Commit ecd25094 authored by Petr Mladek's avatar Petr Mladek
Browse files

livepatch: Selftests of the API for tracking system state changes 

Four selftests for the new API.

Link: http://lkml.kernel.org/r/20191030154313.13263-6-pmladek@suse.com


To: Jiri Kosina <jikos@kernel.org>
Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Cc: Nicolai Stange <nstange@suse.de>
Cc: live-patching@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Acked-by: default avatarMiroslav Benes <mbenes@suse.cz>
Acked-by: default avatarJoe Lawrence <joe.lawrence@redhat.com>
Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
parent e553d2a5

lib/livepatch/Makefile

+4 −1
Original line number Diff line number Diff line
@@ -8,7 +8,10 @@ obj-$(CONFIG_TEST_LIVEPATCH) += test_klp_atomic_replace.o \ 
				test_klp_callbacks_busy.o \

				test_klp_callbacks_mod.o \

				test_klp_livepatch.o \

				test_klp_shadow_vars.o

				test_klp_shadow_vars.o \

				test_klp_state.o \

				test_klp_state2.o \

				test_klp_state3.o



# Target modules to be livepatched require CC_FLAGS_FTRACE

CFLAGS_test_klp_callbacks_busy.o	+= $(CC_FLAGS_FTRACE)

lib/livepatch/test_klp_state.c

0 → 100644
+162 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

// Copyright (C) 2019 SUSE



#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt



#include <linux/slab.h>

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/printk.h>

#include <linux/livepatch.h>



#define CONSOLE_LOGLEVEL_STATE 1

/* Version 1 does not support migration. */

#define CONSOLE_LOGLEVEL_STATE_VERSION 1



static const char *const module_state[] = {

	[MODULE_STATE_LIVE]	= "[MODULE_STATE_LIVE] Normal state",

	[MODULE_STATE_COMING]	= "[MODULE_STATE_COMING] Full formed, running module_init",

	[MODULE_STATE_GOING]	= "[MODULE_STATE_GOING] Going away",

	[MODULE_STATE_UNFORMED]	= "[MODULE_STATE_UNFORMED] Still setting it up",

};



static void callback_info(const char *callback, struct klp_object *obj)

{

	if (obj->mod)

		pr_info("%s: %s -> %s\n", callback, obj->mod->name,

			module_state[obj->mod->state]);

	else

		pr_info("%s: vmlinux\n", callback);

}



static struct klp_patch patch;



static int allocate_loglevel_state(void)

{

	struct klp_state *loglevel_state;



	loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);

	if (!loglevel_state)

		return -EINVAL;



	loglevel_state->data = kzalloc(sizeof(console_loglevel), GFP_KERNEL);

	if (!loglevel_state->data)

		return -ENOMEM;



	pr_info("%s: allocating space to store console_loglevel\n",

		__func__);

	return 0;

}



static void fix_console_loglevel(void)

{

	struct klp_state *loglevel_state;



	loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);

	if (!loglevel_state)

		return;



	pr_info("%s: fixing console_loglevel\n", __func__);

	*(int *)loglevel_state->data = console_loglevel;

	console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;

}



static void restore_console_loglevel(void)

{

	struct klp_state *loglevel_state;



	loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);

	if (!loglevel_state)

		return;



	pr_info("%s: restoring console_loglevel\n", __func__);

	console_loglevel = *(int *)loglevel_state->data;

}



static void free_loglevel_state(void)

{

	struct klp_state *loglevel_state;



	loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);

	if (!loglevel_state)

		return;



	pr_info("%s: freeing space for the stored console_loglevel\n",

		__func__);

	kfree(loglevel_state->data);

}



/* Executed on object patching (ie, patch enablement) */

static int pre_patch_callback(struct klp_object *obj)

{

	callback_info(__func__, obj);

	return allocate_loglevel_state();

}



/* Executed on object unpatching (ie, patch disablement) */

static void post_patch_callback(struct klp_object *obj)

