Commit c77cd87c authored by Eugene (jno) Dvurechenski's avatar Eugene (jno) Dvurechenski Committed by Cornelia Huck
Browse files

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: default avatarEugene (jno) Dvurechenski <jno@linux.vnet.ibm.com>
Signed-off-by: default avatarJens Freimann <jfrei@linux.vnet.ibm.com>
Tested-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: default avatarDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
parent 96298232

pc-bios/s390-ccw/bootmap.c

+27 −0
Original line number Diff line number Diff line
@@ -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)