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