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![Dmitry Vyukov](/assets/img/avatar_default.png)
CPP turns perfectly readable code into a much harder to read syntactic soup. Ingo suggested to write them out as-is in C and ignore the higher linecount. Do this. (As a side effect, plain C functions will be easier to KASAN-instrument as well.) Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kasan-dev@googlegroups.com Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/a35b983dd3be937a3cf63c4e2db487de2cdc7b8f.1497690003.git.dvyukov@google.com [ Beautified the C code some more and twiddled the changelog to mention the linecount increase and the KASAN benefit. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
278 lines
5.9 KiB
C
278 lines
5.9 KiB
C
#ifndef _ASM_X86_ATOMIC_H
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#define _ASM_X86_ATOMIC_H
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#include <linux/compiler.h>
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#include <linux/types.h>
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#include <asm/alternative.h>
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#include <asm/cmpxchg.h>
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#include <asm/rmwcc.h>
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#include <asm/barrier.h>
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/*
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* Atomic operations that C can't guarantee us. Useful for
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* resource counting etc..
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*/
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#define ATOMIC_INIT(i) { (i) }
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/**
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* atomic_read - read atomic variable
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* @v: pointer of type atomic_t
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*
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* Atomically reads the value of @v.
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*/
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static __always_inline int atomic_read(const atomic_t *v)
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{
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return READ_ONCE((v)->counter);
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}
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/**
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* atomic_set - set atomic variable
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* @v: pointer of type atomic_t
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* @i: required value
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*
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* Atomically sets the value of @v to @i.
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*/
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static __always_inline void atomic_set(atomic_t *v, int i)
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{
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WRITE_ONCE(v->counter, i);
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}
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/**
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* atomic_add - add integer to atomic variable
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* @i: integer value to add
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* @v: pointer of type atomic_t
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*
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* Atomically adds @i to @v.
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*/
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static __always_inline void atomic_add(int i, atomic_t *v)
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{
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asm volatile(LOCK_PREFIX "addl %1,%0"
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: "+m" (v->counter)
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: "ir" (i));
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}
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/**
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* atomic_sub - subtract integer from atomic variable
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* @i: integer value to subtract
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* @v: pointer of type atomic_t
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*
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* Atomically subtracts @i from @v.
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*/
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static __always_inline void atomic_sub(int i, atomic_t *v)
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{
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asm volatile(LOCK_PREFIX "subl %1,%0"
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: "+m" (v->counter)
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: "ir" (i));
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}
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/**
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* atomic_sub_and_test - subtract value from variable and test result
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* @i: integer value to subtract
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* @v: pointer of type atomic_t
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*
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* Atomically subtracts @i from @v and returns
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* true if the result is zero, or false for all
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* other cases.
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*/
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static __always_inline bool atomic_sub_and_test(int i, atomic_t *v)
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{
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GEN_BINARY_RMWcc(LOCK_PREFIX "subl", v->counter, "er", i, "%0", e);
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}
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/**
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* atomic_inc - increment atomic variable
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* @v: pointer of type atomic_t
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*
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* Atomically increments @v by 1.
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*/
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static __always_inline void atomic_inc(atomic_t *v)
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{
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asm volatile(LOCK_PREFIX "incl %0"
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: "+m" (v->counter));
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}
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/**
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* atomic_dec - decrement atomic variable
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* @v: pointer of type atomic_t
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*
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* Atomically decrements @v by 1.
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*/
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static __always_inline void atomic_dec(atomic_t *v)
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{
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asm volatile(LOCK_PREFIX "decl %0"
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: "+m" (v->counter));
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}
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/**
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* atomic_dec_and_test - decrement and test
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* @v: pointer of type atomic_t
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*
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* Atomically decrements @v by 1 and
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* returns true if the result is 0, or false for all other
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* cases.
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*/
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static __always_inline bool atomic_dec_and_test(atomic_t *v)
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{
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GEN_UNARY_RMWcc(LOCK_PREFIX "decl", v->counter, "%0", e);
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}
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/**
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* atomic_inc_and_test - increment and test
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* @v: pointer of type atomic_t
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*
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* Atomically increments @v by 1
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* and returns true if the result is zero, or false for all
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* other cases.
