2 #include <linux/sched.h>
3 #include <linux/init.h>
4 #include <linux/init_task.h>
7 #include <asm/uaccess.h>
8 #include <asm/pgtable.h>
9 #include <asm/processor.h>
11 #include <asm/fixmap.h>
13 #define DOUBLEFAULT_STACKSIZE (1024)
14 static unsigned long doublefault_stack[DOUBLEFAULT_STACKSIZE];
15 #define STACK_START (unsigned long)(doublefault_stack+DOUBLEFAULT_STACKSIZE)
17 #define ptr_ok(x) (((x) > __PAGE_OFFSET && (x) < (__PAGE_OFFSET + 0x01000000)) || ((x) >= FIXADDR_START))
19 static void doublefault_fn(void)
21 struct Xgt_desc_struct gdt_desc = {0, 0};
22 unsigned long gdt, tss;
24 __asm__ __volatile__("sgdt %0": "=m" (gdt_desc): :"memory");
25 gdt = gdt_desc.address;
27 printk("double fault, gdt at %08lx [%d bytes]\n", gdt, gdt_desc.size);
30 gdt += GDT_ENTRY_TSS << 3;
31 tss = *(u16 *)(gdt+2);
32 tss += *(u8 *)(gdt+4) << 16;
33 tss += *(u8 *)(gdt+7) << 24;
34 printk("double fault, tss at %08lx\n", tss);
37 struct tss_struct *t = (struct tss_struct *)tss;
39 printk("eip = %08lx, esp = %08lx\n", t->eip, t->esp);
41 printk("eax = %08lx, ebx = %08lx, ecx = %08lx, edx = %08lx\n",
42 t->eax, t->ebx, t->ecx, t->edx);
43 printk("esi = %08lx, edi = %08lx, ebp = %08lx\n",
44 t->esi, t->edi, t->ebp);
48 for (;;) /* nothing */;
51 struct tss_struct doublefault_tss __cacheline_aligned = {
55 .io_bitmap_base = INVALID_IO_BITMAP_OFFSET,
57 .eip = (unsigned long) doublefault_fn,
58 .eflags = X86_EFLAGS_SF | 0x2, /* 0x2 bit is always set */
65 .__cr3 = __pa(swapper_pg_dir)