diff options
Diffstat (limited to 'include/asm-x86/percpu.h')
| -rw-r--r-- | include/asm-x86/percpu.h | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/include/asm-x86/percpu.h b/include/asm-x86/percpu.h index 736fc3bb8e1..4e91ee1e37a 100644 --- a/include/asm-x86/percpu.h +++ b/include/asm-x86/percpu.h @@ -22,6 +22,32 @@ DECLARE_PER_CPU(struct x8664_pda, pda); +/* + * These are supposed to be implemented as a single instruction which + * operates on the per-cpu data base segment. x86-64 doesn't have + * that yet, so this is a fairly inefficient workaround for the + * meantime. The single instruction is atomic with respect to + * preemption and interrupts, so we need to explicitly disable + * interrupts here to achieve the same effect. However, because it + * can be used from within interrupt-disable/enable, we can't actually + * disable interrupts; disabling preemption is enough. + */ +#define x86_read_percpu(var) \ + ({ \ + typeof(per_cpu_var(var)) __tmp; \ + preempt_disable(); \ + __tmp = __get_cpu_var(var); \ + preempt_enable(); \ + __tmp; \ + }) + +#define x86_write_percpu(var, val) \ + do { \ + preempt_disable(); \ + __get_cpu_var(var) = (val); \ + preempt_enable(); \ + } while(0) + #else /* CONFIG_X86_64 */ #ifdef __ASSEMBLY__ @@ -143,4 +169,50 @@ do { \ #define x86_or_percpu(var, val) percpu_to_op("or", per_cpu__##var, val) #endif /* !__ASSEMBLY__ */ #endif /* !CONFIG_X86_64 */ + +#ifdef CONFIG_SMP + +/* + * Define the "EARLY_PER_CPU" macros. These are used for some per_cpu + * variables that are initialized and accessed before there are per_cpu + * areas allocated. + */ + +#define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue) \ + DEFINE_PER_CPU(_type, _name) = _initvalue; \ + __typeof__(_type) _name##_early_map[NR_CPUS] __initdata = \ + { [0 ... NR_CPUS-1] = _initvalue }; \ + __typeof__(_type) *_name##_early_ptr = _name##_early_map + +#define EXPORT_EARLY_PER_CPU_SYMBOL(_name) \ + EXPORT_PER_CPU_SYMBOL(_name) + +#define DECLARE_EARLY_PER_CPU(_type, _name) \ + DECLARE_PER_CPU(_type, _name); \ + extern __typeof__(_type) *_name##_early_ptr; \ + extern __typeof__(_type) _name##_early_map[] + +#define early_per_cpu_ptr(_name) (_name##_early_ptr) +#define early_per_cpu_map(_name, _idx) (_name##_early_map[_idx]) +#define early_per_cpu(_name, _cpu) \ + (early_per_cpu_ptr(_name) ? \ + early_per_cpu_ptr(_name)[_cpu] : \ + per_cpu(_name, _cpu)) + +#else /* !CONFIG_SMP */ +#define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue) \ + DEFINE_PER_CPU(_type, _name) = _initvalue + +#define EXPORT_EARLY_PER_CPU_SYMBOL(_name) \ + EXPORT_PER_CPU_SYMBOL(_name) + +#define DECLARE_EARLY_PER_CPU(_type, _name) \ + DECLARE_PER_CPU(_type, _name) + +#define early_per_cpu(_name, _cpu) per_cpu(_name, _cpu) +#define early_per_cpu_ptr(_name) NULL +/* no early_per_cpu_map() */ + +#endif /* !CONFIG_SMP */ + #endif /* _ASM_X86_PERCPU_H_ */ |