arch/x86/kernel/irq.c

   1 /*
   2  * Common interrupt code for 32 and 64 bit
   3  */
   4 #include <linux/cpu.h>
   5 #include <linux/interrupt.h>
   6 #include <linux/kernel_stat.h>
   7 #include <linux/of.h>
   8 #include <linux/seq_file.h>
   9 #include <linux/smp.h>
  10 #include <linux/ftrace.h>
  11 #include <linux/delay.h>
  12 #include <linux/export.h>
  13
  14 #include <asm/apic.h>
  15 #include <asm/io_apic.h>
  16 #include <asm/irq.h>
  17 #include <asm/idle.h>
  18 #include <asm/mce.h>
  19 #include <asm/hw_irq.h>
  20
  21 atomic_t irq_err_count;
  22
  23 /* Function pointer for generic interrupt vector handling */
  24 void (*x86_platform_ipi_callback)(void) = NULL;
  25
  26 /*
  27  * 'what should we do if we get a hw irq event on an illegal vector'.
  28  * each architecture has to answer this themselves.
  29  */
  30 void ack_bad_irq(unsigned int irq)
  31 {
  32         if (printk_ratelimit())
  33                 pr_err("unexpected IRQ trap at vector %02x\n", irq);
  34
  35         /*
  36          * Currently unexpected vectors happen only on SMP and APIC.
  37          * We _must_ ack these because every local APIC has only N
  38          * irq slots per priority level, and a 'hanging, unacked' IRQ
  39          * holds up an irq slot - in excessive cases (when multiple
  40          * unexpected vectors occur) that might lock up the APIC
  41          * completely.
  42          * But only ack when the APIC is enabled -AK
  43          */
  44         ack_APIC_irq();
  45 }
  46
  47 #define irq_stats(x)            (&per_cpu(irq_stat, x))
  48 /*
  49  * /proc/interrupts printing for arch specific interrupts
  50  */
  51 int arch_show_interrupts(struct seq_file *p, int prec)
  52 {
  53         int j;
  54
  55         seq_printf(p, "%*s: ", prec, "NMI");
  56         for_each_online_cpu(j)
  57                 seq_printf(p, "%10u ", irq_stats(j)->__nmi_count);
  58         seq_printf(p, "  Non-maskable interrupts\n");
  59 #ifdef CONFIG_X86_LOCAL_APIC
  60         seq_printf(p, "%*s: ", prec, "LOC");
  61         for_each_online_cpu(j)
  62                 seq_printf(p, "%10u ", irq_stats(j)->apic_timer_irqs);
  63         seq_printf(p, "  Local timer interrupts\n");
  64
  65         seq_printf(p, "%*s: ", prec, "SPU");
  66         for_each_online_cpu(j)
  67                 seq_printf(p, "%10u ", irq_stats(j)->irq_spurious_count);
  68         seq_printf(p, "  Spurious interrupts\n");
  69         seq_printf(p, "%*s: ", prec, "PMI");
  70         for_each_online_cpu(j)
  71                 seq_printf(p, "%10u ", irq_stats(j)->apic_perf_irqs);
  72         seq_printf(p, "  Performance monitoring interrupts\n");
  73         seq_printf(p, "%*s: ", prec, "IWI");
  74         for_each_online_cpu(j)
  75                 seq_printf(p, "%10u ", irq_stats(j)->apic_irq_work_irqs);
  76         seq_printf(p, "  IRQ work interrupts\n");
  77 #endif
  78         if (x86_platform_ipi_callback) {
  79                 seq_printf(p, "%*s: ", prec, "PLT");
  80                 for_each_online_cpu(j)
  81                         seq_printf(p, "%10u ", irq_stats(j)->x86_platform_ipis);
  82                 seq_printf(p, "  Platform interrupts\n");
  83         }
  84 #ifdef CONFIG_SMP
  85         seq_printf(p, "%*s: ", prec, "RES");
