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_4KSTACKS
  52 /*
  53  * per-CPU IRQ handling contexts (thread information and stack)
  54  */
  55 union irq_ctx {
  56         struct thread_info      tinfo;
  57         u32                     stack[THREAD_SIZE/sizeof(u32)];
  58 };
  59
  60 static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
  61 static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
  62 #endif
  63
  64 /*
  65  * do_IRQ handles all normal device IRQ's (the special
  66  * SMP cross-CPU interrupts have their own specific
  67  * handlers).
  68  */
  69 unsigned int do_IRQ(struct pt_regs *regs)
  70 {
  71         struct pt_regs *old_regs;
  72         /* high bit used in ret_from_ code */
  73         int irq = ~regs->orig_ax;
  74         struct irq_desc *desc = irq_desc + irq;
  75 #ifdef CONFIG_4KSTACKS
  76         union irq_ctx *curctx, *irqctx;
  77         u32 *isp;
  78 #endif
  79
  80         if (unlikely((unsigned)irq >= NR_IRQS)) {
  81                 printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
  82                                         __FUNCTION__, irq);
  83                 BUG();
  84         }
  85
  86         old_regs = set_irq_regs(regs);
  87         irq_enter();
  88 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  89         /* Debugging check for stack overflow: is there less than 1KB free? */
  90         {
  91                 long sp;
  92
  93                 __asm__ __volatile__("andl %%esp,%0" :
  94                                         "=r" (sp) : "0" (THREAD_SIZE - 1));
  95                 if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
  96                         printk("do_IRQ: stack overflow: %ld\n",
  97                                 sp - sizeof(struct thread_info));
  98                         dump_stack();
  99                 }
 100         }
 101 #endif
 102
 103 #ifdef CONFIG_4KSTACKS
 104
 105         curctx = (union irq_ctx *) current_thread_info();
 106         irqctx = hardirq_ctx[smp_processor_id()];
 107
 108         /*
 109          * this is where we switch to the IRQ stack. However, if we are
 110          * already using the IRQ stack (because we interrupted a hardirq
 111          * handler) we can't do that and just have to keep using the
 112          * current stack (which is the irq stack already after all)
 113          */
 114         if (curctx != irqctx) {
 115                 int arg1, arg2, bx;
 116
 117                 /* build the stack frame on the IRQ stack */
 118                 isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
 119                 irqctx->tinfo.task = curctx->tinfo.task;
 120                 irqctx->tinfo.previous_esp = current_stack_pointer;
 121
 122                 /*
 123                  * Copy the softirq bits in preempt_count so that the
 124                  * softirq checks work in the hardirq context.
 125                  */
 126                 irqctx->tinfo.preempt_count =
 127                         (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
 128                         (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
 129
 130                 asm volatile(
 131                         "       xchgl  %%ebx,%%esp    \n"
 132                         "       call   *%%edi         \n"
 133                         "       movl   %%ebx,%%esp    \n"
 134                         : "=a" (arg1), "=d" (arg2), "=b" (bx)
 135                         :  "0" (irq),   "1" (desc),  "2" (isp),
 136                            "D" (desc->handle_irq)
 137                         : "memory", "cc"
 138                 );
 139         } else
 140 #endif
 141                 desc->handle_irq(irq, desc);
 142
 143         irq_exit();
 144         set_irq_regs(old_regs);
 145         return 1;
 146 }
 147
 148 #ifdef CONFIG_4KSTACKS
 149
 150 static char softirq_stack[NR_CPUS * THREAD_SIZE]
 151                 __attribute__((__section__(".bss.page_aligned")));
 152
 153 static char hardirq_stack[NR_CPUS * THREAD_SIZE]
 154                 __attribute__((__section__(".bss.page_aligned")));
 155
 156 /*
