arch/x86/kernel/irq_32.c

   1 /*
   2  *      Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
   3  *
   4  * This file contains the lowest level x86-specific interrupt
   5  * entry, irq-stacks and irq statistics code. All the remaining
   6  * irq logic is done by the generic kernel/irq/ code and
   7  * by the x86-specific irq controller code. (e.g. i8259.c and
   8  * io_apic.c.)
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/seq_file.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/kernel_stat.h>
  15 #include <linux/notifier.h>
  16 #include <linux/cpu.h>
  17 #include <linux/delay.h>
  18
  19 #include <asm/apic.h>
  20 #include <asm/uaccess.h>
  21
  22 DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
  23 EXPORT_PER_CPU_SYMBOL(irq_stat);
  24
  25 DEFINE_PER_CPU(struct pt_regs *, irq_regs);
  26 EXPORT_PER_CPU_SYMBOL(irq_regs);
  27
  28 /*
  29  * 'what should we do if we get a hw irq event on an illegal vector'.
  30  * each architecture has to answer this themselves.
  31  */
  32 void ack_bad_irq(unsigned int irq)
  33 {
  34         printk(KERN_ERR "unexpected IRQ trap at vector %02x\n", irq);
  35
  36 #ifdef CONFIG_X86_LOCAL_APIC
  37         /*
  38          * Currently unexpected vectors happen only on SMP and APIC.
  39          * We _must_ ack these because every local APIC has only N
  40          * irq slots per priority level, and a 'hanging, unacked' IRQ
  41          * holds up an irq slot - in excessive cases (when multiple
  42          * unexpected vectors occur) that might lock up the APIC
  43          * completely.
  44          * But only ack when the APIC is enabled -AK
  45          */
  46         if (cpu_has_apic)
  47                 ack_APIC_irq();
  48 #endif
  49 }
  50
  51 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  52 /* Debugging check for stack overflow: is there less than 1KB free? */
  53 static int check_stack_overflow(void)
  54 {
  55         long sp;
  56
  57         __asm__ __volatile__("andl %%esp,%0" :
  58                              "=r" (sp) : "0" (THREAD_SIZE - 1));
  59
  60         return sp < (sizeof(struct thread_info) + STACK_WARN);
  61 }
  62
  63 static void print_stack_overflow(void)
  64 {
  65         printk(KERN_WARNING "low stack detected by irq handler\n");
  66         dump_stack();
  67 }
  68
  69 #else
  70 static inline int check_stack_overflow(void) { return 0; }
  71 static inline void print_stack_overflow(void) { }
  72 #endif
  73
  74 #ifdef CONFIG_4KSTACKS
  75 /*
  76  * per-CPU IRQ handling contexts (thread information and stack)
  77  */
  78 union irq_ctx {
  79         struct thread_info      tinfo;
  80         u32                     stack[THREAD_SIZE/sizeof(u32)];
  81 };
  82
  83 static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
  84 static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
  85
  86 static char softirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;
  87 static char hardirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;
  88
  89 static void call_on_stack(void *func, void *stack)
  90 {
  91         asm volatile("xchgl     %%ebx,%%esp     \n"
  92                      "call      *%%edi          \n"
  93                      "movl      %%ebx,%%esp     \n"
  94                      : "=b" (stack)
  95                      : "0" (stack),
  96                        "D"(func)
  97                      : "memory", "cc", "edx", "ecx", "eax");
  98 }
  99
 100 static inline int
 101 execute_on_irq_stack(int overflow, struct irq_desc *desc, int irq)
 102 {
 103         union irq_ctx *curctx, *irqctx;
 104         u32 *isp, arg1, arg2;
 105
 106         curctx = (union irq_ctx *) current_thread_info();
 107         irqctx = hardirq_ctx[smp_processor_id()];
 108
 109         /*
 110          * this is where we switch to the IRQ stack. However, if we are
 111          * already using the IRQ stack (because we interrupted a hardirq
 112          * handler) we can't do that and just have to keep using the
 113          * current stack (which is the irq stack already after all)
 114          */
 115         if (unlikely(curctx == irqctx))
 116                 return 0;
 117
 118         /* build the stack frame on the IRQ stack */
 119         isp = (u32 *) ((char*)irqctx + sizeof(*irqctx));
 120         irqctx->tinfo.task = curctx->tinfo.task;
 121         irqctx->tinfo.previous_esp = current_stack_pointer;
 122
 123         /*
 124          * Copy the softirq bits in preempt_count so that the
 125          * softirq checks work in the hardirq context.
