diff options
| -rw-r--r-- | arch/x86/Makefrag.am | 1 | ||||
| -rw-r--r-- | arch/x86/machine/atomic.h | 77 |
2 files changed, 78 insertions, 0 deletions
diff --git a/arch/x86/Makefrag.am b/arch/x86/Makefrag.am index d3e4aa51..6e61160c 100644 --- a/arch/x86/Makefrag.am +++ b/arch/x86/Makefrag.am @@ -2,6 +2,7 @@ x86_FILES = \ arch/x86/machine/acpimp.c \ arch/x86/machine/acpimp.h \ arch/x86/machine/asm.h \ + arch/x86/machine/atomic.h \ arch/x86/machine/biosmem.c \ arch/x86/machine/biosmem.h \ arch/x86/machine/boot_asm.S \ diff --git a/arch/x86/machine/atomic.h b/arch/x86/machine/atomic.h new file mode 100644 index 00000000..3386a530 --- /dev/null +++ b/arch/x86/machine/atomic.h @@ -0,0 +1,77 @@ +/* + * Copyright (c) 2012 Richard Braun. + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * 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/>. + * + * + * Atomic operations. + * + * Note that it cannot be assumed these operations imply a compiler or a + * memory barrier. + */ + +#ifndef _X86_ATOMIC_H +#define _X86_ATOMIC_H + +static inline void +atomic_add(volatile unsigned long *ptr, long delta) +{ + asm volatile("lock add %1, %0" + : "+m" (*ptr) + : "r" (delta)); +} + +static inline void +atomic_and(volatile unsigned long *ptr, unsigned long bits) +{ + asm volatile("lock and %1, %0" + : "+m" (*ptr) + : "r" (bits)); +} + +static inline void +atomic_or(volatile unsigned long *ptr, unsigned long bits) +{ + asm volatile("lock or %1, %0" + : "+m" (*ptr) + : "r" (bits)); +} + +static inline unsigned long +atomic_swap(volatile unsigned long *ptr, unsigned long newval) +{ + unsigned long prev; + + /* The xchg instruction doesn't need a lock prefix */ + asm volatile("xchg %1, %0" + : "+m" (*ptr), "=r" (prev) + : "1" (newval)); + + return prev; +} + +static inline unsigned long +atomic_cas(volatile unsigned long *ptr, unsigned long oldval, + unsigned long newval) +{ + unsigned long prev; + + asm volatile("lock cmpxchg %3, %0" + : "+m" (*ptr), "=a" (prev) + : "1" (oldval), "r" (newval)); + + return prev; +} + +#endif /* _X86_ATOMIC_H */ |