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