From 1ff3b404019adf9d605224e1dce0677a0375d274 Mon Sep 17 00:00:00 2001 From: Vaibhav Jain Date: Sun, 4 Mar 2018 23:01:32 +0530 Subject: [PATCH] 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 Reviewed-by: Balbir Singh [mpe: Fix build break when CONFIG_DEBUG_FS=n] Signed-off-by: Michael Ellerman --- 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 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; } -- 2.30.2