diff options
Diffstat (limited to 'kernel/ksysfs.c')
| -rw-r--r-- | kernel/ksysfs.c | 273 |
1 files changed, 273 insertions, 0 deletions
diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c new file mode 100644 index 000000000..65dba9076 --- /dev/null +++ b/kernel/ksysfs.c @@ -0,0 +1,273 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * kernel/ksysfs.c - sysfs attributes in /sys/kernel, which + * are not related to any other subsystem + * + * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org> + */ + +#include <linux/kobject.h> +#include <linux/string.h> +#include <linux/sysfs.h> +#include <linux/export.h> +#include <linux/init.h> +#include <linux/kexec.h> +#include <linux/profile.h> +#include <linux/stat.h> +#include <linux/sched.h> +#include <linux/capability.h> +#include <linux/compiler.h> + +#include <linux/rcupdate.h> /* rcu_expedited and rcu_normal */ + +#define KERNEL_ATTR_RO(_name) \ +static struct kobj_attribute _name##_attr = __ATTR_RO(_name) + +#define KERNEL_ATTR_RW(_name) \ +static struct kobj_attribute _name##_attr = __ATTR_RW(_name) + +/* current uevent sequence number */ +static ssize_t uevent_seqnum_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum); +} +KERNEL_ATTR_RO(uevent_seqnum); + +#ifdef CONFIG_UEVENT_HELPER +/* uevent helper program, used during early boot */ +static ssize_t uevent_helper_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sprintf(buf, "%s\n", uevent_helper); +} +static ssize_t uevent_helper_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + if (count+1 > UEVENT_HELPER_PATH_LEN) + return -ENOENT; + memcpy(uevent_helper, buf, count); + uevent_helper[count] = '\0'; + if (count && uevent_helper[count-1] == '\n') + uevent_helper[count-1] = '\0'; + return count; +} +KERNEL_ATTR_RW(uevent_helper); +#endif + +#ifdef CONFIG_PROFILING +static ssize_t profiling_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", prof_on); +} +static ssize_t profiling_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + int ret; + + if (prof_on) + return -EEXIST; + /* + * This eventually calls into get_option() which + * has a ton of callers and is not const. It is + * easiest to cast it away here. + */ + profile_setup((char *)buf); + ret = profile_init(); + if (ret) + return ret; + ret = create_proc_profile(); + if (ret) + return ret; + return count; +} +KERNEL_ATTR_RW(profiling); +#endif + +#ifdef CONFIG_KEXEC_CORE +static ssize_t kexec_loaded_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", !!kexec_image); +} +KERNEL_ATTR_RO(kexec_loaded); + +static ssize_t kexec_crash_loaded_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", kexec_crash_loaded()); +} +KERNEL_ATTR_RO(kexec_crash_loaded); + +static ssize_t kexec_crash_size_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + ssize_t size = crash_get_memory_size(); + + if (size < 0) + return size; + + return sprintf(buf, "%zd\n", size); +} +static ssize_t kexec_crash_size_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + unsigned long cnt; + int ret; + + if (kstrtoul(buf, 0, &cnt)) + return -EINVAL; + + ret = crash_shrink_memory(cnt); + return ret < 0 ? ret : count; +} +KERNEL_ATTR_RW(kexec_crash_size); + +#endif /* CONFIG_KEXEC_CORE */ + +#ifdef CONFIG_CRASH_CORE + +static ssize_t vmcoreinfo_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + phys_addr_t vmcore_base = paddr_vmcoreinfo_note(); + return sprintf(buf, "%pa %x\n", &vmcore_base, + (unsigned int)VMCOREINFO_NOTE_SIZE); +} +KERNEL_ATTR_RO(vmcoreinfo); + +#endif /* CONFIG_CRASH_CORE */ + +/* whether file capabilities are enabled */ +static ssize_t fscaps_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", file_caps_enabled); +} +KERNEL_ATTR_RO(fscaps); + +#ifndef CONFIG_TINY_RCU +int rcu_expedited; +static ssize_t rcu_expedited_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", READ_ONCE(rcu_expedited)); +} +static ssize_t rcu_expedited_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + if (kstrtoint(buf, 0, &rcu_expedited)) + return -EINVAL; + + return count; +} +KERNEL_ATTR_RW(rcu_expedited); + +int rcu_normal; +static ssize_t rcu_normal_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", READ_ONCE(rcu_normal)); +} +static ssize_t rcu_normal_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + if (kstrtoint(buf, 0, &rcu_normal)) + return -EINVAL; + + return count; +} +KERNEL_ATTR_RW(rcu_normal); +#endif /* #ifndef CONFIG_TINY_RCU */ + +/* + * Make /sys/kernel/notes give the raw contents of our kernel .notes section. + */ +extern const void __start_notes __weak; +extern const void __stop_notes __weak; +#define notes_size (&__stop_notes - &__start_notes) + +static ssize_t notes_read(struct file *filp, struct kobject *kobj, + struct bin_attribute *bin_attr, + char *buf, loff_t off, size_t count) +{ + memcpy(buf, &__start_notes + off, count); + return count; +} + +static struct bin_attribute notes_attr __ro_after_init = { + .attr = { + .name = "notes", + .mode = S_IRUGO, + }, + .read = ¬es_read, +}; + +struct kobject *kernel_kobj; +EXPORT_SYMBOL_GPL(kernel_kobj); + +static struct attribute * kernel_attrs[] = { + &fscaps_attr.attr, + &uevent_seqnum_attr.attr, +#ifdef CONFIG_UEVENT_HELPER + &uevent_helper_attr.attr, +#endif +#ifdef CONFIG_PROFILING + &profiling_attr.attr, +#endif +#ifdef CONFIG_KEXEC_CORE + &kexec_loaded_attr.attr, + &kexec_crash_loaded_attr.attr, + &kexec_crash_size_attr.attr, +#endif +#ifdef CONFIG_CRASH_CORE + &vmcoreinfo_attr.attr, +#endif +#ifndef CONFIG_TINY_RCU + &rcu_expedited_attr.attr, + &rcu_normal_attr.attr, +#endif + NULL +}; + +static const struct attribute_group kernel_attr_group = { + .attrs = kernel_attrs, +}; + +static int __init ksysfs_init(void) +{ + int error; + + kernel_kobj = kobject_create_and_add("kernel", NULL); + if (!kernel_kobj) { + error = -ENOMEM; + goto exit; + } + error = sysfs_create_group(kernel_kobj, &kernel_attr_group); + if (error) + goto kset_exit; + + if (notes_size > 0) { + notes_attr.size = notes_size; + error = sysfs_create_bin_file(kernel_kobj, ¬es_attr); + if (error) + goto group_exit; + } + + return 0; + +group_exit: + sysfs_remove_group(kernel_kobj, &kernel_attr_group); +kset_exit: + kobject_put(kernel_kobj); +exit: + return error; +} + +core_initcall(ksysfs_init); |