linux/arch/x86/include/asm/smp.h
Ingo Molnar 6dbde35308 percpu: add optimized generic percpu accessors
It is an optimization and a cleanup, and adds the following new
generic percpu methods:

  percpu_read()
  percpu_write()
  percpu_add()
  percpu_sub()
  percpu_and()
  percpu_or()
  percpu_xor()

and implements support for them on x86. (other architectures will fall
back to a default implementation)

The advantage is that for example to read a local percpu variable,
instead of this sequence:

 return __get_cpu_var(var);

 ffffffff8102ca2b:	48 8b 14 fd 80 09 74 	mov    -0x7e8bf680(,%rdi,8),%rdx
 ffffffff8102ca32:	81
 ffffffff8102ca33:	48 c7 c0 d8 59 00 00 	mov    $0x59d8,%rax
 ffffffff8102ca3a:	48 8b 04 10          	mov    (%rax,%rdx,1),%rax

We can get a single instruction by using the optimized variants:

 return percpu_read(var);

 ffffffff8102ca3f:	65 48 8b 05 91 8f fd 	mov    %gs:0x7efd8f91(%rip),%rax

I also cleaned up the x86-specific APIs and made the x86 code use
these new generic percpu primitives.

tj: * fixed generic percpu_sub() definition as Roel Kluin pointed out
    * added percpu_and() for completeness's sake
    * made generic percpu ops atomic against preemption

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Tejun Heo <tj@kernel.org>
2009-01-16 14:20:31 +01:00

