pc-bios/s390-ccw/main.c

   1 /*
   2  * S390 virtio-ccw loading program
   3  *
   4  * Copyright (c) 2013 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 "libc.h"
  12 #include "helper.h"
  13 #include "s390-arch.h"
  14 #include "s390-ccw.h"
  15 #include "cio.h"
  16 #include "virtio.h"
  17 #include "virtio-scsi.h"
  18 #include "dasd-ipl.h"
  19
  20 char stack[PAGE_SIZE * 8] __attribute__((__aligned__(PAGE_SIZE)));
  21 static SubChannelId blk_schid = { .one = 1 };
  22 static char loadparm_str[LOADPARM_LEN + 1];
  23 QemuIplParameters qipl;
  24 IplParameterBlock iplb __attribute__((__aligned__(PAGE_SIZE)));
  25 static bool have_iplb;
  26 static uint16_t cutype;
  27 LowCore *lowcore; /* Yes, this *is* a pointer to address 0 */
  28
  29 #define LOADPARM_PROMPT "PROMPT  "
  30 #define LOADPARM_EMPTY  "        "
  31 #define BOOT_MENU_FLAG_MASK (QIPL_FLAG_BM_OPTS_CMD | QIPL_FLAG_BM_OPTS_ZIPL)
  32
  33 /*
  34  * Principles of Operations (SA22-7832-09) chapter 17 requires that
  35  * a subsystem-identification is at 184-187 and bytes 188-191 are zero
  36  * after list-directed-IPL and ccw-IPL.
  37  */
  38 void write_subsystem_identification(void)
  39 {
  40     lowcore->subchannel_id = blk_schid.sch_id;
  41     lowcore->subchannel_nr = blk_schid.sch_no;
  42     lowcore->io_int_parm = 0;
  43 }
  44
  45 void write_iplb_location(void)
  46 {
  47     if (cutype == CU_TYPE_VIRTIO && virtio_get_device_type() != VIRTIO_ID_NET) {
  48         lowcore->ptr_iplb = ptr2u32(&iplb);
  49     }
  50 }
  51
  52 unsigned int get_loadparm_index(void)
  53 {
  54     return atoui(loadparm_str);
  55 }
  56
  57 static int is_dev_possibly_bootable(int dev_no, int sch_no)
  58 {
  59     bool is_virtio;
  60     Schib schib;
  61     int r;
  62
  63     blk_schid.sch_no = sch_no;
  64     r = stsch_err(blk_schid, &schib);
  65     if (r == 3 || r == -EIO) {
  66         return -ENODEV;
  67     }
  68     if (!schib.pmcw.dnv) {
  69         return false;
  70     }
  71
  72     enable_subchannel(blk_schid);
  73     cutype = cu_type(blk_schid);
  74
  75     /*
  76      * Note: we always have to run virtio_is_supported() here to make
  77      * sure that the vdev.senseid data gets pre-initialized correctly
  78      */
  79     is_virtio = virtio_is_supported(blk_schid);
  80
  81     /* No specific devno given, just return whether the device is possibly bootable */
  82     if (dev_no < 0) {
  83         switch (cutype) {
  84         case CU_TYPE_VIRTIO:
  85             if (is_virtio) {
  86                 /*
  87                  * Skip net devices since no IPLB is created and therefore
  88                  * no network bootloader has been loaded
  89                  */
  90                 if (virtio_get_device_type() != VIRTIO_ID_NET) {
  91                     return true;
  92                 }
  93             }
  94             return false;
  95         case CU_TYPE_DASD_3990:
  96         case CU_TYPE_DASD_2107:
  97             return true;
  98         default:
  99             return false;
 100         }
 101     }
 102
 103     /* Caller asked for a specific devno */
 104     if (schib.pmcw.dev == dev_no) {
 105         return true;
 106     }
 107
 108     return false;
 109 }
 110
 111 /*
 112  * Find the subchannel connected to the given device (dev_no) and fill in the
 113  * subchannel information block (schib) with the connected subchannel's info.
 114  * NOTE: The global variable blk_schid is updated to contain the subchannel
 115  * information.
 116  *
 117  * If the caller gives dev_no=-1 then the user did not specify a boot device.
 118  * In this case we'll just use the first potentially bootable device we find.
 119  */
 120 static bool find_subch(int dev_no)
 121 {
 122     int i, r;
 123
 124     for (i = 0; i < 0x10000; i++) {
 125         r = is_dev_possibly_bootable(dev_no, i);
 126         if (r < 0) {
 127             break;
 128         }
 129         if (r == true) {
 130             return true;
 131         }
 132     }
 133
 134     return false;
 135 }
 136
 137 static void menu_setup(void)
 138 {
 139     if (memcmp(loadparm_str, LOADPARM_PROMPT, LOADPARM_LEN) == 0) {
 140         menu_set_parms(QIPL_FLAG_BM_OPTS_CMD, 0);
 141         return;
 142     }
 143
 144     /* If loadparm was set to any other value, then do not enable menu */
 145     if (memcmp(loadparm_str, LOADPARM_EMPTY, LOADPARM_LEN) != 0) {
 146         return;
 147     }
 148
 149     switch (iplb.pbt) {
 150     case S390_IPL_TYPE_CCW:
 151     case S390_IPL_TYPE_QEMU_SCSI:
 152         menu_set_parms(qipl.qipl_flags & BOOT_MENU_FLAG_MASK,
 153                        qipl.boot_menu_timeout);
 154         return;
 155     }
 156 }
 157
 158 /*
 159  * Initialize the channel I/O subsystem so we can talk to our ipl/boot device.