{

	callback_info(__func__, obj);

	fix_console_loglevel();

}



/* Executed on object unpatching (ie, patch disablement) */

static void pre_unpatch_callback(struct klp_object *obj)

{

	callback_info(__func__, obj);

	restore_console_loglevel();

}



/* Executed on object unpatching (ie, patch disablement) */

static void post_unpatch_callback(struct klp_object *obj)

{

	callback_info(__func__, obj);

	free_loglevel_state();

}



static struct klp_func no_funcs[] = {

	{}

};



static struct klp_object objs[] = {

	{

		.name = NULL,	/* vmlinux */

		.funcs = no_funcs,

		.callbacks = {

			.pre_patch = pre_patch_callback,

			.post_patch = post_patch_callback,

			.pre_unpatch = pre_unpatch_callback,

			.post_unpatch = post_unpatch_callback,

		},

	}, { }

};



static struct klp_state states[] = {

	{

		.id = CONSOLE_LOGLEVEL_STATE,

		.version = CONSOLE_LOGLEVEL_STATE_VERSION,

	}, { }

};



static struct klp_patch patch = {

	.mod = THIS_MODULE,

	.objs = objs,

	.states = states,

	.replace = true,

};



static int test_klp_callbacks_demo_init(void)

{

	return klp_enable_patch(&patch);

}



static void test_klp_callbacks_demo_exit(void)

{

}



module_init(test_klp_callbacks_demo_init);

module_exit(test_klp_callbacks_demo_exit);

MODULE_LICENSE("GPL");

MODULE_INFO(livepatch, "Y");

MODULE_AUTHOR("Petr Mladek <pmladek@suse.com>");

MODULE_DESCRIPTION("Livepatch test: system state modification");

lib/livepatch/test_klp_state2.c

0 → 100644
+191 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

// Copyright (C) 2019 SUSE



#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt



#include <linux/slab.h>

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/printk.h>

#include <linux/livepatch.h>



#define CONSOLE_LOGLEVEL_STATE 1

/* Version 2 supports migration. */

#define CONSOLE_LOGLEVEL_STATE_VERSION 2



static const char *const module_state[] = {

	[MODULE_STATE_LIVE]	= "[MODULE_STATE_LIVE] Normal state",

	[MODULE_STATE_COMING]	= "[MODULE_STATE_COMING] Full formed, running module_init",

	[MODULE_STATE_GOING]	= "[MODULE_STATE_GOING] Going away",

	[MODULE_STATE_UNFORMED]	= "[MODULE_STATE_UNFORMED] Still setting it up",

};



static void callback_info(const char *callback, struct klp_object *obj)

{

	if (obj->mod)

		pr_info("%s: %s -> %s\n", callback, obj->mod->name,

			module_state[obj->mod->state]);

	else

		pr_info("%s: vmlinux\n", callback);

}



static struct klp_patch patch;



static int allocate_loglevel_state(void)

{

	struct klp_state *loglevel_state, *prev_loglevel_state;



	prev_loglevel_state = klp_get_prev_state(CONSOLE_LOGLEVEL_STATE);

	if (prev_loglevel_state) {

		pr_info("%s: space to store console_loglevel already allocated\n",

		__func__);

		return 0;

	}



	loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);

	if (!loglevel_state)

		return -EINVAL;



	loglevel_state->data = kzalloc(sizeof(console_loglevel), GFP_KERNEL);

	if (!loglevel_state->data)

		return -ENOMEM;



	pr_info("%s: allocating space to store console_loglevel\n",

		__func__);

	return 0;

}



static void fix_console_loglevel(void)

{

	struct klp_state *loglevel_state, *prev_loglevel_state;



	loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);

	if (!loglevel_state)

		return;



	prev_loglevel_state = klp_get_prev_state(CONSOLE_LOGLEVEL_STATE);

	if (prev_loglevel_state) {

		pr_info("%s: taking over the console_loglevel change\n",

		__func__);

		loglevel_state->data = prev_loglevel_state->data;

		return;