  86         for_each_online_cpu(j)
  87                 seq_printf(p, "%10u ", irq_stats(j)->irq_resched_count);
  88         seq_printf(p, "  Rescheduling interrupts\n");
  89         seq_printf(p, "%*s: ", prec, "CAL");
  90         for_each_online_cpu(j)
  91                 seq_printf(p, "%10u ", irq_stats(j)->irq_call_count);
  92         seq_printf(p, "  Function call interrupts\n");
  93         seq_printf(p, "%*s: ", prec, "TLB");
  94         for_each_online_cpu(j)
  95                 seq_printf(p, "%10u ", irq_stats(j)->irq_tlb_count);
  96         seq_printf(p, "  TLB shootdowns\n");
  97 #endif
  98 #ifdef CONFIG_X86_THERMAL_VECTOR
  99         seq_printf(p, "%*s: ", prec, "TRM");
 100         for_each_online_cpu(j)
 101                 seq_printf(p, "%10u ", irq_stats(j)->irq_thermal_count);
 102         seq_printf(p, "  Thermal event interrupts\n");
 103 #endif
 104 #ifdef CONFIG_X86_MCE_THRESHOLD
 105         seq_printf(p, "%*s: ", prec, "THR");
 106         for_each_online_cpu(j)
 107                 seq_printf(p, "%10u ", irq_stats(j)->irq_threshold_count);
 108         seq_printf(p, "  Threshold APIC interrupts\n");
 109 #endif
 110 #ifdef CONFIG_X86_MCE
 111         seq_printf(p, "%*s: ", prec, "MCE");
 112         for_each_online_cpu(j)
 113                 seq_printf(p, "%10u ", per_cpu(mce_exception_count, j));
 114         seq_printf(p, "  Machine check exceptions\n");
 115         seq_printf(p, "%*s: ", prec, "MCP");
 116         for_each_online_cpu(j)
 117                 seq_printf(p, "%10u ", per_cpu(mce_poll_count, j));
 118         seq_printf(p, "  Machine check polls\n");
 119 #endif
 120         seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
 121 #if defined(CONFIG_X86_IO_APIC)
 122         seq_printf(p, "%*s: %10u\n", prec, "MIS", atomic_read(&irq_mis_count));
 123 #endif
 124         return 0;
 125 }
 126
 127 /*
 128  * /proc/stat helpers
 129  */
 130 u64 arch_irq_stat_cpu(unsigned int cpu)
 131 {
 132         u64 sum = irq_stats(cpu)->__nmi_count;
 133
 134 #ifdef CONFIG_X86_LOCAL_APIC
 135         sum += irq_stats(cpu)->apic_timer_irqs;
 136         sum += irq_stats(cpu)->irq_spurious_count;
 137         sum += irq_stats(cpu)->apic_perf_irqs;
 138         sum += irq_stats(cpu)->apic_irq_work_irqs;
 139 #endif
 140         if (x86_platform_ipi_callback)
 141                 sum += irq_stats(cpu)->x86_platform_ipis;
 142 #ifdef CONFIG_SMP
 143         sum += irq_stats(cpu)->irq_resched_count;
 144         sum += irq_stats(cpu)->irq_call_count;
 145         sum += irq_stats(cpu)->irq_tlb_count;
 146 #endif
 147 #ifdef CONFIG_X86_THERMAL_VECTOR
 148         sum += irq_stats(cpu)->irq_thermal_count;
 149 #endif
 150 #ifdef CONFIG_X86_MCE_THRESHOLD
 151         sum += irq_stats(cpu)->irq_threshold_count;
 152 #endif
 153 #ifdef CONFIG_X86_MCE
 154         sum += per_cpu(mce_exception_count, cpu);
 155         sum += per_cpu(mce_poll_count, cpu);
 156 #endif
 157         return sum;
 158 }
 159
 160 u64 arch_irq_stat(void)
 161 {
 162         u64 sum = atomic_read(&irq_err_count);
 163         return sum;
 164 }
 165
 166
 167 /*
 168  * do_IRQ handles all normal device IRQ's (the special
 169  * SMP cross-CPU interrupts have their own specific
 170  * handlers).