 126          */
 127         irqctx->tinfo.preempt_count =
 128                 (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
 129                 (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
 130
 131         if (unlikely(overflow))
 132                 call_on_stack(print_stack_overflow, isp);
 133
 134         asm volatile("xchgl     %%ebx,%%esp     \n"
 135                      "call      *%%edi          \n"
 136                      "movl      %%ebx,%%esp     \n"
 137                      : "=a" (arg1), "=d" (arg2), "=b" (isp)
 138                      :  "0" (irq),   "1" (desc),  "2" (isp),
 139                         "D" (desc->handle_irq)
 140                      : "memory", "cc", "ecx");
 141         return 1;
 142 }
 143
 144 /*
 145  * allocate per-cpu stacks for hardirq and for softirq processing
 146  */
 147 void __cpuinit irq_ctx_init(int cpu)
 148 {
 149         union irq_ctx *irqctx;
 150
 151         if (hardirq_ctx[cpu])
 152                 return;
 153
 154         irqctx = (union irq_ctx*) &hardirq_stack[cpu*THREAD_SIZE];
 155         irqctx->tinfo.task              = NULL;
 156         irqctx->tinfo.exec_domain       = NULL;
 157         irqctx->tinfo.cpu               = cpu;
 158         irqctx->tinfo.preempt_count     = HARDIRQ_OFFSET;
 159         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 160
 161         hardirq_ctx[cpu] = irqctx;
 162
 163         irqctx = (union irq_ctx*) &softirq_stack[cpu*THREAD_SIZE];
 164         irqctx->tinfo.task              = NULL;
 165         irqctx->tinfo.exec_domain       = NULL;
 166         irqctx->tinfo.cpu               = cpu;
 167         irqctx->tinfo.preempt_count     = 0;
 168         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 169
 170         softirq_ctx[cpu] = irqctx;
 171
 172         printk(KERN_DEBUG "CPU %u irqstacks, hard=%p soft=%p\n",
 173                cpu,hardirq_ctx[cpu],softirq_ctx[cpu]);
 174 }
 175
 176 void irq_ctx_exit(int cpu)
 177 {
 178         hardirq_ctx[cpu] = NULL;
 179 }
 180
 181 asmlinkage void do_softirq(void)
 182 {
 183         unsigned long flags;
 184         struct thread_info *curctx;
 185         union irq_ctx *irqctx;
 186         u32 *isp;
 187
 188         if (in_interrupt())
 189                 return;
 190
 191         local_irq_save(flags);
 192
 193         if (local_softirq_pending()) {
 194                 curctx = current_thread_info();
 195                 irqctx = softirq_ctx[smp_processor_id()];
 196                 irqctx->tinfo.task = curctx->task;
 197                 irqctx->tinfo.previous_esp = current_stack_pointer;
 198
 199                 /* build the stack frame on the softirq stack */
 200                 isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
 201
 202                 call_on_stack(__do_softirq, isp);
 203                 /*
 204                  * Shouldnt happen, we returned above if in_interrupt():
 205                  */
 206                 WARN_ON_ONCE(softirq_count());
 207         }
 208
 209         local_irq_restore(flags);
 210 }
 211
 212 #else
 213 static inline int
 214 execute_on_irq_stack(int overflow, struct irq_desc *desc, int irq) { return 0; }
 215 #endif
 216
 217 /*
 218  * do_IRQ handles all normal device IRQ's (the special
 219  * SMP cross-CPU interrupts have their own specific
 220  * handlers).