 157  * allocate per-cpu stacks for hardirq and for softirq processing
 158  */
 159 void irq_ctx_init(int cpu)
 160 {
 161         union irq_ctx *irqctx;
 162
 163         if (hardirq_ctx[cpu])
 164                 return;
 165
 166         irqctx = (union irq_ctx*) &hardirq_stack[cpu*THREAD_SIZE];
 167         irqctx->tinfo.task              = NULL;
 168         irqctx->tinfo.exec_domain       = NULL;
 169         irqctx->tinfo.cpu               = cpu;
 170         irqctx->tinfo.preempt_count     = HARDIRQ_OFFSET;
 171         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 172
 173         hardirq_ctx[cpu] = irqctx;
 174
 175         irqctx = (union irq_ctx*) &softirq_stack[cpu*THREAD_SIZE];
 176         irqctx->tinfo.task              = NULL;
 177         irqctx->tinfo.exec_domain       = NULL;
 178         irqctx->tinfo.cpu               = cpu;
 179         irqctx->tinfo.preempt_count     = 0;
 180         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 181
 182         softirq_ctx[cpu] = irqctx;
 183
 184         printk("CPU %u irqstacks, hard=%p soft=%p\n",
 185                 cpu,hardirq_ctx[cpu],softirq_ctx[cpu]);
 186 }
 187
 188 void irq_ctx_exit(int cpu)
 189 {
 190         hardirq_ctx[cpu] = NULL;
 191 }
 192
 193 extern asmlinkage void __do_softirq(void);
 194
 195 asmlinkage void do_softirq(void)
 196 {
 197         unsigned long flags;
 198         struct thread_info *curctx;
 199         union irq_ctx *irqctx;
 200         u32 *isp;
 201
 202         if (in_interrupt())
 203                 return;
 204
 205         local_irq_save(flags);
 206
 207         if (local_softirq_pending()) {
 208                 curctx = current_thread_info();
 209                 irqctx = softirq_ctx[smp_processor_id()];
 210                 irqctx->tinfo.task = curctx->task;
 211                 irqctx->tinfo.previous_esp = current_stack_pointer;
 212
 213                 /* build the stack frame on the softirq stack */
 214                 isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
 215
 216                 asm volatile(
 217                         "       xchgl   %%ebx,%%esp     \n"
 218                         "       call    __do_softirq    \n"
 219                         "       movl    %%ebx,%%esp     \n"
 220                         : "=b"(isp)
 221                         : "0"(isp)
 222                         : "memory", "cc", "edx", "ecx", "eax"
 223                 );
 224                 /*
 225                  * Shouldnt happen, we returned above if in_interrupt():
 226                  */
 227                 WARN_ON_ONCE(softirq_count());
 228         }
 229
 230         local_irq_restore(flags);
 231 }
 232 #endif
 233
 234 /*
 235  * Interrupt statistics:
 236  */
 237
 238 atomic_t irq_err_count;
 239
 240 /*
 241  * /proc/interrupts printing:
 242  */
 243
 244 int show_interrupts(struct seq_file *p, void *v)
 245 {
 246         int i = *(loff_t *) v, j;
 247         struct irqaction * action;
 248         unsigned long flags;
 249
 250         if (i == 0) {
 251                 seq_printf(p, "           ");
 252                 for_each_online_cpu(j)
 253                         seq_printf(p, "CPU%-8d",j);
 254                 seq_putc(p, '\n');
 255         }
 256
 257         if (i < NR_IRQS) {
 258                 unsigned any_count = 0;
 259
 260                 spin_lock_irqsave(&irq_desc[i].lock, flags);
 261 #ifndef CONFIG_SMP
 262                 any_count = kstat_irqs(i);
 263 #else
 264                 for_each_online_cpu(j)
 265                         any_count |= kstat_cpu(j).irqs[i];
 266 #endif
 267                 action = irq_desc[i].action;
 268                 if (!action && !any_count)
 269                         goto skip;
 270                 seq_printf(p, "%3d: ",i);
 271 #ifndef CONFIG_SMP
 272                 seq_printf(p, "%10u ", kstat_irqs(i));
 273 #else
 274                 for_each_online_cpu(j)
 275                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
 276 #endif
 277                 seq_printf(p, " %8s", irq_desc[i].chip->name);
 278                 seq_printf(p, "-%-8s", irq_desc[i].name);
 279
 280                 if (action) {
