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 18 static void doublefault_fn(void) 19 { 20 struct Xgt_desc_struct 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 i386_hw_tss *t = (struct i386_hw_tss *)tss; 37 38 printk(KERN_EMERG "eip = %08lx, esp = %08lx\n", t->eip, t->esp); 39 40 printk(KERN_EMERG "eax = %08lx, ebx = %08lx, ecx = %08lx, edx = %08lx\n", 41 t->eax, t->ebx, t->ecx, t->edx); 42 printk(KERN_EMERG "esi = %08lx, edi = %08lx\n", 43 t->esi, t->edi); 44 } 45 } 46 47 for (;;) 48 cpu_relax(); 49 } 50 51 struct tss_struct doublefault_tss __cacheline_aligned = { 52 .x86_tss = { 53 .esp0 = STACK_START, 54 .ss0 = __KERNEL_DS, 55 .ldt = 0, 56 .io_bitmap_base = INVALID_IO_BITMAP_OFFSET, 57 58 .eip = (unsigned long) doublefault_fn, 59 /* 0x2 bit is always set */ 60 .eflags = X86_EFLAGS_SF | 0x2, 61 .esp = 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(swapper_pg_dir) 69 } 70 }; 71