linux-kernel - [PATCH 6/6] kprobe: move sysctl_kprobes

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Message-Id: <20211129211943.640266-7-mcgrof@kernel.org>
Date:   Mon, 29 Nov 2021 13:19:43 -0800
From:   Luis Chamberlain <mcgrof@...nel.org>
To:     akpm@...ux-foundation.org, viro@...iv.linux.org.uk,
        keescook@...omium.org, yzaikin@...gle.com, nixiaoming@...wei.com,
        ebiederm@...ssion.com, steve@....org,
        mcgrof@...badil.infradead.org, mcgrof@...nel.org,
        christian.brauner@...ntu.com, ebiggers@...gle.com,
        naveen.n.rao@...ux.ibm.com, davem@...emloft.net,
        mhiramat@...nel.org, anil.s.keshavamurthy@...el.com
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 6/6] kprobe: move sysctl_kprobes_optimization to kprobes.c

From: Xiaoming Ni <nixiaoming@...wei.com>

The kernel/sysctl.c is a kitchen sink where everyone leaves
their dirty dishes, this makes it very difficult to maintain.

To help with this maintenance let's start by moving sysctls to
places where they actually belong. The proc sysctl maintainers
do not want to know what sysctl knobs you wish to add for your own
piece of code, we just care about the core logic.

Move sysctl_kprobes_optimization from kernel/sysctl.c to kernel/kprobes.c.
Use register_sysctl() to register the sysctl interface.

Signed-off-by: Xiaoming Ni <nixiaoming@...wei.com>
[mcgrof: fix compile issue when CONFIG_OPTPROBES is disabled]
Signed-off-by: Luis Chamberlain <mcgrof@...nel.org>
---
 include/linux/kprobes.h |  6 ------
 kernel/kprobes.c        | 30 ++++++++++++++++++++++++++----
 kernel/sysctl.c         | 12 ------------
 3 files changed, 26 insertions(+), 22 deletions(-)

diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index e974caf39d3e..e9c3687c84d5 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -346,12 +346,6 @@ extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
 
 DEFINE_INSN_CACHE_OPS(optinsn);
 
-#ifdef CONFIG_SYSCTL
-extern int sysctl_kprobes_optimization;
-extern int proc_kprobes_optimization_handler(struct ctl_table *table,
-					     int write, void *buffer,
-					     size_t *length, loff_t *ppos);
-#endif /* CONFIG_SYSCTL */
 extern void wait_for_kprobe_optimizer(void);
 #else /* !CONFIG_OPTPROBES */
 static inline void wait_for_kprobe_optimizer(void) { }
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index e9db0c810554..ee76ff64b49e 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -48,6 +48,9 @@
 #define KPROBE_HASH_BITS 6
 #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
 
+#if !defined(CONFIG_OPTPROBES) || !defined(CONFIG_SYSCTL)
+#define kprobe_sysctls_init() do { } while (0)
+#endif
 
 static int kprobes_initialized;
 /* kprobe_table can be accessed by
@@ -938,10 +941,10 @@ static void unoptimize_all_kprobes(void)
 }
 
 static DEFINE_MUTEX(kprobe_sysctl_mutex);
-int sysctl_kprobes_optimization;
-int proc_kprobes_optimization_handler(struct ctl_table *table, int write,
-				      void *buffer, size_t *length,
-				      loff_t *ppos)
+static int sysctl_kprobes_optimization;
+static int proc_kprobes_optimization_handler(struct ctl_table *table,
+					     int write, void *buffer,
+					     size_t *length, loff_t *ppos)
 {
 	int ret;
 
@@ -957,6 +960,24 @@ int proc_kprobes_optimization_handler(struct ctl_table *table, int write,
 
 	return ret;
 }
+
+static struct ctl_table kprobe_sysctls[] = {
+	{
+		.procname	= "kprobes-optimization",
+		.data		= &sysctl_kprobes_optimization,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_kprobes_optimization_handler,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{}
+};
+
+static void __init kprobe_sysctls_init(void)
+{
+	register_sysctl_init("debug", kprobe_sysctls);
+}
 #endif /* CONFIG_SYSCTL */
 
 /* Put a breakpoint for a probe. */
@@ -2581,6 +2602,7 @@ static int __init init_kprobes(void)
 		err = register_module_notifier(&kprobe_module_nb);
 
 	kprobes_initialized = (err == 0);
+	kprobe_sysctls_init();
 	return err;
 }
 early_initcall(init_kprobes);
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index a4c352f0a514..7f07b058b180 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -55,7 +55,6 @@
 #include <linux/reboot.h>
 #include <linux/ftrace.h>
 #include <linux/perf_event.h>
-#include <linux/kprobes.h>
 #include <linux/oom.h>
 #include <linux/kmod.h>
 #include <linux/capability.h>
@@ -2817,17 +2816,6 @@ static struct ctl_table debug_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec
 	},
-#endif
-#if defined(CONFIG_OPTPROBES)
-	{
-		.procname	= "kprobes-optimization",
-		.data		= &sysctl_kprobes_optimization,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_kprobes_optimization_handler,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
-	},
 #endif
 	{ }
 };
-- 
2.33.0