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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 <asm/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->insn + x->insn;
}
#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 */
}
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