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Diffstat (limited to 'arch/x86/include/asm/percpu.h')
| -rw-r--r-- | arch/x86/include/asm/percpu.h | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h new file mode 100644 index 000000000000..e10a1d0678cf --- /dev/null +++ b/arch/x86/include/asm/percpu.h @@ -0,0 +1,218 @@ +#ifndef ASM_X86__PERCPU_H +#define ASM_X86__PERCPU_H + +#ifdef CONFIG_X86_64 +#include <linux/compiler.h> + +/* Same as asm-generic/percpu.h, except that we store the per cpu offset + in the PDA. Longer term the PDA and every per cpu variable + should be just put into a single section and referenced directly + from %gs */ + +#ifdef CONFIG_SMP +#include <asm/pda.h> + +#define __per_cpu_offset(cpu) (cpu_pda(cpu)->data_offset) +#define __my_cpu_offset read_pda(data_offset) + +#define per_cpu_offset(x) (__per_cpu_offset(x)) + +#endif +#include <asm-generic/percpu.h> + +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__ + +/* + * PER_CPU finds an address of a per-cpu variable. + * + * Args: + * var - variable name + * reg - 32bit register + * + * The resulting address is stored in the "reg" argument. + * + * Example: + * PER_CPU(cpu_gdt_descr, %ebx) + */ +#ifdef CONFIG_SMP +#define PER_CPU(var, reg) \ + movl %fs:per_cpu__##this_cpu_off, reg; \ + lea per_cpu__##var(reg), reg +#define PER_CPU_VAR(var) %fs:per_cpu__##var +#else /* ! SMP */ +#define PER_CPU(var, reg) \ + movl $per_cpu__##var, reg +#define PER_CPU_VAR(var) per_cpu__##var +#endif /* SMP */ + +#else /* ...!ASSEMBLY */ + +/* + * PER_CPU finds an address of a per-cpu variable. + * + * Args: + * var - variable name + * cpu - 32bit register containing the current CPU number + * + * The resulting address is stored in the "cpu" argument. + * + * Example: + * PER_CPU(cpu_gdt_descr, %ebx) + */ +#ifdef CONFIG_SMP + +#define __my_cpu_offset x86_read_percpu(this_cpu_off) + +/* fs segment starts at (positive) offset == __per_cpu_offset[cpu] */ +#define __percpu_seg "%%fs:" + +#else /* !SMP */ + +#define __percpu_seg "" + +#endif /* SMP */ + +#include <asm-generic/percpu.h> + +/* We can use this directly for local CPU (faster). */ +DECLARE_PER_CPU(unsigned long, this_cpu_off); + +/* For arch-specific code, we can use direct single-insn ops (they + * don't give an lvalue though). */ +extern void __bad_percpu_size(void); + +#define percpu_to_op(op, var, val) \ +do { \ + typedef typeof(var) T__; \ + if (0) { \ + T__ tmp__; \ + tmp__ = (val); \ + } \ + switch (sizeof(var)) { \ + case 1: \ + asm(op "b %1,"__percpu_seg"%0" \ + : "+m" (var) \ + : "ri" ((T__)val)); \ + break; \ + case 2: \ + asm(op "w %1,"__percpu_seg"%0" \ + : "+m" (var) \ + : "ri" ((T__)val)); \ + break; \ + case 4: \ + asm(op "l %1,"__percpu_seg"%0" \ + : "+m" (var) \ + : "ri" ((T__)val)); \ + break; \ + default: __bad_percpu_size(); \ + } \ +} while (0) + +#define percpu_from_op(op, var) \ +({ \ + typeof(var) ret__; \ + switch (sizeof(var)) { \ + case 1: \ + asm(op "b "__percpu_seg"%1,%0" \ + : "=r" (ret__) \ + : "m" (var)); \ + break; \ + case 2: \ + asm(op "w "__percpu_seg"%1,%0" \ + : "=r" (ret__) \ + : "m" (var)); \ + break; \ + case 4: \ + asm(op "l "__percpu_seg"%1,%0" \ + : "=r" (ret__) \ + : "m" (var)); \ + break; \ + default: __bad_percpu_size(); \ + } \ + ret__; \ +}) + +#define x86_read_percpu(var) percpu_from_op("mov", per_cpu__##var) +#define x86_write_percpu(var, val) percpu_to_op("mov", per_cpu__##var, val) +#define x86_add_percpu(var, val) percpu_to_op("add", per_cpu__##var, val) +#define x86_sub_percpu(var, val) percpu_to_op("sub", per_cpu__##var, val) +#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 __refdata = _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 */ |