1 files changed, 37 insertions, 10 deletions

diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
index d600bd350704..87acc25d7a3e 100644
--- a/arch/arm/kernel/hw_breakpoint.c
+++ b/arch/arm/kernel/hw_breakpoint.c
@@ -238,8 +238,8 @@ static int enable_monitor_mode(void)
 	ARM_DBG_READ(c1, 0, dscr);
 
 	/* Ensure that halting mode is disabled. */
-	if (WARN_ONCE(dscr & ARM_DSCR_HDBGEN, "halting debug mode enabled."
-				"Unable to access hardware resources.")) {
+	if (WARN_ONCE(dscr & ARM_DSCR_HDBGEN,
+			"halting debug mode enabled. Unable to access hardware resources.\n")) {
 		ret = -EPERM;
 		goto out;
 	}
@@ -377,7 +377,7 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
 		}
 	}
 
-	if (WARN_ONCE(i == max_slots, "Can't find any breakpoint slot")) {
+	if (WARN_ONCE(i == max_slots, "Can't find any breakpoint slot\n")) {
 		ret = -EBUSY;
 		goto out;
 	}
@@ -423,7 +423,7 @@ void arch_uninstall_hw_breakpoint(struct perf_event *bp)
 		}
 	}
 
-	if (WARN_ONCE(i == max_slots, "Can't find any breakpoint slot"))
+	if (WARN_ONCE(i == max_slots, "Can't find any breakpoint slot\n"))
 		return;
 
 	/* Reset the control register. */
@@ -635,7 +635,7 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp)
 	if (WARN_ONCE(!bp->overflow_handler &&
 		(arch_check_bp_in_kernelspace(bp) || !core_has_mismatch_brps()
 		 || !bp->hw.bp_target),
-			"overflow handler required but none found")) {
+			"overflow handler required but none found\n")) {
 		ret = -EINVAL;
 	}
 out:
@@ -836,9 +836,11 @@ static int hw_breakpoint_pending(unsigned long addr, unsigned int fsr,
 /*
  * One-time initialisation.
  */
-static void reset_ctrl_regs(void *unused)
+static void reset_ctrl_regs(void *info)
 {
-	int i;
+	int i, cpu = smp_processor_id();
+	u32 dbg_power;
+	cpumask_t *cpumask = info;
 
 	/*
 	 * v7 debug contains save and restore registers so that debug state
@@ -850,11 +852,29 @@ static void reset_ctrl_regs(void *unused)
 	 */
 	if (debug_arch >= ARM_DEBUG_ARCH_V7_ECP14) {
 		/*
+		 * Ensure sticky power-down is clear (i.e. debug logic is
+		 * powered up).
+		 */
+		asm volatile("mrc p14, 0, %0, c1, c5, 4" : "=r" (dbg_power));
+		if ((dbg_power & 0x1) == 0) {
+			pr_warning("CPU %d debug is powered down!\n", cpu);
+			cpumask_or(cpumask, cpumask, cpumask_of(cpu));
+			return;
+		}
+
+		/*
 		 * Unconditionally clear the lock by writing a value
 		 * other than 0xC5ACCE55 to the access register.
 		 */
 		asm volatile("mcr p14, 0, %0, c1, c0, 4" : : "r" (0));
 		isb();
+
+		/*
+		 * Clear any configured vector-catch events before
+		 * enabling monitor mode.
+		 */
+		asm volatile("mcr p14, 0, %0, c0, c7, 0" : : "r" (0));
+		isb();
 	}
 
 	if (enable_monitor_mode())
@@ -887,6 +907,7 @@ static struct notifier_block __cpuinitdata dbg_reset_nb = {
 static int __init arch_hw_breakpoint_init(void)
 {
 	u32 dscr;
+	cpumask_t cpumask = { CPU_BITS_NONE };
 
 	debug_arch = get_debug_arch();
 
@@ -911,13 +932,19 @@ static int __init arch_hw_breakpoint_init(void)
 	 * Reset the breakpoint resources. We assume that a halting
 	 * debugger will leave the world in a nice state for us.
 	 */
-	on_each_cpu(reset_ctrl_regs, NULL, 1);
+	on_each_cpu(reset_ctrl_regs, &cpumask, 1);
+	if (!cpumask_empty(&cpumask)) {
+		core_num_brps = 0;
+		core_num_reserved_brps = 0;
+		core_num_wrps = 0;
+		return 0;
+	}
 
 	ARM_DBG_READ(c1, 0, dscr);
 	if (dscr & ARM_DSCR_HDBGEN) {
 		max_watchpoint_len = 4;
-		pr_warning("halting debug mode enabled. Assuming maximum "
-			   "watchpoint size of %u bytes.", max_watchpoint_len);
+		pr_warning("halting debug mode enabled. Assuming maximum watchpoint size of %u bytes.\n",
+			   max_watchpoint_len);
 	} else {
 		/* Work out the maximum supported watchpoint length. */
 		max_watchpoint_len = get_max_wp_len();