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 #define CREATE_TRACE_POINTS
  22 #include <asm/trace/irq_vectors.h>
  23
  24 atomic_t irq_err_count;
  25
  26 /* Function pointer for generic interrupt vector handling */
  27 void (*x86_platform_ipi_callback)(void) = NULL;
  28
  29 /*
  30  * 'what should we do if we get a hw irq event on an illegal vector'.
  31  * each architecture has to answer this themselves.
  32  */
  33 void ack_bad_irq(unsigned int irq)
  34 {
  35         if (printk_ratelimit())
  36                 pr_err("unexpected IRQ trap at vector %02x\n", irq);
  37
  38         /*
  39          * Currently unexpected vectors happen only on SMP and APIC.
  40          * We _must_ ack these because every local APIC has only N
  41          * irq slots per priority level, and a 'hanging, unacked' IRQ
  42          * holds up an irq slot - in excessive cases (when multiple
  43          * unexpected vectors occur) that might lock up the APIC
  44          * completely.
  45          * But only ack when the APIC is enabled -AK
  46          */
  47         ack_APIC_irq();
  48 }
  49
  50 #define irq_stats(x)            (&per_cpu(irq_stat, x))
  51 /*
  52  * /proc/interrupts printing for arch specific interrupts
  53  */
  54 int arch_show_interrupts(struct seq_file *p, int prec)
  55 {
  56         int j;
  57
  58         seq_printf(p, "%*s: ", prec, "NMI");
  59         for_each_online_cpu(j)
  60                 seq_printf(p, "%10u ", irq_stats(j)->__nmi_count);
  61         seq_printf(p, "  Non-maskable interrupts\n");
  62 #ifdef CONFIG_X86_LOCAL_APIC
  63         seq_printf(p, "%*s: ", prec, "LOC");
  64         for_each_online_cpu(j)
  65                 seq_printf(p, "%10u ", irq_stats(j)->apic_timer_irqs);
  66         seq_printf(p, "  Local timer interrupts\n");
  67
  68         seq_printf(p, "%*s: ", prec, "SPU");
  69         for_each_online_cpu(j)
  70                 seq_printf(p, "%10u ", irq_stats(j)->irq_spurious_count);
  71         seq_printf(p, "  Spurious interrupts\n");
  72         seq_printf(p, "%*s: ", prec, "PMI");
  73         for_each_online_cpu(j)
  74                 seq_printf(p, "%10u ", irq_stats(j)->apic_perf_irqs);
  75         seq_printf(p, "  Performance monitoring interrupts\n");
  76         seq_printf(p, "%*s: ", prec, "IWI");
  77         for_each_online_cpu(j)
  78                 seq_printf(p, "%10u ", irq_stats(j)->apic_irq_work_irqs);
  79         seq_printf(p, "  IRQ work interrupts\n");
  80         seq_printf(p, "%*s: ", prec, "RTR");
  81         for_each_online_cpu(j)
  82                 seq_printf(p, "%10u ", irq_stats(j)->icr_read_retry_count);
  83         seq_printf(p, "  APIC ICR read retries\n");
  84 #endif
  85         if (x86_platform_ipi_callback) {
  86                 seq_printf(p, "%*s: ", prec, "PLT");
  87                 for_each_online_cpu(j)
  88                         seq_printf(p, "%10u ", irq_stats(j)->x86_platform_ipis);
  89                 seq_printf(p, "  Platform interrupts\n");
  90         }
  91 #ifdef CONFIG_SMP
  92         seq_printf(p, "%*s: ", prec, "RES");
  93         for_each_online_cpu(j)
  94                 seq_printf(p, "%10u ", irq_stats(j)->irq_resched_count);
  95         seq_printf(p, "  Rescheduling interrupts\n");
  96         seq_printf(p, "%*s: ", prec, "CAL");
  97         for_each_online_cpu(j)
  98                 seq_printf(p, "%10u ", irq_stats(j)->irq_call_count -
  99                                         irq_stats(j)->irq_tlb_count);
 100         seq_printf(p, "  Function call interrupts\n");
 101         seq_printf(p, "%*s: ", prec, "TLB");
 102         for_each_online_cpu(j)
 103                 seq_printf(p, "%10u ", irq_stats(j)->irq_tlb_count);
 104         seq_printf(p, "  TLB shootdowns\n");
 105 #endif
 106 #ifdef CONFIG_X86_THERMAL_VECTOR
 107         seq_printf(p, "%*s: ", prec, "TRM");
 108         for_each_online_cpu(j)
