linux/drivers/firmware/efi/runtime-map.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * linux/drivers/efi/runtime-map.c
   4 * Copyright (C) 2013 Red Hat, Inc., Dave Young <dyoung@redhat.com>
   5 */
   6
   7#include <linux/string.h>
   8#include <linux/kernel.h>
   9#include <linux/module.h>
  10#include <linux/types.h>
  11#include <linux/efi.h>
  12#include <linux/slab.h>
  13
  14#include <asm/setup.h>
  15
  16struct efi_runtime_map_entry {
  17        efi_memory_desc_t md;
  18        struct kobject kobj;   /* kobject for each entry */
  19};
  20
  21static struct efi_runtime_map_entry **map_entries;
  22
  23struct map_attribute {
  24        struct attribute attr;
  25        ssize_t (*show)(struct efi_runtime_map_entry *entry, char *buf);
  26};
  27
  28static inline struct map_attribute *to_map_attr(struct attribute *attr)
  29{
  30        return container_of(attr, struct map_attribute, attr);
  31}
  32
  33static ssize_t type_show(struct efi_runtime_map_entry *entry, char *buf)
  34{
  35        return snprintf(buf, PAGE_SIZE, "0x%x\n", entry->md.type);
  36}
  37
  38#define EFI_RUNTIME_FIELD(var) entry->md.var
  39
  40#define EFI_RUNTIME_U64_ATTR_SHOW(name) \
  41static ssize_t name##_show(struct efi_runtime_map_entry *entry, char *buf) \
  42{ \
  43        return snprintf(buf, PAGE_SIZE, "0x%llx\n", EFI_RUNTIME_FIELD(name)); \
  44}
  45
  46EFI_RUNTIME_U64_ATTR_SHOW(phys_addr);
  47EFI_RUNTIME_U64_ATTR_SHOW(virt_addr);
  48EFI_RUNTIME_U64_ATTR_SHOW(num_pages);
  49EFI_RUNTIME_U64_ATTR_SHOW(attribute);
  50
  51static inline struct efi_runtime_map_entry *to_map_entry(struct kobject *kobj)
  52{
  53        return container_of(kobj, struct efi_runtime_map_entry, kobj);
  54}
  55
  56static ssize_t map_attr_show(struct kobject *kobj, struct attribute *attr,
  57                              char *buf)
  58{
  59        struct efi_runtime_map_entry *entry = to_map_entry(kobj);
  60        struct map_attribute *map_attr = to_map_attr(attr);
  61
  62        return map_attr->show(entry, buf);
  63}
  64
  65static struct map_attribute map_type_attr = __ATTR_RO_MODE(type, 0400);
  66static struct map_attribute map_phys_addr_attr = __ATTR_RO_MODE(phys_addr, 0400);
  67static struct map_attribute map_virt_addr_attr = __ATTR_RO_MODE(virt_addr, 0400);
  68static struct map_attribute map_num_pages_attr = __ATTR_RO_MODE(num_pages, 0400);
  69static struct map_attribute map_attribute_attr = __ATTR_RO_MODE(attribute, 0400);
  70
  71/*
  72 * These are default attributes that are added for every memmap entry.
  73 */
  74static struct attribute *def_attrs[] = {
  75        &map_type_attr.attr,
  76        &map_phys_addr_attr.attr,
  77        &map_virt_addr_attr.attr,
  78        &map_num_pages_attr.attr,
  79        &map_attribute_attr.attr,
  80        NULL
  81};
  82
  83static const struct sysfs_ops map_attr_ops = {
  84        .show = map_attr_show,
  85};
  86
  87static void map_release(struct kobject *kobj)
  88{
  89        struct efi_runtime_map_entry *entry;
  90
  91        entry = to_map_entry(kobj);
  92        kfree(entry);
  93}
  94
  95static struct kobj_type __refdata map_ktype = {
  96        .sysfs_ops      = &map_attr_ops,
  97        .default_attrs  = def_attrs,
  98        .release        = map_release,
  99};
 100
 101static struct kset *map_kset;
 102
 103static struct efi_runtime_map_entry *
 104add_sysfs_runtime_map_entry(struct kobject *kobj, int nr,
 105                            efi_memory_desc_t *md)
 106{
 107        int ret;
 108        struct efi_runtime_map_entry *entry;
 109
 110        if (!map_kset) {
 111                map_kset = kset_create_and_add("runtime-map", NULL, kobj);
 112                if (!map_kset)
 113                        return ERR_PTR(-ENOMEM);
 114        }
 115
 116        entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 117        if (!entry) {
 118                kset_unregister(map_kset);
 119                map_kset = NULL;
 120                return ERR_PTR(-ENOMEM);
 121        }
 122
 123        memcpy(&entry->md, md, sizeof(efi_memory_desc_t));
 124
 125        kobject_init(&entry->kobj, &map_ktype);
 126        entry->kobj.kset = map_kset;
 127        ret = kobject_add(&entry->kobj, NULL, "%d", nr);
 128        if (ret) {
 129                kobject_put(&entry->kobj);
 130                kset_unregister(map_kset);
 131                map_kset = NULL;
 132                return ERR_PTR(ret);
 133        }
 134
 135        return entry;
 136}
 137
 138int efi_get_runtime_map_size(void)
 139{
 140        return efi.memmap.nr_map * efi.memmap.desc_size;
 141}
 142
 143int efi_get_runtime_map_desc_size(void)
 144{
 145        return efi.memmap.desc_size;
 146}
 147
 148int efi_runtime_map_copy(void *buf, size_t bufsz)
 149{
 150        size_t sz = efi_get_runtime_map_size();
 151
 152        if (sz > bufsz)
 153                sz = bufsz;
 154
 155        memcpy(buf, efi.memmap.map, sz);
 156        return 0;
 157}
 158
 159int __init efi_runtime_map_init(struct kobject *efi_kobj)
 160{
 161        int i, j, ret = 0;
 162        struct efi_runtime_map_entry *entry;
 163        efi_memory_desc_t *md;
 164
 165        if (!efi_enabled(EFI_MEMMAP))
 166                return 0;
 167
 168        map_entries = kcalloc(efi.memmap.nr_map, sizeof(entry), GFP_KERNEL);
 169        if (!map_entries) {
 170                ret = -ENOMEM;
 171                goto out;
 172        }
 173
 174        i = 0;
 175        for_each_efi_memory_desc(md) {
 176                entry = add_sysfs_runtime_map_entry(efi_kobj, i, md);
 177                if (IS_ERR(entry)) {
 178                        ret = PTR_ERR(entry);
 179                        goto out_add_entry;
 180                }
 181                *(map_entries + i++) = entry;
 182        }
 183
 184        return 0;
 185out_add_entry:
 186        for (j = i - 1; j >= 0; j--) {
 187                entry = *(map_entries + j);
 188                kobject_put(&entry->kobj);
 189        }
 190out:
 191        return ret;
 192}
 193