1 #include <linux/module.h> 2 #include <linux/spinlock.h> 3 #include <asm/uaccess.h> 4 5 6 int fixup_exception(struct pt_regs *regs) 7 { 8 const struct exception_table_entry *fixup; 9 10 #ifdef CONFIG_PNPBIOS 11 if (unlikely(SEGMENT_IS_PNP_CODE(regs->cs))) { 12 extern u32 pnp_bios_fault_eip, pnp_bios_fault_esp; 13 extern u32 pnp_bios_is_utter_crap; 14 pnp_bios_is_utter_crap = 1; 15 printk(KERN_CRIT "PNPBIOS fault.. attempting recovery.\n"); 16 __asm__ volatile( 17 "movl %0, %%esp\n\t" 18 "jmp *%1\n\t" 19 : : "g" (pnp_bios_fault_esp), "g" (pnp_bios_fault_eip)); 20 panic("do_trap: can't hit this"); 21 } 22 #endif 23 24 fixup = search_exception_tables(regs->ip); 25 if (fixup) { 26 /* If fixup is less than 16, it means uaccess error */ 27 if (fixup->fixup < 16) { 28 current_thread_info()->uaccess_err = -EFAULT; 29 regs->ip += fixup->fixup; 30 return 1; 31 } 32 regs->ip = fixup->fixup; 33 return 1; 34 } 35 36 return 0; 37 } 38 39 #ifdef CONFIG_X86_64 40 /* 41 * Need to defined our own search_extable on X86_64 to work around 42 * a B stepping K8 bug. 43 */ 44 const struct exception_table_entry * 45 search_extable(const struct exception_table_entry *first, 46 const struct exception_table_entry *last, 47 unsigned long value) 48 { 49 /* B stepping K8 bug */ 50 if ((value >> 32) == 0) 51 value |= 0xffffffffUL << 32; 52 53 while (first <= last) { 54 const struct exception_table_entry *mid; 55 long diff; 56 57 mid = (last - first) / 2 + first; 58 diff = mid->insn - value; 59 if (diff == 0) 60 return mid; 61 else if (diff < 0) 62 first = mid+1; 63 else 64 last = mid-1; 65 } 66 return NULL; 67 } 68 #endif 69