 109                 seq_printf(p, "%10u ", irq_stats(j)->irq_thermal_count);
 110         seq_printf(p, "  Thermal event interrupts\n");
 111 #endif
 112 #ifdef CONFIG_X86_MCE_THRESHOLD
 113         seq_printf(p, "%*s: ", prec, "THR");
 114         for_each_online_cpu(j)
 115                 seq_printf(p, "%10u ", irq_stats(j)->irq_threshold_count);
 116         seq_printf(p, "  Threshold APIC interrupts\n");
 117 #endif
 118 #ifdef CONFIG_X86_MCE
 119         seq_printf(p, "%*s: ", prec, "MCE");
 120         for_each_online_cpu(j)
 121                 seq_printf(p, "%10u ", per_cpu(mce_exception_count, j));
 122         seq_printf(p, "  Machine check exceptions\n");
 123         seq_printf(p, "%*s: ", prec, "MCP");
 124         for_each_online_cpu(j)
 125                 seq_printf(p, "%10u ", per_cpu(mce_poll_count, j));
 126         seq_printf(p, "  Machine check polls\n");
 127 #endif
 128 #if defined(CONFIG_HYPERV) || defined(CONFIG_XEN)
 129         seq_printf(p, "%*s: ", prec, "THR");
 130         for_each_online_cpu(j)
 131                 seq_printf(p, "%10u ", irq_stats(j)->irq_hv_callback_count);
 132         seq_printf(p, "  Hypervisor callback interrupts\n");
 133 #endif
 134         seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
 135 #if defined(CONFIG_X86_IO_APIC)
 136         seq_printf(p, "%*s: %10u\n", prec, "MIS", atomic_read(&irq_mis_count));
 137 #endif
 138         return 0;
 139 }
 140
 141 /*
 142  * /proc/stat helpers
 143  */
 144 u64 arch_irq_stat_cpu(unsigned int cpu)
 145 {
 146         u64 sum = irq_stats(cpu)->__nmi_count;
 147
 148 #ifdef CONFIG_X86_LOCAL_APIC
 149         sum += irq_stats(cpu)->apic_timer_irqs;
 150         sum += irq_stats(cpu)->irq_spurious_count;
 151         sum += irq_stats(cpu)->apic_perf_irqs;
 152         sum += irq_stats(cpu)->apic_irq_work_irqs;
 153         sum += irq_stats(cpu)->icr_read_retry_count;
 154 #endif
 155         if (x86_platform_ipi_callback)
 156                 sum += irq_stats(cpu)->x86_platform_ipis;
 157 #ifdef CONFIG_SMP
 158         sum += irq_stats(cpu)->irq_resched_count;
 159         sum += irq_stats(cpu)->irq_call_count;
 160 #endif
 161 #ifdef CONFIG_X86_THERMAL_VECTOR
 162         sum += irq_stats(cpu)->irq_thermal_count;
 163 #endif
 164 #ifdef CONFIG_X86_MCE_THRESHOLD
 165         sum += irq_stats(cpu)->irq_threshold_count;
 166 #endif
 167 #ifdef CONFIG_X86_MCE
 168         sum += per_cpu(mce_exception_count, cpu);
 169         sum += per_cpu(mce_poll_count, cpu);
 170 #endif
 171         return sum;
 172 }
 173
 174 u64 arch_irq_stat(void)
 175 {
 176         u64 sum = atomic_read(&irq_err_count);
 177         return sum;
 178 }
 179
 180
 181 /*
 182  * do_IRQ handles all normal device IRQ's (the special
 183  * SMP cross-CPU interrupts have their own specific
 184  * handlers).
 185  */
 186 __visible unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
 187 {
 188         struct pt_regs *old_regs = set_irq_regs(regs);
 189
 190         /* high bit used in ret_from_ code  */
 191         unsigned vector = ~regs->orig_ax;
 192         unsigned irq;
 193
 194         irq_enter();
 195         exit_idle();
 196
 197         irq = __this_cpu_read(vector_irq[vector]);
 198
 199         if (!handle_irq(irq, regs)) {
 200                 ack_APIC_irq();
 201
 202                 if (irq != VECTOR_RETRIGGERED) {
 203                         pr_emerg_ratelimited("%s: %d.%d No irq handler for vector (irq %d)\n",
 204                                              __func__, smp_processor_id(),
 205                                              vector, irq);
 206                 } else {
 207                         __this_cpu_write(vector_irq[vector], VECTOR_UNDEFINED);
 208                 }
 209         }
 210
 211         irq_exit();
 212
 213         set_irq_regs(old_regs);
 214         return 1;
 215 }
 216
 217 /*
 218  * Handler for X86_PLATFORM_IPI_VECTOR.
