LXR linux/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
  12enum {
  13        LINUX_RAID_PARTITION = 0xfd,    /* autodetect RAID partition */
  14};
  15
  16struct 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
  36int 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}
  88