 281                         seq_printf(p, "  %s", action->name);
 282                         while ((action = action->next) != NULL)
 283                                 seq_printf(p, ", %s", action->name);
 284                 }
 285
 286                 seq_putc(p, '\n');
 287 skip:
 288                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
 289         } else if (i == NR_IRQS) {
 290                 seq_printf(p, "NMI: ");
 291                 for_each_online_cpu(j)
 292                         seq_printf(p, "%10u ", nmi_count(j));
 293                 seq_printf(p, "  Non-maskable interrupts\n");
 294 #ifdef CONFIG_X86_LOCAL_APIC
 295                 seq_printf(p, "LOC: ");
 296                 for_each_online_cpu(j)
 297                         seq_printf(p, "%10u ",
 298                                 per_cpu(irq_stat,j).apic_timer_irqs);
 299                 seq_printf(p, "  Local timer interrupts\n");
 300 #endif
 301 #ifdef CONFIG_SMP
 302                 seq_printf(p, "RES: ");
 303                 for_each_online_cpu(j)
 304                         seq_printf(p, "%10u ",
 305                                 per_cpu(irq_stat,j).irq_resched_count);
 306                 seq_printf(p, "  Rescheduling interrupts\n");
 307                 seq_printf(p, "CAL: ");
 308                 for_each_online_cpu(j)
 309                         seq_printf(p, "%10u ",
 310                                 per_cpu(irq_stat,j).irq_call_count);
 311                 seq_printf(p, "  function call interrupts\n");
 312                 seq_printf(p, "TLB: ");
 313                 for_each_online_cpu(j)
 314                         seq_printf(p, "%10u ",
 315                                 per_cpu(irq_stat,j).irq_tlb_count);
 316                 seq_printf(p, "  TLB shootdowns\n");
 317 #endif
 318                 seq_printf(p, "TRM: ");
 319                 for_each_online_cpu(j)
 320                         seq_printf(p, "%10u ",
 321                                 per_cpu(irq_stat,j).irq_thermal_count);
 322                 seq_printf(p, "  Thermal event interrupts\n");
 323                 seq_printf(p, "SPU: ");
 324                 for_each_online_cpu(j)
 325                         seq_printf(p, "%10u ",
 326                                 per_cpu(irq_stat,j).irq_spurious_count);
 327                 seq_printf(p, "  Spurious interrupts\n");
 328                 seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
 329 #if defined(CONFIG_X86_IO_APIC)
 330                 seq_printf(p, "MIS: %10u\n", atomic_read(&irq_mis_count));
 331 #endif
 332         }
 333         return 0;
 334 }
 335
 336 #ifdef CONFIG_HOTPLUG_CPU
 337 #include <mach_apic.h>
 338
 339 void fixup_irqs(cpumask_t map)
 340 {
 341         unsigned int irq;
 342         static int warned;
 343
 344         for (irq = 0; irq < NR_IRQS; irq++) {
 345                 cpumask_t mask;
 346                 if (irq == 2)
 347                         continue;
 348
 349                 cpus_and(mask, irq_desc[irq].affinity, map);
 350                 if (any_online_cpu(mask) == NR_CPUS) {
 351                         printk("Breaking affinity for irq %i\n", irq);
 352                         mask = map;
 353                 }
 354                 if (irq_desc[irq].chip->set_affinity)
 355                         irq_desc[irq].chip->set_affinity(irq, mask);
 356                 else if (irq_desc[irq].action && !(warned++))
 357                         printk("Cannot set affinity for irq %i\n", irq);
 358         }
 359
 360 #if 0
 361         barrier();
 362         /* Ingo Molnar says: "after the IO-APIC masks have been redirected
 363            [note the nop - the interrupt-enable boundary on x86 is two
 364            instructions from sti] - to flush out pending hardirqs and
 365            IPIs. After this point nothing is supposed to reach this CPU." */
 366         __asm__ __volatile__("sti; nop; cli");
 367         barrier();
 368 #else
 369         /* That doesn't seem sufficient.  Give it 1ms. */
 370         local_irq_enable();
 371         mdelay(1);
 372         local_irq_disable();
 373 #endif
 374 }
 375 #endif
 376