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