1#include <linux/module.h>
 2#include <linux/spinlock.h>
 3#include <asm/uaccess.h>
 4
 
 
 5
 6int 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}

  1#include <linux/module.h>
 
  2#include <asm/uaccess.h>
  3
  4typedef bool (*ex_handler_t)(const struct exception_table_entry *,
  5			    struct pt_regs *, int);
  6
  7static inline unsigned long
  8ex_fixup_addr(const struct exception_table_entry *x)
  9{
 10	return (unsigned long)&x->fixup + x->fixup;
 11}
 12static inline ex_handler_t
 13ex_fixup_handler(const struct exception_table_entry *x)
 14{
 15	return (ex_handler_t)((unsigned long)&x->handler + x->handler);
 16}
 17
 18bool ex_handler_default(const struct exception_table_entry *fixup,
 19		       struct pt_regs *regs, int trapnr)
 20{
 21	regs->ip = ex_fixup_addr(fixup);
 22	return true;
 23}
 24EXPORT_SYMBOL(ex_handler_default);
 25
 26bool ex_handler_fault(const struct exception_table_entry *fixup,
 27		     struct pt_regs *regs, int trapnr)
 28{
 29	regs->ip = ex_fixup_addr(fixup);
 30	regs->ax = trapnr;
 31	return true;
 32}
 33EXPORT_SYMBOL_GPL(ex_handler_fault);
 34
 35bool ex_handler_ext(const struct exception_table_entry *fixup,
 36		   struct pt_regs *regs, int trapnr)
 37{
 38	/* Special hack for uaccess_err */
 39	current_thread_info()->uaccess_err = 1;
 40	regs->ip = ex_fixup_addr(fixup);
 41	return true;
 42}
 43EXPORT_SYMBOL(ex_handler_ext);
 44
 45bool ex_has_fault_handler(unsigned long ip)
 46{
 47	const struct exception_table_entry *e;
 48	ex_handler_t handler;
 49
 50	e = search_exception_tables(ip);
 51	if (!e)
 52		return false;
 53	handler = ex_fixup_handler(e);
 54
 55	return handler == ex_handler_fault;
 56}
 57
 58int fixup_exception(struct pt_regs *regs, int trapnr)
 59{
 60	const struct exception_table_entry *e;
 61	ex_handler_t handler;
 62
 63#ifdef CONFIG_PNPBIOS
 64	if (unlikely(SEGMENT_IS_PNP_CODE(regs->cs))) {
 65		extern u32 pnp_bios_fault_eip, pnp_bios_fault_esp;
 66		extern u32 pnp_bios_is_utter_crap;
 67		pnp_bios_is_utter_crap = 1;
 68		printk(KERN_CRIT "PNPBIOS fault.. attempting recovery.\n");
 69		__asm__ volatile(
 70			"movl %0, %%esp\n\t"
 71			"jmp *%1\n\t"
 72			: : "g" (pnp_bios_fault_esp), "g" (pnp_bios_fault_eip));
 73		panic("do_trap: can't hit this");
 74	}
 75#endif
 76
 77	e = search_exception_tables(regs->ip);
 78	if (!e)
 79		return 0;
 80
 81	handler = ex_fixup_handler(e);
 82	return handler(e, regs, trapnr);
 83}
 84
 85/* Restricted version used during very early boot */
 86int __init early_fixup_exception(unsigned long *ip)
 87{
 88	const struct exception_table_entry *e;
 89	unsigned long new_ip;
 90	ex_handler_t handler;
 91
 92	e = search_exception_tables(*ip);
 93	if (!e)
 94		return 0;
 95
 96	new_ip  = ex_fixup_addr(e);
 97	handler = ex_fixup_handler(e);
 98
 99	/* special handling not supported during early boot */
100	if (handler != ex_handler_default)
101		return 0;
102
103	*ip = new_ip;
104	return 1;
105}