Linux-2.6.12-rc2
[linux-2.6.git] / 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)
13 static 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 + 0x1000000)
17
18 static void doublefault_fn(void)
19 {
20         struct Xgt_desc_struct gdt_desc = {0, 0};
21         unsigned long gdt, tss;
22
23         __asm__ __volatile__("sgdt %0": "=m" (gdt_desc): :"memory");
24         gdt = gdt_desc.address;
25
26         printk("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("double fault, tss at %08lx\n", tss);
34
35                 if (ptr_ok(tss)) {
36                         struct tss_struct *t = (struct tss_struct *)tss;
37
38                         printk("eip = %08lx, esp = %08lx\n", t->eip, t->esp);
39
40                         printk("eax = %08lx, ebx = %08lx, ecx = %08lx, edx = %08lx\n",
41                                 t->eax, t->ebx, t->ecx, t->edx);
42                         printk("esi = %08lx, edi = %08lx\n",
43                                 t->esi, t->edi);
44                 }
45         }
46
47         for (;;) /* nothing */;
48 }
49
50 struct tss_struct doublefault_tss __cacheline_aligned = {
51         .esp0           = STACK_START,
52         .ss0            = __KERNEL_DS,
53         .ldt            = 0,
54         .io_bitmap_base = INVALID_IO_BITMAP_OFFSET,
55
56         .eip            = (unsigned long) doublefault_fn,
57         .eflags         = X86_EFLAGS_SF | 0x2,  /* 0x2 bit is always set */
58         .esp            = STACK_START,
59         .es             = __USER_DS,
60         .cs             = __KERNEL_CS,
61         .ss             = __KERNEL_DS,
62         .ds             = __USER_DS,
63
64         .__cr3          = __pa(swapper_pg_dir)
65 };