syscall.c 6.6 KB

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  1. #include "u.h"
  2. #include "../port/lib.h"
  3. #include "mem.h"
  4. #include "dat.h"
  5. #include "fns.h"
  6. #include "../port/error.h"
  7. #include "../port/systab.h"
  8. #include <tos.h>
  9. #include "ureg.h"
  10. #include "arm.h"
  11. typedef struct {
  12. uintptr ip;
  13. Ureg* arg0;
  14. char* arg1;
  15. char msg[ERRMAX];
  16. Ureg* old;
  17. Ureg ureg;
  18. } NFrame;
  19. /*
  20. * Return user to state before notify()
  21. */
  22. static void
  23. noted(Ureg* cur, uintptr arg0)
  24. {
  25. NFrame *nf;
  26. Ureg *nur;
  27. qlock(&up->debug);
  28. if(arg0 != NRSTR && !up->notified){
  29. qunlock(&up->debug);
  30. pprint("call to noted() when not notified\n");
  31. pexit("Suicide", 0);
  32. }
  33. up->notified = 0;
  34. fpunoted();
  35. nf = up->ureg;
  36. /* sanity clause */
  37. if(!okaddr(PTR2UINT(nf), sizeof(NFrame), 0)){
  38. qunlock(&up->debug);
  39. pprint("bad ureg in noted %#p\n", nf);
  40. pexit("Suicide", 0);
  41. }
  42. /* don't let user change system flags */
  43. nur = &nf->ureg;
  44. nur->psr &= PsrMask|PsrDfiq|PsrDirq;
  45. nur->psr |= (cur->psr & ~(PsrMask|PsrDfiq|PsrDirq));
  46. memmove(cur, nur, sizeof(Ureg));
  47. switch((int)arg0){
  48. case NCONT:
  49. case NRSTR:
  50. if(!okaddr(nur->pc, BY2WD, 0) || !okaddr(nur->sp, BY2WD, 0)){
  51. qunlock(&up->debug);
  52. pprint("suicide: trap in noted\n");
  53. pexit("Suicide", 0);
  54. }
  55. up->ureg = nf->old;
  56. qunlock(&up->debug);
  57. break;
  58. case NSAVE:
  59. if(!okaddr(nur->pc, BY2WD, 0) || !okaddr(nur->sp, BY2WD, 0)){
  60. qunlock(&up->debug);
  61. pprint("suicide: trap in noted\n");
  62. pexit("Suicide", 0);
  63. }
  64. qunlock(&up->debug);
  65. splhi();
  66. nf->arg1 = nf->msg;
  67. nf->arg0 = &nf->ureg;
  68. nf->ip = 0;
  69. cur->sp = PTR2UINT(nf);
  70. break;
  71. default:
  72. pprint("unknown noted arg %#p\n", arg0);
  73. up->lastnote.flag = NDebug;
  74. /*FALLTHROUGH*/
  75. case NDFLT:
  76. if(up->lastnote.flag == NDebug){
  77. qunlock(&up->debug);
  78. pprint("suicide: %s\n", up->lastnote.msg);
  79. }
  80. else
  81. qunlock(&up->debug);
  82. pexit(up->lastnote.msg, up->lastnote.flag != NDebug);
  83. }
  84. }
  85. /*
  86. * Call user, if necessary, with note.
  87. * Pass user the Ureg struct and the note on his stack.
  88. */
  89. int
  90. notify(Ureg* ureg)
  91. {
  92. int l;
  93. Note *n;
  94. u32int s;
  95. uintptr sp;
  96. NFrame *nf;
  97. if(up->procctl)
  98. procctl(up);
  99. if(up->nnote == 0)
  100. return 0;
  101. fpunotify(ureg);
  102. s = spllo();
  103. qlock(&up->debug);
  104. up->notepending = 0;
  105. n = &up->note[0];
  106. if(strncmp(n->msg, "sys:", 4) == 0){
  107. l = strlen(n->msg);
  108. if(l > ERRMAX-23) /* " pc=0x0123456789abcdef\0" */
  109. l = ERRMAX-23;
  110. snprint(n->msg + l, sizeof n->msg - l, " pc=%#lux", ureg->pc);
  111. }
  112. if(n->flag != NUser && (up->notified || up->notify == 0)){
  113. if(n->flag == NDebug)
  114. pprint("suicide: %s\n", n->msg);
  115. qunlock(&up->debug);
  116. pexit(n->msg, n->flag != NDebug);
  117. }
  118. if(up->notified){
  119. qunlock(&up->debug);
  120. splhi();
  121. return 0;
  122. }
  123. if(up->notify == nil){
  124. qunlock(&up->debug);
  125. pexit(n->msg, n->flag != NDebug);
  126. }
  127. if(!okaddr(PTR2UINT(up->notify), 1, 0)){
  128. pprint("suicide: notify function address %#p\n", up->notify);
  129. qunlock(&up->debug);
  130. pexit("Suicide", 0);
  131. }
  132. sp = ureg->sp - sizeof(NFrame);
  133. if(!okaddr(sp, sizeof(NFrame), 1)){
  134. qunlock(&up->debug);
  135. pprint("suicide: notify stack address %#p\n", sp);
  136. pexit("Suicide", 0);
  137. }
  138. nf = UINT2PTR(sp);
  139. memmove(&nf->ureg, ureg, sizeof(Ureg));
  140. nf->old = up->ureg;
  141. up->ureg = nf;
  142. memmove(nf->msg, up->note[0].msg, ERRMAX);
  143. nf->arg1 = nf->msg;
  144. nf->arg0 = &nf->ureg;
  145. nf->ip = 0;
  146. ureg->sp = sp;
  147. ureg->pc = PTR2UINT(up->notify);
  148. up->notified = 1;
