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>
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@ -118,10 +118,26 @@ static int zipl_magic(uint8_t *ptr)
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return 1;
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return 1;
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}
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}
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#define FREE_SPACE_FILLER '\xAA'
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static inline bool unused_space(const void *p, unsigned int size)
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{
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int i;
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const unsigned char *m = p;
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for (i = 0; i < size; i++) {
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if (m[i] != FREE_SPACE_FILLER) {
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return false;
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}
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}
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return true;
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}
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static int zipl_load_segment(struct component_entry *entry)
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static int zipl_load_segment(struct component_entry *entry)
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{
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{
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const int max_entries = (SECTOR_SIZE / sizeof(struct scsi_blockptr));
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const int max_entries = (SECTOR_SIZE / sizeof(struct scsi_blockptr));
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struct scsi_blockptr *bprs = (void*)sec;
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struct scsi_blockptr *bprs = (void*)sec;
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const int bprs_size = sizeof(sec);
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uint64_t blockno;
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uint64_t blockno;
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long address;
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long address;
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int i;
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int i;
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@ -133,6 +149,7 @@ static int zipl_load_segment(struct component_entry *entry)
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debug_print_int("addr", address);
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debug_print_int("addr", address);
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do {
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do {
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memset(bprs, FREE_SPACE_FILLER, bprs_size);
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if (virtio_read(blockno, (uint8_t *)bprs)) {
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if (virtio_read(blockno, (uint8_t *)bprs)) {
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debug_print_int("failed reading bprs at", blockno);
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debug_print_int("failed reading bprs at", blockno);
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goto fail;
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goto fail;
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@ -150,6 +167,16 @@ static int zipl_load_segment(struct component_entry *entry)
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if (i == (max_entries - 1))
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if (i == (max_entries - 1))
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break;
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break;
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if (bprs[i].blockct == 0 && unused_space(&bprs[i + 1],
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sizeof(struct scsi_blockptr))) {
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/* This is a "continue" pointer.
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* This ptr is the last one in the current script section.
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* I.e. the next ptr must point to the unused memory area.
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* The blockno is not zero, so the upper loop must continue
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* reading next section of BPRS.
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*/
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break;
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}
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address = virtio_load_direct(cur_desc[0], cur_desc[1], 0,
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address = virtio_load_direct(cur_desc[0], cur_desc[1], 0,
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(void*)address);
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(void*)address);
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if (address == -1)
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if (address == -1)
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