1 // SPDX-License-Identifier: GPL-2.0-or-later
3  * HW_breakpoint: a unified kernel/user-space hardware breakpoint facility,
53  * Atomic: we hold the counter->ctx->lock and we only handle variables
71 		return -EBUSY;  in arch_install_hw_breakpoint()
74 	 * Do not install DABR values if the instruction must be single-stepped.  in arch_install_hw_breakpoint()
77 	if (!info->perf_single_step)  in arch_install_hw_breakpoint()
89  * Atomic: we hold the counter->ctx->lock and we only handle variables
114 	return bp->overflow_handler == ptrace_triggered;  in is_ptrace_bp()
122 	return is_kernel_addr(hw->address);  in arch_check_bp_in_kernelspace()
133 		return -EINVAL;  in arch_bp_generic_fields()
145  *   |------------v--|------v--------|
147  *   |---------------|---------------|
148  *    <---8 bytes--->
151  *   start_addr = address & ~(HW_BREAKPOINT_SIZE - 1)
162 	start_addr = ALIGN_DOWN(hw->address, HW_BREAKPOINT_SIZE);  in hw_breakpoint_validate_len()
163 	end_addr = ALIGN(hw->address + hw->len, HW_BREAKPOINT_SIZE);  in hw_breakpoint_validate_len()
164 	hw_len = end_addr - start_addr;  in hw_breakpoint_validate_len()
170 		    (ALIGN_DOWN(start_addr, SZ_512) != ALIGN_DOWN(end_addr - 1, SZ_512)))  in hw_breakpoint_validate_len()
171 			return -EINVAL;  in hw_breakpoint_validate_len()
178 		return -EINVAL;  in hw_breakpoint_validate_len()
180 	hw->hw_len = hw_len;  in hw_breakpoint_validate_len()
185  * Validate the arch-specific HW Breakpoint register settings
191 	int ret = -EINVAL;  in hw_breakpoint_arch_parse()
193 	if (!bp || !attr->bp_len)  in hw_breakpoint_arch_parse()
196 	hw->type = HW_BRK_TYPE_TRANSLATE;  in hw_breakpoint_arch_parse()
197 	if (attr->bp_type & HW_BREAKPOINT_R)  in hw_breakpoint_arch_parse()
198 		hw->type |= HW_BRK_TYPE_READ;  in hw_breakpoint_arch_parse()
199 	if (attr->bp_type & HW_BREAKPOINT_W)  in hw_breakpoint_arch_parse()
200 		hw->type |= HW_BRK_TYPE_WRITE;  in hw_breakpoint_arch_parse()
201 	if (hw->type == HW_BRK_TYPE_TRANSLATE)  in hw_breakpoint_arch_parse()
204 	if (!attr->exclude_user)  in hw_breakpoint_arch_parse()
205 		hw->type |= HW_BRK_TYPE_USER;  in hw_breakpoint_arch_parse()
206 	if (!attr->exclude_kernel)  in hw_breakpoint_arch_parse()
207 		hw->type |= HW_BRK_TYPE_KERNEL;  in hw_breakpoint_arch_parse()
208 	if (!attr->exclude_hv)  in hw_breakpoint_arch_parse()
209 		hw->type |= HW_BRK_TYPE_HYP;  in hw_breakpoint_arch_parse()
210 	hw->address = attr->bp_addr;  in hw_breakpoint_arch_parse()
211 	hw->len = attr->bp_len;  in hw_breakpoint_arch_parse()
214 		return -ENODEV;  in hw_breakpoint_arch_parse()
224  * The perf watchpoint will simply re-trigger once the thread is started again,
238 		if (unlikely(bp && counter_arch_bp(bp)->perf_single_step))  in thread_change_pc()
244 	regs_set_return_msr(regs, regs->msr & ~MSR_SE);  in thread_change_pc()
248 		info->perf_single_step = false;  in thread_change_pc()
266  * We've failed in reliably handling the hw-breakpoint. Unregister
272 	     counter_arch_bp(bp)->address);  in handler_error()
279 			   counter_arch_bp(bp)->address);  in larx_stcx_err()
289 	/* Do not emulate user-space instructions, instead single-step them */  in stepping_handler()
295 			counter_arch_bp(bp[i])->perf_single_step = true;  in stepping_handler()
298 		regs_set_return_msr(regs, regs->msr | MSR_SE);  in stepping_handler()
334 		hw_end_addr = ALIGN(info->address + info->len, HW_BREAKPOINT_SIZE);  in handle_p10dd1_spurious_exception()
340 		if ((hw_end_addr - 1) >= ea)  in handle_p10dd1_spurious_exception()
347 		if (((hw_end_addr - 1) >> 10) != (ea >> 10))  in handle_p10dd1_spurious_exception()
366 			counter_arch_bp(bp[i])->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ;  in handle_p10dd1_spurious_exception()
381 	struct pt_regs *regs = args->regs;  in hw_breakpoint_handler()
413 		info->type &= ~HW_BRK_TYPE_EXTRANEOUS_IRQ;  in hw_breakpoint_handler()
446 	 * Return early after invoking user-callback function without restoring  in hw_breakpoint_handler()
448 	 * one-shot mode. The ptrace-ed process will receive the SIGTRAP signal  in hw_breakpoint_handler()
478 	 * As a policy, the callback is invoked in a 'trigger-after-execute'  in hw_breakpoint_handler()
484 		if (!(counter_arch_bp(bp[i])->type & HW_BRK_TYPE_EXTRANEOUS_IRQ))  in hw_breakpoint_handler()
502  * Handle single-step exceptions following a DABR hit.
508 	struct pt_regs *regs = args->regs;  in single_step_dabr_instruction()
512 	 * Check if we are single-stepping as a result of a  in single_step_dabr_instruction()
526 		if (!info->perf_single_step)  in single_step_dabr_instruction()
532 		 * We shall invoke the user-defined callback function in the  in single_step_dabr_instruction()
533 		 * single stepping handler to confirm to 'trigger-after-execute'  in single_step_dabr_instruction()
536 		if (!(info->type & HW_BRK_TYPE_EXTRANEOUS_IRQ))  in single_step_dabr_instruction()
539 		info->perf_single_step = false;  in single_step_dabr_instruction()
544 	 * If the process was being single-stepped by ptrace, let the  in single_step_dabr_instruction()
545 	 * other single-step actions occur (e.g. generate SIGTRAP).  in single_step_dabr_instruction()
583 	struct thread_struct *t = &tsk->thread;  in flush_ptrace_hw_breakpoint()
586 		unregister_hw_breakpoint(t->ptrace_bps[i]);  in flush_ptrace_hw_breakpoint()
587 		t->ptrace_bps[i] = NULL;  in flush_ptrace_hw_breakpoint()
603 	 * one-shot behaviour for breakpoint exceptions in PPC64.  in ptrace_triggered()
607 	attr = bp->attr;  in ptrace_triggered()