arch/x86/kernel/i8259_32.c

   1 #include <linux/errno.h>
   2 #include <linux/signal.h>
   3 #include <linux/sched.h>
   4 #include <linux/ioport.h>
   5 #include <linux/interrupt.h>
   6 #include <linux/slab.h>
   7 #include <linux/random.h>
   8 #include <linux/init.h>
   9 #include <linux/kernel_stat.h>
  10 #include <linux/sysdev.h>
  11 #include <linux/bitops.h>
  12
  13 #include <asm/atomic.h>
  14 #include <asm/system.h>
  15 #include <asm/io.h>
  16 #include <asm/timer.h>
  17 #include <asm/pgtable.h>
  18 #include <asm/delay.h>
  19 #include <asm/desc.h>
  20 #include <asm/apic.h>
  21 #include <asm/arch_hooks.h>
  22 #include <asm/i8259.h>
  23
  24
  25
  26 /*
  27  * Note that on a 486, we don't want to do a SIGFPE on an irq13
  28  * as the irq is unreliable, and exception 16 works correctly
  29  * (ie as explained in the intel literature). On a 386, you
  30  * can't use exception 16 due to bad IBM design, so we have to
  31  * rely on the less exact irq13.
  32  *
  33  * Careful.. Not only is IRQ13 unreliable, but it is also
  34  * leads to races. IBM designers who came up with it should
  35  * be shot.
  36  */
  37
  38
  39 static irqreturn_t math_error_irq(int cpl, void *dev_id)
  40 {
  41         extern void math_error(void __user *);
  42         outb(0,0xF0);
  43         if (ignore_fpu_irq || !boot_cpu_data.hard_math)
  44                 return IRQ_NONE;
  45         math_error((void __user *)get_irq_regs()->ip);
  46         return IRQ_HANDLED;
  47 }
  48
  49 /*
  50  * New motherboards sometimes make IRQ 13 be a PCI interrupt,
  51  * so allow interrupt sharing.
  52  */
  53 static struct irqaction fpu_irq = {
  54         .handler = math_error_irq,
  55         .mask = CPU_MASK_NONE,
  56         .name = "fpu",
  57 };
  58
  59 void __init init_ISA_irqs (void)
  60 {
  61         int i;
  62
  63 #ifdef CONFIG_X86_LOCAL_APIC
  64         init_bsp_APIC();
  65 #endif
  66         init_8259A(0);
  67
  68         /*
  69          * 16 old-style INTA-cycle interrupts:
  70          */
  71         for (i = 0; i < 16; i++) {
  72                 set_irq_chip_and_handler_name(i, &i8259A_chip,
  73                                               handle_level_irq, "XT");
  74         }
  75 }
  76
  77 /* Overridden in paravirt.c */
  78 void init_IRQ(void) __attribute__((weak, alias("native_init_IRQ")));
  79
  80 void __init native_init_IRQ(void)
  81 {
  82         int i;
  83
  84         /* all the set up before the call gates are initialised */
  85         pre_intr_init_hook();
  86
  87         /*
  88          * Cover the whole vector space, no vector can escape
  89          * us. (some of these will be overridden and become
  90          * 'special' SMP interrupts)
  91          */
  92         for (i = 0; i < (NR_VECTORS - FIRST_EXTERNAL_VECTOR); i++) {
  93                 int vector = FIRST_EXTERNAL_VECTOR + i;
  94                 if (i >= NR_IRQS)
  95                         break;
  96                 /* SYSCALL_VECTOR was reserved in trap_init. */
  97                 if (!test_bit(vector, used_vectors))
  98                         set_intr_gate(vector, interrupt[i]);
  99         }
 100
 101         /* setup after call gates are initialised (usually add in
 102          * the architecture specific gates)
 103          */
 104         intr_init_hook();
 105
 106         /*
 107          * External FPU? Set up irq13 if so, for
 108          * original braindamaged IBM FERR coupling.
 109          */
 110         if (boot_cpu_data.hard_math && !cpu_has_fpu)
 111                 setup_irq(FPU_IRQ, &fpu_irq);
 112
 113         irq_ctx_init(smp_processor_id());
 114 }