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		put_dev_sector(sect);
54		return 0;
55	}
56	ui = ((__be32 *) (label + 1)) - 1;
57	for(csum = 0; ui >= ((__be32 *) label);) {
58		cs = *ui--;
59		csum += be32_to_cpu(cs);
60	}
61	if(csum) {
62		printk(KERN_WARNING "Dev %s SGI disklabel: csum bad, label corrupted\n",
63		       state->disk->disk_name);
64		put_dev_sector(sect);
65		return 0;
66	}
67	/* All SGI disk labels have 16 partitions, disks under Linux only
68	 * have 15 minor's.  Luckily there are always a few zero length
69	 * partitions which we don't care about so we never overflow the
70	 * current_minor.
71	 */
72	for(i = 0; i < 16; i++, p++) {
73		blocks = be32_to_cpu(p->num_blocks);
74		start  = be32_to_cpu(p->first_block);
75		if (blocks) {
76			put_partition(state, slot, start, blocks);
77			if (be32_to_cpu(p->type) == LINUX_RAID_PARTITION)
78				state->parts[slot].flags = ADDPART_FLAG_RAID;
79		}
80		slot++;
81	}
82	strlcat(state->pp_buf, "\n", PAGE_SIZE);
83	put_dev_sector(sect);
84	return 1;
85}