diff options
Diffstat (limited to 'tools/testing/selftests/livepatch/test_modules/test_klp_syscall.c')
-rw-r--r-- | tools/testing/selftests/livepatch/test_modules/test_klp_syscall.c | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/tools/testing/selftests/livepatch/test_modules/test_klp_syscall.c b/tools/testing/selftests/livepatch/test_modules/test_klp_syscall.c new file mode 100644 index 000000000000..dd802783ea84 --- /dev/null +++ b/tools/testing/selftests/livepatch/test_modules/test_klp_syscall.c @@ -0,0 +1,116 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2017-2023 SUSE + * Authors: Libor Pechacek <lpechacek@suse.cz> + * Nicolai Stange <nstange@suse.de> + * Marcos Paulo de Souza <mpdesouza@suse.com> + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/livepatch.h> + +#if defined(__x86_64__) +#define FN_PREFIX __x64_ +#elif defined(__s390x__) +#define FN_PREFIX __s390x_ +#elif defined(__aarch64__) +#define FN_PREFIX __arm64_ +#else +/* powerpc does not select ARCH_HAS_SYSCALL_WRAPPER */ +#define FN_PREFIX +#endif + +/* Protects klp_pids */ +static DEFINE_MUTEX(kpid_mutex); + +static unsigned int npids, npids_pending; +static int klp_pids[NR_CPUS]; +module_param_array(klp_pids, int, &npids_pending, 0); +MODULE_PARM_DESC(klp_pids, "Array of pids to be transitioned to livepatched state."); + +static ssize_t npids_show(struct kobject *kobj, struct kobj_attribute *attr, + char *buf) +{ + return sprintf(buf, "%u\n", npids_pending); +} + +static struct kobj_attribute klp_attr = __ATTR_RO(npids); +static struct kobject *klp_kobj; + +static asmlinkage long lp_sys_getpid(void) +{ + int i; + + mutex_lock(&kpid_mutex); + if (npids_pending > 0) { + for (i = 0; i < npids; i++) { + if (current->pid == klp_pids[i]) { + klp_pids[i] = 0; + npids_pending--; + break; + } + } + } + mutex_unlock(&kpid_mutex); + + return task_tgid_vnr(current); +} + +static struct klp_func vmlinux_funcs[] = { + { + .old_name = __stringify(FN_PREFIX) "sys_getpid", + .new_func = lp_sys_getpid, + }, {} +}; + +static struct klp_object objs[] = { + { + /* name being NULL means vmlinux */ + .funcs = vmlinux_funcs, + }, {} +}; + +static struct klp_patch patch = { + .mod = THIS_MODULE, + .objs = objs, +}; + +static int livepatch_init(void) +{ + int ret; + + klp_kobj = kobject_create_and_add("test_klp_syscall", kernel_kobj); + if (!klp_kobj) + return -ENOMEM; + + ret = sysfs_create_file(klp_kobj, &klp_attr.attr); + if (ret) { + kobject_put(klp_kobj); + return ret; + } + + /* + * Save the number pids to transition to livepatched state before the + * number of pending pids is decremented. + */ + npids = npids_pending; + + return klp_enable_patch(&patch); +} + +static void livepatch_exit(void) +{ + kobject_put(klp_kobj); +} + +module_init(livepatch_init); +module_exit(livepatch_exit); +MODULE_LICENSE("GPL"); +MODULE_INFO(livepatch, "Y"); +MODULE_AUTHOR("Libor Pechacek <lpechacek@suse.cz>"); +MODULE_AUTHOR("Nicolai Stange <nstange@suse.de>"); +MODULE_AUTHOR("Marcos Paulo de Souza <mpdesouza@suse.com>"); +MODULE_DESCRIPTION("Livepatch test: syscall transition"); |