cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

cramfs_fs.h (3570B)

      1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
      2#ifndef _UAPI__CRAMFS_H
      3#define _UAPI__CRAMFS_H
      4
      5#include <linux/types.h>
      6#include <linux/magic.h>
      7
      8#define CRAMFS_SIGNATURE	"Compressed ROMFS"
      9
     10/*
     11 * Width of various bitfields in struct cramfs_inode.
     12 * Primarily used to generate warnings in mkcramfs.
     13 */
     14#define CRAMFS_MODE_WIDTH 16
     15#define CRAMFS_UID_WIDTH 16
     16#define CRAMFS_SIZE_WIDTH 24
     17#define CRAMFS_GID_WIDTH 8
     18#define CRAMFS_NAMELEN_WIDTH 6
     19#define CRAMFS_OFFSET_WIDTH 26
     20
     21/*
     22 * Since inode.namelen is a unsigned 6-bit number, the maximum cramfs
     23 * path length is 63 << 2 = 252.
     24 */
     25#define CRAMFS_MAXPATHLEN (((1 << CRAMFS_NAMELEN_WIDTH) - 1) << 2)
     26
     27/*
     28 * Reasonably terse representation of the inode data.
     29 */
     30struct cramfs_inode {
     31	__u32 mode:CRAMFS_MODE_WIDTH, uid:CRAMFS_UID_WIDTH;
     32	/* SIZE for device files is i_rdev */
     33	__u32 size:CRAMFS_SIZE_WIDTH, gid:CRAMFS_GID_WIDTH;
     34	/* NAMELEN is the length of the file name, divided by 4 and
     35           rounded up.  (cramfs doesn't support hard links.) */
     36	/* OFFSET: For symlinks and non-empty regular files, this
     37	   contains the offset (divided by 4) of the file data in
     38	   compressed form (starting with an array of block pointers;
     39	   see README).  For non-empty directories it is the offset
     40	   (divided by 4) of the inode of the first file in that
     41	   directory.  For anything else, offset is zero. */
     42	__u32 namelen:CRAMFS_NAMELEN_WIDTH, offset:CRAMFS_OFFSET_WIDTH;
     43};
     44
     45struct cramfs_info {
     46	__u32 crc;
     47	__u32 edition;
     48	__u32 blocks;
     49	__u32 files;
     50};
     51
     52/*
     53 * Superblock information at the beginning of the FS.
     54 */
     55struct cramfs_super {
     56	__u32 magic;			/* 0x28cd3d45 - random number */
     57	__u32 size;			/* length in bytes */
     58	__u32 flags;			/* feature flags */
     59	__u32 future;			/* reserved for future use */
     60	__u8 signature[16];		/* "Compressed ROMFS" */
     61	struct cramfs_info fsid;	/* unique filesystem info */
     62	__u8 name[16];			/* user-defined name */
     63	struct cramfs_inode root;	/* root inode data */
     64};
     65
     66/*
     67 * Feature flags
     68 *
     69 * 0x00000000 - 0x000000ff: features that work for all past kernels
     70 * 0x00000100 - 0xffffffff: features that don't work for past kernels
     71 */
     72#define CRAMFS_FLAG_FSID_VERSION_2	0x00000001	/* fsid version #2 */
     73#define CRAMFS_FLAG_SORTED_DIRS		0x00000002	/* sorted dirs */
     74#define CRAMFS_FLAG_HOLES		0x00000100	/* support for holes */
     75#define CRAMFS_FLAG_WRONG_SIGNATURE	0x00000200	/* reserved */
     76#define CRAMFS_FLAG_SHIFTED_ROOT_OFFSET	0x00000400	/* shifted root fs */
     77#define CRAMFS_FLAG_EXT_BLOCK_POINTERS	0x00000800	/* block pointer extensions */
     78
     79/*
     80 * Valid values in super.flags.  Currently we refuse to mount
     81 * if (flags & ~CRAMFS_SUPPORTED_FLAGS).  Maybe that should be
     82 * changed to test super.future instead.
     83 */
     84#define CRAMFS_SUPPORTED_FLAGS	( 0x000000ff \
     85				| CRAMFS_FLAG_HOLES \
     86				| CRAMFS_FLAG_WRONG_SIGNATURE \
     87				| CRAMFS_FLAG_SHIFTED_ROOT_OFFSET \
     88				| CRAMFS_FLAG_EXT_BLOCK_POINTERS )
     89
     90/*
     91 * Block pointer flags
     92 *
     93 * The maximum block offset that needs to be represented is roughly:
     94 *
     95 *   (1 << CRAMFS_OFFSET_WIDTH) * 4 +
     96 *   (1 << CRAMFS_SIZE_WIDTH) / PAGE_SIZE * (4 + PAGE_SIZE)
     97 *   = 0x11004000
     98 *
     99 * That leaves room for 3 flag bits in the block pointer table.
    100 */
    101#define CRAMFS_BLK_FLAG_UNCOMPRESSED	(1 << 31)
    102#define CRAMFS_BLK_FLAG_DIRECT_PTR	(1 << 30)
    103
    104#define CRAMFS_BLK_FLAGS	( CRAMFS_BLK_FLAG_UNCOMPRESSED \
    105				| CRAMFS_BLK_FLAG_DIRECT_PTR )
    106
    107/*
    108 * Direct blocks are at least 4-byte aligned.
    109 * Pointers to direct blocks are shifted down by 2 bits.
    110 */
    111#define CRAMFS_BLK_DIRECT_PTR_SHIFT	2
    112
    113#endif /* _UAPI__CRAMFS_H */