1 #include <linux/mm.h>
2 #include <linux/sched.h>
3 #include <linux/init_task.h>
4 #include <linux/fs.h>
5
6 #include <asm/uaccess.h>
7 #include <asm/pgtable.h>
8 #include <asm/processor.h>
9 #include <asm/desc.h>
10
11 #ifdef CONFIG_X86_32
12
13 #define DOUBLEFAULT_STACKSIZE (1024)
14 static unsigned long doublefault_stack[DOUBLEFAULT_STACKSIZE];
15 #define STACK_START (unsigned long)(doublefault_stack+DOUBLEFAULT_STACKSIZE)
16
17 #define ptr_ok(x) ((x) > PAGE_OFFSET && (x) < PAGE_OFFSET + MAXMEM)
18
doublefault_fn(void)19 static void doublefault_fn(void)
20 {
21 struct desc_ptr gdt_desc = {0, 0};
22 unsigned long gdt, tss;
23
24 native_store_gdt(&gdt_desc);
25 gdt = gdt_desc.address;
26
27 printk(KERN_EMERG "PANIC: double fault, gdt at %08lx [%d bytes]\n", gdt, gdt_desc.size);
28
29 if (ptr_ok(gdt)) {
30 gdt += GDT_ENTRY_TSS << 3;
31 tss = get_desc_base((struct desc_struct *)gdt);
32 printk(KERN_EMERG "double fault, tss at %08lx\n", tss);
33
34 if (ptr_ok(tss)) {
35 struct x86_hw_tss *t = (struct x86_hw_tss *)tss;
36
37 printk(KERN_EMERG "eip = %08lx, esp = %08lx\n",
38 t->ip, t->sp);
39
40 printk(KERN_EMERG "eax = %08lx, ebx = %08lx, ecx = %08lx, edx = %08lx\n",
41 t->ax, t->bx, t->cx, t->dx);
42 printk(KERN_EMERG "esi = %08lx, edi = %08lx\n",
43 t->si, t->di);
44 }
45 }
46
47 for (;;)
48 cpu_relax();
49 }
50
51 struct tss_struct doublefault_tss __cacheline_aligned = {
52 .x86_tss = {
53 .sp0 = STACK_START,
54 .ss0 = __KERNEL_DS,
55 .ldt = 0,
56 .io_bitmap_base = INVALID_IO_BITMAP_OFFSET,
57
58 .ip = (unsigned long) doublefault_fn,
59 /* 0x2 bit is always set */
60 .flags = X86_EFLAGS_SF | 0x2,
61 .sp = 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_nodebug(swapper_pg_dir),
69 }
70 };
71
72 /* dummy for do_double_fault() call */
df_debug(struct pt_regs * regs,long error_code)73 void df_debug(struct pt_regs *regs, long error_code) {}
74
75 #else /* !CONFIG_X86_32 */
76
df_debug(struct pt_regs * regs,long error_code)77 void df_debug(struct pt_regs *regs, long error_code)
78 {
79 pr_emerg("PANIC: double fault, error_code: 0x%lx\n", error_code);
80 show_regs(regs);
81 panic("Machine halted.");
82 }
83 #endif
84