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-rw-r--r--arch/arm/kernel/hw_breakpoint.c28
1 files changed, 15 insertions, 13 deletions
diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
index 983558eb902..8e9532152bd 100644
--- a/arch/arm/kernel/hw_breakpoint.c
+++ b/arch/arm/kernel/hw_breakpoint.c
@@ -228,6 +228,13 @@ static int get_num_brps(void)
* be put into halting debug mode at any time by an external debugger
* but there is nothing we can do to prevent that.
*/
+static int monitor_mode_enabled(void)
+{
+ u32 dscr;
+ ARM_DBG_READ(c1, 0, dscr);
+ return !!(dscr & ARM_DSCR_MDBGEN);
+}
+
static int enable_monitor_mode(void)
{
u32 dscr;
@@ -321,14 +328,9 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
struct perf_event **slot, **slots;
- int i, max_slots, ctrl_base, val_base, ret = 0;
+ int i, max_slots, ctrl_base, val_base;
u32 addr, ctrl;
- /* Ensure that we are in monitor mode and halting mode is disabled. */
- ret = enable_monitor_mode();
- if (ret)
- goto out;
-
addr = info->address;
ctrl = encode_ctrl_reg(info->ctrl) | 0x1;
@@ -355,10 +357,8 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
}
}
- if (WARN_ONCE(i == max_slots, "Can't find any breakpoint slot\n")) {
- ret = -EBUSY;
- goto out;
- }
+ if (WARN_ONCE(i == max_slots, "Can't find any breakpoint slot\n"))
+ return -EBUSY;
/* Override the breakpoint data with the step data. */
if (info->step_ctrl.enabled) {
@@ -376,9 +376,7 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
/* Setup the control register. */
write_wb_reg(ctrl_base + i, ctrl);
-
-out:
- return ret;
+ return 0;
}
void arch_uninstall_hw_breakpoint(struct perf_event *bp)
@@ -589,6 +587,10 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp)
int ret = 0;
u32 offset, alignment_mask = 0x3;
+ /* Ensure that we are in monitor debug mode. */
+ if (!monitor_mode_enabled())
+ return -ENODEV;
+
/* Build the arch_hw_breakpoint. */
ret = arch_build_bp_info(bp);
if (ret)