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pc-bios/s390-ccw: fix for fragmented SCSI bootmap 

We need to interpret the last entry of the bootmap with zero
block count as "continuation pointer".
The "last entry" is being detected by pre-filling of the scratch
space with known values and respective look-ahead.

Signed-off-by: Eugene (jno) Dvurechenski <jno@linux.vnet.ibm.com>
Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
This commit is contained in:
Eugene (jno) Dvurechenski 2014-06-18 14:16:46 +02:00 committed by Cornelia Huck
parent 9629823290
commit c77cd87cf5
1 changed files with 27 additions and 0 deletions
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27
pc-bios/s390-ccw/bootmap.c
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@ -118,10 +118,26 @@ static int zipl_magic(uint8_t *ptr)
return 1;
}
#define FREE_SPACE_FILLER '\xAA'
static inline bool unused_space(const void *p, unsigned int size)
{
int i;
const unsigned char *m = p;
for (i = 0; i < size; i++) {
if (m[i] != FREE_SPACE_FILLER) {
return false;
}
}
return true;
}
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;
const int bprs_size = sizeof(sec);
uint64_t blockno;
long address;
int i;
@ -133,6 +149,7 @@ static int zipl_load_segment(struct component_entry *entry)
debug_print_int("addr", address);
do {
memset(bprs, FREE_SPACE_FILLER, bprs_size);
if (virtio_read(blockno, (uint8_t *)bprs)) {
debug_print_int("failed reading bprs at", blockno);
goto fail;
@ -150,6 +167,16 @@ static int zipl_load_segment(struct component_entry *entry)
if (i == (max_entries - 1))
break;
if (bprs[i].blockct == 0 && unused_space(&bprs[i + 1],
sizeof(struct scsi_blockptr))) {
/* This is a "continue" pointer.
* This ptr is the last one in the current script section.
* I.e. the next ptr must point to the unused memory area.
* The blockno is not zero, so the upper loop must continue
* reading next section of BPRS.
*/
break;
}
address = virtio_load_direct(cur_desc[0], cur_desc[1], 0,
(void*)address);
if (address == -1)