I/O Subsystem. More...

Collaboration diagram for I/O Subsystem:

Detailed Description

I/O Subsystem.

The I/O subsystem is responsible for asynchronous input and output operations within PatchworkOS.

Modules
	I/O Request Packet
	I/O Request Packet.

	Kernel-side I/O Ring Interface
	Programmable submission/completion interface.

Data Structures
struct	sqe_t
	Asynchronous submission queue entry (SQE). More...

struct	cqe_t
	Asynchronous completion queue entry (CQE). More...

struct	ioring_ctrl_t
	Shared ring control structure. More...

Macros
#define	IO_OFF_CUR ((ssize_t) - 1)
	Use the current file offset.

#define	IO_SEEK_SET (1)
	Use the start of the file.

#define	IO_SEEK_END (2)
	Use the end of the file.

#define	IO_SEEK_CUR (3)
	Use the current file offset.

#define	IO_POLL_READ (1 << 0)
	File descriptor is ready to read.

#define	IO_POLL_WRITE (1 << 1)
	File descriptor is ready to write.

#define	IO_POLL_ERROR (1 << 2)
	File descriptor caused an error.

#define	IO_POLL_HUP (1 << 3)
	File descriptor is closed.

#define	IO_POLL_NVAL (1 << 4)
	Invalid file descriptor.

#define	IO_OP_NOP 0
	No-op operation.

#define	IO_OP_READ 1
	Read operation.

#define	IO_OP_WRITE 2
	Write operation.

#define	IO_OP_POLL 3
	Poll operation.

#define	IO_OP_MAX 4
	The maximum number of operation.

#define	SQE_REG0 (0)
	The first register.

#define	SQE_REG1 (1)
	The second register.

#define	SQE_REG2 (2)
	The third register.

#define	SQE_REG3 (3)
	The fourth register.

#define	SQE_REG4 (4)
	The fifth register.

#define	SQE_REG5 (5)
	The sixth register.

#define	SQE_REG6 (6)
	The seventh register.

#define	SQE_REG_NONE (7)
	No register.

#define	SQE_REGS_MAX (7)
	The maximum number of registers.

#define	SQE_REG_SHIFT (3)
	The bitshift for each register specifier in a `sqe_flags_t`.

#define	SQE_REG_MASK (0b111)
	The bitmask for a register specifier in a `sqe_flags_t`.

#define	SQE_LOAD0 (0)
	The offset to specify the register to load into the first argument.

#define	SQE_LOAD1 (SQE_LOAD0 + SQE_REG_SHIFT)
	The offset to specify the register to load into the second argument.

#define	SQE_LOAD2 (SQE_LOAD1 + SQE_REG_SHIFT)
	The offset to specify the register to load into the third argument.

#define	SQE_LOAD3 (SQE_LOAD2 + SQE_REG_SHIFT)
	The offset to specify the register to load into the fourth argument.

#define	SQE_LOAD4 (SQE_LOAD3 + SQE_REG_SHIFT)
	The offset to specify the register to load into the fifth argument.

#define	SQE_SAVE (SQE_LOAD4 + SQE_REG_SHIFT)
	The offset to specify the register to save the result into.

#define	_SQE_FLAGS (SQE_SAVE + SQE_REG_SHIFT)
	The bitshift for where bit flags start in a `sqe_flags_t`.

#define	SQE_LINK (1 << (_SQE_FLAGS))

#define	SQE_HARDLINK (1 << (_SQE_FLAGS + 1))

#define	SQE_CREATE(_op, _flags, _timeout, _data)
	Macro to create an asynchronous submission queue entry (SQE).

Typedefs
typedef uint64_t	io_whence_t
	Seek origin type.

typedef uint64_t	io_events_t
	Poll events type.

typedef uint32_t	io_op_t
	I/O operation code type.

typedef uint32_t	sqe_flags_t
	Submission queue entry (SQE) flags.

Functions
struct	ALIGNED (64) ioring_ctrl

Variables
	ioring_ctrl_t

Macro Definition Documentation

◆ IO_OFF_CUR

#define IO_OFF_CUR ((ssize_t) - 1)

Use the current file offset.

Definition at line 27 of file ioring.h.

◆ IO_SEEK_SET

#define IO_SEEK_SET (1)

Use the start of the file.

Definition at line 30 of file ioring.h.

◆ IO_SEEK_END

#define IO_SEEK_END (2)

Use the end of the file.

Definition at line 31 of file ioring.h.

◆ IO_SEEK_CUR

#define IO_SEEK_CUR (3)

Use the current file offset.

Definition at line 32 of file ioring.h.

◆ IO_POLL_READ

#define IO_POLL_READ (1 << 0)

File descriptor is ready to read.

Definition at line 35 of file ioring.h.

◆ IO_POLL_WRITE

#define IO_POLL_WRITE (1 << 1)

File descriptor is ready to write.

Definition at line 36 of file ioring.h.

◆ IO_POLL_ERROR

#define IO_POLL_ERROR (1 << 2)

File descriptor caused an error.

Definition at line 37 of file ioring.h.

◆ IO_POLL_HUP

#define IO_POLL_HUP (1 << 3)

File descriptor is closed.

Definition at line 38 of file ioring.h.

◆ IO_POLL_NVAL

#define IO_POLL_NVAL (1 << 4)

Invalid file descriptor.

Definition at line 39 of file ioring.h.