 171  */
 172 unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
 173 {
 174         struct pt_regs *old_regs = set_irq_regs(regs);
 175
 176         /* high bit used in ret_from_ code  */
 177         unsigned vector = ~regs->orig_ax;
 178         unsigned irq;
 179
 180         exit_idle();
 181         irq_enter();
 182
 183         irq = __this_cpu_read(vector_irq[vector]);
 184
 185         if (!handle_irq(irq, regs)) {
 186                 ack_APIC_irq();
 187
 188                 if (printk_ratelimit())
 189                         pr_emerg("%s: %d.%d No irq handler for vector (irq %d)\n",
 190                                 __func__, smp_processor_id(), vector, irq);
 191         }
 192
 193         irq_exit();
 194
 195         set_irq_regs(old_regs);
 196         return 1;
 197 }
 198
 199 /*
 200  * Handler for X86_PLATFORM_IPI_VECTOR.
 201  */
 202 void smp_x86_platform_ipi(struct pt_regs *regs)
 203 {
 204         struct pt_regs *old_regs = set_irq_regs(regs);
 205
 206         ack_APIC_irq();
 207
 208         exit_idle();
 209
 210         irq_enter();
 211
 212         inc_irq_stat(x86_platform_ipis);
 213
 214         if (x86_platform_ipi_callback)
 215                 x86_platform_ipi_callback();
 216
 217         irq_exit();
 218
 219         set_irq_regs(old_regs);
 220 }
 221
 222 EXPORT_SYMBOL_GPL(vector_used_by_percpu_irq);
 223
 224 #ifdef CONFIG_HOTPLUG_CPU
 225 /*
 226  * This cpu is going to be removed and its vectors migrated to the remaining
 227  * online cpus.  Check to see if there are enough vectors in the remaining cpus.
 228  * This function is protected by stop_machine().
 229  */
 230 int check_irq_vectors_for_cpu_disable(void)
 231 {
 232         int irq, cpu;
 233         unsigned int this_cpu, vector, this_count, count;
 234         struct irq_desc *desc;
 235         struct irq_data *data;
 236         struct cpumask affinity_new, online_new;
 237
 238         this_cpu = smp_processor_id();
 239         cpumask_copy(&online_new, cpu_online_mask);
 240         cpu_clear(this_cpu, online_new);
 241
 242         this_count = 0;
 243         for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
 244                 irq = __this_cpu_read(vector_irq[vector]);
 245                 if (irq >= 0) {
 246                         desc = irq_to_desc(irq);
 247                         data = irq_desc_get_irq_data(desc);
 248                         cpumask_copy(&affinity_new, data->affinity);
 249                         cpu_clear(this_cpu, affinity_new);
 250
 251                         /* Do not count inactive or per-cpu irqs. */
 252                         if (!irq_has_action(irq) || irqd_is_per_cpu(data))
 253                                 continue;
 254
 255                         /*
 256                          * A single irq may be mapped to multiple
 257                          * cpu's vector_irq[] (for example IOAPIC cluster
 258                          * mode).  In this case we have two
 259                          * possibilities:
 260                          *
 261                          * 1) the resulting affinity mask is empty; that is
 262                          * this the down'd cpu is the last cpu in the irq's
 263                          * affinity mask, or
 264                          *
 265                          * 2) the resulting affinity mask is no longer
 266                          * a subset of the online cpus but the affinity
 267                          * mask is not zero; that is the down'd cpu is the
 268                          * last online cpu in a user set affinity mask.
