From 919c9b8187bc8aa66388e50248c7f6c5b0c87e97 Mon Sep 17 00:00:00 2001 From: Michael Neuling Date: Thu, 17 May 2018 15:37:14 +1000 Subject: [PATCH] powerpc/ptrace: Fix enforcement of DAWR constraints commit cd6ef7eebf171bfcba7dc2df719c2a4958775040 upstream. Back when we first introduced the DAWR, in commit 4ae7ebe9522a ("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: 4ae7ebe9522a ("powerpc: Change hardware breakpoint to allow longer ranges") Cc: stable@vger.kernel.org # v3.9+ Signed-off-by: Michael Neuling Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/kernel/hw_breakpoint.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c index 53b9c1dfd7d9..ceafad83ef50 100644 --- a/arch/powerpc/kernel/hw_breakpoint.c +++ b/arch/powerpc/kernel/hw_breakpoint.c @@ -175,8 +175,8 @@ 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 > -- 2.20.1