1 // SPDX-License-Identifier: GPL-2.0-only
10  * HW_breakpoint: a unified kernel/user-space hardware breakpoint facility,
13 #define pr_fmt(fmt) "hw-breakpoint: " fmt
150 	/* We don't support the memory-mapped interface. */  in debug_arch_supported()
215 	return core_has_mismatch_brps() ? brps - 1 : brps;  in get_num_brps()
256 		return -ENODEV;  in enable_monitor_mode()
264 		return -EPERM;  in enable_monitor_mode()
292  * Check if 8-bit byte-address select is available.
298 	struct arch_hw_breakpoint_ctrl ctrl;  in get_max_wp_len()  local
304 	memset(&ctrl, 0, sizeof(ctrl));  in get_max_wp_len()
305 	ctrl.len = ARM_BREAKPOINT_LEN_8;  in get_max_wp_len()
306 	ctrl_reg = encode_ctrl_reg(ctrl);  in get_max_wp_len()
330 	u32 addr, ctrl;  in arch_install_hw_breakpoint()  local
332 	addr = info->address;  in arch_install_hw_breakpoint()
333 	ctrl = encode_ctrl_reg(info->ctrl) | 0x1;  in arch_install_hw_breakpoint()
335 	if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE) {  in arch_install_hw_breakpoint()
360 		return -EBUSY;  in arch_install_hw_breakpoint()
364 	if (info->step_ctrl.enabled) {  in arch_install_hw_breakpoint()
365 		addr = info->trigger & ~0x3;  in arch_install_hw_breakpoint()
366 		ctrl = encode_ctrl_reg(info->step_ctrl);  in arch_install_hw_breakpoint()
367 		if (info->ctrl.type != ARM_BREAKPOINT_EXECUTE) {  in arch_install_hw_breakpoint()
378 	write_wb_reg(ctrl_base + i, ctrl);  in arch_install_hw_breakpoint()
388 	if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE) {  in arch_uninstall_hw_breakpoint()
416 	if (info->ctrl.type != ARM_BREAKPOINT_EXECUTE &&  in arch_uninstall_hw_breakpoint()
417 	    info->step_ctrl.enabled) {  in arch_uninstall_hw_breakpoint()
453 	unsigned int len;  in arch_check_bp_in_kernelspace()  local
456 	va = hw->address;  in arch_check_bp_in_kernelspace()
457 	len = get_hbp_len(hw->ctrl.len);  in arch_check_bp_in_kernelspace()
459 	return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE);  in arch_check_bp_in_kernelspace()
467 int arch_bp_generic_fields(struct arch_hw_breakpoint_ctrl ctrl,  in arch_bp_generic_fields()  argument
471 	switch (ctrl.type) {  in arch_bp_generic_fields()
485 		return -EINVAL;  in arch_bp_generic_fields()
488 	/* Len */  in arch_bp_generic_fields()
489 	switch (ctrl.len) {  in arch_bp_generic_fields()
503 		return -EINVAL;  in arch_bp_generic_fields()
517 	switch (attr->bp_type) {  in arch_build_bp_info()
519 		hw->ctrl.type = ARM_BREAKPOINT_EXECUTE;  in arch_build_bp_info()
522 		hw->ctrl.type = ARM_BREAKPOINT_LOAD;  in arch_build_bp_info()
525 		hw->ctrl.type = ARM_BREAKPOINT_STORE;  in arch_build_bp_info()
528 		hw->ctrl.type = ARM_BREAKPOINT_LOAD | ARM_BREAKPOINT_STORE;  in arch_build_bp_info()
531 		return -EINVAL;  in arch_build_bp_info()
534 	/* Len */  in arch_build_bp_info()
535 	switch (attr->bp_len) {  in arch_build_bp_info()
537 		hw->ctrl.len = ARM_BREAKPOINT_LEN_1;  in arch_build_bp_info()
540 		hw->ctrl.len = ARM_BREAKPOINT_LEN_2;  in arch_build_bp_info()
543 		hw->ctrl.len = ARM_BREAKPOINT_LEN_4;  in arch_build_bp_info()
546 		hw->ctrl.len = ARM_BREAKPOINT_LEN_8;  in arch_build_bp_info()
547 		if ((hw->ctrl.type != ARM_BREAKPOINT_EXECUTE)  in arch_build_bp_info()
552 		return -EINVAL;  in arch_build_bp_info()
561 	if (hw->ctrl.type == ARM_BREAKPOINT_EXECUTE &&  in arch_build_bp_info()
562 	    hw->ctrl.len != ARM_BREAKPOINT_LEN_2 &&  in arch_build_bp_info()
563 	    hw->ctrl.len != ARM_BREAKPOINT_LEN_4)  in arch_build_bp_info()
564 		return -EINVAL;  in arch_build_bp_info()
567 	hw->address = attr->bp_addr;  in arch_build_bp_info()
570 	hw->ctrl.privilege = ARM_BREAKPOINT_USER;  in arch_build_bp_info()
572 		hw->ctrl.privilege |= ARM_BREAKPOINT_PRIV;  in arch_build_bp_info()
575 	hw->ctrl.enabled = !attr->disabled;  in arch_build_bp_info()
578 	hw->ctrl.mismatch = 0;  in arch_build_bp_info()
584  * Validate the arch-specific HW Breakpoint register settings.
