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2024-10-22 8ac6c7a54ed1b98d142dce24b11c6de6a1e239a5 
 kernel/arch/arm/probes/kprobes/core.c
....@@ -1,3 +1,4 @@
1
+// SPDX-License-Identifier: GPL-2.0-only
12 /*
23  * arch/arm/kernel/kprobes.c
34  *
....@@ -8,15 +9,6 @@
89  *
910  * Nicolas Pitre <nico@marvell.com>
1011  * Copyright (C) 2007 Marvell Ltd.
11
- *
12
- * This program is free software; you can redistribute it and/or modify
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- * it under the terms of the GNU General Public License version 2 as
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- * published by the Free Software Foundation.
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- *
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- * This program is distributed in the hope that it will be useful,
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- * but WITHOUT ANY WARRANTY; without even the implied warranty of
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- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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- * General Public License for more details.
2012  */
2113 
2214 #include <linux/kernel.h>
....@@ -239,7 +231,7 @@
239231  * kprobe, and that level is reserved for user kprobe handlers, so we can't
240232  * risk encountering a new kprobe in an interrupt handler.
241233  */
242
-void __kprobes kprobe_handler(struct pt_regs *regs)
234
+static void __kprobes kprobe_handler(struct pt_regs *regs)
243235 {
244236 	struct kprobe *p, *cur;
245237 	struct kprobe_ctlblk *kcb;
....@@ -288,7 +280,7 @@
288280 				/* A nested probe was hit in FIQ, it is a BUG */
289281 				pr_warn("Unrecoverable kprobe detected.\n");
290282 				dump_kprobe(p);
291
-				/* fall through */
283
+				fallthrough;
292284 			default:
293285 				/* impossible cases */
294286 				BUG();
....@@ -421,87 +413,15 @@
421413 /* Called from kretprobe_trampoline */
422414 static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
423415 {
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-	struct kretprobe_instance *ri = NULL;
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-	struct hlist_head *head, empty_rp;
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-	struct hlist_node *tmp;
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-	unsigned long flags, orig_ret_address = 0;
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-	unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;
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-	kprobe_opcode_t *correct_ret_addr = NULL;
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-
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-	INIT_HLIST_HEAD(&empty_rp);
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-	kretprobe_hash_lock(current, &head, &flags);
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-
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-	/*
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-	 * It is possible to have multiple instances associated with a given
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-	 * task either because multiple functions in the call path have
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-	 * a return probe installed on them, and/or more than one return
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-	 * probe was registered for a target function.
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-	 *
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-	 * We can handle this because:
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-	 *     - instances are always inserted at the head of the list
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-	 *     - when multiple return probes are registered for the same
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-	 *       function, the first instance's ret_addr will point to the
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-	 *       real return address, and all the rest will point to
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-	 *       kretprobe_trampoline
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-	 */
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-	hlist_for_each_entry_safe(ri, tmp, head, hlist) {
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-		if (ri->task != current)
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-			/* another task is sharing our hash bucket */
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-			continue;
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-
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-		orig_ret_address = (unsigned long)ri->ret_addr;
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-
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-		if (orig_ret_address != trampoline_address)
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-			/*
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-			 * This is the real return address. Any other
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-			 * instances associated with this task are for
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-			 * other calls deeper on the call stack
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-			 */
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-			break;
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-	}
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-
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-	kretprobe_assert(ri, orig_ret_address, trampoline_address);
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-
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-	correct_ret_addr = ri->ret_addr;
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-	hlist_for_each_entry_safe(ri, tmp, head, hlist) {
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-		if (ri->task != current)
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-			/* another task is sharing our hash bucket */
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-			continue;
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-
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-		orig_ret_address = (unsigned long)ri->ret_addr;
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-		if (ri->rp && ri->rp->handler) {
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-			__this_cpu_write(current_kprobe, &ri->rp->kp);
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-			get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE;
475
-			ri->ret_addr = correct_ret_addr;
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-			ri->rp->handler(ri, regs);
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-			__this_cpu_write(current_kprobe, NULL);
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-		}
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-
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-		recycle_rp_inst(ri, &empty_rp);
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-
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-		if (orig_ret_address != trampoline_address)
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-			/*
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-			 * This is the real return address. Any other
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-			 * instances associated with this task are for
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-			 * other calls deeper on the call stack
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-			 */
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-			break;
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-	}
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-
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-	kretprobe_hash_unlock(current, &flags);
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-
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-	hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
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-		hlist_del(&ri->hlist);
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-		kfree(ri);
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-	}
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-
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-	return (void *)orig_ret_address;
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+	return (void *)kretprobe_trampoline_handler(regs, &kretprobe_trampoline,
417
+						    (void *)regs->ARM_fp);
499418 }
500419 
501420 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
502421 				      struct pt_regs *regs)
503422 {
504423 	ri->ret_addr = (kprobe_opcode_t *)regs->ARM_lr;
424
+	ri->fp = (void *)regs->ARM_fp;
505425 
506426 	/* Replace the return addr with trampoline addr. */
507427 	regs->ARM_lr = (unsigned long)&kretprobe_trampoline;