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  1. /*
  2.  * Copyright (C) 2006 Ondrej Palkovsky
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. #include <libadt/list.h>
  30. #include <psthread.h>
  31. #include <malloc.h>
  32. #include <unistd.h>
  33. #include <thread.h>
  34. #include <stdio.h>
  35. #include <kernel/arch/faddr.h>
  36.  
  37.  
  38. #ifndef PSTHREAD_INITIAL_STACK_PAGES_NO
  39. #define PSTHREAD_INITIAL_STACK_PAGES_NO 1
  40. #endif
  41.  
  42. static LIST_INITIALIZE(ready_list);
  43.  
  44. static void psthread_exit(void) __attribute__ ((noinline));
  45. static void psthread_main(void);
  46.  
  47. /** Setup PSthread information into TCB structure */
  48. psthread_data_t * psthread_setup(tcb_t *tcb)
  49. {
  50.     psthread_data_t *pt;
  51.  
  52.     pt = malloc(sizeof(*pt));
  53.     if (!pt) {
  54.         return NULL;
  55.     }
  56.  
  57.     tcb->pst_data = pt;
  58.     pt->tcb = tcb;
  59.  
  60.     return pt;
  61. }
  62.  
  63. void psthread_teardown(psthread_data_t *pt)
  64. {
  65.     free(pt);
  66. }
  67.  
  68. /** Function to preempt to other pseudo thread without adding
  69.  * currently running pseudo thread to ready_list.
  70.  */
  71. void psthread_exit(void)
  72. {
  73.     psthread_data_t *pt;
  74.  
  75.     if (list_empty(&ready_list)) {
  76.         /* Wait on IPC queue etc... */
  77.         printf("Cannot exit!!!\n");
  78.         _exit(0);
  79.     }
  80.     pt = list_get_instance(ready_list.next, psthread_data_t, link);
  81.     list_remove(&pt->link);
  82.     context_restore(&pt->ctx);
  83. }
  84.  
  85. /** Function that is called on entry to new uspace thread */
  86. void psthread_main(void)
  87. {
  88.     psthread_data_t *pt = __tcb_get()->pst_data;
  89.  
  90.     pt->retval = pt->func(pt->arg);
  91.  
  92.     pt->finished = 1;
  93.     if (pt->waiter)
  94.         list_append(&pt->waiter->link, &ready_list);
  95.  
  96.     psthread_exit();
  97. }
  98.  
  99. /** Schedule next userspace pseudo thread.
  100.  *
  101.  * @return 0 if there is no ready pseudo thread, 1 otherwise.
  102.  */
  103. int psthread_schedule_next(void)
  104. {
  105.     psthread_data_t *pt;
  106.  
  107.     if (list_empty(&ready_list))
  108.         return 0;
  109.  
  110.     pt = __tcb_get()->pst_data;
  111.     if (!context_save(&pt->ctx))
  112.         return 1;
  113.    
  114.     list_append(&pt->link, &ready_list);
  115.     pt = list_get_instance(ready_list.next, psthread_data_t, link);
  116.     list_remove(&pt->link);
  117.  
  118.     context_restore(&pt->ctx);
  119. }
  120.  
  121. /** Wait for uspace pseudo thread to finish.
  122.  *
  123.  * @param psthrid Pseudo thread to wait for.
  124.  *
  125.  * @return Value returned by the finished thread.
  126.  */
  127. int psthread_join(pstid_t psthrid)
  128. {
  129.     volatile psthread_data_t *pt, *mypt;
  130.     volatile int retval;
  131.  
  132.     /* Handle psthrid = Kernel address -> it is wait for call */
  133.     pt = (psthread_data_t *) psthrid;
  134.  
  135.     if (!pt->finished) {
  136.         mypt = __tcb_get()->pst_data;
  137.         if (context_save(&((psthread_data_t *) mypt)->ctx)) {
  138.             pt->waiter = (psthread_data_t *) mypt;
  139.             psthread_exit();
  140.         }
  141.     }
  142.     retval = pt->retval;
  143.  
  144.     free(pt->stack);
  145.     __free_tls(pt->tcb);
  146.     psthread_teardown((void *)pt);
  147.  
  148.     return retval;
  149. }
  150.  
  151. /**
  152.  * Create a userspace thread and append it to ready list.
  153.  *
  154.  * @param func Pseudo thread function.
  155.  * @param arg Argument to pass to func.
  156.  *
  157.  * @return 0 on failure, TLS of the new pseudo thread.
  158.  */
  159. pstid_t psthread_create(int (*func)(void *), void *arg)
  160. {
  161.     psthread_data_t *pt;
  162.     tcb_t *tcb;
  163.  
  164.     tcb = __make_tls();
  165.     if (!tcb)
  166.         return 0;
  167.  
  168.     pt = psthread_setup(tcb);
  169.     if (!pt) {
  170.         __free_tls(tcb);
  171.         return 0;
  172.     }
  173.     pt->stack = (char *) malloc(PSTHREAD_INITIAL_STACK_PAGES_NO*getpagesize());
  174.  
  175.     if (!pt->stack) {
  176.         __free_tls(tcb);
  177.         psthread_teardown(pt);
  178.         return 0;
  179.     }
  180.  
  181.     pt->arg= arg;
  182.     pt->func = func;
  183.     pt->finished = 0;
  184.     pt->waiter = NULL;
  185.  
  186.     context_save(&pt->ctx);
  187.     context_set(&pt->ctx, FADDR(psthread_main), pt->stack, PSTHREAD_INITIAL_STACK_PAGES_NO*getpagesize(),
  188.             tcb);
  189.  
  190.     list_append(&pt->link, &ready_list);
  191.  
  192.     return (pstid_t )pt;
  193. }
  194.