LXR linux/arch/i386/kernel/doublefault.c

   1#include <linux/mm.h>
   2#include <linux/sched.h>
   3#include <linux/init.h>
   4#include <linux/init_task.h>
   5#include <linux/fs.h>
   6
   7#include <asm/uaccess.h>
   8#include <asm/pgtable.h>
   9#include <asm/processor.h>
  10#include <asm/desc.h>
  11
  12#define DOUBLEFAULT_STACKSIZE (1024)
  13static unsigned long doublefault_stack[DOUBLEFAULT_STACKSIZE];
  14#define STACK_START (unsigned long)(doublefault_stack+DOUBLEFAULT_STACKSIZE)
  15
  16#define ptr_ok(x) ((x) > PAGE_OFFSET && (x) < PAGE_OFFSET + MAXMEM)
  17
  18static void doublefault_fn(void)
  19{
  20        struct Xgt_desc_struct gdt_desc = {0, 0};
  21        unsigned long gdt, tss;
  22
  23        store_gdt(&gdt_desc);
  24        gdt = gdt_desc.address;
  25
  26        printk(KERN_EMERG "PANIC: double fault, gdt at %08lx [%d bytes]\n", gdt, gdt_desc.size);
  27
  28        if (ptr_ok(gdt)) {
  29                gdt += GDT_ENTRY_TSS << 3;
  30                tss = *(u16 *)(gdt+2);
  31                tss += *(u8 *)(gdt+4) << 16;
  32                tss += *(u8 *)(gdt+7) << 24;
  33                printk(KERN_EMERG "double fault, tss at %08lx\n", tss);
  34
  35                if (ptr_ok(tss)) {
  36                        struct i386_hw_tss *t = (struct i386_hw_tss *)tss;
  37
  38                        printk(KERN_EMERG "eip = %08lx, esp = %08lx\n", t->eip, t->esp);
  39
  40                        printk(KERN_EMERG "eax = %08lx, ebx = %08lx, ecx = %08lx, edx = %08lx\n",
  41                                t->eax, t->ebx, t->ecx, t->edx);
  42                        printk(KERN_EMERG "esi = %08lx, edi = %08lx\n",
  43                                t->esi, t->edi);
  44                }
  45        }
  46
  47        for (;;)
  48                cpu_relax();
  49}
  50
  51struct tss_struct doublefault_tss __cacheline_aligned = {
  52        .x86_tss = {
  53                .esp0           = STACK_START,
  54                .ss0            = __KERNEL_DS,
  55                .ldt            = 0,
  56                .io_bitmap_base = INVALID_IO_BITMAP_OFFSET,
  57
  58                .eip            = (unsigned long) doublefault_fn,
  59                /* 0x2 bit is always set */
  60                .eflags         = X86_EFLAGS_SF | 0x2,
  61                .esp            = STACK_START,
  62                .es             = __USER_DS,
  63                .cs             = __KERNEL_CS,
  64                .ss             = __KERNEL_DS,
  65                .ds             = __USER_DS,
  66                .fs             = __KERNEL_PERCPU,
  67
  68                .__cr3          = __pa(swapper_pg_dir)
  69        }
  70};
  71