pc-bios/s390-ccw: El Torito s390x boot entry check

Boot entry is considered compatible if boot image is Linux kernel
with matching S390 Linux magic string.

Empty boot images with sector_count == 0 are considered broken.

Signed-off-by: Maxim Samoylov <max7255@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
This commit is contained in:
Maxim Samoylov 2015-10-12 17:50:20 +02:00 committed by Cornelia Huck
parent 866cac91e0
commit ba21f0cca8
2 changed files with 18 additions and 1 deletions

View File

@ -450,7 +450,16 @@ static void ipl_scsi(void)
static bool is_iso_bc_entry_compatible(IsoBcSection *s)
{
return true;
uint8_t *magic_sec = (uint8_t *)(sec + ISO_SECTOR_SIZE);
if (s->unused || !s->sector_count) {
return false;
}
read_iso_sector(bswap32(s->load_rba), magic_sec,
"Failed to read image sector 0");
/* Checking bytes 8 - 32 for S390 Linux magic */
return !_memcmp(magic_sec + 8, linux_s390_magic, 24);
}
static void load_iso_bc_entry(IsoBcSection *load)

View File

@ -495,6 +495,14 @@ typedef struct IsoBcHdr {
uint8_t id[28];
} __attribute__((packed)) IsoBcHdr;
/*
* Match two CCWs located after PSW and eight filler bytes.
* From libmagic and arch/s390/kernel/head.S.
*/
const uint8_t linux_s390_magic[] = "\x02\x00\x00\x18\x60\x00\x00\x50\x02\x00"
"\x00\x68\x60\x00\x00\x50\x40\x40\x40\x40"
"\x40\x40\x40\x40";
typedef struct IsoBcEntry {
uint8_t id;
union {