livepatch/selftests: add klp-convert

Add a simple klp-convert livepatch selftest that exercises various
symbol homonym sympos scenarios.

Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>

lib/livepatch/Makefile

@@ -7,8 +7,15 @@ obj-$(CONFIG_TEST_LIVEPATCH) += test_klp_atomic_replace.o \
 				test_klp_callbacks_demo2.o \
 				test_klp_callbacks_busy.o \
 				test_klp_callbacks_mod.o \
+				test_klp_convert1.o \
+				test_klp_convert2.o \
+				test_klp_convert_mod.o \
 				test_klp_livepatch.o \
 				test_klp_shadow_vars.o \
 				test_klp_state.o \
 				test_klp_state2.o \
 				test_klp_state3.o
+
+test_klp_convert_mod-y := \
+	test_klp_convert_mod_a.o \
+	test_klp_convert_mod_b.o

lib/livepatch/test_klp_convert.h

@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _TEST_KLP_CONVERT_
+#define _TEST_KLP_CONVERT_
+
+/* klp-convert symbols - vmlinux */
+extern char *saved_command_line;
+/* klp-convert symbols - test_klp_convert_mod.ko */
+extern char driver_name[];
+extern char homonym_string[];
+extern const char *get_homonym_string(void);
+extern const char *test_klp_get_driver_name(void);
+
+#endif

lib/livepatch/test_klp_convert1.c

@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2019 Joe Lawrence <joe.lawrence@redhat.com>
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/livepatch.h>
+#include "test_klp_convert.h"
+
+void print_saved_command_line(void)
+{
+	pr_info("saved_command_line, 0: %s\n", saved_command_line);
+}
+
+void print_driver_name(void)
+{
+	pr_info("driver_name, 0: %s\n", driver_name);
+	pr_info("test_klp_get_driver_name(), 0: %s\n", test_klp_get_driver_name());
+}
+
+void print_homonym_string(void)
+{
+	pr_info("homonym_string, 1: %s\n", homonym_string);
+	pr_info("get_homonym_string(), 1: %s\n", get_homonym_string());
+}
+
+/* provide a sysfs handle to invoke debug functions */
+static int print_debug;
+static int print_debug_set(const char *val, const struct kernel_param *kp)
+{
+	print_saved_command_line();
+	print_driver_name();
+	print_homonym_string();
+
+	return 0;
+}
+static const struct kernel_param_ops print_debug_ops = {
+	.set = print_debug_set,
+	.get = param_get_int,
+};
+module_param_cb(print_debug, &print_debug_ops, &print_debug, 0200);
+MODULE_PARM_DESC(print_debug, "print klp-convert debugging info");
+
+/*
+ * saved_command_line is a unique symbol, so the sympos annotation is
+ * optional.  Provide to test that sympos=0 works correctly.
+ */
+KLP_MODULE_RELOC(vmlinux) vmlinux_relocs[] = {
+	KLP_SYMPOS(saved_command_line, 0)
+};
+
+/*
+ * driver_name symbols can be found in vmlinux (multiple) and also
+ * test_klp_convert_mod, therefore the annotation is required to
+ * clarify that we want the one from test_klp_convert_mod.
+ *
+ * test_klp_convert_mod contains multiple homonym_string and
+ * get_homonym_string symbols, test resolving the first set here and
+ *  the others in test_klp_convert2.c
+ *
+ * test_klp_get_driver_name is a uniquely named symbol, test that sympos=0
+ * work correctly.
+ */
+KLP_MODULE_RELOC(test_klp_convert_mod) test_klp_convert_mod_relocs_a[] = {
+	KLP_SYMPOS(driver_name, 0),
+	KLP_SYMPOS(homonym_string, 1),
+	KLP_SYMPOS(get_homonym_string, 1),
+	KLP_SYMPOS(test_klp_get_driver_name, 0),
+};
+
+static struct klp_func funcs[] = {
+	{
+	}, { }
+};
+
+static struct klp_object objs[] = {
+	{
+		/* name being NULL means vmlinux */
+		.funcs = funcs,
+	},
+	{
+		.name = "test_klp_convert_mod",
+		.funcs = funcs,
+	}, { }
+};
+
+static struct klp_patch patch = {
+	.mod = THIS_MODULE,
+	.objs = objs,
+};
+
+static int test_klp_convert_init(void)
+{
+	int ret;
+
+	ret = klp_enable_patch(&patch);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static void test_klp_convert_exit(void)
+{
+}
+
+module_init(test_klp_convert_init);
+module_exit(test_klp_convert_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>");
+MODULE_DESCRIPTION("Livepatch test: klp-convert1");
+MODULE_INFO(livepatch, "Y");

