On 03.01.2016 17:05, Ard Biesheuvel wrote:
> This adds support to the generic search_extable() and sort_extable()
> implementations for dealing with exception table entries whose fields
> contain relative offsets rather than absolute addresses.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
I tested the generic parts with an upcoming patch which handles relative
exception tables on the parisc platform.
Everything worked as expected.
So for the non arch-relevant changes:
Acked-by: Helge Deller <deller@xxxxxx>
Helge
> ---
> lib/extable.c | 50 ++++++++++++++++----
> 1 file changed, 41 insertions(+), 9 deletions(-)
>
> diff --git a/lib/extable.c b/lib/extable.c
> index 4cac81ec225e..0be02ad561e9 100644
> --- a/lib/extable.c
> +++ b/lib/extable.c
> @@ -14,7 +14,37 @@
> #include <linux/sort.h>
> #include <asm/uaccess.h>
>
> +#ifndef ARCH_HAS_RELATIVE_EXTABLE
> +#define ex_to_insn(x) ((x)->insn)
> +#else
> +static inline unsigned long ex_to_insn(const struct exception_table_entry *x)
> +{
> + return (unsigned long)&x->insn + x->insn;
> +}
> +#endif
> +
> #ifndef ARCH_HAS_SORT_EXTABLE
> +#ifndef ARCH_HAS_RELATIVE_EXTABLE
> +#define swap_ex NULL
> +#else
> +static void swap_ex(void *a, void *b, int size)
> +{
> + struct exception_table_entry *x = a, *y = b, tmp;
> + int delta = b - a;
> +
> + tmp = *x;
> + x->insn = y->insn + delta;
> + y->insn = tmp.insn - delta;
> +
> +#ifdef swap_ex_entry_fixup
> + swap_ex_entry_fixup(x, y, tmp, delta);
> +#else
> + x->fixup = y->fixup + delta;
> + y->fixup = tmp.fixup - delta;
> +#endif
> +}
> +#endif /* ARCH_HAS_RELATIVE_EXTABLE */
> +
> /*
> * The exception table needs to be sorted so that the binary
> * search that we use to find entries in it works properly.
> @@ -26,9 +56,9 @@ static int cmp_ex(const void *a, const void *b)
> const struct exception_table_entry *x = a, *y = b;
>
> /* avoid overflow */
> - if (x->insn > y->insn)
> + if (ex_to_insn(x) > ex_to_insn(y))
> return 1;
> - if (x->insn < y->insn)
> + if (ex_to_insn(x) < ex_to_insn(y))
> return -1;
> return 0;
> }
> @@ -37,7 +67,7 @@ void sort_extable(struct exception_table_entry *start,
> struct exception_table_entry *finish)
> {
> sort(start, finish - start, sizeof(struct exception_table_entry),
> - cmp_ex, NULL);
> + cmp_ex, swap_ex);
> }
>
> #ifdef CONFIG_MODULES
> @@ -48,13 +78,15 @@ void sort_extable(struct exception_table_entry *start,
> void trim_init_extable(struct module *m)
> {
> /*trim the beginning*/
> - while (m->num_exentries && within_module_init(m->extable[0].insn, m)) {
> + while (m->num_exentries &&
> + within_module_init(ex_to_insn(&m->extable[0]), m)) {
> m->extable++;
> m->num_exentries--;
> }
> /*trim the end*/
> while (m->num_exentries &&
> - within_module_init(m->extable[m->num_exentries-1].insn, m))
> + within_module_init(ex_to_insn(&m->extable[m->num_exentries - 1]),
> + m))
> m->num_exentries--;
> }
> #endif /* CONFIG_MODULES */
> @@ -81,13 +113,13 @@ search_extable(const struct exception_table_entry *first,
> * careful, the distance between value and insn
> * can be larger than MAX_LONG:
> */
> - if (mid->insn < value)
> + if (ex_to_insn(mid) < value)
> first = mid + 1;
> - else if (mid->insn > value)
> + else if (ex_to_insn(mid) > value)
> last = mid - 1;
> else
> return mid;
> - }
> - return NULL;
> + }
> + return NULL;
> }
> #endif
>
--
To unsubscribe from this list: send the line "unsubscribe linux-s390" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
