LXR uboot/lib/smbios-parser.c

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Copyright (C) 2020, Bachmann electronic GmbH
   4 */
   5
   6#define LOG_CATEGORY    LOGC_BOOT
   7
   8#include <common.h>
   9#include <smbios.h>
  10
  11static inline int verify_checksum(const struct smbios_entry *e)
  12{
  13        /*
  14         * Checksums for SMBIOS tables are calculated to have a value, so that
  15         * the sum over all bytes yields zero (using unsigned 8 bit arithmetic).
  16         */
  17        u8 *byte = (u8 *)e;
  18        u8 sum = 0;
  19
  20        for (int i = 0; i < e->length; i++)
  21                sum += byte[i];
  22
  23        return sum;
  24}
  25
  26const struct smbios_entry *smbios_entry(u64 address, u32 size)
  27{
  28        const struct smbios_entry *entry = (struct smbios_entry *)(uintptr_t)address;
  29
  30        if (!address | !size)
  31                return NULL;
  32
  33        if (memcmp(entry->anchor, "_SM_", 4))
  34                return NULL;
  35
  36        if (verify_checksum(entry))
  37                return NULL;
  38
  39        return entry;
  40}
  41
  42static u8 *find_next_header(u8 *pos)
  43{
  44        /* search for _double_ NULL bytes */
  45        while (!((*pos == 0) && (*(pos + 1) == 0)))
  46                pos++;
  47
  48        /* step behind the double NULL bytes */
  49        pos += 2;
  50
  51        return pos;
  52}
  53
  54static struct smbios_header *get_next_header(struct smbios_header *curr)
  55{
  56        u8 *pos = ((u8 *)curr) + curr->length;
  57
  58        return (struct smbios_header *)find_next_header(pos);
  59}
  60
  61static const struct smbios_header *next_header(const struct smbios_header *curr)
  62{
  63        u8 *pos = ((u8 *)curr) + curr->length;
  64
  65        return (struct smbios_header *)find_next_header(pos);
  66}
  67
  68const struct smbios_header *smbios_header(const struct smbios_entry *entry, int type)
  69{
  70        const unsigned int num_header = entry->struct_count;
  71        const struct smbios_header *header = (struct smbios_header *)((uintptr_t)entry->struct_table_address);
  72
  73        for (unsigned int i = 0; i < num_header; i++) {
  74                if (header->type == type)
  75                        return header;
  76
  77                header = next_header(header);
  78        }
  79
  80        return NULL;
  81}
  82
  83static char *string_from_smbios_table(const struct smbios_header *header,
  84                                      int idx)
  85{
  86        unsigned int i = 1;
  87        u8 *pos;
  88
  89        if (!header)
  90                return NULL;
  91
  92        pos = ((u8 *)header) + header->length;
  93
  94        while (i < idx) {
  95                if (*pos == 0x0)
  96                        i++;
  97
  98                pos++;
  99        }
 100
 101        return (char *)pos;
 102}
 103
 104char *smbios_string(const struct smbios_header *header, int index)
 105{
 106        if (!header)
 107                return NULL;
 108
 109        return string_from_smbios_table(header, index);
 110}
 111
 112int smbios_update_version_full(void *smbios_tab, const char *version)
 113{
 114        const struct smbios_header *hdr;
 115        struct smbios_type0 *bios;
 116        uint old_len, len;
 117        char *ptr;
 118
 119        log_info("Updating SMBIOS table at %p\n", smbios_tab);
 120        hdr = smbios_header(smbios_tab, SMBIOS_BIOS_INFORMATION);
 121        if (!hdr)
 122                return log_msg_ret("tab", -ENOENT);
 123        bios = (struct smbios_type0 *)hdr;
 124        ptr = smbios_string(hdr, bios->bios_ver);
 125        if (!ptr)
 126                return log_msg_ret("str", -ENOMEDIUM);
 127
 128        /*
 129         * This string is supposed to have at least enough bytes and is
 130         * padded with spaces. Update it, taking care not to move the
 131         * \0 terminator, so that other strings in the string table
 132         * are not disturbed. See smbios_add_string()
 133         */
 134        old_len = strnlen(ptr, SMBIOS_STR_MAX);
 135        len = strnlen(version, SMBIOS_STR_MAX);
 136        if (len > old_len)
 137                return log_ret(-ENOSPC);
 138
 139        log_debug("Replacing SMBIOS type 0 version string '%s'\n", ptr);
 140        memcpy(ptr, version, len);
 141#ifdef LOG_DEBUG
 142        print_buffer((ulong)ptr, ptr, 1, old_len + 1, 0);
 143#endif
 144
 145        return 0;
 146}
 147
 148struct smbios_filter_param {
 149        u32 offset;
 150        u32 size;
 151        bool is_string;
 152};
 153
 154struct smbios_filter_table {
 155        int type;
 156        struct smbios_filter_param *params;
 157        u32 count;
 158};
 159
 160struct smbios_filter_param smbios_type1_filter_params[] = {
 161        {offsetof(struct smbios_type1, serial_number),