  149. up->nnote--;
  150. memmove(&up->lastnote, &up->note[0], sizeof(Note));
  151. memmove(&up->note[0], &up->note[1], up->nnote*sizeof(Note));
  152. qunlock(&up->debug);
  153. splx(s);
  154. return 1;
  155. }
  156. void
  157. syscall(Ureg* ureg)
  158. {
  159. char *e;
  160. u32int s;
  161. ulong sp;
  162. long ret;
  163. int i, scallnr;
  164. if(!userureg(ureg))
  165. panic("syscall: from kernel: pc %#lux r14 %#lux psr %#lux",
  166. ureg->pc, ureg->r14, ureg->psr);
  167. cycles(&up->kentry);
  168. m->syscall++;
  169. up->insyscall = 1;
  170. up->pc = ureg->pc;
  171. up->dbgreg = ureg;
  172. if(up->procctl == Proc_tracesyscall){
  173. up->procctl = Proc_stopme;
  174. procctl(up);
  175. }
  176. scallnr = ureg->r0;
  177. up->scallnr = scallnr;
  178. if(scallnr == RFORK)
  179. fpusysrfork(ureg);
  180. spllo();
  181. sp = ureg->sp;
  182. up->nerrlab = 0;
  183. ret = -1;
  184. if(!waserror()){
  185. if(scallnr >= nsyscall){
  186. pprint("bad sys call number %d pc %#lux\n",
  187. scallnr, ureg->pc);
  188. postnote(up, 1, "sys: bad sys call", NDebug);
  189. error(Ebadarg);
  190. }
  191. if(sp < (USTKTOP-BY2PG) || sp > (USTKTOP-sizeof(Sargs)-BY2WD))
  192. validaddr(sp, sizeof(Sargs)+BY2WD, 0);
  193. up->s = *((Sargs*)(sp+BY2WD));
  194. up->psstate = sysctab[scallnr];
  195. /* iprint("%s: syscall %s\n", up->text, sysctab[scallnr]?sysctab[scallnr]:"huh?"); */
  196. ret = systab[scallnr](up->s.args);
  197. poperror();
  198. }else{
  199. /* failure: save the error buffer for errstr */
  200. e = up->syserrstr;
  201. up->syserrstr = up->errstr;
  202. up->errstr = e;
  203. }
  204. if(up->nerrlab){
  205. print("bad errstack [%d]: %d extra\n", scallnr, up->nerrlab);
  206. for(i = 0; i < NERR; i++)
  207. print("sp=%#p pc=%#p\n",
  208. up->errlab[i].sp, up->errlab[i].pc);
  209. panic("error stack");
  210. }
  211. /*
  212. * Put return value in frame. On the x86 the syscall is
  213. * just another trap and the return value from syscall is
  214. * ignored. On other machines the return value is put into
  215. * the results register by caller of syscall.
  216. */
  217. ureg->r0 = ret;
  218. if(up->procctl == Proc_tracesyscall){
  219. up->procctl = Proc_stopme;
  220. s = splhi();
  221. procctl(up);
  222. splx(s);
  223. }
  224. up->insyscall = 0;
  225. up->psstate = 0;
  226. if(scallnr == NOTED)
  227. noted(ureg, *(ulong*)(sp+BY2WD));
  228. splhi();
  229. if(scallnr != RFORK && (up->procctl || up->nnote))
  230. notify(ureg);
  231. /* if we delayed sched because we held a lock, sched now */
  232. if(up->delaysched){
  233. sched();
  234. splhi();
  235. }
  236. kexit(ureg);
  237. }
  238. long /* void* */
  239. execregs(ulong entry, ulong ssize, ulong nargs)
  240. {
  241. ulong *sp;
  242. Ureg *ureg;
  243. sp = (ulong*)(USTKTOP - ssize);
  244. *--sp = nargs;
  245. ureg = up->dbgreg;
  246. // memset(ureg, 0, 15*sizeof(ulong));
  247. ureg->r13 = (ulong)sp;
  248. ureg->pc = entry;
  249. //print("%lud: EXECREGS pc %#ux sp %#ux nargs %ld\n", up->pid, ureg->pc, ureg->r13, nargs);
  250. /*
  251. * return the address of kernel/user shared data
  252. * (e.g. clock stuff)
  253. */
  254. return USTKTOP-sizeof(Tos);
  255. }
  256. void
  257. sysprocsetup(Proc* p)
  258. {
  259. fpusysprocsetup(p);
  260. }
  261. /*
  262. * Craft a return frame which will cause the child to pop out of
  263. * the scheduler in user mode with the return register zero. Set
  264. * pc to point to a l.s return function.
  265. */
  266. void
  267. forkchild(Proc *p, Ureg *ureg)
  268. {
  269. Ureg *cureg;
  270. //print("%lud setting up for forking child %lud\n", up->pid, p->pid);
  271. p->sched.sp = (ulong)p->kstack+KSTACK-sizeof(Ureg);
  272. p->sched.pc = (ulong)forkret;
  273. cureg = (Ureg*)(p->sched.sp);
  274. memmove(cureg, ureg, sizeof(Ureg));
  275. /* syscall returns 0 for child */
  276. cureg->r0 = 0;
  277. /* Things from bottom of syscall which were never executed */
  278. p->psstate = 0;
  279. p->insyscall = 0;
  280. fpusysrforkchild(p, cureg, up);
  281. }