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 + MAXMEM)
17
doublefault_fn(void)18 static void doublefault_fn(void)
19 {
20 struct desc_ptr 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 x86_hw_tss *t = (struct x86_hw_tss *)tss;
37
38 printk(KERN_EMERG "eip = %08lx, esp = %08lx\n",
39 t->ip, t->sp);
40
41 printk(KERN_EMERG "eax = %08lx, ebx = %08lx, ecx = %08lx, edx = %08lx\n",
42 t->ax, t->bx, t->cx, t->dx);
43 printk(KERN_EMERG "esi = %08lx, edi = %08lx\n",
44 t->si, t->di);
45 }
46 }
47
48 for (;;)
49 cpu_relax();
50 }
51
52 struct tss_struct doublefault_tss __cacheline_aligned = {
53 .x86_tss = {
54 .sp0 = STACK_START,
55 .ss0 = __KERNEL_DS,
56 .ldt = 0,
57 .io_bitmap_base = INVALID_IO_BITMAP_OFFSET,
58
59 .ip = (unsigned long) doublefault_fn,
60 /* 0x2 bit is always set */
61 .flags = X86_EFLAGS_SF | 0x2,
62 .sp = STACK_START,
63 .es = __USER_DS,
64 .cs = __KERNEL_CS,
65 .ss = __KERNEL_DS,
66 .ds = __USER_DS,
67 .fs = __KERNEL_PERCPU,
68
69 .__cr3 = __pa_nodebug(swapper_pg_dir),
70 }
71 };
72