 221  */
 222 unsigned int do_IRQ(struct pt_regs *regs)
 223 {
 224         struct pt_regs *old_regs;
 225         /* high bit used in ret_from_ code */
 226         int overflow, irq = ~regs->orig_ax;
 227         struct irq_desc *desc = irq_desc + irq;
 228
 229         if (unlikely((unsigned)irq >= NR_IRQS)) {
 230                 printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
 231                                         __func__, irq);
 232                 BUG();
 233         }
 234
 235         old_regs = set_irq_regs(regs);
 236         irq_enter();
 237
 238         overflow = check_stack_overflow();
 239
 240         if (!execute_on_irq_stack(overflow, desc, irq)) {
 241                 if (unlikely(overflow))
 242                         print_stack_overflow();
 243                 desc->handle_irq(irq, desc);
 244         }
 245
 246         irq_exit();
 247         set_irq_regs(old_regs);
 248         return 1;
 249 }
 250
 251 /*
 252  * Interrupt statistics:
 253  */
 254
 255 atomic_t irq_err_count;
 256
 257 /*
 258  * /proc/interrupts printing:
 259  */
 260
 261 int show_interrupts(struct seq_file *p, void *v)
 262 {
 263         int i = *(loff_t *) v, j;
 264         struct irqaction * action;
 265         unsigned long flags;
 266
 267         if (i == 0) {
 268                 seq_printf(p, "           ");
 269                 for_each_online_cpu(j)
 270                         seq_printf(p, "CPU%-8d",j);
 271                 seq_putc(p, '\n');
 272         }
 273
 274         if (i < NR_IRQS) {
 275                 unsigned any_count = 0;
 276
 277                 spin_lock_irqsave(&irq_desc[i].lock, flags);
 278 #ifndef CONFIG_SMP
 279                 any_count = kstat_irqs(i);
 280 #else
 281                 for_each_online_cpu(j)
 282                         any_count |= kstat_cpu(j).irqs[i];
 283 #endif
 284                 action = irq_desc[i].action;
 285                 if (!action && !any_count)
 286                         goto skip;
 287                 seq_printf(p, "%3d: ",i);
 288 #ifndef CONFIG_SMP
 289                 seq_printf(p, "%10u ", kstat_irqs(i));
 290 #else
 291                 for_each_online_cpu(j)
 292                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
 293 #endif
 294                 seq_printf(p, " %8s", irq_desc[i].chip->name);
 295                 seq_printf(p, "-%-8s", irq_desc[i].name);
 296
 297                 if (action) {
 298                         seq_printf(p, "  %s", action->name);
 299                         while ((action = action->next) != NULL)
 300                                 seq_printf(p, ", %s", action->name);
 301                 }
 302
 303                 seq_putc(p, '\n');
 304 skip:
 305                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
 306         } else if (i == NR_IRQS) {
 307                 seq_printf(p, "NMI: ");
 308                 for_each_online_cpu(j)
 309                         seq_printf(p, "%10u ", nmi_count(j));
 310                 seq_printf(p, "  Non-maskable interrupts\n");
 311 #ifdef CONFIG_X86_LOCAL_APIC
 312                 seq_printf(p, "LOC: ");
 313                 for_each_online_cpu(j)
 314                         seq_printf(p, "%10u ",
 315                                 per_cpu(irq_stat,j).apic_timer_irqs);
 316                 seq_printf(p, "  Local timer interrupts\n");
 317 #endif
 318 #ifdef CONFIG_SMP
 319                 seq_printf(p, "RES: ");
 320                 for_each_online_cpu(j)
 321                         seq_printf(p, "%10u ",
 322                                 per_cpu(irq_stat,j).irq_resched_count);
 323                 seq_printf(p, "  Rescheduling interrupts\n");
 324                 seq_printf(p, "CAL: ");
 325                 for_each_online_cpu(j)
