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kernel/linux-imx6_3.14.28/arch/ia64/mm/extable.c 2.95 KB
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  /*
   * Kernel exception handling table support.  Derived from arch/alpha/mm/extable.c.
   *
   * Copyright (C) 1998, 1999, 2001-2002, 2004 Hewlett-Packard Co
   *	David Mosberger-Tang <davidm@hpl.hp.com>
   */
  
  #include <linux/sort.h>
  
  #include <asm/uaccess.h>
  #include <linux/module.h>
  
  static int cmp_ex(const void *a, const void *b)
  {
  	const struct exception_table_entry *l = a, *r = b;
  	u64 lip = (u64) &l->addr + l->addr;
  	u64 rip = (u64) &r->addr + r->addr;
  
  	/* avoid overflow */
  	if (lip > rip)
  		return 1;
  	if (lip < rip)
  		return -1;
  	return 0;
  }
  
  static void swap_ex(void *a, void *b, int size)
  {
  	struct exception_table_entry *l = a, *r = b, tmp;
  	u64 delta = (u64) r - (u64) l;
  
  	tmp = *l;
  	l->addr = r->addr + delta;
  	l->cont = r->cont + delta;
  	r->addr = tmp.addr - delta;
  	r->cont = tmp.cont - delta;
  }
  
  /*
   * Sort the exception table. It's usually already sorted, but there
   * may be unordered entries due to multiple text sections (such as the
   * .init text section). Note that the exception-table-entries contain
   * location-relative addresses, which requires a bit of care during
   * sorting to avoid overflows in the offset members (e.g., it would
   * not be safe to make a temporary copy of an exception-table entry on
   * the stack, because the stack may be more than 2GB away from the
   * exception-table).
   */
  void sort_extable (struct exception_table_entry *start,
  		   struct exception_table_entry *finish)
  {
  	sort(start, finish - start, sizeof(struct exception_table_entry),
  	     cmp_ex, swap_ex);
  }
  
  static inline unsigned long ex_to_addr(const struct exception_table_entry *x)
  {
  	return (unsigned long)&x->addr + x->addr;
  }
  
  #ifdef CONFIG_MODULES
  /*
   * Any entry referring to the module init will be at the beginning or
   * the end.
   */
  void trim_init_extable(struct module *m)
  {
  	/*trim the beginning*/
  	while (m->num_exentries &&
  	       within_module_init(ex_to_addr(&m->extable[0]), m)) {
  		m->extable++;
  		m->num_exentries--;
  	}
  	/*trim the end*/
  	while (m->num_exentries &&
  	       within_module_init(ex_to_addr(&m->extable[m->num_exentries-1]),
  				  m))
  		m->num_exentries--;
  }
  #endif /* CONFIG_MODULES */
  
  const struct exception_table_entry *
  search_extable (const struct exception_table_entry *first,
  		const struct exception_table_entry *last,
  		unsigned long ip)
  {
  	const struct exception_table_entry *mid;
  	unsigned long mid_ip;
  	long diff;
  
          while (first <= last) {
  		mid = &first[(last - first)/2];
  		mid_ip = (u64) &mid->addr + mid->addr;
  		diff = mid_ip - ip;
                  if (diff == 0)
                          return mid;
                  else if (diff < 0)
                          first = mid + 1;
                  else
                          last = mid - 1;
          }
          return NULL;
  }
  
  void
  ia64_handle_exception (struct pt_regs *regs, const struct exception_table_entry *e)
  {
  	long fix = (u64) &e->cont + e->cont;
  
  	regs->r8 = -EFAULT;
  	if (fix & 4)
  		regs->r9 = 0;
  	regs->cr_iip = fix & ~0xf;
  	ia64_psr(regs)->ri = fix & 0x3;		/* set continuation slot number */
  }