From: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Date: Thu, 14 May 2020 11:17:40 +0000 (+0530)
Subject: powerpc/watchpoint/xmon: Don't allow breakpoint overwriting
X-Git-Tag: v5.10.7~2436^2~104
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=514db915e7b33e7eaf8e40192b93380f79b319b5;p=platform%2Fkernel%2Flinux-rpi.git

powerpc/watchpoint/xmon: Don't allow breakpoint overwriting

Xmon allows overwriting breakpoints because it's supported by only
one DAWR. But with multiple DAWRs, overwriting becomes ambiguous
or unnecessary complicated. So let's not allow it.

Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Michael Neuling <mikey@neuling.org>
Link: https://lore.kernel.org/r/20200514111741.97993-16-ravi.bangoria@linux.ibm.com
---

diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 30b3e3d99..094bf47 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -1399,6 +1399,10 @@ bpt_cmds(void)
 			printf("Hardware data breakpoint not supported on this cpu\n");
 			break;
 		}
+		if (dabr.enabled) {
+			printf("Couldn't find free breakpoint register\n");
+			break;
+		}
 		mode = 7;
 		cmd = inchar();
 		if (cmd == 'r')