arch/x86/kernel/ipi.c

   1 #include <linux/cpumask.h>
   2 #include <linux/interrupt.h>
   3 #include <linux/init.h>
   4
   5 #include <linux/mm.h>
   6 #include <linux/delay.h>
   7 #include <linux/spinlock.h>
   8 #include <linux/kernel_stat.h>
   9 #include <linux/mc146818rtc.h>
  10 #include <linux/cache.h>
  11 #include <linux/cpu.h>
  12 #include <linux/module.h>
  13
  14 #include <asm/smp.h>
  15 #include <asm/mtrr.h>
  16 #include <asm/tlbflush.h>
  17 #include <asm/mmu_context.h>
  18 #include <asm/apic.h>
  19 #include <asm/proto.h>
  20
  21 #ifdef CONFIG_X86_32
  22 #include <mach_apic.h>
  23 #include <mach_ipi.h>
  24
  25 /*
  26  * the following functions deal with sending IPIs between CPUs.
  27  *
  28  * We use 'broadcast', CPU->CPU IPIs and self-IPIs too.
  29  */
  30
  31 static inline int __prepare_ICR(unsigned int shortcut, int vector)
  32 {
  33         unsigned int icr = shortcut | APIC_DEST_LOGICAL;
  34
  35         switch (vector) {
  36         default:
  37                 icr |= APIC_DM_FIXED | vector;
  38                 break;
  39         case NMI_VECTOR:
  40                 icr |= APIC_DM_NMI;
  41                 break;
  42         }
  43         return icr;
  44 }
  45
  46 static inline int __prepare_ICR2(unsigned int mask)
  47 {
  48         return SET_APIC_DEST_FIELD(mask);
  49 }
  50
  51 void __send_IPI_shortcut(unsigned int shortcut, int vector)
  52 {
  53         /*
  54          * Subtle. In the case of the 'never do double writes' workaround
  55          * we have to lock out interrupts to be safe.  As we don't care
  56          * of the value read we use an atomic rmw access to avoid costly
  57          * cli/sti.  Otherwise we use an even cheaper single atomic write
  58          * to the APIC.
  59          */
  60         unsigned int cfg;
  61
  62         /*
  63          * Wait for idle.
  64          */
  65         apic_wait_icr_idle();
  66
  67         /*
  68          * No need to touch the target chip field
  69          */
  70         cfg = __prepare_ICR(shortcut, vector);
  71
  72         /*
  73          * Send the IPI. The write to APIC_ICR fires this off.
  74          */
  75         apic_write(APIC_ICR, cfg);
  76 }
  77
  78 void send_IPI_self(int vector)
  79 {
  80         __send_IPI_shortcut(APIC_DEST_SELF, vector);
  81 }
  82
  83 /*
  84  * This is used to send an IPI with no shorthand notation (the destination is
  85  * specified in bits 56 to 63 of the ICR).
  86  */
  87 static inline void __send_IPI_dest_field(unsigned long mask, int vector)
  88 {
  89         unsigned long cfg;
  90
  91         /*
  92          * Wait for idle.
  93          */
  94         if (unlikely(vector == NMI_VECTOR))
  95                 safe_apic_wait_icr_idle();
  96         else
  97                 apic_wait_icr_idle();
  98
  99         /*
 100          * prepare target chip field
 101          */
 102         cfg = __prepare_ICR2(mask);
 103         apic_write(APIC_ICR2, cfg);
 104
 105         /*
 106          * program the ICR
 107          */
 108         cfg = __prepare_ICR(0, vector);
 109
 110         /*
 111          * Send the IPI. The write to APIC_ICR fires this off.
 112          */
 113         apic_write(APIC_ICR, cfg);
 114 }
 115
 116 /*
 117  * This is only used on smaller machines.
 118  */
 119 void send_IPI_mask_bitmask(const struct cpumask *cpumask, int vector)
 120 {
 121         unsigned long mask = cpumask_bits(cpumask)[0];
 122         unsigned long flags;
 123
 124         local_irq_save(flags);
 125         WARN_ON(mask & ~cpumask_bits(cpu_online_mask)[0]);
 126         __send_IPI_dest_field(mask, vector);
 127         local_irq_restore(flags);
 128 }
 129
 130 void send_IPI_mask_sequence(const struct cpumask *mask, int vector)
 131 {
 132         unsigned long flags;
 133         unsigned int query_cpu;
 134
 135         /*
 136          * Hack. The clustered APIC addressing mode doesn't allow us to send
 137          * to an arbitrary mask, so I do a unicasts to each CPU instead. This
 138          * should be modified to do 1 message per cluster ID - mbligh
 139          */
 140
 141         local_irq_save(flags);
 142         for_each_cpu(query_cpu, mask)
 143                 __send_IPI_dest_field(cpu_to_logical_apicid(query_cpu), vector);
 144         local_irq_restore(flags);
 145 }
 146
 147 void send_IPI_mask_allbutself(const struct cpumask *mask, int vector)
 148 {
 149         unsigned long flags;
 150         unsigned int query_cpu;
 151         unsigned int this_cpu = smp_processor_id();
 152
 153         /* See Hack comment above */
 154
 155         local_irq_save(flags);
 156         for_each_cpu(query_cpu, mask)
 157                 if (query_cpu != this_cpu)
 158                         __send_IPI_dest_field(cpu_to_logical_apicid(query_cpu),
 159                                               vector);
 160         local_irq_restore(flags);
 161 }
 162
 163 /* must come after the send_IPI functions above for inlining */
 164 static int convert_apicid_to_cpu(int apic_id)
 165 {
 166         int i;
 167
 168         for_each_possible_cpu(i) {
 169                 if (per_cpu(x86_cpu_to_apicid, i) == apic_id)
 170                         return i;
 171         }
 172         return -1;
 173 }
 174
 175 int safe_smp_processor_id(void)
 176 {
 177         int apicid, cpuid;
 178
 179         if (!boot_cpu_has(X86_FEATURE_APIC))
 180                 return 0;
 181
 182         apicid = hard_smp_processor_id();
 183         if (apicid == BAD_APICID)
 184                 return 0;
 185
 186         cpuid = convert_apicid_to_cpu(apicid);
 187
 188         return cpuid >= 0 ? cpuid : 0;
 189 }
 190 #endif