define ATOMIC_OPS(op, c_op, asm_op) \ ATOMIC_OP(op, c_op, asm_op) \ ATOMIC_OP_RETURN(op, c_op, asm_op) \ ATOMIC_FETCH_OP(op, c_op, asm_op) ATOMIC_OPS(add, +=, addu) ATOMIC_OPS(sub, -=, subu) #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 #undef ATOMIC_OPS #define ATOMIC_OPS(op, c_op, asm_op) \ ATOMIC_OP(op, c_op, asm_op) \ ATOMIC_FETCH_OP(op, c_op, asm_op) ATOMIC_OPS(and, &=, and) ATOMIC_OPS(or, |=, or) ATOMIC_OPS(xor, ^=, xor) #define atomic_fetch_and_relaxed atomic_fetch_and_relaxed #define atomic_fetch_or_relaxed atomic_fetch_or_relaxed #define atomic_fetch_xor_relaxed atomic_fetch_xor_relaxed #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. */ static __inline__ int atomic_sub_if_positive(int i, atomic_t * v) { int result; smp_mb__before_llsc(); if (kernel_uses_llsc) { int temp; __asm__ __volatile__( " .set push \n" " .set "MIPS_ISA_LEVEL" \n" "1: ll %1, %2 # atomic_sub_if_positive\n" " .set pop \n" " subu %0, %1, %3 \n" " move %1, %0 \n" " bltz %0, 1f \n" " .set push \n" " .set "MIPS_ISA_LEVEL" \n" " sc %1, %2 \n" "\t" __scbeqz " %1, 1b \n" "1: \n" " .set pop \n" : "=&r" (result), "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (v->counter) : "Ir" (i)); } else { 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_llsc_mb(); return result; } #define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n))) #define atomic_xchg(v, new) (xchg(&((v)->counter), (new))) /* * atomic_dec_if_positive - decrement by 1 if old value positive * @v: pointer of type atomic_t */ #define atomic_dec_if_positive(v) atomic_sub_if_positive(1, v) #ifdef CONFIG_64BIT #define ATOMIC64_INIT(i) { (i) } /* * atomic64_read - read atomic variable * @v: pointer of type atomic64_t * */ #define atomic64_read(v) READ_ONCE((v)->counter) /* * atomic64_set - set atomic variable * @v: pointer of type atomic64_t * @i: required value */ #define atomic64_set(v, i) WRITE_ONCE((v)->counter, (i)) #define ATOMIC64_OP(op, c_op, asm_op) \ static __inline__ void atomic64_##op(long i, atomic64_t * v) \ { \ if (kernel_uses_llsc) { \ long temp; \ \ loongson_llsc_mb(); \ __asm__ __volatile__( \ " .set push \n" \ " .set "MIPS_ISA_LEVEL" \n" \ "1: lld %0, %1 # atomic64_" #op " \n" \ " " #asm_op " %0, %2 \n" \ " scd %0, %1 \n" \ "\t" __scbeqz " %0, 1b \n" \ " .set pop \n" \ : "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (v->counter) \ : "Ir" (i)); \ } else { \ unsigned long flags; \ \ raw_local_irq_save(flags); \ v->counter c_op i; \ raw_local_irq_restore(flags); \ } \ } #define ATOMIC64_OP_RETURN(op, c_op, asm_op) \ static __inline__ long atomic64_##op##_return_relaxed(long i, atomic64_t * v) \ { \ long result; \ \ if (kernel_uses_llsc) { \ long temp; \ \ loongson_llsc_mb(); \ __asm__ __volatile__( \ " .set push \n" \ " .set "MIPS_ISA_LEVEL" \n" \ "1: lld %1, %2 # atomic64_" #op "_return\n" \ " " #asm_op " %0, %1, %3 \n" \ " scd %0, %2 \n" \ "\t" __scbeqz " %0, 1b \n" \ " " #asm_op " %0, %1, %3 \n" \ " .set pop \n" \ : "=&r" (result), "=&r" (temp), \ "+" GCC_OFF_SMALL_ASM() (v->counter) \ : "Ir" (i)); \ } else { \ 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; \ } #define ATOMIC64_FETCH_OP(op, c_op, asm_op) \ static __inline__ long atomic64_fetch_##op##_relaxed(long i, atomic64_t * v) \ { \ long result; \ \ if (kernel_uses_llsc) { \ long temp; \ \ loongson_llsc_mb(); \ __asm__ __volatile__( \ " .set push \n" \ " .set "MIPS_ISA_LEVEL" \n" \ "1: lld %1, %2 # atomic64_fetch_" #op "\n" \ " " #asm_op " %0, %1, %3 \n" \ " scd %0, %2 \n" \ "\t" __scbeqz " %0, 1b \n" \ " move %0, %1 \n" \ " .set pop \n" \ : "=&r" (result), "=&r" (temp), \ "+" GCC_OFF_SMALL_ASM() (v->counter) \ : "Ir" (i)); \ } else { \ unsigned long flags; \ \ raw_local_irq_save(flags); \ result = v->counter; \ v->counter c_op i; \ raw_local_irq_restore(flags); \ } \ \ return result; \ } #define ATOMIC64_OPS(op, c_op, asm_op) \ ATOMIC64_OP(op, c_op, asm_op) \ ATOMIC64_OP_RETURN(op, c_op, asm_op) \ ATOMIC64_FETCH_OP(op, c_op, asm_op) ATOMIC64_OPS(add, +=, daddu) ATOMIC64_OPS(sub, -=, dsubu) #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 #undef ATOMIC64_OPS #define ATOMIC64_OPS(op, c_op, asm_op) \ ATOMIC64_OP(op, c_op, asm_op) \ ATOMIC64_FETCH_OP(op, c_op, asm_op) ATOMIC64_OPS(and, &=, and) ATOMIC64_OPS(or, |=, or) ATOMIC64_OPS(xor, ^=, xor) #define atomic64_fetch_and_relaxed atomic64_fetch_and_relaxed #define atomic64_fetch_or_relaxed atomic64_fetch_or_relaxed #define atomic64_fetch_xor_relaxed atomic64_fetch_xor_relaxed #undef ATOMIC64_OPS #undef ATOMIC64_FETCH_OP #undef ATOMIC64_OP_RETURN #undef ATOMIC64_OP /* * atomic64_sub_if_positive - conditionally subtract integer from atomic * variable * @i: integer value to subtract * @v: pointer of type atomic64_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. */ static __inline__ long atomic64_sub_if_positive(long i, atomic64_t * v) { long result; smp_mb__before_llsc(); if (kernel_uses_llsc) { long temp; __asm__ __volatile__( " .set push \n" " .set "MIPS_ISA_LEVEL" \n" "1: lld %1, %2 # atomic64_sub_if_positive\n" " dsubu %0, %1, %3 \n" " move %1, %0 \n" " bltz %0, 1f \n" " scd %1, %2 \n" "\t" __scbeqz " %1, 1b \n" "1: \n" " .set pop \n" : "=&r" (result), "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (v->counter) : "Ir" (i)); } else { 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_llsc_mb(); return result; } #define atomic64_cmpxchg(v, o, n) \ ((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n))) #define atomic64_xchg(v, new) (xchg(&((v)->counter), (new))) /* * atomic64_dec_if_positive - decrement by 1 if old value positive * @v: pointer of type atomic64_t */ #define atomic64_dec_if_positive(v) atomic64_sub_if_positive(1, v) #endif /* CONFIG_64BIT */ #endif /* _ASM_ATOMIC_H */