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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. static LIST_INITIALIZE(ready_list);
  38.  
  39. static void psthread_exit(void) __attribute__ ((noinline));
  40. static void psthread_main(void);
  41.  
  42. /** Setup PSthread information into TCB structure */
  43. psthread_data_t * psthread_setup(tcb_t *tcb)
  44. {
  45.     psthread_data_t *pt;
  46.  
  47.     pt = malloc(sizeof(*pt));
  48.     if (!pt) {
  49.         return NULL;
  50.     }
  51.  
  52.     tcb->pst_data = pt;
  53.     pt->tcb = tcb;
  54.  
  55.     return pt;
  56. }
  57.  
  58. void psthread_teardown(psthread_data_t *pt)
  59. {
  60.     free(pt);
  61. }
  62.  
  63. /** Function to preempt to other pseudo thread without adding
  64.  * currently running pseudo thread to ready_list.
  65.  */
  66. void psthread_exit(void)
  67. {
  68.     psthread_data_t *pt;
  69.  
  70.     if (list_empty(&ready_list)) {
  71.         /* Wait on IPC queue etc... */
  72.         printf("Cannot exit!!!\n");
  73.         _exit(0);
  74.     }
  75.     pt = list_get_instance(ready_list.next, psthread_data_t, link);
  76.     list_remove(&pt->link);
  77.     context_restore(&pt->ctx);
  78. }
  79.  
  80. /** Function that is called on entry to new uspace thread */
  81. void psthread_main(void)
  82. {
  83.     psthread_data_t *pt = __tcb_get()->pst_data;
  84.  
  85.     pt->retval = pt->func(pt->arg);
  86.  
  87.     pt->finished = 1;
  88.     if (pt->waiter)
  89.         list_append(&pt->waiter->link, &ready_list);
  90.  
  91.     psthread_exit();
  92. }
  93.  
  94. /** Schedule next userspace pseudo thread.
  95.  *
  96.  * @return 0 if there is no ready pseudo thread, 1 otherwise.
  97.  */
  98. int psthread_schedule_next(void)
  99. {
  100.     psthread_data_t *pt;
  101.  
  102.     if (list_empty(&ready_list))
  103.         return 0;
  104.  
  105.     pt = __tcb_get()->pst_data;
  106.     if (!context_save(&pt->ctx))
  107.         return 1;
  108.    
  109.     list_append(&pt->link, &ready_list);
  110.     pt = list_get_instance(ready_list.next, psthread_data_t, link);
  111.     list_remove(&pt->link);
  112.  
  113.     context_restore(&pt->ctx);
  114. }
  115.  
  116. /** Wait for uspace pseudo thread to finish.
  117.  *
  118.  * @param psthrid Pseudo thread to wait for.
  119.  *
  120.  * @return Value returned by the finished thread.
  121.  */
  122. int psthread_join(pstid_t psthrid)
  123. {
  124.     volatile psthread_data_t *pt, *mypt;
  125.     volatile int retval;
  126.  
  127.     /* Handle psthrid = Kernel address -> it is wait for call */
  128.     pt = (psthread_data_t *) psthrid;
  129.  
  130.     if (!pt->finished) {
  131.         mypt = __tcb_get()->pst_data;
  132.         if (context_save(&((psthread_data_t *) mypt)->ctx)) {
  133.             pt->waiter = (psthread_data_t *) mypt;
  134.             psthread_exit();
  135.         }
  136.     }
  137.     retval = pt->retval;
  138.  
  139.     free(pt->stack);
  140.     __free_tls(pt->tcb);
  141.     psthread_teardown((void *)pt);
  142.  
  143.     return retval;
  144. }
  145.  
  146. /**
  147.  * Create a userspace thread and append it to ready list.
  148.  *
  149.  * @param func Pseudo thread function.
  150.  * @param arg Argument to pass to func.
  151.  *
  152.  * @return 0 on failure, TLS of the new pseudo thread.
  153.  */
  154. pstid_t psthread_create(int (*func)(void *), void *arg)
  155. {
  156.     psthread_data_t *pt;
  157.     tcb_t *tcb;
  158.  
  159.     tcb = __make_tls();
  160.     if (!tcb)
  161.         return 0;
  162.  
  163.     pt = psthread_setup(tcb);
  164.     if (!pt) {
  165.         __free_tls(tcb);
  166.         return 0;
  167.     }
  168.     pt->stack = (char *) malloc(getpagesize());
  169.  
  170.     if (!pt->stack) {
  171.         __free_tls(tcb);
  172.         psthread_teardown(pt);
  173.         return 0;
  174.     }
  175.  
  176.     pt->arg= arg;
  177.     pt->func = func;
  178.     pt->finished = 0;
  179.     pt->waiter = NULL;
  180.  
  181.     context_save(&pt->ctx);
  182.     context_set(&pt->ctx, FADDR(psthread_main), pt->stack, getpagesize(),
  183.             tcb);
  184.  
  185.     list_append(&pt->link, &ready_list);
  186.  
  187.     return (pstid_t )pt;
  188. }
  189.