diff options
Diffstat (limited to 'lib/livepatch/test_klp_state2.c')
| -rw-r--r-- | lib/livepatch/test_klp_state2.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/lib/livepatch/test_klp_state2.c b/lib/livepatch/test_klp_state2.c new file mode 100644 index 000000000..c978ea4d5 --- /dev/null +++ b/lib/livepatch/test_klp_state2.c @@ -0,0 +1,191 @@ +// 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"); |