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authorVaibhav Jain <vaibhav@linux.vnet.ibm.com>2018-03-04 23:01:32 +0530
committerMichael Ellerman <mpe@ellerman.id.au>2018-03-13 15:50:05 +1100
commit1ff3b404019adf9d605224e1dce0677a0375d274 (patch)
treee12830b3eafd08ffa3064b9bced36faed5f057c9 /arch/powerpc/xmon
parente1368d0c9edbc366e45216e7295fd61ae55c2b12 (diff)
powerpc/xmon: Clear all breakpoints when xmon is disabled via debugfs
Presently when xmon is disabled by debugfs any existing instruction/data-access breakpoints set are not disabled. This may lead to kernel oops when those breakpoints are hit as the necessary debugger hooks aren't installed. Hence this patch introduces a new function named clear_all_bpt() which is called when xmon is disabled via debugfs. The function will unpatch/clear all the trap and ciabr/dab based breakpoints. Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com> Reviewed-by: Balbir Singh <bsingharora@gmail.com> [mpe: Fix build break when CONFIG_DEBUG_FS=n] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/xmon')
-rw-r--r--arch/powerpc/xmon/xmon.c24
1 files changed, 24 insertions, 0 deletions
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index ee4b6071007d..3ddf9dd9a55f 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -3664,11 +3664,35 @@ device_initcall(setup_xmon_sysrq);
#endif /* CONFIG_MAGIC_SYSRQ */
#ifdef CONFIG_DEBUG_FS
+static void clear_all_bpt(void)
+{
+ int i;
+
+ /* clear/unpatch all breakpoints */
+ remove_bpts();
+ remove_cpu_bpts();
+
+ /* Disable all breakpoints */
+ for (i = 0; i < NBPTS; ++i)
+ bpts[i].enabled = 0;
+
+ /* Clear any data or iabr breakpoints */
+ if (iabr || dabr.enabled) {
+ iabr = NULL;
+ dabr.enabled = 0;
+ }
+
+ printf("xmon: All breakpoints cleared\n");
+}
+
static int xmon_dbgfs_set(void *data, u64 val)
{
xmon_on = !!val;
xmon_init(xmon_on);
+ /* make sure all breakpoints removed when disabling */
+ if (!xmon_on)
+ clear_all_bpt();
return 0;
}