	}



	pr_info("%s: fixing console_loglevel\n", __func__);

	*(int *)loglevel_state->data = console_loglevel;

	console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;

}



static void restore_console_loglevel(void)

{

	struct klp_state *loglevel_state, *prev_loglevel_state;



	prev_loglevel_state = klp_get_prev_state(CONSOLE_LOGLEVEL_STATE);

	if (prev_loglevel_state) {

		pr_info("%s: passing the console_loglevel change back to the old livepatch\n",

		__func__);

		return;

	}



	loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);

	if (!loglevel_state)

		return;



	pr_info("%s: restoring console_loglevel\n", __func__);

	console_loglevel = *(int *)loglevel_state->data;

}



static void free_loglevel_state(void)

{

	struct klp_state *loglevel_state, *prev_loglevel_state;



	prev_loglevel_state = klp_get_prev_state(CONSOLE_LOGLEVEL_STATE);

	if (prev_loglevel_state) {

		pr_info("%s: keeping space to store console_loglevel\n",

		__func__);

		return;

	}



	loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);

	if (!loglevel_state)

		return;



	pr_info("%s: freeing space for the stored console_loglevel\n",

		__func__);

	kfree(loglevel_state->data);

}



/* Executed on object patching (ie, patch enablement) */

static int pre_patch_callback(struct klp_object *obj)

{

	callback_info(__func__, obj);

	return allocate_loglevel_state();

}



/* Executed on object unpatching (ie, patch disablement) */

static void post_patch_callback(struct klp_object *obj)

{

	callback_info(__func__, obj);

	fix_console_loglevel();

}



/* Executed on object unpatching (ie, patch disablement) */

static void pre_unpatch_callback(struct klp_object *obj)

{

	callback_info(__func__, obj);

	restore_console_loglevel();

}



/* Executed on object unpatching (ie, patch disablement) */

static void post_unpatch_callback(struct klp_object *obj)

{

	callback_info(__func__, obj);

	free_loglevel_state();

}



static struct klp_func no_funcs[] = {

	{}

};



static struct klp_object objs[] = {

	{

		.name = NULL,	/* vmlinux */

		.funcs = no_funcs,

		.callbacks = {

			.pre_patch = pre_patch_callback,

			.post_patch = post_patch_callback,

			.pre_unpatch = pre_unpatch_callback,

			.post_unpatch = post_unpatch_callback,

		},

	}, { }

};



static struct klp_state states[] = {

	{

		.id = CONSOLE_LOGLEVEL_STATE,

		.version = CONSOLE_LOGLEVEL_STATE_VERSION,

	}, { }

};



static struct klp_patch patch = {

	.mod = THIS_MODULE,

	.objs = objs,

	.states = states,

	.replace = true,

};



static int test_klp_callbacks_demo_init(void)

{

	return klp_enable_patch(&patch);

}



static void test_klp_callbacks_demo_exit(void)

{

}



module_init(test_klp_callbacks_demo_init);

module_exit(test_klp_callbacks_demo_exit);

MODULE_LICENSE("GPL");

MODULE_INFO(livepatch, "Y");

MODULE_AUTHOR("Petr Mladek <pmladek@suse.com>");

MODULE_DESCRIPTION("Livepatch test: system state modification");

lib/livepatch/test_klp_state3.c

0 → 100644
+5 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

// Copyright (C) 2019 SUSE



/* The console loglevel fix is the same in the next cumulative patch. */

#include "test_klp_state2.c"

tools/testing/selftests/livepatch/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ TEST_PROGS_EXTENDED := functions.sh 
TEST_PROGS := \

	test-livepatch.sh \

	test-callbacks.sh \

	test-shadow-vars.sh

	test-shadow-vars.sh \

	test-state.sh



include ../lib.mk

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