powerpc/hw_brk: Fix off by one error when validating DAWR region end

The Data Address Watchpoint Register (DAWR) on POWER8 can take a 512
byte range but this range must not cross a 512 byte boundary.

Unfortunately we were off by one when calculating the end of the region,
hence we were not allowing some breakpoint regions which were actually
valid.  This fixes this error.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Reported-by: Edjunior Barbosa Machado <emachado@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org # 3.9+
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Michael Neuling 2013-07-01 14:19:50 +10:00 committed by Benjamin Herrenschmidt
parent 40847e5660
commit e2a800beac

View File

@ -176,7 +176,7 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp)
length_max = 512 ; /* 64 doublewords */
/* DAWR region can't cross 512 boundary */
if ((bp->attr.bp_addr >> 10) !=
((bp->attr.bp_addr + bp->attr.bp_len) >> 10))
((bp->attr.bp_addr + bp->attr.bp_len - 1) >> 10))
return -EINVAL;
}
if (info->len >