Merge "arm64: kernel: implement HW breakpoints CPU PM notifier" (75e54843) · Commits · e / devices / android_kernel_sony_msm8994_rework

arch/arm64/kernel/hw_breakpoint.c

+66 −13

Original line number	Diff line number	Diff line
		@@ -20,6 +20,7 @@

		#define pr_fmt(fmt) "hw-breakpoint: " fmt

		#include <linux/cpu_pm.h>
		#include <linux/errno.h>
		#include <linux/hw_breakpoint.h>
		#include <linux/perf_event.h>
		@@ -171,7 +172,8 @@ static enum debug_el debug_exception_level(int privilege)

		enum hw_breakpoint_ops {
		HW_BREAKPOINT_INSTALL,
		HW_BREAKPOINT_UNINSTALL
		HW_BREAKPOINT_UNINSTALL,
		HW_BREAKPOINT_RESTORE
		};

		/**
		@@ -210,6 +212,10 @@ static int hw_breakpoint_slot_setup(struct perf_event **slots, int max_slots,
		return i;
		}
		break;
		case HW_BREAKPOINT_RESTORE:
		if (*slot == bp)
		return i;
		break;
		default:
		pr_warn_once("Unhandled hw breakpoint ops %d\n", ops);
		return -EINVAL;
		@@ -256,7 +262,8 @@ static int hw_breakpoint_control(struct perf_event *bp,
		* level.
		*/
		enable_debug_monitors(dbg_el);

		/* Fall through */
		case HW_BREAKPOINT_RESTORE:
		/* Setup the address register. */
		write_wb_reg(val_reg, i, info->address);

		@@ -840,20 +847,38 @@ void hw_breakpoint_thread_switch(struct task_struct *next)
		/*
		* CPU initialisation.
		*/
		static void reset_ctrl_regs(void *unused)
		static void hw_breakpoint_reset(void *unused)
		{
		int i;

		for (i = 0; i < core_num_brps; ++i) {
		struct perf_event **slots;
		/*
		* When a CPU goes through cold-boot, it does not have any installed
		* slot, so it is safe to share the same function for restoring and
		* resetting breakpoints; when a CPU is hotplugged in, it goes
		* through the slots, which are all empty, hence it just resets control
		* and value for debug registers.
		* When this function is triggered on warm-boot through a CPU PM
		* notifier some slots might be initialized; if so they are
		* reprogrammed according to the debug slots content.
		*/
		for (slots = this_cpu_ptr(bp_on_reg), i = 0; i < core_num_brps; ++i) {
		if (slots[i]) {
		hw_breakpoint_control(slots[i], HW_BREAKPOINT_RESTORE);
		} else {
		write_wb_reg(AARCH64_DBG_REG_BCR, i, 0UL);
		write_wb_reg(AARCH64_DBG_REG_BVR, i, 0UL);
		}
		}

		for (i = 0; i < core_num_wrps; ++i) {
		for (slots = this_cpu_ptr(wp_on_reg), i = 0; i < core_num_wrps; ++i) {
		if (slots[i]) {
		hw_breakpoint_control(slots[i], HW_BREAKPOINT_RESTORE);
		} else {
		write_wb_reg(AARCH64_DBG_REG_WCR, i, 0UL);
		write_wb_reg(AARCH64_DBG_REG_WVR, i, 0UL);
		}
		}
		}

		static int __cpuinit hw_breakpoint_reset_notify(struct notifier_block *self,
		unsigned long action,
		@@ -861,7 +886,7 @@ static int __cpuinit hw_breakpoint_reset_notify(struct notifier_block *self,
		{
		int cpu = (long)hcpu;
		if (action == CPU_ONLINE)
		smp_call_function_single(cpu, reset_ctrl_regs, NULL, 1);
		smp_call_function_single(cpu, hw_breakpoint_reset, NULL, 1);
		return NOTIFY_OK;
		}

		@@ -869,6 +894,33 @@ static struct notifier_block __cpuinitdata hw_breakpoint_reset_nb = {
		.notifier_call = hw_breakpoint_reset_notify,
		};

		#ifdef CONFIG_CPU_PM
		static int hw_breakpoint_cpu_pm_notify(struct notifier_block *self,
		unsigned long action,
		void *v)
		{
		if (action == CPU_PM_EXIT) {
		hw_breakpoint_reset(NULL);
		return NOTIFY_OK;
		}

		return NOTIFY_DONE;
		}

		static struct notifier_block hw_breakpoint_cpu_pm_nb = {
		.notifier_call = hw_breakpoint_cpu_pm_notify,
		};

		static void __init hw_breakpoint_pm_init(void)
		{
		cpu_pm_register_notifier(&hw_breakpoint_cpu_pm_nb);
		}
		#else
		static inline void hw_breakpoint_pm_init(void)
		{
		}
		#endif

		/*
		* One-time initialisation.
		*/
		@@ -884,8 +936,8 @@ 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.
		*/
		smp_call_function(reset_ctrl_regs, NULL, 1);
		reset_ctrl_regs(NULL);
		smp_call_function(hw_breakpoint_reset, NULL, 1);
		hw_breakpoint_reset(NULL);

		/* Register debug fault handlers. */
		hook_debug_fault_code(DBG_ESR_EVT_HWBP, breakpoint_handler, SIGTRAP,
		@@ -895,6 +947,7 @@ static int __init arch_hw_breakpoint_init(void)

		/* Register hotplug notifier. */
		register_cpu_notifier(&hw_breakpoint_reset_nb);
		hw_breakpoint_pm_init();

		return 0;
		}