lib/livepatch/test_klp_convert2.c

@@ -0,0 +1,110 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2019 Joe Lawrence <joe.lawrence@redhat.com>
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/livepatch.h>
+#include "test_klp_convert.h"
+
+void print_saved_command_line(void)
+{
+	pr_info("saved_command_line (auto): %s\n", saved_command_line);
+}
+
+void print_driver_name(void)
+{
+	pr_info("driver_name, 0: %s\n", driver_name);
+	pr_info("test_klp_get_driver_name(), (auto): %s\n", test_klp_get_driver_name());
+}
+
+void print_homonym_string(void)
+{
+	pr_info("homonym_string, 2: %s\n", homonym_string);
+	pr_info("get_homonym_string(), 2: %s\n", get_homonym_string());
+}
+
+/* provide a sysfs handle to invoke debug functions */
+static int print_debug;
+static int print_debug_set(const char *val, const struct kernel_param *kp)
+{
+	print_saved_command_line();
+	print_driver_name();
+	print_homonym_string();
+
+	return 0;
+}
+static const struct kernel_param_ops print_debug_ops = {
+	.set = print_debug_set,
+	.get = param_get_int,
+};
+module_param_cb(print_debug, &print_debug_ops, &print_debug, 0200);
+MODULE_PARM_DESC(print_debug, "print klp-convert debugging info");
+
+/*
+ * saved_command_line is a uniquely named symbol, so the sympos
+ * annotation is optional.  Skip it and test that klp-convert can
+ * resolve the symbol on its own.
+ */
+
+/*
+ * driver_name symbols can be found in vmlinux (multiple) and also
+ * test_klp_convert_mod, therefore the annotation is required to
+ * clarify that we want the one from test_klp_convert_mod.
+ *
+ * test_klp_convert_mod contains multiple homonym_string symbols,
+ * test_klp_convert1.c resolved to the first one, resolve to the
+ * second one here.
+ *
+ * test_klp_get_driver_name is a uniquely named symbol, test klp-convert can
+ * resolve it automatically.
+ */
+KLP_MODULE_RELOC(test_klp_convert_mod) test_klp_convert_mod_relocs_a[] = {
+	KLP_SYMPOS(driver_name, 0),
+	KLP_SYMPOS(homonym_string, 2),
+	KLP_SYMPOS(get_homonym_string, 2),
+};
+
+static struct klp_func funcs[] = {
+	{
+	}, { }
+};
+
+static struct klp_object objs[] = {
+	{
+		/* name being NULL means vmlinux */
+		.funcs = funcs,
+	},
+	{
+		.name = "test_klp_convert_mod",
+		.funcs = funcs,
+	}, { }
+};
+
+static struct klp_patch patch = {
+	.mod = THIS_MODULE,
+	.objs = objs,
+};
+
+static int test_klp_convert_init(void)
+{
+	int ret;
+
+	ret = klp_enable_patch(&patch);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static void test_klp_convert_exit(void)
+{
+}
+
+module_init(test_klp_convert_init);
+module_exit(test_klp_convert_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>");
+MODULE_DESCRIPTION("Livepatch test: klp-convert2");
+MODULE_INFO(livepatch, "Y");

lib/livepatch/test_klp_convert_mod_a.c

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2019 Joe Lawrence <joe.lawrence@redhat.com>
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+
+/* Unique symbols that don't need sympos annotation */
+static const char driver_name[] = KBUILD_MODNAME;
+__used static const char *test_klp_get_driver_name(void)
+{
+	return driver_name;
+}
+
+/* Common symbol names that need sympos */
+static const char homonym_string[] = "homonym string A";
+__used static const char *get_homonym_string(void)
+{
+	return homonym_string;
+}
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>");
+MODULE_DESCRIPTION("Livepatch test: klp-convert module");

lib/livepatch/test_klp_convert_mod_b.c

@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2019 Joe Lawrence <joe.lawrence@redhat.com>
+
+/*
+ * A second compilation unit to provide another set of similarly named
+ * symbols, forcing a livepatch to use sympos annotations.
+ */
+
+static const char homonym_string[] = "homonym string B";
+__used static const char *get_homonym_string(void)
+{
+	return homonym_string;
+}