From 08078d00ab1749a6f84148a00d8d26572af4ec97 Mon Sep 17 00:00:00 2001
Message-Id: <08078d00ab1749a6f84148a00d8d26572af4ec97.1586900628.git.jpoimboe@redhat.com>
From: Josh Poimboeuf <jpoimboe@redhat.com>
Date: Tue, 14 Apr 2020 15:17:51 -0500
Subject: [PATCH] kpatch module integration test

This tests several things related to the patching of modules:

- 'kpatch_string' tests the referencing of a symbol which is outside the
  .o, but inside the patch module.

- alternatives patching (.altinstructions)

- paravirt patching (.parainstructions)

- jump labels (5.8+ kernels only) -- including dynamic printk

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 fs/nfsd/export.c         | 30 ++++++++++++++++++++++++++++++
 net/netlink/af_netlink.c |  5 +++++
 2 files changed, 35 insertions(+)

diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index a1143f7c2201..253c15ad82b2 100644
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -1196,15 +1196,45 @@ static void exp_flags(struct seq_file *m, int flag, int fsid,
 	}
 }
 
+#include <linux/version.h>
+extern char *kpatch_string(void);
+
 static int e_show(struct seq_file *m, void *p)
 {
 	struct cache_head *cp = p;
 	struct svc_export *exp = container_of(cp, struct svc_export, h);
 	struct cache_detail *cd = m->private;
+#ifdef CONFIG_X86_64
+	unsigned long long sched_clock;
+
+	alternative("ud2", "call yield", X86_FEATURE_ALWAYS);
+	alternative("call yield", "ud2", X86_FEATURE_IA64);
+
+	sched_clock = paravirt_sched_clock();
+	if (!jiffies)
+		printk("kpatch: sched_clock: %llu\n", sched_clock);
+#endif
+
+	pr_debug("kpatch: pr_debug() test\n");
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 8, 0)
+{
+	static DEFINE_STATIC_KEY_TRUE(kpatch_key);
+
+	if (static_branch_unlikely(&mcsafe_key))
+		printk("kpatch: mcsafe_key\n");
+
+	BUG_ON(!static_branch_likely(&kpatch_key));
+	static_branch_disable(&kpatch_key);
+	BUG_ON(static_branch_likely(&kpatch_key));
+	static_branch_enable(&kpatch_key);
+}
+#endif
 
 	if (p == SEQ_START_TOKEN) {
 		seq_puts(m, "# Version 1.1\n");
 		seq_puts(m, "# Path Client(Flags) # IPs\n");
+		seq_puts(m, kpatch_string());
 		return 0;
 	}
 
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 44fa4ea5df76..dc36ec2901b8 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2809,4 +2809,9 @@ static int __init netlink_proto_init(void)
 	panic("netlink_init: Cannot allocate nl_table\n");
 }
 
+char *kpatch_string(void)
+{
+	return "# kpatch\n";
+}
+
 core_initcall(netlink_proto_init);
-- 
2.21.1