 326                         seq_printf(p, "%10u ",
 327                                 per_cpu(irq_stat,j).irq_call_count);
 328                 seq_printf(p, "  Function call interrupts\n");
 329                 seq_printf(p, "TLB: ");
 330                 for_each_online_cpu(j)
 331                         seq_printf(p, "%10u ",
 332                                 per_cpu(irq_stat,j).irq_tlb_count);
 333                 seq_printf(p, "  TLB shootdowns\n");
 334 #endif
 335 #ifdef CONFIG_X86_MCE
 336                 seq_printf(p, "TRM: ");
 337                 for_each_online_cpu(j)
 338                         seq_printf(p, "%10u ",
 339                                 per_cpu(irq_stat,j).irq_thermal_count);
 340                 seq_printf(p, "  Thermal event interrupts\n");
 341 #endif
 342 #ifdef CONFIG_X86_LOCAL_APIC
 343                 seq_printf(p, "SPU: ");
 344                 for_each_online_cpu(j)
 345                         seq_printf(p, "%10u ",
 346                                 per_cpu(irq_stat,j).irq_spurious_count);
 347                 seq_printf(p, "  Spurious interrupts\n");
 348 #endif
 349                 seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
 350 #if defined(CONFIG_X86_IO_APIC)
 351                 seq_printf(p, "MIS: %10u\n", atomic_read(&irq_mis_count));
 352 #endif
 353         }
 354         return 0;
 355 }
 356
 357 /*
 358  * /proc/stat helpers
 359  */
 360 u64 arch_irq_stat_cpu(unsigned int cpu)
 361 {
 362         u64 sum = nmi_count(cpu);
 363
 364 #ifdef CONFIG_X86_LOCAL_APIC
 365         sum += per_cpu(irq_stat, cpu).apic_timer_irqs;
 366 #endif
 367 #ifdef CONFIG_SMP
 368         sum += per_cpu(irq_stat, cpu).irq_resched_count;
 369         sum += per_cpu(irq_stat, cpu).irq_call_count;
 370         sum += per_cpu(irq_stat, cpu).irq_tlb_count;
 371 #endif
 372 #ifdef CONFIG_X86_MCE
 373         sum += per_cpu(irq_stat, cpu).irq_thermal_count;
 374 #endif
 375 #ifdef CONFIG_X86_LOCAL_APIC
 376         sum += per_cpu(irq_stat, cpu).irq_spurious_count;
 377 #endif
 378         return sum;
 379 }
 380
 381 u64 arch_irq_stat(void)
 382 {
 383         u64 sum = atomic_read(&irq_err_count);
 384
 385 #ifdef CONFIG_X86_IO_APIC
 386         sum += atomic_read(&irq_mis_count);
 387 #endif
 388         return sum;
 389 }
 390
 391 #ifdef CONFIG_HOTPLUG_CPU
 392 #include <mach_apic.h>
 393
 394 void fixup_irqs(cpumask_t map)
 395 {
 396         unsigned int irq;
 397         static int warned;
 398
 399         for (irq = 0; irq < NR_IRQS; irq++) {
 400                 cpumask_t mask;
 401                 if (irq == 2)
 402                         continue;
 403
 404                 cpus_and(mask, irq_desc[irq].affinity, map);
 405                 if (any_online_cpu(mask) == NR_CPUS) {
 406                         printk("Breaking affinity for irq %i\n", irq);
 407                         mask = map;
 408                 }
 409                 if (irq_desc[irq].chip->set_affinity)
 410                         irq_desc[irq].chip->set_affinity(irq, mask);
 411                 else if (irq_desc[irq].action && !(warned++))
 412                         printk("Cannot set affinity for irq %i\n", irq);
 413         }
 414
 415 #if 0
 416         barrier();
 417         /* Ingo Molnar says: "after the IO-APIC masks have been redirected
 418            [note the nop - the interrupt-enable boundary on x86 is two
 419            instructions from sti] - to flush out pending hardirqs and
 420            IPIs. After this point nothing is supposed to reach this CPU." */
 421         __asm__ __volatile__("sti; nop; cli");
 422         barrier();
 423 #else
 424         /* That doesn't seem sufficient.  Give it 1ms. */
 425         local_irq_enable();
 426         mdelay(1);
 427         local_irq_disable();
 428 #endif
 429 }
 430 #endif
 431