1 | /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ |
2 | #ifndef _ASM_GENERIC_IOCTL_H |
3 | #define _ASM_GENERIC_IOCTL_H |
4 | |
5 | /* ioctl command encoding: 32 bits total, command in lower 16 bits, |
6 | * size of the parameter structure in the lower 14 bits of the |
7 | * upper 16 bits. |
8 | * Encoding the size of the parameter structure in the ioctl request |
9 | * is useful for catching programs compiled with old versions |
10 | * and to avoid overwriting user space outside the user buffer area. |
11 | * The highest 2 bits are reserved for indicating the ``access mode''. |
12 | * NOTE: This limits the max parameter size to 16kB -1 ! |
13 | */ |
14 | |
15 | /* |
16 | * The following is for compatibility across the various Linux |
17 | * platforms. The generic ioctl numbering scheme doesn't really enforce |
18 | * a type field. De facto, however, the top 8 bits of the lower 16 |
19 | * bits are indeed used as a type field, so we might just as well make |
20 | * this explicit here. Please be sure to use the decoding macros |
21 | * below from now on. |
22 | */ |
23 | #define _IOC_NRBITS 8 |
24 | #define _IOC_TYPEBITS 8 |
25 | |
26 | /* |
27 | * Let any architecture override either of the following before |
28 | * including this file. |
29 | */ |
30 | |
31 | #ifndef _IOC_SIZEBITS |
32 | # define _IOC_SIZEBITS 14 |
33 | #endif |
34 | |
35 | #ifndef _IOC_DIRBITS |
36 | # define _IOC_DIRBITS 2 |
37 | #endif |
38 | |
39 | #define _IOC_NRMASK ((1 << _IOC_NRBITS)-1) |
40 | #define _IOC_TYPEMASK ((1 << _IOC_TYPEBITS)-1) |
41 | #define _IOC_SIZEMASK ((1 << _IOC_SIZEBITS)-1) |
42 | #define _IOC_DIRMASK ((1 << _IOC_DIRBITS)-1) |
43 | |
44 | #define _IOC_NRSHIFT 0 |
45 | #define _IOC_TYPESHIFT (_IOC_NRSHIFT+_IOC_NRBITS) |
46 | #define _IOC_SIZESHIFT (_IOC_TYPESHIFT+_IOC_TYPEBITS) |
47 | #define _IOC_DIRSHIFT (_IOC_SIZESHIFT+_IOC_SIZEBITS) |
48 | |
49 | /* |
50 | * Direction bits, which any architecture can choose to override |
51 | * before including this file. |
52 | * |
53 | * NOTE: _IOC_WRITE means userland is writing and kernel is |
54 | * reading. _IOC_READ means userland is reading and kernel is writing. |
55 | */ |
56 | |
57 | #ifndef _IOC_NONE |
58 | # define _IOC_NONE 0U |
59 | #endif |
60 | |
61 | #ifndef _IOC_WRITE |
62 | # define _IOC_WRITE 1U |
63 | #endif |
64 | |
65 | #ifndef _IOC_READ |
66 | # define _IOC_READ 2U |
67 | #endif |
68 | |
69 | #define _IOC(dir,type,nr,size) \ |
70 | (((dir) << _IOC_DIRSHIFT) | \ |
71 | ((type) << _IOC_TYPESHIFT) | \ |
72 | ((nr) << _IOC_NRSHIFT) | \ |
73 | ((size) << _IOC_SIZESHIFT)) |
74 | |
75 | #define _IOC_TYPECHECK(t) (sizeof(t)) |
76 | |
77 | /* |
78 | * Used to create numbers. |
79 | * |
80 | * NOTE: _IOW means userland is writing and kernel is reading. _IOR |
81 | * means userland is reading and kernel is writing. |
82 | */ |
83 | #define _IO(type,nr) _IOC(_IOC_NONE,(type),(nr),0) |
84 | #define _IOR(type,nr,size) _IOC(_IOC_READ,(type),(nr),(_IOC_TYPECHECK(size))) |
85 | #define _IOW(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size))) |
86 | #define _IOWR(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size))) |
87 | #define _IOR_BAD(type,nr,size) _IOC(_IOC_READ,(type),(nr),sizeof(size)) |
88 | #define _IOW_BAD(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),sizeof(size)) |
89 | #define _IOWR_BAD(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size)) |
90 | |
91 | /* used to decode ioctl numbers.. */ |
92 | #define _IOC_DIR(nr) (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK) |
93 | #define _IOC_TYPE(nr) (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK) |
94 | #define _IOC_NR(nr) (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK) |
95 | #define _IOC_SIZE(nr) (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK) |
96 | |
97 | /* ...and for the drivers/sound files... */ |
98 | |
99 | #define IOC_IN (_IOC_WRITE << _IOC_DIRSHIFT) |
100 | #define IOC_OUT (_IOC_READ << _IOC_DIRSHIFT) |
101 | #define IOC_INOUT ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT) |
102 | #define IOCSIZE_MASK (_IOC_SIZEMASK << _IOC_SIZESHIFT) |
103 | #define IOCSIZE_SHIFT (_IOC_SIZESHIFT) |
104 | |
105 | #endif /* _ASM_GENERIC_IOCTL_H */ |
106 | |