Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) // SPDX-License-Identifier: GPL-2.0-or-later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3)  * Dynamic Ftrace based Kprobes Optimization
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5)  * Copyright (C) Hitachi Ltd., 2012
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7) #include <linux/kprobes.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8) #include <linux/ptrace.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9) #include <linux/hardirq.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #include <linux/preempt.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) #include <linux/ftrace.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include "common.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) /* Ftrace callback handler for kprobes -- called under preepmt disabed */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) 			   struct ftrace_ops *ops, struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) 	struct kprobe *p;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) 	struct kprobe_ctlblk *kcb;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) 	/* Preempt is disabled by ftrace */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) 	p = get_kprobe((kprobe_opcode_t *)ip);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) 	if (unlikely(!p) || kprobe_disabled(p))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) 	kcb = get_kprobe_ctlblk();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) 	if (kprobe_running()) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) 		kprobes_inc_nmissed_count(p);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) 		unsigned long orig_ip = regs->ip;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) 		/* Kprobe handler expects regs->ip = ip + 1 as breakpoint hit */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) 		regs->ip = ip + sizeof(kprobe_opcode_t);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) 		__this_cpu_write(current_kprobe, p);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) 		kcb->kprobe_status = KPROBE_HIT_ACTIVE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) 		if (!p->pre_handler || !p->pre_handler(p, regs)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) 			/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) 			 * Emulate singlestep (and also recover regs->ip)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) 			 * as if there is a 5byte nop
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) 			 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) 			regs->ip = (unsigned long)p->addr + MCOUNT_INSN_SIZE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) 			if (unlikely(p->post_handler)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) 				kcb->kprobe_status = KPROBE_HIT_SSDONE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) 				p->post_handler(p, regs, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) 			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) 			regs->ip = orig_ip;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) 		 * If pre_handler returns !0, it changes regs->ip. We have to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) 		 * skip emulating post_handler.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) 		__this_cpu_write(current_kprobe, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) NOKPROBE_SYMBOL(kprobe_ftrace_handler);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) int arch_prepare_kprobe_ftrace(struct kprobe *p)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) 	p->ainsn.insn = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) 	p->ainsn.boostable = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) }