22  * AArch64 PCS assigns the frame pointer to x29.
36 void start_backtrace(struct stackframe *frame, unsigned long fp,  in start_backtrace()  argument
39 	frame->fp = fp;  in start_backtrace()
40 	frame->pc = pc;  in start_backtrace()
42 	frame->graph = 0;  in start_backtrace()
54 	bitmap_zero(frame->stacks_done, __NR_STACK_TYPES);  in start_backtrace()
55 	frame->prev_fp = 0;  in start_backtrace()
56 	frame->prev_type = STACK_TYPE_UNKNOWN;  in start_backtrace()
60  * Unwind from one frame record (A) to the next frame record (B).
62  * We terminate early if the location of B indicates a malformed chain of frame
66 int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)  in unwind_frame()  argument
68 	unsigned long fp = frame->fp;  in unwind_frame()
74 	/* Final frame; nothing to unwind */  in unwind_frame()
84 	if (test_bit(info.type, frame->stacks_done))  in unwind_frame()
100 	if (info.type == frame->prev_type) {  in unwind_frame()
101 		if (fp <= frame->prev_fp)  in unwind_frame()
104 		set_bit(frame->prev_type, frame->stacks_done);  in unwind_frame()
108 	 * Record this frame record's values and location. The prev_fp and  in unwind_frame()
111 	frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp));  in unwind_frame()
112 	frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8));  in unwind_frame()
113 	frame->prev_fp = fp;  in unwind_frame()
114 	frame->prev_type = info.type;  in unwind_frame()
118 		(ptrauth_strip_insn_pac(frame->pc) == (unsigned long)return_to_handler)) {  in unwind_frame()
122 		 * modified a return address (LR) in a stack frame  in unwind_frame()
126 		ret_stack = ftrace_graph_get_ret_stack(tsk, frame->graph++);  in unwind_frame()
129 		frame->pc = ret_stack->ret;  in unwind_frame()
133 	frame->pc = ptrauth_strip_insn_pac(frame->pc);  in unwind_frame()
139 void notrace walk_stackframe(struct task_struct *tsk, struct stackframe *frame,  in walk_stackframe()  argument
145 		if (!fn(data, frame->pc))  in walk_stackframe()
147 		ret = unwind_frame(tsk, frame);  in walk_stackframe()
162 	struct stackframe frame;  in dump_backtrace()  local
180 		start_backtrace(&frame,  in dump_backtrace()
187 		start_backtrace(&frame,  in dump_backtrace()
194 		/* skip until specified stack frame */  in dump_backtrace()
196 			dump_backtrace_entry(frame.pc, loglvl);  in dump_backtrace()
197 		} else if (frame.fp == regs->regs[29]) {  in dump_backtrace()
202 			 * stack frame does not contain the corresponding pc  in dump_backtrace()
208 	} while (!unwind_frame(tsk, &frame));  in dump_backtrace()
225 	struct stackframe frame;  in arch_stack_walk()  local
228 		start_backtrace(&frame, regs->regs[29], regs->pc);  in arch_stack_walk()
230 		start_backtrace(&frame,  in arch_stack_walk()
234 		start_backtrace(&frame, thread_saved_fp(task),  in arch_stack_walk()
237 	walk_stackframe(task, &frame, consume_entry, cookie);  in arch_stack_walk()