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 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 = get_desc_base((struct desc_struct *)gdt); 31 printk(KERN_EMERG "double fault, tss at %08lx\n", tss); 32 33 if (ptr_ok(tss)) { 34 struct x86_hw_tss *t = (struct x86_hw_tss *)tss; 35 36 printk(KERN_EMERG "eip = %08lx, esp = %08lx\n", 37 t->ip, t->sp); 38 39 printk(KERN_EMERG "eax = %08lx, ebx = %08lx, ecx = %08lx, edx = %08lx\n", 40 t->ax, t->bx, t->cx, t->dx); 41 printk(KERN_EMERG "esi = %08lx, edi = %08lx\n", 42 t->si, t->di); 43 } 44 } 45 46 for (;;) 47 cpu_relax(); 48} 49 50struct tss_struct doublefault_tss __cacheline_aligned = { 51 .x86_tss = { 52 .sp0 = STACK_START, 53 .ss0 = __KERNEL_DS, 54 .ldt = 0, 55 .io_bitmap_base = INVALID_IO_BITMAP_OFFSET, 56 57 .ip = (unsigned long) doublefault_fn, 58 /* 0x2 bit is always set */ 59 .flags = X86_EFLAGS_SF | 0x2, 60 .sp = STACK_START, 61 .es = __USER_DS, 62 .cs = __KERNEL_CS, 63 .ss = __KERNEL_DS, 64 .ds = __USER_DS, 65 .fs = __KERNEL_PERCPU, 66 67 .__cr3 = __pa_nodebug(swapper_pg_dir), 68 } 69}; 70