From 9999e48639b3cecb08ffb37358bcba3b48161b29 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Fri, 10 May 2024 08:50:17 +0000
Subject: [PATCH] add ax88772_rst

---
 kernel/arch/mips/kernel/kprobes.c |   78 ++++----------------------------------
 1 files changed, 9 insertions(+), 69 deletions(-)

diff --git a/kernel/arch/mips/kernel/kprobes.c b/kernel/arch/mips/kernel/kprobes.c
index 54cd675..54dfba8 100644
--- a/kernel/arch/mips/kernel/kprobes.c
+++ b/kernel/arch/mips/kernel/kprobes.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  Kernel Probes (KProbes)
  *  arch/mips/kernel/kprobes.c
@@ -8,19 +9,6 @@
  *  Some portions copied from the powerpc version.
  *
  *   Copyright (C) IBM Corporation, 2002, 2004
- *
- *  This program is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation; version 2 of the License.
- *
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
- *
- *  You should have received a copy of the GNU General Public License
- *  along with this program; if not, write to the Free Software
- *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
 #include <linux/kprobes.h>
@@ -98,9 +86,9 @@
 		goto out;
 	}
 
-	if ((probe_kernel_read(&prev_insn, p->addr - 1,
-				sizeof(mips_instruction)) == 0) &&
-				insn_has_delayslot(prev_insn)) {
+	if (copy_from_kernel_nofault(&prev_insn, p->addr - 1,
+			sizeof(mips_instruction)) == 0 &&
+	    insn_has_delayslot(prev_insn)) {
 		pr_notice("Kprobes for branch delayslot are not supported\n");
 		ret = -EINVAL;
 		goto out;
@@ -232,7 +220,7 @@
 
 unaligned:
 	pr_notice("%s: unaligned epc - sending SIGBUS.\n", current->comm);
-	force_sig(SIGBUS, current);
+	force_sig(SIGBUS);
 	return -EFAULT;
 
 }
@@ -410,7 +398,7 @@
 	return 1;
 }
 
-static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 {
 	struct kprobe *cur = kprobe_running();
 	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
@@ -489,6 +477,7 @@
 				      struct pt_regs *regs)
 {
 	ri->ret_addr = (kprobe_opcode_t *) regs->regs[31];
+	ri->fp = NULL;
 
 	/* Replace the return addr with trampoline addr */
 	regs->regs[31] = (unsigned long)kretprobe_trampoline;
@@ -500,57 +489,8 @@
 static int __kprobes trampoline_probe_handler(struct kprobe *p,
 						struct pt_regs *regs)
 {
-	struct kretprobe_instance *ri = NULL;
-	struct hlist_head *head, empty_rp;
-	struct hlist_node *tmp;
-	unsigned long flags, orig_ret_address = 0;
-	unsigned long trampoline_address = (unsigned long)kretprobe_trampoline;
-
-	INIT_HLIST_HEAD(&empty_rp);
-	kretprobe_hash_lock(current, &head, &flags);
-
-	/*
-	 * It is possible to have multiple instances associated with a given
-	 * task either because an multiple functions in the call path
-	 * have a return probe installed on them, and/or more than one return
-	 * return probe was registered for a target function.
-	 *
-	 * We can handle this because:
-	 *     - instances are always inserted at the head of the list
-	 *     - when multiple return probes are registered for the same
-	 *	 function, the first instance's ret_addr will point to the
-	 *	 real return address, and all the rest will point to
-	 *	 kretprobe_trampoline
-	 */
-	hlist_for_each_entry_safe(ri, tmp, head, hlist) {
-		if (ri->task != current)
-			/* another task is sharing our hash bucket */
-			continue;
-
-		if (ri->rp && ri->rp->handler)
-			ri->rp->handler(ri, regs);
-
-		orig_ret_address = (unsigned long)ri->ret_addr;
-		recycle_rp_inst(ri, &empty_rp);
-
-		if (orig_ret_address != trampoline_address)
-			/*
-			 * This is the real return address. Any other
-			 * instances associated with this task are for
-			 * other calls deeper on the call stack
-			 */
-			break;
-	}
-
-	kretprobe_assert(ri, orig_ret_address, trampoline_address);
-	instruction_pointer(regs) = orig_ret_address;
-
-	kretprobe_hash_unlock(current, &flags);
-
-	hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
-		hlist_del(&ri->hlist);
-		kfree(ri);
-	}
+	instruction_pointer(regs) = __kretprobe_trampoline_handler(regs,
+						kretprobe_trampoline, NULL);
 	/*
 	 * By returning a non-zero value, we are telling
 	 * kprobe_handler() that we don't want the post_handler

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