xref: /dragonfly/sys/sys/msgport.h (revision 1ab20d67)
1 /*
2  * SYS/MSGPORT.H
3  *
4  *	Implements LWKT messages and ports.
5  *
6  * $DragonFly: src/sys/sys/msgport.h,v 1.17 2004/04/20 01:52:24 dillon Exp $
7  */
8 
9 #ifndef _SYS_MSGPORT_H_
10 #define _SYS_MSGPORT_H_
11 
12 #ifndef _SYS_QUEUE_H_
13 #include <sys/queue.h>		/* TAILQ_* macros */
14 #endif
15 #ifndef _SYS_STDINT_H_
16 #include <sys/stdint.h>
17 #endif
18 
19 struct lwkt_msg;
20 struct lwkt_port;
21 struct thread;
22 
23 typedef struct lwkt_msg		*lwkt_msg_t;
24 typedef struct lwkt_port	*lwkt_port_t;
25 
26 typedef TAILQ_HEAD(lwkt_msg_queue, lwkt_msg) lwkt_msg_queue;
27 
28 /*
29  * LWKT command message operator type.  This type holds a message's
30  * 'command'.  The command format is opaque to the LWKT messaging system,
31  * meaning that it is specific to whatever convention the API chooses.
32  * By convention lwkt_cmd_t is passed by value and is expected to
33  * efficiently fit into a machine register.
34  */
35 typedef union lwkt_cmd {
36     int		cm_op;
37     int		(*cm_func)(lwkt_msg_t msg);
38 } lwkt_cmd_t;
39 
40 /*
41  * The standard message and port structure for communications between
42  * threads.  See kern/lwkt_msgport.c for documentation on how messages and
43  * ports work.
44  *
45  * For the most part a message may only be manipulated by whomever currently
46  * owns it, which generally means the originating port if the message has
47  * not been sent yet or has been replied, and the target port if the message
48  * has been sent and/or is undergoing processing.
49  *
50  * The one exception to this rule is an abort.  Aborts must be initiated
51  * by the originator and may 'chase' the target (especially if a message
52  * is being forwarded), potentially even 'chase' the message all the way
53  * back to the originator if it races against the target replying the
54  * message.  The ms_abort_port field is the only field that may be modified
55  * by the originator or intermediate target (when the abort is chasing
56  * a forwarding or reply op).  An abort may cause a reply to be delayed
57  * until the abort catches up to it.
58  *
59  * Messages which support an abort will have MSGF_ABORTABLE set, indicating
60  * that the ms_abort field has been initialized.  An abort will cause a
61  * message to be requeued to the target port so the target sees the same
62  * message twice:  once during initial processing of the message, and a
63  * second time to process the abort request.  lwkt_getport() will detect
64  * the requeued abort and will copy ms_abort into ms_cmd before returning
65  * the requeued message the second time.  This makes target processing a
66  * whole lot less complex.
67  *
68  * NOTE! 64-bit-align this structure.
69  */
70 typedef struct lwkt_msg {
71     TAILQ_ENTRY(lwkt_msg) ms_node;	/* link node (see note above) */
72     union {
73 	struct lwkt_msg *ms_next;	/* chaining / cache */
74 	union sysunion	*ms_sysunnext;	/* chaining / cache */
75 	struct lwkt_msg	*ms_umsg;	/* user message (UVA address) */
76     } opaque;
77     lwkt_port_t ms_target_port;		/* current target or relay port */
78     lwkt_port_t	ms_reply_port;		/* async replies returned here */
79     lwkt_port_t ms_abort_port;		/* abort chasing port */
80     lwkt_cmd_t	ms_cmd;			/* message command operator */
81     lwkt_cmd_t	ms_abort;		/* message abort operator */
82     int		ms_flags;		/* message flags */
83 #define ms_copyout_start	ms_msgsize
84     int		ms_msgsize;		/* size of message */
85     int		ms_error;		/* positive error code or 0 */
86     union {
87 	void	*ms_resultp;		/* misc pointer data or result */
88 	int	ms_result;		/* standard 'int'eger result */
89 	long	ms_lresult;		/* long result */
90 	int	ms_fds[2];		/* two int bit results */
91 	__int32_t ms_result32;		/* 32 bit result */
92 	__int64_t ms_result64;		/* 64 bit result */
93 	__off_t	ms_offset;		/* off_t result */
94     } u;
95 #define ms_copyout_end	ms_pad[0]
96     int		ms_pad[2];		/* future use */
97 } lwkt_msg;
98 
99 #define ms_copyout_size	(offsetof(struct lwkt_msg, ms_copyout_end) - offsetof(struct lwkt_msg, ms_copyout_start))
100 
101 #define MSGF_DONE	0x0001		/* asynch message is complete */
102 #define MSGF_REPLY1	0x0002		/* asynch message has been returned */
103 #define MSGF_QUEUED	0x0004		/* message has been queued sanitychk */
104 #define MSGF_ASYNC	0x0008		/* sync/async hint */
105 #define MSGF_ABORTED	0x0010		/* indicate pending abort */
106 #define MSGF_PCATCH	0x0020		/* catch proc signal while waiting */
107 #define MSGF_REPLY2	0x0040		/* reply processed by rport cpu */
108 #define MSGF_ABORTABLE	0x0080		/* message supports abort */
109 #define MSGF_RETRIEVED	0x0100		/* message retrieved on target */
110 
111 #define MSG_CMD_CDEV	0x00010000
112 #define MSG_CMD_VFS	0x00020000
113 #define MSG_CMD_SYSCALL	0x00030000
114 #define MSG_SUBCMD_MASK	0x0000FFFF
115 
116 #ifdef _KERNEL
117 #ifdef MALLOC_DECLARE
118 MALLOC_DECLARE(M_LWKTMSG);
119 #endif
120 #endif
121 
122 typedef struct lwkt_port {
123     lwkt_msg_queue	mp_msgq;
124     int			mp_flags;
125     int			mp_refs;	/* references to port structure */
126     struct thread	*mp_td;
127     int			(*mp_putport)(lwkt_port_t, lwkt_msg_t);
128     void *		(*mp_waitport)(lwkt_port_t, lwkt_msg_t);
129     void		(*mp_replyport)(lwkt_port_t, lwkt_msg_t);
130     void		(*mp_abortport)(lwkt_port_t, lwkt_msg_t);
131 } lwkt_port;
132 
133 #define MSGPORTF_WAITING	0x0001
134 
135 /*
136  * These functions are good for userland as well as the kernel.  The
137  * messaging function support for userland is provided by the kernel's
138  * kern/lwkt_msgport.c.  The port functions are provided by userland.
139  */
140 void lwkt_initport(lwkt_port_t, struct thread *);
141 void lwkt_sendmsg(lwkt_port_t, lwkt_msg_t);
142 int lwkt_domsg(lwkt_port_t, lwkt_msg_t);
143 int lwkt_forwardmsg(lwkt_port_t, lwkt_msg_t);
144 void lwkt_abortmsg(lwkt_msg_t);
145 void *lwkt_getport(lwkt_port_t);
146 
147 int lwkt_default_putport(lwkt_port_t port, lwkt_msg_t msg);
148 void *lwkt_default_waitport(lwkt_port_t port, lwkt_msg_t msg);
149 void lwkt_default_replyport(lwkt_port_t port, lwkt_msg_t msg);
150 void lwkt_default_abortport(lwkt_port_t port, lwkt_msg_t msg);
151 
152 #endif
153