 219  */
 220 void __smp_x86_platform_ipi(void)
 221 {
 222         inc_irq_stat(x86_platform_ipis);
 223
 224         if (x86_platform_ipi_callback)
 225                 x86_platform_ipi_callback();
 226 }
 227
 228 __visible void smp_x86_platform_ipi(struct pt_regs *regs)
 229 {
 230         struct pt_regs *old_regs = set_irq_regs(regs);
 231
 232         entering_ack_irq();
 233         __smp_x86_platform_ipi();
 234         exiting_irq();
 235         set_irq_regs(old_regs);
 236 }
 237
 238 #ifdef CONFIG_HAVE_KVM
 239 /*
 240  * Handler for POSTED_INTERRUPT_VECTOR.
 241  */
 242 __visible void smp_kvm_posted_intr_ipi(struct pt_regs *regs)
 243 {
 244         struct pt_regs *old_regs = set_irq_regs(regs);
 245
 246         ack_APIC_irq();
 247
 248         irq_enter();
 249
 250         exit_idle();
 251
 252         inc_irq_stat(kvm_posted_intr_ipis);
 253
 254         irq_exit();
 255
 256         set_irq_regs(old_regs);
 257 }
 258 #endif
 259
 260 __visible void smp_trace_x86_platform_ipi(struct pt_regs *regs)
 261 {
 262         struct pt_regs *old_regs = set_irq_regs(regs);
 263
 264         entering_ack_irq();
 265         trace_x86_platform_ipi_entry(X86_PLATFORM_IPI_VECTOR);
 266         __smp_x86_platform_ipi();
 267         trace_x86_platform_ipi_exit(X86_PLATFORM_IPI_VECTOR);
 268         exiting_irq();
 269         set_irq_regs(old_regs);
 270 }
 271
 272 EXPORT_SYMBOL_GPL(vector_used_by_percpu_irq);
 273
 274 #ifdef CONFIG_HOTPLUG_CPU
 275
 276 /* These two declarations are only used in check_irq_vectors_for_cpu_disable()
 277  * below, which is protected by stop_machine().  Putting them on the stack
 278  * results in a stack frame overflow.  Dynamically allocating could result in a
 279  * failure so declare these two cpumasks as global.
 280  */
 281 static struct cpumask affinity_new, online_new;
 282
 283 /*
 284  * This cpu is going to be removed and its vectors migrated to the remaining
 285  * online cpus.  Check to see if there are enough vectors in the remaining cpus.
 286  * This function is protected by stop_machine().
 287  */
 288 int check_irq_vectors_for_cpu_disable(void)
 289 {
 290         int irq, cpu;
 291         unsigned int this_cpu, vector, this_count, count;
 292         struct irq_desc *desc;
 293         struct irq_data *data;
 294
 295         this_cpu = smp_processor_id();
 296         cpumask_copy(&online_new, cpu_online_mask);
 297         cpu_clear(this_cpu, online_new);
 298
 299         this_count = 0;
 300         for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
 301                 irq = __this_cpu_read(vector_irq[vector]);
 302                 if (irq >= 0) {
 303                         desc = irq_to_desc(irq);
 304                         data = irq_desc_get_irq_data(desc);
 305                         cpumask_copy(&affinity_new, data->affinity);
 306                         cpu_clear(this_cpu, affinity_new);
 307
 308                         /* Do not count inactive or per-cpu irqs. */
 309                         if (!irq_has_action(irq) || irqd_is_per_cpu(data))
 310                                 continue;
 311
 312                         /*
 313                          * A single irq may be mapped to multiple
 314                          * cpu's vector_irq[] (for example IOAPIC cluster
 315                          * mode).  In this case we have two
 316                          * possibilities:
 317                          *
 318                          * 1) the resulting affinity mask is empty; that is
 319                          * this the down'd cpu is the last cpu in the irq's
 320                          * affinity mask, or
 321                          *
 322                          * 2) the resulting affinity mask is no longer
 323                          * a subset of the online cpus but the affinity
 324                          * mask is not zero; that is the down'd cpu is the
 325                          * last online cpu in a user set affinity mask.
