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Message-Id: <20190815050616.2547-2-cmr@informatik.wtf>
Date: Thu, 15 Aug 2019 00:06:15 -0500
From: "Christopher M. Riedl" <cmr@...ormatik.wtf>
To: linuxppc-dev@...abs.org,
kernel-hardening@...ts.openwall.com
Subject: [RFC PATCH v4 1/2] powerpc/xmon: Allow listing active breakpoints in read-only mode
Xmon can enter read-only mode dynamically due to changes in kernel
lockdown state. This transition does not clear active breakpoints and
any these breakpoints should remain visible to the xmon'er.
Signed-off-by: Christopher M. Riedl <cmr@...ormatik.wtf>
---
arch/powerpc/xmon/xmon.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index d0620d762a5a..bb63ecc599fd 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -1045,10 +1045,6 @@ cmds(struct pt_regs *excp)
set_lpp_cmd();
break;
case 'b':
- if (xmon_is_ro) {
- printf(xmon_ro_msg);
- break;
- }
bpt_cmds();
break;
case 'C':
@@ -1317,11 +1313,16 @@ bpt_cmds(void)
struct bpt *bp;
cmd = inchar();
+
switch (cmd) {
#ifndef CONFIG_PPC_8xx
static const char badaddr[] = "Only kernel addresses are permitted for breakpoints\n";
int mode;
case 'd': /* bd - hardware data breakpoint */
+ if (xmon_is_ro) {
+ printf(xmon_ro_msg);
+ break;
+ }
if (!ppc_breakpoint_available()) {
printf("Hardware data breakpoint not supported on this cpu\n");
break;
@@ -1349,6 +1350,10 @@ bpt_cmds(void)
break;
case 'i': /* bi - hardware instr breakpoint */
+ if (xmon_is_ro) {
+ printf(xmon_ro_msg);
+ break;
+ }
if (!cpu_has_feature(CPU_FTR_ARCH_207S)) {
printf("Hardware instruction breakpoint "
"not supported on this cpu\n");
@@ -1372,6 +1377,10 @@ bpt_cmds(void)
#endif
case 'c':
+ if (xmon_is_ro) {
+ printf(xmon_ro_msg);
+ break;
+ }
if (!scanhex(&a)) {
/* clear all breakpoints */
for (i = 0; i < NBPTS; ++i)
@@ -1407,7 +1416,7 @@ bpt_cmds(void)
break;
}
termch = cmd;
- if (!scanhex(&a)) {
+ if (xmon_is_ro || !scanhex(&a)) {
/* print all breakpoints */
printf(" type address\n");
if (dabr.enabled) {
--
2.22.0
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