Messages in this thread Patch in this message | | | From | Vaibhav Jain <> | Subject | [PATCH] xmon: Clear all breakpoints when xmon is disabled via debugfs | Date | Sun, 4 Mar 2018 23:01:32 +0530 |
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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> --- arch/powerpc/xmon/xmon.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+)
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index e9c7ec8f15f8..f43aacd74625 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -903,6 +903,27 @@ static void remove_bpts(void) } } +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 void remove_cpu_bpts(void) { hw_breakpoint_disable(); @@ -3671,6 +3692,9 @@ 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; } -- 2.14.3
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