221 lines
4.9 KiB
C

#ifndef _ASM_X86_SMP_H
#define _ASM_X86_SMP_H
#ifndef __ASSEMBLY__
#include <linux/cpumask.h>
#include <linux/init.h>
#include <asm/percpu.h>
/*
* We need the APIC definitions automatically as part of 'smp.h'
*/
#ifdef CONFIG_X86_LOCAL_APIC
# include <asm/mpspec.h>
# include <asm/apic.h>
# ifdef CONFIG_X86_IO_APIC
# include <asm/io_apic.h>
# endif
#endif
#include <asm/pda.h>
#include <asm/thread_info.h>
#include <asm/cpumask.h>
extern int smp_num_siblings;
extern unsigned int num_processors;
DECLARE_PER_CPU(cpumask_t, cpu_sibling_map);
DECLARE_PER_CPU(cpumask_t, cpu_core_map);
DECLARE_PER_CPU(u16, cpu_llc_id);
#ifdef CONFIG_X86_32
DECLARE_PER_CPU(int, cpu_number);
#endif
static inline struct cpumask *cpu_sibling_mask(int cpu)
{
return &per_cpu(cpu_sibling_map, cpu);
}
static inline struct cpumask *cpu_core_mask(int cpu)
{
return &per_cpu(cpu_core_map, cpu);
}
DECLARE_EARLY_PER_CPU(u16, x86_cpu_to_apicid);
DECLARE_EARLY_PER_CPU(u16, x86_bios_cpu_apicid);
/* Static state in head.S used to set up a CPU */
extern struct {
void *sp;
unsigned short ss;
} stack_start;
struct smp_ops {
void (*smp_prepare_boot_cpu)(void);
void (*smp_prepare_cpus)(unsigned max_cpus);
void (*smp_cpus_done)(unsigned max_cpus);
void (*smp_send_stop)(void);
void (*smp_send_reschedule)(int cpu);
int (*cpu_up)(unsigned cpu);
int (*cpu_disable)(void);
void (*cpu_die)(unsigned int cpu);
void (*play_dead)(void);
void (*send_call_func_ipi)(const struct cpumask *mask);
void (*send_call_func_single_ipi)(int cpu);
};
/* Globals due to paravirt */
extern void set_cpu_sibling_map(int cpu);
#ifdef CONFIG_SMP
#ifndef CONFIG_PARAVIRT
#define startup_ipi_hook(phys_apicid, start_eip, start_esp) do { } while (0)
#endif
extern struct smp_ops smp_ops;
static inline void smp_send_stop(void)
{
smp_ops.smp_send_stop();
}
static inline void smp_prepare_boot_cpu(void)
{
smp_ops.smp_prepare_boot_cpu();
}
static inline void smp_prepare_cpus(unsigned int max_cpus)
{
smp_ops.smp_prepare_cpus(max_cpus);
}
static inline void smp_cpus_done(unsigned int max_cpus)
{
smp_ops.smp_cpus_done(max_cpus);
}
static inline int __cpu_up(unsigned int cpu)
{
return smp_ops.cpu_up(cpu);
}
static inline int __cpu_disable(void)
{
return smp_ops.cpu_disable();
}
static inline void __cpu_die(unsigned int cpu)
{
smp_ops.cpu_die(cpu);
}
static inline void play_dead(void)
{
smp_ops.play_dead();
}
static inline void smp_send_reschedule(int cpu)
{
smp_ops.smp_send_reschedule(cpu);
}
static inline void arch_send_call_function_single_ipi(int cpu)
{
smp_ops.send_call_func_single_ipi(cpu);
}
static inline void arch_send_call_function_ipi(cpumask_t mask)
{
smp_ops.send_call_func_ipi(&mask);
}
void cpu_disable_common(void);
void native_smp_prepare_boot_cpu(void);
void native_smp_prepare_cpus(unsigned int max_cpus);
void native_smp_cpus_done(unsigned int max_cpus);
int native_cpu_up(unsigned int cpunum);
int native_cpu_disable(void);
void native_cpu_die(unsigned int cpu);
void native_play_dead(void);
void play_dead_common(void);
void native_send_call_func_ipi(const struct cpumask *mask);
void native_send_call_func_single_ipi(int cpu);
void smp_store_cpu_info(int id);
#define cpu_physical_id(cpu) per_cpu(x86_cpu_to_apicid, cpu)
/* We don't mark CPUs online until __cpu_up(), so we need another measure */
static inline int num_booting_cpus(void)
{
return cpumask_weight(cpu_callout_mask);
}
#endif /* CONFIG_SMP */
extern unsigned disabled_cpus __cpuinitdata;
#ifdef CONFIG_X86_32_SMP
/*
* This function is needed by all SMP systems. It must _always_ be valid
* from the initial startup. We map APIC_BASE very early in page_setup(),
* so this is correct in the x86 case.
*/
#define raw_smp_processor_id() (percpu_read(cpu_number))
extern int safe_smp_processor_id(void);
#elif defined(CONFIG_X86_64_SMP)
#define raw_smp_processor_id() read_pda(cpunumber)
#define stack_smp_processor_id() \
({ \
struct thread_info *ti; \
__asm__("andq %%rsp,%0; ":"=r" (ti) : "0" (CURRENT_MASK)); \
ti->cpu; \
})
#define safe_smp_processor_id() smp_processor_id()
#endif
#ifdef CONFIG_X86_LOCAL_APIC
#ifndef CONFIG_X86_64
static inline int logical_smp_processor_id(void)
{
/* we don't want to mark this access volatile - bad code generation */
return GET_APIC_LOGICAL_ID(*(u32 *)(APIC_BASE + APIC_LDR));
}
#include <mach_apicdef.h>
static inline unsigned int read_apic_id(void)
{
unsigned int reg;
reg = *(u32 *)(APIC_BASE + APIC_ID);
return GET_APIC_ID(reg);
}
#endif
# if defined(APIC_DEFINITION) || defined(CONFIG_X86_64)
extern int hard_smp_processor_id(void);
# else
#include <mach_apicdef.h>
static inline int hard_smp_processor_id(void)
{
/* we don't want to mark this access volatile - bad code generation */
return read_apic_id();
}
# endif /* APIC_DEFINITION */
#else /* CONFIG_X86_LOCAL_APIC */
# ifndef CONFIG_SMP
# define hard_smp_processor_id() 0
# endif
#endif /* CONFIG_X86_LOCAL_APIC */
#endif /* __ASSEMBLY__ */
#endif /* _ASM_X86_SMP_H */