pc-bios/s390-ccw/bootmap.c

   1 /*
   2  * QEMU S390 bootmap interpreter
   3  *
   4  * Copyright (c) 2009 Alexander Graf <agraf@suse.de>
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2 or (at
   7  * your option) any later version. See the COPYING file in the top-level
   8  * directory.
   9  */
  10
  11 #include "s390-ccw.h"
  12
  13 // #define DEBUG_FALLBACK
  14
  15 #ifdef DEBUG_FALLBACK
  16 #define dputs(txt) \
  17     do { sclp_print("zipl: " txt); } while (0)
  18 #else
  19 #define dputs(fmt, ...) \
  20     do { } while (0)
  21 #endif
  22
  23 struct scsi_blockptr {
  24     uint64_t blockno;
  25     uint16_t size;
  26     uint16_t blockct;
  27     uint8_t reserved[4];
  28 } __attribute__ ((packed));
  29
  30 struct component_entry {
  31     struct scsi_blockptr data;
  32     uint8_t pad[7];
  33     uint8_t component_type;
  34     uint64_t load_address;
  35 } __attribute((packed));
  36
  37 struct component_header {
  38     uint8_t magic[4];
  39     uint8_t type;
  40     uint8_t reserved[27];
  41 } __attribute((packed));
  42
  43 struct mbr {
  44     uint8_t magic[4];
  45     uint32_t version_id;
  46     uint8_t reserved[8];
  47     struct scsi_blockptr blockptr;
  48 } __attribute__ ((packed));
  49
  50 #define ZIPL_MAGIC                      "zIPL"
  51
  52 #define ZIPL_COMP_HEADER_IPL            0x00
  53 #define ZIPL_COMP_HEADER_DUMP           0x01
  54
  55 #define ZIPL_COMP_ENTRY_LOAD            0x02
  56 #define ZIPL_COMP_ENTRY_EXEC            0x01
  57
  58 /* Scratch space */
  59 static uint8_t sec[SECTOR_SIZE] __attribute__((__aligned__(SECTOR_SIZE)));
  60
  61 /* Check for ZIPL magic. Returns 0 if not matched. */
  62 static int zipl_magic(uint8_t *ptr)
  63 {
  64     uint32_t *p = (void*)ptr;
  65     uint32_t *z = (void*)ZIPL_MAGIC;
  66
  67     if (*p != *z) {
  68         debug_print_int("invalid magic", *p);
  69         virtio_panic("invalid magic");
  70     }
  71
  72     return 1;
  73 }
  74
  75 static int zipl_load_segment(struct component_entry *entry)
  76 {
  77     const int max_entries = (SECTOR_SIZE / sizeof(struct scsi_blockptr));
  78     struct scsi_blockptr *bprs = (void*)sec;
  79     uint64_t blockno;
  80     long address;
  81     int i;
  82
  83     blockno = entry->data.blockno;
  84     address = entry->load_address;
  85
  86     debug_print_int("loading segment at block", blockno);
  87     debug_print_int("addr", address);
  88
  89     do {
  90         if (virtio_read(blockno, (uint8_t *)bprs)) {
  91             debug_print_int("failed reading bprs at", blockno);
  92             goto fail;
  93         }
  94
  95         for (i = 0;; i++) {
  96             u64 *cur_desc = (void*)&bprs[i];
  97
  98             blockno = bprs[i].blockno;
  99             if (!blockno)
 100                 break;
 101
 102             /* we need the updated blockno for the next indirect entry in the
 103                chain, but don't want to advance address */
 104             if (i == (max_entries - 1))
 105                 break;
 106
 107             address = virtio_load_direct(cur_desc[0], cur_desc[1], 0,
 108                                          (void*)address);
 109             if (address == -1)
 110                 goto fail;
 111         }
 112     } while (blockno);
 113
 114     return 0;
 115
 116 fail:
 117     sclp_print("failed loading segment\n");
 118     return -1;
 119 }
 120
 121 /* Run a zipl program */
 122 static int zipl_run(struct scsi_blockptr *pte)
 123 {
 124     struct component_header *header;
 125     struct component_entry *entry;
 126     void (*ipl)(void);
 127     uint8_t tmp_sec[SECTOR_SIZE];
 128
 129     virtio_read(pte->blockno, tmp_sec);
 130     header = (struct component_header *)tmp_sec;
 131
 132     if (!zipl_magic(tmp_sec)) {
 133         goto fail;
 134     }
 135
 136     if (header->type != ZIPL_COMP_HEADER_IPL) {
 137         goto fail;
 138     }
 139
 140     dputs("start loading images\n");
 141
 142     /* Load image(s) into RAM */
 143     entry = (struct component_entry *)(&header[1]);
 144     while (entry->component_type == ZIPL_COMP_ENTRY_LOAD) {
 145         if (zipl_load_segment(entry) < 0) {
 146             goto fail;
 147         }
 148
 149         entry++;
 150
 151         if ((uint8_t*)(&entry[1]) > (tmp_sec + SECTOR_SIZE)) {
 152             goto fail;
 153         }
 154     }
 155
 156     if (entry->component_type != ZIPL_COMP_ENTRY_EXEC) {
 157         goto fail;
 158     }
 159
 160     /* Ensure the guest output starts fresh */
 161     sclp_print("\n");
 162
 163     /* And run the OS! */
 164     ipl = (void*)(entry->load_address & 0x7fffffff);
 165     debug_print_addr("set IPL addr to", ipl);
 166     /* should not return */
 167     ipl();
 168
 169     return 0;
 170
 171 fail:
 172     sclp_print("failed running zipl\n");
 173     return -1;
 174 }
 175
 176 int zipl_load(void)
 177 {
 178     struct mbr *mbr = (void*)sec;
 179     uint8_t *ns, *ns_end;
 180     int program_table_entries = 0;
 181     int pte_len = sizeof(struct scsi_blockptr);
 182     struct scsi_blockptr *prog_table_entry;
 183     const char *error = "";
 184
 185     /* Grab the MBR */
 186     virtio_read(0, (void*)mbr);
 187
 188     dputs("checking magic\n");
 189
 190     if (!zipl_magic(mbr->magic)) {
 191         error = "zipl_magic 1";
 192         goto fail;
 193     }
 194
 195     debug_print_int("program table", mbr->blockptr.blockno);
 196
 197     /* Parse the program table */
 198     if (virtio_read(mbr->blockptr.blockno, sec)) {
 199         error = "virtio_read";
 200         goto fail;
 201     }
 202
 203     if (!zipl_magic(sec)) {
 204         error = "zipl_magic 2";
 205         goto fail;
 206     }
 207
 208     ns_end = sec + SECTOR_SIZE;
 209     for (ns = (sec + pte_len); (ns + pte_len) < ns_end; ns++) {
 210         prog_table_entry = (struct scsi_blockptr *)ns;
 211         if (!prog_table_entry->blockno) {
 212             break;
 213         }
 214
 215         program_table_entries++;
 216     }
 217
 218     debug_print_int("program table entries", program_table_entries);
 219
 220     if (!program_table_entries) {
 221         goto fail;
 222     }
 223
 224     /* Run the default entry */
 225
 226     prog_table_entry = (struct scsi_blockptr *)(sec + pte_len);
 227
 228     return zipl_run(prog_table_entry);
 229
 230 fail:
 231     sclp_print("failed loading zipl: ");
 232     sclp_print(error);
 233     sclp_print("\n");
 234     return -1;
 235 }