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/*
* QEMU S390 bootmap interpreter
*
* Copyright (c) 2009 Alexander Graf <agraf@suse.de>
*
* This work is licensed under the terms of the GNU GPL, version 2 or (at
* your option) any later version. See the COPYING file in the top-level
* directory.
*/
#include "s390-ccw.h"
// #define DEBUG_FALLBACK
#ifdef DEBUG_FALLBACK
#define dputs(txt) \
do { sclp_print("zipl: " txt); } while (0)
#else
#define dputs(fmt, ...) \
do { } while (0)
#endif
struct scsi_blockptr {
uint64_t blockno;
uint16_t size;
uint16_t blockct;
uint8_t reserved[4];
} __attribute__ ((packed));
struct component_entry {
struct scsi_blockptr data;
uint8_t pad[7];
uint8_t component_type;
uint64_t load_address;
} __attribute((packed));
struct component_header {
uint8_t magic[4];
uint8_t type;
uint8_t reserved[27];
} __attribute((packed));
struct mbr {
uint8_t magic[4];
uint32_t version_id;
uint8_t reserved[8];
struct scsi_blockptr blockptr;
} __attribute__ ((packed));
#define ZIPL_MAGIC "zIPL"
#define ZIPL_COMP_HEADER_IPL 0x00
#define ZIPL_COMP_HEADER_DUMP 0x01
#define ZIPL_COMP_ENTRY_LOAD 0x02
#define ZIPL_COMP_ENTRY_EXEC 0x01
/* Scratch space */
static uint8_t sec[SECTOR_SIZE] __attribute__((__aligned__(SECTOR_SIZE)));
/* Check for ZIPL magic. Returns 0 if not matched. */
static int zipl_magic(uint8_t *ptr)
{
uint32_t *p = (void*)ptr;
uint32_t *z = (void*)ZIPL_MAGIC;
if (*p != *z) {
debug_print_int("invalid magic", *p);
virtio_panic("invalid magic");
}
return 1;
}
static int zipl_load_segment(struct component_entry *entry)
{
const int max_entries = (SECTOR_SIZE / sizeof(struct scsi_blockptr));
struct scsi_blockptr *bprs = (void*)sec;
uint64_t blockno;
long address;
int i;
blockno = entry->data.blockno;
address = entry->load_address;
debug_print_int("loading segment at block", blockno);
debug_print_int("addr", address);
do {
if (virtio_read(blockno, (uint8_t *)bprs)) {
debug_print_int("failed reading bprs at", blockno);
goto fail;
}
for (i = 0;; i++) {
u64 *cur_desc = (void*)&bprs[i];
blockno = bprs[i].blockno;
if (!blockno)
break;
/* we need the updated blockno for the next indirect entry in the
chain, but don't want to advance address */
if (i == (max_entries - 1))
break;
address = virtio_load_direct(cur_desc[0], cur_desc[1], 0,
(void*)address);
if (address == -1)
goto fail;
}
} while (blockno);
return 0;
fail:
sclp_print("failed loading segment\n");
return -1;
}
/* Run a zipl program */
static int zipl_run(struct scsi_blockptr *pte)
{
struct component_header *header;
struct component_entry *entry;
void (*ipl)(void);
uint8_t tmp_sec[SECTOR_SIZE];
virtio_read(pte->blockno, tmp_sec);
header = (struct component_header *)tmp_sec;
if (!zipl_magic(tmp_sec)) {
goto fail;
}
if (header->type != ZIPL_COMP_HEADER_IPL) {
goto fail;
}
dputs("start loading images\n");
/* Load image(s) into RAM */
entry = (struct component_entry *)(&header[1]);
while (entry->component_type == ZIPL_COMP_ENTRY_LOAD) {
if (zipl_load_segment(entry) < 0) {
goto fail;
}
entry++;
if ((uint8_t*)(&entry[1]) > (tmp_sec + SECTOR_SIZE)) {
goto fail;
}
}
if (entry->component_type != ZIPL_COMP_ENTRY_EXEC) {
goto fail;
}
/* Ensure the guest output starts fresh */
sclp_print("\n");
/* And run the OS! */
ipl = (void*)(entry->load_address & 0x7fffffff);
debug_print_addr("set IPL addr to", ipl);
/* should not return */
ipl();
return 0;
fail:
sclp_print("failed running zipl\n");
return -1;
}
int zipl_load(void)
{
struct mbr *mbr = (void*)sec;
uint8_t *ns, *ns_end;
int program_table_entries = 0;
int pte_len = sizeof(struct scsi_blockptr);
struct scsi_blockptr *prog_table_entry;
const char *error = "";
/* Grab the MBR */
virtio_read(0, (void*)mbr);
dputs("checking magic\n");
if (!zipl_magic(mbr->magic)) {
error = "zipl_magic 1";
goto fail;
}
debug_print_int("program table", mbr->blockptr.blockno);
/* Parse the program table */
if (virtio_read(mbr->blockptr.blockno, sec)) {
error = "virtio_read";
goto fail;
}
if (!zipl_magic(sec)) {
error = "zipl_magic 2";
goto fail;
}
ns_end = sec + SECTOR_SIZE;
for (ns = (sec + pte_len); (ns + pte_len) < ns_end; ns++) {
prog_table_entry = (struct scsi_blockptr *)ns;
if (!prog_table_entry->blockno) {
break;
}
program_table_entries++;
}
debug_print_int("program table entries", program_table_entries);
if (!program_table_entries) {
goto fail;
}
/* Run the default entry */
prog_table_entry = (struct scsi_blockptr *)(sec + pte_len);
return zipl_run(prog_table_entry);
fail:
sclp_print("failed loading zipl: ");
sclp_print(error);
sclp_print("\n");
return -1;
}
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