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  1. /*
  2.  * Copyright (C) 2001-2004 Jakub Jermar
  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. /** @addtogroup genericproc
  30.  * @{
  31.  */
  32.  
  33. /**
  34.  * @file
  35.  * @brief   Thread management functions.
  36.  */
  37.  
  38. #include <proc/scheduler.h>
  39. #include <proc/thread.h>
  40. #include <proc/task.h>
  41. #include <proc/uarg.h>
  42. #include <mm/frame.h>
  43. #include <mm/page.h>
  44. #include <arch/asm.h>
  45. #include <arch.h>
  46. #include <synch/synch.h>
  47. #include <synch/spinlock.h>
  48. #include <synch/waitq.h>
  49. #include <synch/rwlock.h>
  50. #include <cpu.h>
  51. #include <func.h>
  52. #include <context.h>
  53. #include <adt/btree.h>
  54. #include <adt/list.h>
  55. #include <typedefs.h>
  56. #include <time/clock.h>
  57. #include <config.h>
  58. #include <arch/interrupt.h>
  59. #include <smp/ipi.h>
  60. #include <arch/faddr.h>
  61. #include <atomic.h>
  62. #include <memstr.h>
  63. #include <print.h>
  64. #include <mm/slab.h>
  65. #include <debug.h>
  66. #include <main/uinit.h>
  67. #include <syscall/copy.h>
  68. #include <errno.h>
  69.  
  70.  
  71. /** Thread states */
  72. char *thread_states[] = {
  73.     "Invalid",
  74.     "Running",
  75.     "Sleeping",
  76.     "Ready",
  77.     "Entering",
  78.     "Exiting",
  79.     "Undead"
  80. };
  81.  
  82. /** Lock protecting the threads_btree B+tree. For locking rules, see declaration thereof. */
  83. SPINLOCK_INITIALIZE(threads_lock);
  84.  
  85. /** B+tree of all threads.
  86.  *
  87.  * When a thread is found in the threads_btree B+tree, it is guaranteed to exist as long
  88.  * as the threads_lock is held.
  89.  */
  90. btree_t threads_btree;     
  91.  
  92. SPINLOCK_INITIALIZE(tidlock);
  93. __u32 last_tid = 0;
  94.  
  95. static slab_cache_t *thread_slab;
  96. #ifdef ARCH_HAS_FPU
  97. slab_cache_t *fpu_context_slab;
  98. #endif
  99.  
  100. /** Thread wrapper
  101.  *
  102.  * This wrapper is provided to ensure that every thread
  103.  * makes a call to thread_exit() when its implementing
  104.  * function returns.
  105.  *
  106.  * interrupts_disable() is assumed.
  107.  *
  108.  */
  109. static void cushion(void)
  110. {
  111.     void (*f)(void *) = THREAD->thread_code;
  112.     void *arg = THREAD->thread_arg;
  113.  
  114.     /* this is where each thread wakes up after its creation */
  115.     spinlock_unlock(&THREAD->lock);
  116.     interrupts_enable();
  117.  
  118.     f(arg);
  119.     thread_exit();
  120.     /* not reached */
  121. }
  122.  
  123. /** Initialization and allocation for thread_t structure */
  124. static int thr_constructor(void *obj, int kmflags)
  125. {
  126.     thread_t *t = (thread_t *)obj;
  127.     int status;
  128.  
  129.     spinlock_initialize(&t->lock, "thread_t_lock");
  130.     link_initialize(&t->rq_link);
  131.     link_initialize(&t->wq_link);
  132.     link_initialize(&t->th_link);
  133.    
  134. #ifdef ARCH_HAS_FPU
  135. #  ifdef CONFIG_FPU_LAZY
  136.     t->saved_fpu_context = NULL;
  137. #  else
  138.     t->saved_fpu_context = slab_alloc(fpu_context_slab,kmflags);
  139.     if (!t->saved_fpu_context)
  140.         return -1;
  141. #  endif
  142. #endif 
  143.  
  144.     t->kstack = frame_alloc_rc(STACK_FRAMES, FRAME_KA | kmflags,&status);
  145.     if (status) {
  146. #ifdef ARCH_HAS_FPU
  147.         if (t->saved_fpu_context)
  148.             slab_free(fpu_context_slab,t->saved_fpu_context);
  149. #endif
  150.         return -1;
  151.     }
  152.  
  153.     return 0;
  154. }
  155.  
  156. /** Destruction of thread_t object */
  157. static int thr_destructor(void *obj)
  158. {
  159.     thread_t *t = (thread_t *)obj;
  160.  
  161.     frame_free(KA2PA(t->kstack));
  162. #ifdef ARCH_HAS_FPU
  163.     if (t->saved_fpu_context)
  164.         slab_free(fpu_context_slab,t->saved_fpu_context);
  165. #endif
  166.     return 1; /* One page freed */
  167. }
  168.  
  169. /** Initialize threads
  170.  *
  171.  * Initialize kernel threads support.