 326                          */
 327                         if (cpumask_empty(&affinity_new) ||
 328                             !cpumask_subset(&affinity_new, &online_new))
 329                                 this_count++;
 330                 }
 331         }
 332
 333         count = 0;
 334         for_each_online_cpu(cpu) {
 335                 if (cpu == this_cpu)
 336                         continue;
 337                 for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS;
 338                      vector++) {
 339                         if (per_cpu(vector_irq, cpu)[vector] < 0)
 340                                 count++;
 341                 }
 342         }
 343
 344         if (count < this_count) {
 345                 pr_warn("CPU %d disable failed: CPU has %u vectors assigned and there are only %u available.\n",
 346                         this_cpu, this_count, count);
 347                 return -ERANGE;
 348         }
 349         return 0;
 350 }
 351
 352 /* A cpu has been removed from cpu_online_mask.  Reset irq affinities. */
 353 void fixup_irqs(void)
 354 {
 355         unsigned int irq, vector;
 356         static int warned;
 357         struct irq_desc *desc;
 358         struct irq_data *data;
 359         struct irq_chip *chip;
 360
 361         for_each_irq_desc(irq, desc) {
 362                 int break_affinity = 0;
 363                 int set_affinity = 1;
 364                 const struct cpumask *affinity;
 365
 366                 if (!desc)
 367                         continue;
 368                 if (irq == 2)
 369                         continue;
 370
 371                 /* interrupt's are disabled at this point */
 372                 raw_spin_lock(&desc->lock);
 373
 374                 data = irq_desc_get_irq_data(desc);
 375                 affinity = data->affinity;
 376                 if (!irq_has_action(irq) || irqd_is_per_cpu(data) ||
 377                     cpumask_subset(affinity, cpu_online_mask)) {
 378                         raw_spin_unlock(&desc->lock);
 379                         continue;
 380                 }
 381
 382                 /*
 383                  * Complete the irq move. This cpu is going down and for
 384                  * non intr-remapping case, we can't wait till this interrupt
 385                  * arrives at this cpu before completing the irq move.
 386                  */
 387                 irq_force_complete_move(irq);
 388
 389                 if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
 390                         break_affinity = 1;
 391                         affinity = cpu_online_mask;
 392                 }
 393
 394                 chip = irq_data_get_irq_chip(data);
 395                 if (!irqd_can_move_in_process_context(data) && chip->irq_mask)
 396                         chip->irq_mask(data);
 397
 398                 if (chip->irq_set_affinity)
 399                         chip->irq_set_affinity(data, affinity, true);
 400                 else if (!(warned++))
 401                         set_affinity = 0;
 402
 403                 /*
 404                  * We unmask if the irq was not marked masked by the
 405                  * core code. That respects the lazy irq disable
 406                  * behaviour.
 407                  */
 408                 if (!irqd_can_move_in_process_context(data) &&
 409                     !irqd_irq_masked(data) && chip->irq_unmask)
 410                         chip->irq_unmask(data);
 411
 412                 raw_spin_unlock(&desc->lock);
 413
 414                 if (break_affinity && set_affinity)
 415                         pr_notice("Broke affinity for irq %i\n", irq);
 416                 else if (!set_affinity)
 417                         pr_notice("Cannot set affinity for irq %i\n", irq);
 418         }
 419
 420         /*
 421          * We can remove mdelay() and then send spuriuous interrupts to
 422          * new cpu targets for all the irqs that were handled previously by
 423          * this cpu. While it works, I have seen spurious interrupt messages
 424          * (nothing wrong but still...).
 425          *
 426          * So for now, retain mdelay(1) and check the IRR and then send those
 427          * interrupts to new targets as this cpu is already offlined...
 428          */
 429         mdelay(1);
 430
 431         for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
 432                 unsigned int irr;
 433
 434                 if (__this_cpu_read(vector_irq[vector]) <= VECTOR_UNDEFINED)
 435                         continue;
 436
 437                 irr = apic_read(APIC_IRR + (vector / 32 * 0x10));
 438                 if (irr  & (1 << (vector % 32))) {
 439                         irq = __this_cpu_read(vector_irq[vector]);
 440
 441                         desc = irq_to_desc(irq);
 442                         data = irq_desc_get_irq_data(desc);
 443                         chip = irq_data_get_irq_chip(data);
 444                         raw_spin_lock(&desc->lock);
 445                         if (chip->irq_retrigger) {
 446                                 chip->irq_retrigger(data);
 447                                 __this_cpu_write(vector_irq[vector], VECTOR_RETRIGGERED);
 448                         }
 449                         raw_spin_unlock(&desc->lock);
 450                 }
 451                 if (__this_cpu_read(vector_irq[vector]) != VECTOR_RETRIGGERED)
 452                         __this_cpu_write(vector_irq[vector], VECTOR_UNDEFINED);
 453         }
 454 }
 455 #endif