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kernel/linux-imx6_3.14.28/arch/alpha/mm/extable.c 2.33 KB
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  /*
   * linux/arch/alpha/mm/extable.c
   */
  
  #include <linux/module.h>
  #include <linux/sort.h>
  #include <asm/uaccess.h>
  
  static inline unsigned long ex_to_addr(const struct exception_table_entry *x)
  {
  	return (unsigned long)&x->insn + x->insn;
  }
  
  static void swap_ex(void *a, void *b, int size)
  {
  	struct exception_table_entry *ex_a = a, *ex_b = b;
  	unsigned long addr_a = ex_to_addr(ex_a), addr_b = ex_to_addr(ex_b);
  	unsigned int t = ex_a->fixup.unit;
  
  	ex_a->fixup.unit = ex_b->fixup.unit;
  	ex_b->fixup.unit = t;
  	ex_a->insn = (int)(addr_b - (unsigned long)&ex_a->insn);
  	ex_b->insn = (int)(addr_a - (unsigned long)&ex_b->insn);
  }
  
  /*
   * The exception table needs to be sorted so that the binary
   * search that we use to find entries in it works properly.
   * This is used both for the kernel exception table and for
   * the exception tables of modules that get loaded.
   */
  static int cmp_ex(const void *a, const void *b)
  {
  	const struct exception_table_entry *x = a, *y = b;
  
  	/* avoid overflow */
  	if (ex_to_addr(x) > ex_to_addr(y))
  		return 1;
  	if (ex_to_addr(x) < ex_to_addr(y))
  		return -1;
  	return 0;
  }
  
  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);
  }
  
  #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 value)
  {
          while (first <= last) {
  		const struct exception_table_entry *mid;
  		unsigned long mid_value;
  
  		mid = (last - first) / 2 + first;
  		mid_value = ex_to_addr(mid);
                  if (mid_value == value)
                          return mid;
                  else if (mid_value < value)
                          first = mid+1;
                  else
                          last = mid-1;
          }
  
          return NULL;
  }