 160  */
 161 static void css_setup(void)
 162 {
 163     /*
 164      * Unconditionally enable mss support. In every sane configuration this
 165      * will succeed; and even if it doesn't, stsch_err() can handle it.
 166      */
 167     enable_mss_facility();
 168 }
 169
 170 /*
 171  * Collect various pieces of information from the hypervisor/hardware that
 172  * we'll use to determine exactly how we'll boot.
 173  */
 174 static void boot_setup(void)
 175 {
 176     char lpmsg[] = "LOADPARM=[________]\n";
 177
 178     sclp_get_loadparm_ascii(loadparm_str);
 179     memcpy(lpmsg + 10, loadparm_str, 8);
 180     sclp_print(lpmsg);
 181
 182     /*
 183      * Clear out any potential S390EP magic (see jump_to_low_kernel()),
 184      * so we don't taint our decision-making process during a reboot.
 185      */
 186     memset((char *)S390EP, 0, 6);
 187
 188     have_iplb = store_iplb(&iplb);
 189 }
 190
 191 static void find_boot_device(void)
 192 {
 193     VDev *vdev = virtio_get_device();
 194     bool found;
 195
 196     switch (iplb.pbt) {
 197     case S390_IPL_TYPE_CCW:
 198         debug_print_int("device no. ", iplb.ccw.devno);
 199         blk_schid.ssid = iplb.ccw.ssid & 0x3;
 200         debug_print_int("ssid ", blk_schid.ssid);
 201         found = find_subch(iplb.ccw.devno);
 202         break;
 203     case S390_IPL_TYPE_QEMU_SCSI:
 204         vdev->scsi_device_selected = true;
 205         vdev->selected_scsi_device.channel = iplb.scsi.channel;
 206         vdev->selected_scsi_device.target = iplb.scsi.target;
 207         vdev->selected_scsi_device.lun = iplb.scsi.lun;
 208         blk_schid.ssid = iplb.scsi.ssid & 0x3;
 209         found = find_subch(iplb.scsi.devno);
 210         break;
 211     default:
 212         panic("List-directed IPL not supported yet!\n");
 213     }
 214
 215     IPL_assert(found, "Boot device not found\n");
 216 }
 217
 218 static int virtio_setup(void)
 219 {
 220     VDev *vdev = virtio_get_device();
 221     QemuIplParameters *early_qipl = (QemuIplParameters *)QIPL_ADDRESS;
 222     int ret;
 223
 224     memcpy(&qipl, early_qipl, sizeof(QemuIplParameters));
 225
 226     if (have_iplb) {
 227         menu_setup();
 228     }
 229
 230     switch (vdev->senseid.cu_model) {
 231     case VIRTIO_ID_NET:
 232         sclp_print("Network boot device detected\n");
 233         vdev->netboot_start_addr = qipl.netboot_start_addr;
 234         return 0;
 235     case VIRTIO_ID_BLOCK:
 236         ret = virtio_blk_setup_device(blk_schid);
 237         break;
 238     case VIRTIO_ID_SCSI:
 239         ret = virtio_scsi_setup_device(blk_schid);
 240         break;
 241     default:
 242         panic("\n! No IPL device available !\n");
 243     }
 244
 245     if (!ret) {
 246         IPL_assert(virtio_ipl_disk_is_valid(), "No valid IPL device detected");
 247     }
 248
 249     return ret;
 250 }
 251
 252 static void ipl_boot_device(void)
 253 {
 254     switch (cutype) {
 255     case CU_TYPE_DASD_3990:
 256     case CU_TYPE_DASD_2107:
 257         dasd_ipl(blk_schid, cutype); /* no return */
 258         break;
 259     case CU_TYPE_VIRTIO:
 260         if (virtio_setup() == 0) {
 261             zipl_load();             /* Only returns in case of errors */
 262         }
 263         break;
 264     default:
 265         print_int("Attempting to boot from unexpected device type", cutype);
 266         panic("\nBoot failed.\n");
 267     }
 268 }
 269
 270 /*
 271  * No boot device has been specified, so we have to scan through the
 272  * channels to find one.
 273  */
 274 static void probe_boot_device(void)
 275 {
 276     int ssid, sch_no, ret;
 277
 278     for (ssid = 0; ssid < 0x3; ssid++) {
 279         blk_schid.ssid = ssid;
 280         for (sch_no = 0; sch_no < 0x10000; sch_no++) {
 281             ret = is_dev_possibly_bootable(-1, sch_no);
 282             if (ret < 0) {
 283                 break;
 284             }
 285             if (ret == true) {
 286                 ipl_boot_device();      /* Only returns if unsuccessful */
 287             }
 288         }
 289     }
 290
 291     sclp_print("Could not find a suitable boot device (none specified)\n");
 292 }
 293
 294 void main(void)
 295 {
 296     sclp_setup();
 297     css_setup();
 298     boot_setup();
 299     if (have_iplb) {
 300         find_boot_device();
 301         ipl_boot_device();
 302     } else {
 303         probe_boot_device();
 304     }
 305
 306     panic("Failed to load OS from hard disk\n");
 307 }