hw/acpi/bios-linker-loader.c

   1 /* Dynamic linker/loader of ACPI tables
   2  *
   3  * Copyright (C) 2013 Red Hat Inc
   4  *
   5  * Author: Michael S. Tsirkin <mst@redhat.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include "qemu/osdep.h"
  22 #include "qemu-common.h"
  23 #include "hw/acpi/bios-linker-loader.h"
  24 #include "hw/nvram/fw_cfg.h"
  25
  26 #include "qemu/bswap.h"
  27
  28 #define BIOS_LINKER_LOADER_FILESZ FW_CFG_MAX_FILE_PATH
  29
  30 struct BiosLinkerLoaderEntry {
  31     uint32_t command;
  32     union {
  33         /*
  34          * COMMAND_ALLOCATE - allocate a table from @alloc.file
  35          * subject to @alloc.align alignment (must be power of 2)
  36          * and @alloc.zone (can be HIGH or FSEG) requirements.
  37          *
  38          * Must appear exactly once for each file, and before
  39          * this file is referenced by any other command.
  40          */
  41         struct {
  42             char file[BIOS_LINKER_LOADER_FILESZ];
  43             uint32_t align;
  44             uint8_t zone;
  45         } alloc;
  46
  47         /*
  48          * COMMAND_ADD_POINTER - patch the table (originating from
  49          * @dest_file) at @pointer.offset, by adding a pointer to the table
  50          * originating from @src_file. 1,2,4 or 8 byte unsigned
  51          * addition is used depending on @pointer.size.
  52          */
  53         struct {
  54             char dest_file[BIOS_LINKER_LOADER_FILESZ];
  55             char src_file[BIOS_LINKER_LOADER_FILESZ];
  56             uint32_t offset;
  57             uint8_t size;
  58         } pointer;
  59
  60         /*
  61          * COMMAND_ADD_CHECKSUM - calculate checksum of the range specified by
  62          * @cksum_start and @cksum_length fields,
  63          * and then add the value at @cksum.offset.
  64          * Checksum simply sums -X for each byte X in the range
  65          * using 8-bit math.
  66          */
  67         struct {
  68             char file[BIOS_LINKER_LOADER_FILESZ];
  69             uint32_t offset;
  70             uint32_t start;
  71             uint32_t length;
  72         } cksum;
  73
  74         /* padding */
  75         char pad[124];
  76     };
  77 } QEMU_PACKED;
  78 typedef struct BiosLinkerLoaderEntry BiosLinkerLoaderEntry;
  79
  80 enum {
  81     BIOS_LINKER_LOADER_COMMAND_ALLOCATE     = 0x1,
  82     BIOS_LINKER_LOADER_COMMAND_ADD_POINTER  = 0x2,
  83     BIOS_LINKER_LOADER_COMMAND_ADD_CHECKSUM = 0x3,
  84 };
  85
  86 enum {
  87     BIOS_LINKER_LOADER_ALLOC_ZONE_HIGH = 0x1,
  88     BIOS_LINKER_LOADER_ALLOC_ZONE_FSEG = 0x2,
  89 };
  90
  91 GArray *bios_linker_loader_init(void)
  92 {
  93     return g_array_new(false, true /* clear */, 1);
  94 }
  95
  96 /* Free linker wrapper and return the linker array. */
  97 void *bios_linker_loader_cleanup(GArray *linker)
  98 {
  99     return g_array_free(linker, false);
 100 }
 101
 102 void bios_linker_loader_alloc(GArray *linker,
 103                               const char *file,
 104                               uint32_t alloc_align,
 105                               bool alloc_fseg)
 106 {
 107     BiosLinkerLoaderEntry entry;
 108
 109     memset(&entry, 0, sizeof entry);
 110     strncpy(entry.alloc.file, file, sizeof entry.alloc.file - 1);
 111     entry.command = cpu_to_le32(BIOS_LINKER_LOADER_COMMAND_ALLOCATE);
 112     entry.alloc.align = cpu_to_le32(alloc_align);
 113     entry.alloc.zone = cpu_to_le32(alloc_fseg ?
 114                                     BIOS_LINKER_LOADER_ALLOC_ZONE_FSEG :
 115                                     BIOS_LINKER_LOADER_ALLOC_ZONE_HIGH);
 116
 117     /* Alloc entries must come first, so prepend them */
 118     g_array_prepend_vals(linker, &entry, sizeof entry);
 119 }
 120
 121 void bios_linker_loader_add_checksum(GArray *linker, const char *file,
 122                                      void *table,
 123                                      void *start, unsigned size,
 124                                      uint8_t *checksum)
 125 {
 126     BiosLinkerLoaderEntry entry;
 127
 128     memset(&entry, 0, sizeof entry);
 129     strncpy(entry.cksum.file, file, sizeof entry.cksum.file - 1);
 130     entry.command = cpu_to_le32(BIOS_LINKER_LOADER_COMMAND_ADD_CHECKSUM);
 131     entry.cksum.offset = cpu_to_le32(checksum - (uint8_t *)table);
 132     entry.cksum.start = cpu_to_le32((uint8_t *)start - (uint8_t *)table);
 133     entry.cksum.length = cpu_to_le32(size);
 134
 135     g_array_append_vals(linker, &entry, sizeof entry);
 136 }
 137
 138 void bios_linker_loader_add_pointer(GArray *linker,
 139                                     const char *dest_file,
 140                                     const char *src_file,
 141                                     GArray *table, void *pointer,
 142                                     uint8_t pointer_size)
 143 {
 144     BiosLinkerLoaderEntry entry;
 145     size_t offset = (gchar *)pointer - table->data;
 146
 147     memset(&entry, 0, sizeof entry);
 148     strncpy(entry.pointer.dest_file, dest_file,
 149             sizeof entry.pointer.dest_file - 1);
 150     strncpy(entry.pointer.src_file, src_file,
 151             sizeof entry.pointer.src_file - 1);
 152     entry.command = cpu_to_le32(BIOS_LINKER_LOADER_COMMAND_ADD_POINTER);
 153     assert(table->len >= offset + pointer_size);
 154     entry.pointer.offset = cpu_to_le32(offset);
 155     entry.pointer.size = pointer_size;
 156     assert(pointer_size == 1 || pointer_size == 2 ||
 157            pointer_size == 4 || pointer_size == 8);
 158
 159     g_array_append_vals(linker, &entry, sizeof entry);
 160 }