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powerpc/ptrace: Fix enforcement of DAWR constraints

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Back when we first introduced the DAWR, in commit 4ae7ebe952
("powerpc: Change hardware breakpoint to allow longer ranges"), we
screwed up the constraint making it a 1024 byte boundary rather than a
512. This makes the check overly permissive. Fortunately GDB is the
only real user and it always did they right thing, so we never
noticed.

This fixes the constraint to 512 bytes.

Fixes: 4ae7ebe952 ("powerpc: Change hardware breakpoint to allow longer ranges")
Cc: stable@vger.kernel.org # v3.9+
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Michael Neuling 2018-05-17 15:37:14 +10:00 committed by Michael Ellerman
parent c786cf767b
commit cd6ef7eebf
1 changed files with 2 additions and 2 deletions
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4
arch/powerpc/kernel/hw_breakpoint.c
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@ -178,8 +178,8 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp)
if (cpu_has_feature(CPU_FTR_DAWR)) {
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 - 1) >> 10))
if ((bp->attr.bp_addr >> 9) !=
((bp->attr.bp_addr + bp->attr.bp_len - 1) >> 9))
return -EINVAL;
}
if (info->len >