LXR linux/arch/i386/kernel/smpcommon.c

   1/*
   2 * SMP stuff which is common to all sub-architectures.
   3 */
   4#include <linux/module.h>
   5#include <asm/smp.h>
   6
   7DEFINE_PER_CPU(unsigned long, this_cpu_off);
   8EXPORT_PER_CPU_SYMBOL(this_cpu_off);
   9
  10/* Initialize the CPU's GDT.  This is either the boot CPU doing itself
  11   (still using the master per-cpu area), or a CPU doing it for a
  12   secondary which will soon come up. */
  13__cpuinit void init_gdt(int cpu)
  14{
  15        struct desc_struct *gdt = get_cpu_gdt_table(cpu);
  16
  17        pack_descriptor((u32 *)&gdt[GDT_ENTRY_PERCPU].a,
  18                        (u32 *)&gdt[GDT_ENTRY_PERCPU].b,
  19                        __per_cpu_offset[cpu], 0xFFFFF,
  20                        0x80 | DESCTYPE_S | 0x2, 0x8);
  21
  22        per_cpu(this_cpu_off, cpu) = __per_cpu_offset[cpu];
  23        per_cpu(cpu_number, cpu) = cpu;
  24}
  25
  26
  27/**
  28 * smp_call_function(): Run a function on all other CPUs.
  29 * @func: The function to run. This must be fast and non-blocking.
  30 * @info: An arbitrary pointer to pass to the function.
  31 * @nonatomic: Unused.
  32 * @wait: If true, wait (atomically) until function has completed on other CPUs.
  33 *
  34 * Returns 0 on success, else a negative status code.
  35 *
  36 * If @wait is true, then returns once @func has returned; otherwise
  37 * it returns just before the target cpu calls @func.
  38 *
  39 * You must not call this function with disabled interrupts or from a
  40 * hardware interrupt handler or from a bottom half handler.
  41 */
  42int smp_call_function(void (*func) (void *info), void *info, int nonatomic,
  43                      int wait)
  44{
  45        return smp_call_function_mask(cpu_online_map, func, info, wait);
  46}
  47EXPORT_SYMBOL(smp_call_function);
  48
  49/**
  50 * smp_call_function_single - Run a function on another CPU
  51 * @cpu: The target CPU.  Cannot be the calling CPU.
  52 * @func: The function to run. This must be fast and non-blocking.
  53 * @info: An arbitrary pointer to pass to the function.
  54 * @nonatomic: Unused.
  55 * @wait: If true, wait until function has completed on other CPUs.
  56 *
  57 * Returns 0 on success, else a negative status code.
  58 *
  59 * If @wait is true, then returns once @func has returned; otherwise
  60 * it returns just before the target cpu calls @func.
  61 */
  62int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
  63                             int nonatomic, int wait)
  64{
  65        /* prevent preemption and reschedule on another processor */
  66        int ret;
  67        int me = get_cpu();
  68        if (cpu == me) {
  69                WARN_ON(1);
  70                put_cpu();
  71                return -EBUSY;
  72        }
  73
  74        ret = smp_call_function_mask(cpumask_of_cpu(cpu), func, info, wait);
  75
  76        put_cpu();
  77        return ret;
  78}
  79EXPORT_SYMBOL(smp_call_function_single);
  80