1 /* 
2  * Some notes on locking:
3  *
4  *	All the locking woes come from implementing
5  *	threadinterrupt (and threadkill).
6  *
7  *	_threadgetproc()->thread is always a live pointer.
8  *	p->threads, p->ready, and _threadrgrp also contain
9  * 	live thread pointers.  These may only be consulted
10  *	while holding p->lock or _threadrgrp.lock; in procs
11  *	other than p, the pointers are only guaranteed to be live
12  *	while the lock is still being held.
13  *
14  *	Thread structures can only be freed by the proc
15  *	they belong to.  Threads marked with t->inrendez
16  * 	need to be extracted from the _threadrgrp before
17  *	being freed.
18  *
19  *	_threadrgrp.lock cannot be acquired while holding p->lock.
20  */
21 
22 #include <assert.h>
23 #include <lib9.h>
24 #include <thread.h>
25 #include "label.h"
26 
27 enum{
28 STKSIZE = 16384,
29 STKMAGIC = 0xCAFEBEEF
30 };
31 
32 typedef struct Thread	Thread;
33 typedef struct Proc	Proc;
34 typedef struct Tqueue	Tqueue;
35 typedef struct Pqueue	Pqueue;
36 typedef struct Rgrp		Rgrp;
37 typedef struct Execargs	Execargs;
38 
39 /* must match list in sched.c */
40 typedef enum
41 {
42 	Dead,
43 	Running,
44 	Ready,
45 	Rendezvous,
46 } State;
47 	
48 typedef enum
49 {
50 	Channone,
51 	Chanalt,
52 	Chansend,
53 	Chanrecv,
54 } Chanstate;
55 
56 enum
57 {
58 	RENDHASH = 10009,
59 	Printsize = 2048,
60 	NPRIV = 8,
61 };
62 
63 struct Rgrp
64 {
65 	Lock		lock;
66 	Thread	*hash[RENDHASH];
67 };
68 
69 struct Tqueue		/* Thread queue */
70 {
71 	int		asleep;
72 	Thread	*head;
73 	Thread	*tail;
74 };
75 
76 struct Thread
77 {
78 	Lock		lock;			/* protects thread data structure */
79 	Label	sched;		/* for context switches */
80 	int		id;			/* thread id */
81 	int 		grp;			/* thread group */
82 	int		moribund;	/* thread needs to die */
83 	State		state;		/* run state */
84 	State		nextstate;		/* next run state */
85 	uchar	*stk;			/* top of stack (lowest address of stack) */
86 	uint		stksize;		/* stack size */
87 	Thread	*next;		/* next on ready queue */
88 
89 	Proc		*proc;		/* proc of this thread */
90 	Thread	*nextt;		/* next on list of threads in this proc */
91 	Thread	*prevt;		/* prev on list of threads in this proc */
92 	int		ret;			/* return value for Exec, Fork */
93 
94 	char		*cmdname;	/* ptr to name of thread */
95 
96 	int		inrendez;
97 	Thread	*rendhash;	/* Trgrp linked list */
98 	ulong	rendtag;		/* rendezvous tag */
99 	ulong	rendval;		/* rendezvous value */
100 	int		rendbreak;	/* rendezvous has been taken */
101 
102 	Chanstate	chan;		/* which channel operation is current */
103 	Alt		*alt;			/* pointer to current alt structure (debugging) */
104 
105 	void*	udata[NPRIV];	/* User per-thread data pointer */
106 };
107 
108 struct Execargs
109 {
110 	char		*prog;
111 	char		**args;
112 	int		fd[2];
113 };
114 
115 struct Proc
116 {
117 	Lock		lock;
118 	Label	sched;		/* for context switches */
119 	Proc		*link;		/* in proctab */
120 	int		pid;			/* process id */
121 	int		splhi;		/* delay notes */
122 	Thread	*thread;		/* running thread */
123 
124 	int		needexec;
125 	Execargs	exec;		/* exec argument */
126 	Proc		*newproc;	/* fork argument */
127 	char		exitstr[ERRMAX];	/* exit status */
128 
129 	int		rforkflag;
130 	int		nthreads;
131 	Tqueue	threads;		/* All threads of this proc */
132 	Tqueue	ready;		/* Runnable threads */
133 	Lock		readylock;
134 
135 	char		printbuf[Printsize];
136 	int		blocked;		/* In a rendezvous */
137 	int		pending;		/* delayed note pending */
138 	int		nonotes;		/*  delay notes */
139 	uint		nextID;		/* ID of most recently created thread */
140 	Proc		*next;		/* linked list of Procs */
141 
142 	void		*arg;			/* passed between shared and unshared stk */
143 	char		str[ERRMAX];	/* used by threadexits to avoid malloc */
144 	char		errbuf[ERRMAX];	/* errstr */
145 
146 	void*	udata;		/* User per-proc data pointer */
147 };
148 
149 struct Pqueue {		/* Proc queue */
150 	Lock		lock;
151 	Proc		*head;
152 	Proc		**tail;
153 };
154 
155 struct Ioproc
156 {
157 	int tid;
158 	Channel *c, *creply;
159 	int inuse;
160 	long (*op)(va_list*);
161 	va_list arg;
162 	long ret;
163 	char err[ERRMAX];
164 	Ioproc *next;
165 };
166 
167 void		_gotolabel(Label*);
168 int		_setlabel(Label*);
169 void		_freeproc(Proc*);
170 Proc*	_newproc(void(*)(void*), void*, uint, char*, int, int);
171 int		_procsplhi(void);
172 void		_procsplx(int);
173 void		_sched(void);
174 int		_schedexec(Execargs*);
175 void		_schedexecwait(void);
176 void		_schedexit(Proc*);
177 int		_schedfork(Proc*);
178 void		_schedinit(void*);
179 void		_systhreadinit(void);
180 void		_threadassert(char*);
181 void		_threadbreakrendez(void);
182 void		__threaddebug(ulong, char*, ...);
183 #define _threaddebug if(!_threaddebuglevel){}else __threaddebug
184 void		_threadexitsall(char*);
185 void		_threadflagrendez(Thread*);
186 Proc*	_threadgetproc(void);
187 Proc*	_threaddelproc(void);
188 void		_threadsetproc(Proc*);
189 void		_threadinitstack(Thread*, void(*)(void*), void*);
190 void*	_threadmalloc(long, int);
191 void		_threadnote(void*, char*);
192 void		_threadready(Thread*);
193 ulong	_threadrendezvous(ulong, ulong);
194 void		_threadsignal(void);
195 void		_threadsysfatal(char*, va_list);
196 long		_xdec(long*);
197 void		_xinc(long*);
198 void		_threadremove(Proc*, Thread*);
199 
200 extern int			_threaddebuglevel;
201 extern char*		_threadexitsallstatus;
202 extern Pqueue		_threadpq;
203 extern Channel*	_threadwaitchan;
204 extern Rgrp		_threadrgrp;
205 extern void _stackfree(void*);
206 
207 #define DBGAPPL	(1 << 0)
208 #define DBGSCHED	(1 << 16)
209 #define DBGCHAN	(1 << 17)
210 #define DBGREND	(1 << 18)
211 /* #define DBGKILL	(1 << 19) */
212 #define DBGNOTE	(1 << 20)
213 #define DBGEXEC	(1 << 21)
214 
215 #define ioproc_arg(io, type)	(va_arg((io)->arg, type))
216 extern int _threadgetpid(void);
217 extern void _threadmemset(void*, int, int);
218 extern void _threaddebugmemset(void*, int, int);
219