 162         FIELD_SIZEOF(struct smbios_type1, serial_number), true},
 163        {offsetof(struct smbios_type1, uuid),
 164         FIELD_SIZEOF(struct smbios_type1, uuid), false},
 165        {offsetof(struct smbios_type1, wakeup_type),
 166         FIELD_SIZEOF(struct smbios_type1, wakeup_type), false},
 167};
 168
 169struct smbios_filter_param smbios_type2_filter_params[] = {
 170        {offsetof(struct smbios_type2, serial_number),
 171         FIELD_SIZEOF(struct smbios_type2, serial_number), true},
 172        {offsetof(struct smbios_type2, chassis_location),
 173         FIELD_SIZEOF(struct smbios_type2, chassis_location), false},
 174};
 175
 176struct smbios_filter_param smbios_type3_filter_params[] = {
 177        {offsetof(struct smbios_type3, serial_number),
 178         FIELD_SIZEOF(struct smbios_type3, serial_number), true},
 179        {offsetof(struct smbios_type3, asset_tag_number),
 180         FIELD_SIZEOF(struct smbios_type3, asset_tag_number), true},
 181};
 182
 183struct smbios_filter_param smbios_type4_filter_params[] = {
 184        {offsetof(struct smbios_type4, serial_number),
 185         FIELD_SIZEOF(struct smbios_type4, serial_number), true},
 186        {offsetof(struct smbios_type4, asset_tag),
 187         FIELD_SIZEOF(struct smbios_type4, asset_tag), true},
 188        {offsetof(struct smbios_type4, part_number),
 189         FIELD_SIZEOF(struct smbios_type4, part_number), true},
 190        {offsetof(struct smbios_type4, core_count),
 191         FIELD_SIZEOF(struct smbios_type4, core_count), false},
 192        {offsetof(struct smbios_type4, core_enabled),
 193         FIELD_SIZEOF(struct smbios_type4, core_enabled), false},
 194        {offsetof(struct smbios_type4, thread_count),
 195         FIELD_SIZEOF(struct smbios_type4, thread_count), false},
 196        {offsetof(struct smbios_type4, core_count2),
 197         FIELD_SIZEOF(struct smbios_type4, core_count2), false},
 198        {offsetof(struct smbios_type4, core_enabled2),
 199         FIELD_SIZEOF(struct smbios_type4, core_enabled2), false},
 200        {offsetof(struct smbios_type4, thread_count2),
 201         FIELD_SIZEOF(struct smbios_type4, thread_count2), false},
 202        {offsetof(struct smbios_type4, voltage),
 203         FIELD_SIZEOF(struct smbios_type4, voltage), false},
 204};
 205
 206struct smbios_filter_table smbios_filter_tables[] = {
 207        {SMBIOS_SYSTEM_INFORMATION, smbios_type1_filter_params,
 208         ARRAY_SIZE(smbios_type1_filter_params)},
 209        {SMBIOS_BOARD_INFORMATION, smbios_type2_filter_params,
 210         ARRAY_SIZE(smbios_type2_filter_params)},
 211        {SMBIOS_SYSTEM_ENCLOSURE, smbios_type3_filter_params,
 212         ARRAY_SIZE(smbios_type3_filter_params)},
 213        {SMBIOS_PROCESSOR_INFORMATION, smbios_type4_filter_params,
 214         ARRAY_SIZE(smbios_type4_filter_params)},
 215};
 216
 217static void clear_smbios_table(struct smbios_header *header,
 218                               struct smbios_filter_param *filter,
 219                               u32 count)
 220{
 221        u32 i;
 222        char *str;
 223        u8 string_id;
 224
 225        for (i = 0; i < count; i++) {
 226                if (filter[i].is_string) {
 227                        string_id = *((u8 *)header + filter[i].offset);
 228                        if (string_id == 0) /* string is empty */
 229                                continue;
 230
 231                        str = smbios_string(header, string_id);
 232                        if (!str)
 233                                continue;
 234
 235                        /* string is cleared to space, keep '\0' terminator */
 236                        memset(str, ' ', strlen(str));
 237
 238                } else {
 239                        memset((void *)((u8 *)header + filter[i].offset),
 240                               0, filter[i].size);
 241                }
 242        }
 243}
 244
 245void smbios_prepare_measurement(const struct smbios_entry *entry,
 246                                struct smbios_header *smbios_copy)
 247{
 248        u32 i, j;
 249        struct smbios_header *header;
 250
 251        for (i = 0; i < ARRAY_SIZE(smbios_filter_tables); i++) {
 252                header = smbios_copy;
 253                for (j = 0; j < entry->struct_count; j++) {
 254                        if (header->type == smbios_filter_tables[i].type)
 255                                break;
 256
 257                        header = get_next_header(header);
 258                }
 259                if (j >= entry->struct_count)
 260                        continue;
 261
 262                clear_smbios_table(header,
 263                                   smbios_filter_tables[i].params,
 264                                   smbios_filter_tables[i].count);
 265        }
 266}
 267