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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 
sgi_partition(struct parsed_partitions * state)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 }
84