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*/
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static __always_inline bool atomic_inc_and_test(atomic_t *v)
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{
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GEN_UNARY_RMWcc(LOCK_PREFIX "incl", v->counter, "%0", e);
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}
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/**
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* atomic_add_negative - add and test if negative
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* @i: integer value to add
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* @v: pointer of type atomic_t
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*
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* Atomically adds @i to @v and returns true
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* if the result is negative, or false when
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* result is greater than or equal to zero.
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*/
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static __always_inline bool atomic_add_negative(int i, atomic_t *v)
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{
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GEN_BINARY_RMWcc(LOCK_PREFIX "addl", v->counter, "er", i, "%0", s);
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}
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/**
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* atomic_add_return - add integer and return
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* @i: integer value to add
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* @v: pointer of type atomic_t
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*
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* Atomically adds @i to @v and returns @i + @v
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*/
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static __always_inline int atomic_add_return(int i, atomic_t *v)
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{
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return i + xadd(&v->counter, i);
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}
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/**
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* atomic_sub_return - subtract integer and return
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* @v: pointer of type atomic_t
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* @i: integer value to subtract
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*
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* Atomically subtracts @i from @v and returns @v - @i
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*/
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static __always_inline int atomic_sub_return(int i, atomic_t *v)
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{
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return atomic_add_return(-i, v);
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}
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#define atomic_inc_return(v) (atomic_add_return(1, v))
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#define atomic_dec_return(v) (atomic_sub_return(1, v))
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static __always_inline int atomic_fetch_add(int i, atomic_t *v)
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{
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return xadd(&v->counter, i);
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}
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static __always_inline int atomic_fetch_sub(int i, atomic_t *v)
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{
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return xadd(&v->counter, -i);
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}
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static __always_inline int atomic_cmpxchg(atomic_t *v, int old, int new)
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{
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return cmpxchg(&v->counter, old, new);
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}
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#define atomic_try_cmpxchg atomic_try_cmpxchg
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static __always_inline bool atomic_try_cmpxchg(atomic_t *v, int *old, int new)
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{
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return try_cmpxchg(&v->counter, old, new);
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}
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static inline int atomic_xchg(atomic_t *v, int new)
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{
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return xchg(&v->counter, new);
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}
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static inline void atomic_and(int i, atomic_t *v)
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{
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asm volatile(LOCK_PREFIX "andl %1,%0"
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: "+m" (v->counter)
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: "ir" (i)
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: "memory");
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}
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static inline int atomic_fetch_and(int i, atomic_t *v)
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{
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int val = atomic_read(v);
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do { } while (!atomic_try_cmpxchg(v, &val, val & i));
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return val;
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}
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static inline void atomic_or(int i, atomic_t *v)
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{
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asm volatile(LOCK_PREFIX "orl %1,%0"
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: "+m" (v->counter)
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: "ir" (i)
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: "memory");
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}
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static inline int atomic_fetch_or(int i, atomic_t *v)
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{
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int val = atomic_read(v);
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do { } while (!atomic_try_cmpxchg(v, &val, val | i));
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return val;
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}
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static inline void atomic_xor(int i, atomic_t *v)
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{
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asm volatile(LOCK_PREFIX "xorl %1,%0"
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: "+m" (v->counter)
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: "ir" (i)
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: "memory");
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}
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static inline int atomic_fetch_xor(int i, atomic_t *v)
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{
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int val = atomic_read(v);
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do { } while (!atomic_try_cmpxchg(v, &val, val ^ i));
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return val;
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}
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/**
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* __atomic_add_unless - add unless the number is already a given value
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* @v: pointer of type atomic_t
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* @a: the amount to add to v...
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* @u: ...unless v is equal to u.
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*
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* Atomically adds @a to @v, so long as @v was not already @u.
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* Returns the old value of @v.
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*/
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static __always_inline int __atomic_add_unless(atomic_t *v, int a, int u)
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{
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int c = atomic_read(v);
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do {
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if (unlikely(c == u))
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break;
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} while (!atomic_try_cmpxchg(v, &c, c + a));
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return c;
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}
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#ifdef CONFIG_X86_32
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# include <asm/atomic64_32.h>
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#else
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# include <asm/atomic64_64.h>
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#endif
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#endif /* _ASM_X86_ATOMIC_H */
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