block/partitions/sgi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  fs/partitions/sgi.c
   4  *
   5  *  Code extracted from drivers/block/genhd.c
   6  */
   7
   8 #include "check.h"
   9 #include "sgi.h"
  10
  11 struct sgi_disklabel {
  12         __be32 magic_mushroom;          /* Big fat spliff... */
  13         __be16 root_part_num;           /* Root partition number */
  14         __be16 swap_part_num;           /* Swap partition number */
  15         s8 boot_file[16];               /* Name of boot file for ARCS */
  16         u8 _unused0[48];                /* Device parameter useless crapola.. */
  17         struct sgi_volume {
  18                 s8 name[8];             /* Name of volume */
  19                 __be32 block_num;               /* Logical block number */
  20                 __be32 num_bytes;               /* How big, in bytes */
  21         } volume[15];
  22         struct sgi_partition {
  23                 __be32 num_blocks;              /* Size in logical blocks */
  24                 __be32 first_block;     /* First logical block */
  25                 __be32 type;            /* Type of this partition */
  26         } partitions[16];
  27         __be32 csum;                    /* Disk label checksum */
  28         __be32 _unused1;                        /* Padding */
  29 };
  30
  31 int sgi_partition(struct parsed_partitions *state)
  32 {
  33         int i, csum;
  34         __be32 magic;
  35         int slot = 1;
  36         unsigned int start, blocks;
  37         __be32 *ui, cs;
  38         Sector sect;
  39         struct sgi_disklabel *label;
  40         struct sgi_partition *p;
  41         char b[BDEVNAME_SIZE];
  42
  43         label = read_part_sector(state, 0, &sect);
  44         if (!label)
  45                 return -1;
  46         p = &label->partitions[0];
  47         magic = label->magic_mushroom;
  48         if(be32_to_cpu(magic) != SGI_LABEL_MAGIC) {
  49                 /*printk("Dev %s SGI disklabel: bad magic %08x\n",
  50                        bdevname(bdev, b), be32_to_cpu(magic));*/
  51                 put_dev_sector(sect);
  52                 return 0;
  53         }
  54         ui = ((__be32 *) (label + 1)) - 1;
  55         for(csum = 0; ui >= ((__be32 *) label);) {
  56                 cs = *ui--;
  57                 csum += be32_to_cpu(cs);
  58         }
  59         if(csum) {
  60                 printk(KERN_WARNING "Dev %s SGI disklabel: csum bad, label corrupted\n",
  61                        bdevname(state->bdev, b));
  62                 put_dev_sector(sect);
  63                 return 0;
  64         }
  65         /* All SGI disk labels have 16 partitions, disks under Linux only
  66          * have 15 minor's.  Luckily there are always a few zero length
  67          * partitions which we don't care about so we never overflow the
  68          * current_minor.
  69          */
  70         for(i = 0; i < 16; i++, p++) {
  71                 blocks = be32_to_cpu(p->num_blocks);
  72                 start  = be32_to_cpu(p->first_block);
  73                 if (blocks) {
  74                         put_partition(state, slot, start, blocks);
  75                         if (be32_to_cpu(p->type) == LINUX_RAID_PARTITION)
  76                                 state->parts[slot].flags = ADDPART_FLAG_RAID;
  77                 }
  78                 slot++;
  79         }
  80         strlcat(state->pp_buf, "\n", PAGE_SIZE);
  81         put_dev_sector(sect);
  82         return 1;
  83 }