◆ IO_OP_NOP

#define IO_OP_NOP 0

No-op operation.

Definition at line 42 of file ioring.h.

◆ IO_OP_READ

#define IO_OP_READ 1

Read operation.

Definition at line 43 of file ioring.h.

◆ IO_OP_WRITE

#define IO_OP_WRITE 2

Write operation.

Definition at line 44 of file ioring.h.

◆ IO_OP_POLL

#define IO_OP_POLL 3

Poll operation.

Definition at line 45 of file ioring.h.

◆ IO_OP_MAX

#define IO_OP_MAX 4

The maximum number of operation.

Definition at line 46 of file ioring.h.

◆ SQE_REG0

#define SQE_REG0 (0)

The first register.

Definition at line 49 of file ioring.h.

◆ SQE_REG1

#define SQE_REG1 (1)

The second register.

Definition at line 50 of file ioring.h.

◆ SQE_REG2

#define SQE_REG2 (2)

The third register.

Definition at line 51 of file ioring.h.

◆ SQE_REG3

#define SQE_REG3 (3)

The fourth register.

Definition at line 52 of file ioring.h.

◆ SQE_REG4

#define SQE_REG4 (4)

The fifth register.

Definition at line 53 of file ioring.h.

◆ SQE_REG5

#define SQE_REG5 (5)

The sixth register.

Definition at line 54 of file ioring.h.

◆ SQE_REG6

#define SQE_REG6 (6)

The seventh register.

Definition at line 55 of file ioring.h.

◆ SQE_REG_NONE

#define SQE_REG_NONE (7)

No register.

Definition at line 56 of file ioring.h.

◆ SQE_REGS_MAX

#define SQE_REGS_MAX (7)

The maximum number of registers.

Definition at line 57 of file ioring.h.

◆ SQE_REG_SHIFT

#define SQE_REG_SHIFT (3)

The bitshift for each register specifier in a sqe_flags_t.

Definition at line 58 of file ioring.h.

◆ SQE_REG_MASK

#define SQE_REG_MASK (0b111)

The bitmask for a register specifier in a sqe_flags_t.

Definition at line 59 of file ioring.h.

◆ SQE_LOAD0

#define SQE_LOAD0 (0)

The offset to specify the register to load into the first argument.

Definition at line 61 of file ioring.h.

◆ SQE_LOAD1

#define SQE_LOAD1 (SQE_LOAD0 + SQE_REG_SHIFT)

The offset to specify the register to load into the second argument.

Definition at line 62 of file ioring.h.

◆ SQE_LOAD2

#define SQE_LOAD2 (SQE_LOAD1 + SQE_REG_SHIFT)

The offset to specify the register to load into the third argument.

Definition at line 63 of file ioring.h.

◆ SQE_LOAD3

#define SQE_LOAD3 (SQE_LOAD2 + SQE_REG_SHIFT)

The offset to specify the register to load into the fourth argument.

Definition at line 64 of file ioring.h.

◆ SQE_LOAD4

#define SQE_LOAD4 (SQE_LOAD3 + SQE_REG_SHIFT)

The offset to specify the register to load into the fifth argument.

Definition at line 65 of file ioring.h.

◆ SQE_SAVE

#define SQE_SAVE (SQE_LOAD4 + SQE_REG_SHIFT)

The offset to specify the register to save the result into.

Definition at line 66 of file ioring.h.

◆ _SQE_FLAGS

#define _SQE_FLAGS (SQE_SAVE + SQE_REG_SHIFT)

The bitshift for where bit flags start in a sqe_flags_t.

Definition at line 68 of file ioring.h.

◆ SQE_LINK

#define SQE_LINK (1 << (_SQE_FLAGS))

Only process the next SQE when this one completes successfully) only applies within one enter() call.

Definition at line 73 of file ioring.h.

◆ SQE_HARDLINK

#define SQE_HARDLINK (1 << (_SQE_FLAGS + 1))

Like SQE_LINK but will process the next SQE even if this one fails.

Definition at line 77 of file ioring.h.

◆ SQE_CREATE

#define SQE_CREATE	(	_op,
		_flags,
		_timeout,
		_data
	)

Value:

    { \
        .op = (_op), \
        .flags = (_flags), \
        .timeout = (_timeout), \
        .data = (void*)(_data), \
    }

Macro to create an asynchronous submission queue entry (SQE).

Parameters

_op	The operation to perform.
_flags	Submission flags.
_timeout	Timeout for the operation, `CLOCKS_NEVER` for no timeout.
_data	Private data for the operation.

Definition at line 128 of file ioring.h.

Typedef Documentation

◆ io_whence_t

typedef uint64_t io_whence_t

Seek origin type.

Definition at line 29 of file ioring.h.

◆ io_events_t

typedef uint64_t io_events_t

Poll events type.

Definition at line 34 of file ioring.h.

◆ io_op_t

typedef uint32_t io_op_t

I/O operation code type.

Definition at line 41 of file ioring.h.

◆ sqe_flags_t

typedef uint32_t sqe_flags_t

Submission queue entry (SQE) flags.

Definition at line 48 of file ioring.h.

Function Documentation

◆ ALIGNED()

struct ALIGNED ( 64 )

< Submission head index, updated by the kernel.

< Completion tail index, updated by the kernel.

< Submission tail index, updated by userspace.

< Completion head index, updated by userspace.

< General purpose registers.