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
  10 #define SGI_LABEL_MAGIC 0x0be5a941
  11
  12 enum {
  13         LINUX_RAID_PARTITION = 0xfd,    /* autodetect RAID partition */
  14 };
  15
  16 struct sgi_disklabel {
  17         __be32 magic_mushroom;          /* Big fat spliff... */
  18         __be16 root_part_num;           /* Root partition number */
  19         __be16 swap_part_num;           /* Swap partition number */
  20         s8 boot_file[16];               /* Name of boot file for ARCS */
  21         u8 _unused0[48];                /* Device parameter useless crapola.. */
  22         struct sgi_volume {
  23                 s8 name[8];             /* Name of volume */
  24                 __be32 block_num;               /* Logical block number */
  25                 __be32 num_bytes;               /* How big, in bytes */
  26         } volume[15];
  27         struct sgi_partition {
  28                 __be32 num_blocks;              /* Size in logical blocks */
  29                 __be32 first_block;     /* First logical block */
  30                 __be32 type;            /* Type of this partition */
  31         } partitions[16];
  32         __be32 csum;                    /* Disk label checksum */
  33         __be32 _unused1;                        /* Padding */
  34 };
  35
  36 int sgi_partition(struct parsed_partitions *state)
  37 {
  38         int i, csum;
  39         __be32 magic;
  40         int slot = 1;
  41         unsigned int start, blocks;
  42         __be32 *ui, cs;
  43         Sector sect;
  44         struct sgi_disklabel *label;
  45         struct sgi_partition *p;
  46
  47         label = read_part_sector(state, 0, &sect);
  48         if (!label)
  49                 return -1;
  50         p = &label->partitions[0];
  51         magic = label->magic_mushroom;
  52         if(be32_to_cpu(magic) != SGI_LABEL_MAGIC) {
  53                 /*printk("Dev %s SGI disklabel: bad magic %08x\n",
  54                        state->disk->disk_name, be32_to_cpu(magic));*/
  55                 put_dev_sector(sect);
  56                 return 0;
  57         }
  58         ui = ((__be32 *) (label + 1)) - 1;
  59         for(csum = 0; ui >= ((__be32 *) label);) {
  60                 cs = *ui--;
  61                 csum += be32_to_cpu(cs);
  62         }
  63         if(csum) {
  64                 printk(KERN_WARNING "Dev %s SGI disklabel: csum bad, label corrupted\n",
  65                        state->disk->disk_name);
  66                 put_dev_sector(sect);
  67                 return 0;
  68         }
  69         /* All SGI disk labels have 16 partitions, disks under Linux only
  70          * have 15 minor's.  Luckily there are always a few zero length
  71          * partitions which we don't care about so we never overflow the
  72          * current_minor.
  73          */
  74         for(i = 0; i < 16; i++, p++) {
  75                 blocks = be32_to_cpu(p->num_blocks);
  76                 start  = be32_to_cpu(p->first_block);
  77                 if (blocks) {
  78                         put_partition(state, slot, start, blocks);
  79                         if (be32_to_cpu(p->type) == LINUX_RAID_PARTITION)
  80                                 state->parts[slot].flags = ADDPART_FLAG_RAID;
  81                 }
  82                 slot++;
  83         }
  84         strlcat(state->pp_buf, "\n", PAGE_SIZE);
  85         put_dev_sector(sect);
  86         return 1;
  87 }