From b0b0aa9c7faf94e92320eabd8a1786c7747e40a8 Mon Sep 17 00:00:00 2001
From: Michael Neuling <mikey@neuling.org>
Date: Mon, 24 Jun 2013 15:47:22 +1000
Subject: [PATCH] powerpc/hw_brk: Fix setting of length for exact mode
breakpoints
The smallest match region for both the DABR and DAWR is 8 bytes, so the
kernel needs to filter matches when users want to look at regions smaller than
this.
Currently we set the length of PPC_BREAKPOINT_MODE_EXACT breakpoints to 8.
This is wrong as in exact mode we should only match on 1 address, hence the
length should be 1.
This ensures that the kernel will filter out any exact mode hardware breakpoint
matches on any addresses other than the requested one.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Reported-by: Edjunior Barbosa Machado <emachado@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
arch/powerpc/kernel/ptrace.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index 98c2fc198712aa..64f7bd5b1b0f59 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -1449,7 +1449,9 @@ static long ppc_set_hwdebug(struct task_struct *child,
*/
if (bp_info->addr_mode == PPC_BREAKPOINT_MODE_RANGE_INCLUSIVE) {
len = bp_info->addr2 - bp_info->addr;
- } else if (bp_info->addr_mode != PPC_BREAKPOINT_MODE_EXACT) {
+ } else if (bp_info->addr_mode == PPC_BREAKPOINT_MODE_EXACT)
+ len = 1;
+ else {
ptrace_put_breakpoints(child);
return -EINVAL;
}
--
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