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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Masami Hiramatsu <mhiramat@kernel.org>
Subject: [PATCH 4.19 08/12] Revert "ia64: kprobes: Fix to pass correct trampoline address to the handler"
Date:   Fri, 29 Apr 2022 12:41:25 +0200
Message-Id: <20220429104048.703832413@linuxfoundation.org>
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From: Masami Hiramatsu <mhiramat@kernel.org>

This reverts commit f5f96e3643dc33d6117cf7047e73512046e4858b.

The commit f5f96e3643dc ("ia64: kprobes: Fix to pass correct trampoline
address to the handler") was wrongly backported. It involves another
commit which is a part of another bigger series, so it should not be
backported to the stable tree.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/ia64/kernel/kprobes.c |    9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -411,8 +411,7 @@ static void kretprobe_trampoline(void)
 
 int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
 {
-	regs->cr_iip = __kretprobe_trampoline_handler(regs,
-		dereference_function_descriptor(kretprobe_trampoline), NULL);
+	regs->cr_iip = __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
@@ -428,7 +427,7 @@ void __kprobes arch_prepare_kretprobe(st
 	ri->fp = NULL;
 
 	/* Replace the return addr with trampoline addr */
-	regs->b0 = (unsigned long)dereference_function_descriptor(kretprobe_trampoline);
+	regs->b0 = ((struct fnptr *)kretprobe_trampoline)->ip;
 }
 
 /* Check the instruction in the slot is break */
@@ -958,14 +957,14 @@ static struct kprobe trampoline_p = {
 int __init arch_init_kprobes(void)
 {
 	trampoline_p.addr =
-		dereference_function_descriptor(kretprobe_trampoline);
+		(kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip;
 	return register_kprobe(&trampoline_p);
 }
 
 int __kprobes arch_trampoline_kprobe(struct kprobe *p)
 {
 	if (p->addr ==
-		dereference_function_descriptor(kretprobe_trampoline))
+		(kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip)
 		return 1;
 
 	return 0;