From: Vasily Gorbik <gor@linux.ibm.com>
Date: Wed, 28 Aug 2024 17:06:52 +0000 (+0200)
Subject: s390/kprobes: Avoid stop machine if possible
X-Git-Tag: v6.12-rc1~113^2~37
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=30799152c375c4e1f40c7f2b98d766748d3b3333;p=thirdparty%2Fkernel%2Flinux.git

s390/kprobes: Avoid stop machine if possible

Avoid stop machine on kprobes arm/disarm when sequential instruction
fetching is present.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
---

diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index 05c83505e9799..6295faf0987d8 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -21,6 +21,7 @@
 #include <linux/hardirq.h>
 #include <linux/ftrace.h>
 #include <linux/execmem.h>
+#include <asm/text-patching.h>
 #include <asm/set_memory.h>
 #include <asm/sections.h>
 #include <asm/dis.h>
@@ -152,7 +153,12 @@ void arch_arm_kprobe(struct kprobe *p)
 {
 	struct swap_insn_args args = {.p = p, .arm_kprobe = 1};
 
-	stop_machine_cpuslocked(swap_instruction, &args, NULL);
+	if (MACHINE_HAS_SEQ_INSN) {
+		swap_instruction(&args);
+		text_poke_sync();
+	} else {
+		stop_machine_cpuslocked(swap_instruction, &args, NULL);
+	}
 }
 NOKPROBE_SYMBOL(arch_arm_kprobe);
 
@@ -160,7 +166,12 @@ void arch_disarm_kprobe(struct kprobe *p)
 {
 	struct swap_insn_args args = {.p = p, .arm_kprobe = 0};
 
-	stop_machine_cpuslocked(swap_instruction, &args, NULL);
+	if (MACHINE_HAS_SEQ_INSN) {
+		swap_instruction(&args);
+		text_poke_sync();
+	} else {
+		stop_machine_cpuslocked(swap_instruction, &args, NULL);
+	}
 }
 NOKPROBE_SYMBOL(arch_disarm_kprobe);