595 		return -ENODEV;  in hw_breakpoint_arch_parse()
603 	if (hw->ctrl.len == ARM_BREAKPOINT_LEN_8)  in hw_breakpoint_arch_parse()
605 	offset = hw->address & alignment_mask;  in hw_breakpoint_arch_parse()
613 		if (hw->ctrl.len == ARM_BREAKPOINT_LEN_2)  in hw_breakpoint_arch_parse()
618 		if (hw->ctrl.len == ARM_BREAKPOINT_LEN_1)  in hw_breakpoint_arch_parse()
622 		ret = -EINVAL;  in hw_breakpoint_arch_parse()
626 	hw->address &= ~alignment_mask;  in hw_breakpoint_arch_parse()
627 	hw->ctrl.len <<= offset;  in hw_breakpoint_arch_parse()
631 		 * Mismatch breakpoints are required for single-stepping  in hw_breakpoint_arch_parse()
635 			return -EINVAL;  in hw_breakpoint_arch_parse()
639 			return -EPERM;  in hw_breakpoint_arch_parse()
642 		 * Per-cpu breakpoints are not supported by our stepping  in hw_breakpoint_arch_parse()
645 		if (!bp->hw.target)  in hw_breakpoint_arch_parse()
646 			return -EINVAL;  in hw_breakpoint_arch_parse()
653 		    (hw->ctrl.type == ARM_BREAKPOINT_LOAD ||  in hw_breakpoint_arch_parse()
654 		     hw->ctrl.type == ARM_BREAKPOINT_STORE))  in hw_breakpoint_arch_parse()
655 			return -EINVAL;  in hw_breakpoint_arch_parse()
663  * Enable/disable single-stepping over the breakpoint bp at address addr.
670 	info->step_ctrl.mismatch  = 1;  in enable_single_step()
671 	info->step_ctrl.len	  = ARM_BREAKPOINT_LEN_4;  in enable_single_step()
672 	info->step_ctrl.type	  = ARM_BREAKPOINT_EXECUTE;  in enable_single_step()
673 	info->step_ctrl.privilege = info->ctrl.privilege;  in enable_single_step()
674 	info->step_ctrl.enabled	  = 1;  in enable_single_step()
675 	info->trigger		  = addr;  in enable_single_step()
682 	counter_arch_bp(bp)->step_ctrl.enabled = 0;  in disable_single_step()
690  * addresses. There is no straight-forward way, short of disassembling the
702 					struct arch_hw_breakpoint_ctrl *ctrl)  in get_distance_from_watchpoint()  argument
707 	lens = __ffs(ctrl->len);  in get_distance_from_watchpoint()
708 	lene = __fls(ctrl->len);  in get_distance_from_watchpoint()
713 		return wp_low - addr;  in get_distance_from_watchpoint()
715 		return addr - wp_high;  in get_distance_from_watchpoint()
723 	return !user_mode(regs) && info->ctrl.privilege == ARM_BREAKPOINT_USER;  in watchpoint_fault_on_uaccess()
730 	u32 min_dist = -1, dist;  in watchpoint_handler()
734 	struct arch_hw_breakpoint_ctrl ctrl;  in watchpoint_handler()  local
757 			info->trigger = wp->attr.bp_addr;  in watchpoint_handler()
769 			decode_ctrl_reg(ctrl_reg, &ctrl);  in watchpoint_handler()
770 			dist = get_distance_from_watchpoint(addr, val, &ctrl);  in watchpoint_handler()
781 			info->trigger = addr;  in watchpoint_handler()
784 		pr_debug("watchpoint fired: address = 0x%x\n", info->trigger);  in watchpoint_handler()
799 		 * we can single-step over the watchpoint trigger.  in watchpoint_handler()
807 	if (min_dist > 0 && min_dist != -1) {  in watchpoint_handler()
811 		info->trigger = addr;  in watchpoint_handler()
812 		pr_debug("watchpoint fired: address = 0x%x\n", info->trigger);  in watchpoint_handler()
838 		if (!info->step_ctrl.enabled)  in watchpoint_single_step_handler()
843 		 * single-step.  in watchpoint_single_step_handler()
845 		if (info->trigger != pc)  in watchpoint_single_step_handler()
859 	struct arch_hw_breakpoint_ctrl ctrl;  in breakpoint_handler()  local
864 	addr = regs->ARM_pc;  in breakpoint_handler()
884 		decode_ctrl_reg(ctrl_reg, &ctrl);  in breakpoint_handler()
885 		if ((1 << (addr & 0x3)) & ctrl.len) {  in breakpoint_handler()
886 			info->trigger = addr;  in breakpoint_handler()
896 		if (info->step_ctrl.enabled)  in breakpoint_handler()
902 	/* Handle any pending watchpoint single-step breakpoints. */  in breakpoint_handler()
962  * One-time initialisation.
1019 	 * can be maintained across low-power modes without leaving the debug  in reset_ctrl_regs()
1032 		 * Ensure sticky power-down is clear (i.e. debug logic is  in reset_ctrl_regs()
1037 			err = -EPERM;  in reset_ctrl_regs()
1048 			err = -EPERM;  in reset_ctrl_regs()
1066 	 * Clear any configured vector-catch events before  in reset_ctrl_regs()