 269                          */
 270                         if (cpumask_empty(&affinity_new) ||
 271                             !cpumask_subset(&affinity_new, &online_new))
 272                                 this_count++;
 273                 }
 274         }
 275
 276         count = 0;
 277         for_each_online_cpu(cpu) {
 278                 if (cpu == this_cpu)
 279                         continue;
 280                 for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS;
 281                      vector++) {
 282                         if (per_cpu(vector_irq, cpu)[vector] < 0)
 283                                 count++;
 284                 }
 285         }
 286
 287         if (count < this_count) {
 288                 pr_warn("CPU %d disable failed: CPU has %u vectors assigned and there are only %u available.\n",
 289                         this_cpu, this_count, count);
 290                 return -ERANGE;
 291         }
 292         return 0;
 293 }
 294
 295 /* A cpu has been removed from cpu_online_mask.  Reset irq affinities. */
 296 void fixup_irqs(void)
 297 {
 298         unsigned int irq, vector;
 299         static int warned;
 300         struct irq_desc *desc;
 301         struct irq_data *data;
 302         struct irq_chip *chip;
 303
 304         for_each_irq_desc(irq, desc) {
 305                 int break_affinity = 0;
 306                 int set_affinity = 1;
 307                 const struct cpumask *affinity;
 308
 309                 if (!desc)
 310                         continue;
 311                 if (irq == 2)
 312                         continue;
 313
 314                 /* interrupt's are disabled at this point */
 315                 raw_spin_lock(&desc->lock);
 316
 317                 data = irq_desc_get_irq_data(desc);
 318                 affinity = data->affinity;
 319                 if (!irq_has_action(irq) || irqd_is_per_cpu(data) ||
 320                     cpumask_subset(affinity, cpu_online_mask)) {
 321                         raw_spin_unlock(&desc->lock);
 322                         continue;
 323                 }
 324
 325                 /*
 326                  * Complete the irq move. This cpu is going down and for
 327                  * non intr-remapping case, we can't wait till this interrupt
 328                  * arrives at this cpu before completing the irq move.
 329                  */
 330                 irq_force_complete_move(irq);
 331
 332                 if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
 333                         break_affinity = 1;
 334                         affinity = cpu_all_mask;
 335                 }
 336
 337                 chip = irq_data_get_irq_chip(data);
 338                 if (!irqd_can_move_in_process_context(data) && chip->irq_mask)
 339                         chip->irq_mask(data);
 340
 341                 if (chip->irq_set_affinity)
 342                         chip->irq_set_affinity(data, affinity, true);
 343                 else if (!(warned++))
 344                         set_affinity = 0;
 345
 346                 if (!irqd_can_move_in_process_context(data) &&
 347                     !irqd_irq_disabled(data) && chip->irq_unmask)
 348                         chip->irq_unmask(data);
 349
 350                 raw_spin_unlock(&desc->lock);
 351
 352                 if (break_affinity && set_affinity)
 353                         printk("Broke affinity for irq %i\n", irq);
 354                 else if (!set_affinity)
 355                         printk("Cannot set affinity for irq %i\n", irq);
 356         }
 357
 358         /*
 359          * We can remove mdelay() and then send spuriuous interrupts to
 360          * new cpu targets for all the irqs that were handled previously by
 361          * this cpu. While it works, I have seen spurious interrupt messages
 362          * (nothing wrong but still...).
 363          *
 364          * So for now, retain mdelay(1) and check the IRR and then send those
 365          * interrupts to new targets as this cpu is already offlined...
 366          */
 367         mdelay(1);
 368
 369         for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
 370                 unsigned int irr;
 371
 372                 if (__this_cpu_read(vector_irq[vector]) < 0)
 373                         continue;
 374
 375                 irr = apic_read(APIC_IRR + (vector / 32 * 0x10));
 376                 if (irr  & (1 << (vector % 32))) {
 377                         irq = __this_cpu_read(vector_irq[vector]);
 378
 379                         desc = irq_to_desc(irq);
 380                         data = irq_desc_get_irq_data(desc);
 381                         chip = irq_data_get_irq_chip(data);
 382                         raw_spin_lock(&desc->lock);
 383                         if (chip->irq_retrigger)
 384                                 chip->irq_retrigger(data);
 385                         raw_spin_unlock(&desc->lock);
 386                 }
 387         }
 388 }
 389 #endif