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1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */2#ifndef _UAPI_ASM_GENERIC_IOCTL_H3#define _UAPI_ASM_GENERIC_IOCTL_H4 5/* ioctl command encoding: 32 bits total, command in lower 16 bits,6 * size of the parameter structure in the lower 14 bits of the7 * upper 16 bits.8 * Encoding the size of the parameter structure in the ioctl request9 * is useful for catching programs compiled with old versions10 * 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 Linux17 * platforms. The generic ioctl numbering scheme doesn't really enforce18 * a type field. De facto, however, the top 8 bits of the lower 1619 * bits are indeed used as a type field, so we might just as well make20 * this explicit here. Please be sure to use the decoding macros21 * below from now on.22 */23#define _IOC_NRBITS 824#define _IOC_TYPEBITS 825 26/*27 * Let any architecture override either of the following before28 * including this file.29 */30 31#ifndef _IOC_SIZEBITS32# define _IOC_SIZEBITS 1433#endif34 35#ifndef _IOC_DIRBITS36# define _IOC_DIRBITS 237#endif38 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 045#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 override51 * before including this file.52 *53 * NOTE: _IOC_WRITE means userland is writing and kernel is54 * reading. _IOC_READ means userland is reading and kernel is writing.55 */56 57#ifndef _IOC_NONE58# define _IOC_NONE 0U59#endif60 61#ifndef _IOC_WRITE62# define _IOC_WRITE 1U63#endif64 65#ifndef _IOC_READ66# define _IOC_READ 2U67#endif68 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#ifndef __KERNEL__76#define _IOC_TYPECHECK(t) (sizeof(t))77#endif78 79/*80 * Used to create numbers.81 *82 * NOTE: _IOW means userland is writing and kernel is reading. _IOR83 * means userland is reading and kernel is writing.84 */85#define _IO(type,nr) _IOC(_IOC_NONE,(type),(nr),0)86#define _IOR(type,nr,size) _IOC(_IOC_READ,(type),(nr),(_IOC_TYPECHECK(size)))87#define _IOW(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))88#define _IOWR(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))89#define _IOR_BAD(type,nr,size) _IOC(_IOC_READ,(type),(nr),sizeof(size))90#define _IOW_BAD(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),sizeof(size))91#define _IOWR_BAD(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))92 93/* used to decode ioctl numbers.. */94#define _IOC_DIR(nr) (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)95#define _IOC_TYPE(nr) (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)96#define _IOC_NR(nr) (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)97#define _IOC_SIZE(nr) (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)98 99/* ...and for the drivers/sound files... */100 101#define IOC_IN (_IOC_WRITE << _IOC_DIRSHIFT)102#define IOC_OUT (_IOC_READ << _IOC_DIRSHIFT)103#define IOC_INOUT ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)104#define IOCSIZE_MASK (_IOC_SIZEMASK << _IOC_SIZESHIFT)105#define IOCSIZE_SHIFT (_IOC_SIZESHIFT)106 107#endif /* _UAPI_ASM_GENERIC_IOCTL_H */108