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