dmi-sysfs-.rar_DMI_sysfs

/* * dmi-sysfs.c * * This module exports the DMI tables read-only to userspace through the * sysfs file system. * * Data is currently found below * /sys/firmware/dmi/... * * */ #include <linux/kernel.h> #include <linux/init.h> #include <linux/module.h> #include <linux/types.h> #include <linux/kobject.h> #include <linux/dmi.h> #include <linux/capability.h> #include <linux/slab.h> #include <linux/list.h> #include <linux/io.h> #define MAX_ENTRY_TYPE 255 /* Most of these aren't used, but we consider the top entry type is only 8 bits */ struct dmi_sysfs_entry { struct dmi_header dh; struct kobject kobj; int instance; int position; struct list_head list; struct kobject *child; }; /* * Global list of dmi_sysfs_entry. Even though this should only be * manipulated at setup and teardown, the lazy nature of the kobject * system means we get lazy removes. */ static LIST_HEAD(entry_list); static DEFINE_SPINLOCK(entry_list_lock); /* dmi_sysfs_attribute - Top level attribute. used by all entries. */ struct dmi_sysfs_attribute { struct attribute attr; ssize_t (*show)(struct dmi_sysfs_entry *entry, char *buf); }; #define DMI_SYSFS_ATTR(_entry, _name) \ struct dmi_sysfs_attribute dmi_sysfs_attr_##_entry##_##_name = { \ .attr = {.name = __stringify(_name), .mode = 0400}, \ .show = dmi_sysfs_##_entry##_##_name, \ } /* * dmi_sysfs_mapped_attribute - Attribute where we require the entry be * mapped in. Use in conjunction with dmi_sysfs_specialize_attr_ops. */ struct dmi_sysfs_mapped_attribute { struct attribute attr; ssize_t (*show)(struct dmi_sysfs_entry *entry, const struct dmi_header *dh, char *buf); }; #define DMI_SYSFS_MAPPED_ATTR(_entry, _name) \ struct dmi_sysfs_mapped_attribute dmi_sysfs_attr_##_entry##_##_name = { \ .attr = {.name = __stringify(_name), .mode = 0400}, \ .show = dmi_sysfs_##_entry##_##_name, \ } /************************************************* * Generic DMI entry support. *************************************************/ static void dmi_entry_free(struct kobject *kobj) { kfree(kobj); } static struct dmi_sysfs_entry *to_entry(struct kobject *kobj) { return container_of(kobj, struct dmi_sysfs_entry, kobj); } static struct dmi_sysfs_attribute *to_attr(struct attribute *attr) { return container_of(attr, struct dmi_sysfs_attribute, attr); } static ssize_t dmi_sysfs_attr_show(struct kobject *kobj, struct attribute *_attr, char *buf) { struct dmi_sysfs_entry *entry = to_entry(kobj); struct dmi_sysfs_attribute *attr = to_attr(_attr); /* DMI stuff is only ever admin visible */ if (!capable(CAP_SYS_ADMIN)) return -EACCES; return attr->show(entry, buf); } static const struct sysfs_ops dmi_sysfs_attr_ops = { .show = dmi_sysfs_attr_show, }; typedef ssize_t (*dmi_callback)(struct dmi_sysfs_entry *, const struct dmi_header *dh, void *); struct find_dmi_data { struct dmi_sysfs_entry *entry; dmi_callback callback; void *private; int instance_countdown; ssize_t ret; }; static void find_dmi_entry_helper(const struct dmi_header *dh, void *_data) { struct find_dmi_data *data = _data; struct dmi_sysfs_entry *entry = data->entry; /* Is this the entry we want? */ if (dh->type != entry->dh.type) return; if (data->instance_countdown != 0) { /* try the next instance? */ data->instance_countdown--; return; } /* * Don't ever revisit the instance. Short circuit later * instances by letting the instance_countdown run negative */ data->instance_countdown--; /* Found the entry */ data->ret = data->callback(entry, dh, data->private); } /* State for passing the read parameters through dmi_find_entry() */ struct dmi_read_state { char *buf; loff_t pos; size_t count; }; static ssize_t find_dmi_entry(struct dmi_sysfs_entry *entry, dmi_callback callback, void *private) { struct find_dmi_data data = { .entry = entry, .callback = callback, .private = private, .instance_countdown = entry->instance, .ret = -EIO, /* To signal the entry disappeared */ }; int ret; ret = dmi_walk(find_dmi_entry_helper, &data); /* This shouldn't happen, but just in case. */ if (ret) return -EINVAL; return data.ret; } /* * Calculate and return the byte length of the dmi entry identified by * dh. This includes both the formatted portion as well as the * unformatted string space, including the two trailing nul characters. */ static size_t dmi_entry_length(const struct dmi_header *dh) { const char *p = (const char *)dh; p += dh->length; while (p[0] || p[1]) p++; return 2 + p - (const char *)dh; } /************************************************* * Support bits for specialized DMI entry support *************************************************/ struct dmi_entry_attr_show_data { struct attribute *attr; char *buf; }; static ssize_t dmi_entry_attr_show_helper(struct dmi_sysfs_entry *entry, const struct dmi_header *dh, void *_data) { struct dmi_entry_attr_show_data *data = _data; struct dmi_sysfs_mapped_attribute *attr; attr = container_of(data->attr, struct dmi_sysfs_mapped_attribute, attr); return attr->show(entry, dh, data->buf); } static ssize_t dmi_entry_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) { struct dmi_entry_attr_show_data data = { .attr = attr, .buf = buf, }; /* Find the entry according to our parent and call the * normalized show method hanging off of the attribute */ return find_dmi_entry(to_entry(kobj->parent), dmi_entry_attr_show_helper, &data); } static const struct sysfs_ops dmi_sysfs_specialize_attr_ops = { .show = dmi_entry_attr_show, }; /************************************************* * Specialized DMI entry support. *************************************************/ /*** Type 15 - System Event Table ***/ #define DMI_SEL_ACCESS_METHOD_IO8 0x00 #define DMI_SEL_ACCESS_METHOD_IO2x8 0x01 #define DMI_SEL_ACCESS_METHOD_IO16 0x02 #define DMI_SEL_ACCESS_METHOD_PHYS32 0x03 #define DMI_SEL_ACCESS_METHOD_GPNV 0x04 struct dmi_system_event_log { struct dmi_header header; u16 area_length; u16 header_start_offset; u16 data_start_offset; u8 access_method; u8 status; u32 change_token; union { struct { u16 index_addr; u16 data_addr; } io; u32 phys_addr32; u16 gpnv_handle; u32 access_method_address; }; u8 header_format; u8 type_descriptors_supported_count; u8 per_log_type_descriptor_length; u8 supported_log_type_descriptos[0]; } __packed; #define DMI_SYSFS_SEL_FIELD(_field) \ static ssize_t dmi_sysfs_sel_##_field(struct dmi_sysfs_entry *entry, \ const struct dmi_header *dh, \ char *buf) \ { \ struct dmi_system_event_log sel; \ if (sizeof(sel) > dmi_entry_length(dh)) \ return -EIO; \ memcpy(&sel, dh, sizeof(sel)); \ return sprintf(buf, "%u\n", sel._field); \ } \ static DMI_SYSFS_MAPPED_ATTR(sel, _field) DMI_SYSFS_SEL_FIELD(area_length); DMI_SYSFS_SEL_FIELD(header_start_offset); DMI_SYSFS_SEL_FIELD(data_start_offset); DMI_SYSFS_SEL_FIELD(access_method); DMI_SYSFS_SEL_FIELD(status); DMI_SYSFS_SEL_FIELD(change_token); DMI_SYSFS_SEL_FIELD(access_method_address); DMI_SYSFS_SEL_FIELD(header_format); DMI_SYSFS_SEL_FIELD(type_descriptors_supported_count); DMI_SYSFS_SEL_FIELD(per_log_type_descriptor_length); static struct attribute *dmi_sysfs_sel_attrs[] = { &dmi_sysfs_attr_sel_area_length.attr, &dmi_sysfs_attr_sel_header_start_offset.attr, &dmi_sysfs_attr_sel_data_start_offset.attr, &dmi_sysfs_attr_sel_access_method.attr, &dmi_sysfs_attr_sel_status.attr, &dmi_sysfs_attr_sel_change_token.attr, &dmi_sysfs_attr_sel_access_method_address.attr, &dmi_sysfs_attr_sel_header_format.attr, &dmi_sysfs_attr_sel_type_descriptors_supported_count.attr, &dmi_sysfs_attr_sel_per_log_type_descriptor_length.attr, NULL, }; static struct kobj_type dmi_system_event_log_ktype = { .release = dmi_entry_free, .sysfs_ops = &dmi_sysfs_specialize_attr_ops, .default_attrs = dmi_sysfs_sel_attrs,