  172.  *
  173.  */
  174. void thread_init(void)
  175. {
  176.     THREAD = NULL;
  177.     atomic_set(&nrdy,0);
  178.     thread_slab = slab_cache_create("thread_slab",
  179.                     sizeof(thread_t),0,
  180.                     thr_constructor, thr_destructor, 0);
  181. #ifdef ARCH_HAS_FPU
  182.     fpu_context_slab = slab_cache_create("fpu_slab",
  183.                          sizeof(fpu_context_t),
  184.                          FPU_CONTEXT_ALIGN,
  185.                          NULL, NULL, 0);
  186. #endif
  187.  
  188.     btree_create(&threads_btree);
  189. }
  190.  
  191. /** Make thread ready
  192.  *
  193.  * Switch thread t to the ready state.
  194.  *
  195.  * @param t Thread to make ready.
  196.  *
  197.  */
  198. void thread_ready(thread_t *t)
  199. {
  200.     cpu_t *cpu;
  201.     runq_t *r;
  202.     ipl_t ipl;
  203.     int i, avg;
  204.  
  205.     ipl = interrupts_disable();
  206.  
  207.     spinlock_lock(&t->lock);
  208.  
  209.     ASSERT(! (t->state == Ready));
  210.  
  211.     i = (t->priority < RQ_COUNT -1) ? ++t->priority : t->priority;
  212.    
  213.     cpu = CPU;
  214.     if (t->flags & X_WIRED) {
  215.         cpu = t->cpu;
  216.     }
  217.     t->state = Ready;
  218.     spinlock_unlock(&t->lock);
  219.    
  220.     /*
  221.      * Append t to respective ready queue on respective processor.
  222.      */
  223.     r = &cpu->rq[i];
  224.     spinlock_lock(&r->lock);
  225.     list_append(&t->rq_link, &r->rq_head);
  226.     r->n++;
  227.     spinlock_unlock(&r->lock);
  228.  
  229.     atomic_inc(&nrdy);
  230.     avg = atomic_get(&nrdy) / config.cpu_active;
  231.     atomic_inc(&cpu->nrdy);
  232.  
  233.     interrupts_restore(ipl);
  234. }
  235.  
  236. /** Destroy thread memory structure
  237.  *
  238.  * Detach thread from all queues, cpus etc. and destroy it.
  239.  *
  240.  * Assume thread->lock is held!!
  241.  */
  242. void thread_destroy(thread_t *t)
  243. {
  244.     bool destroy_task = false; 
  245.  
  246.     ASSERT(t->state == Exiting || t->state == Undead);
  247.     ASSERT(t->task);
  248.     ASSERT(t->cpu);
  249.  
  250.     spinlock_lock(&t->cpu->lock);
  251.     if(t->cpu->fpu_owner==t)
  252.         t->cpu->fpu_owner=NULL;
  253.     spinlock_unlock(&t->cpu->lock);
  254.  
  255.     spinlock_unlock(&t->lock);
  256.  
  257.     spinlock_lock(&threads_lock);
  258.     btree_remove(&threads_btree, (btree_key_t) ((__address ) t), NULL);
  259.     spinlock_unlock(&threads_lock);
  260.  
  261.     /*
  262.      * Detach from the containing task.
  263.      */
  264.     spinlock_lock(&t->task->lock);
  265.     list_remove(&t->th_link);
  266.     if (--t->task->refcount == 0) {
  267.         t->task->accept_new_threads = false;
  268.         destroy_task = true;
  269.     }
  270.     spinlock_unlock(&t->task->lock);   
  271.    
  272.     if (destroy_task)
  273.         task_destroy(t->task);
  274.    
  275.     slab_free(thread_slab, t);
  276. }
  277.  
  278. /** Create new thread
  279.  *
  280.  * Create a new thread.
  281.  *
  282.  * @param func  Thread's implementing function.
  283.  * @param arg   Thread's implementing function argument.
  284.  * @param task  Task to which the thread belongs.
  285.  * @param flags Thread flags.
  286.  * @param name  Symbolic name.
  287.  *
  288.  * @return New thread's structure on success, NULL on failure.
  289.  *
  290.  */
  291. thread_t *thread_create(void (* func)(void *), void *arg, task_t *task, int flags, char *name)
  292. {
  293.     thread_t *t;
  294.     ipl_t ipl;
  295.    
  296.     t = (thread_t *) slab_alloc(thread_slab, 0);
  297.     if (!t)
  298.         return NULL;
  299.  
  300.     thread_create_arch(t);
  301.    
  302.     /* Not needed, but good for debugging */
  303.     memsetb((__address)t->kstack, THREAD_STACK_SIZE * 1<<STACK_FRAMES, 0);
  304.    
  305.     ipl = interrupts_disable();
  306.     spinlock_lock(&tidlock);
  307.     t->tid = ++last_tid;
  308.     spinlock_unlock(&tidlock);
  309.     interrupts_restore(ipl);
  310.    
  311.     context_save(&t->saved_context);
  312.     context_set(&t->saved_context, FADDR(cushion), (__address) t->kstack, THREAD_STACK_SIZE);
  313.    
  314.     the_initialize((the_t *) t->kstack);
  315.    
  316.     ipl = interrupts_disable();
  317.     t->saved_context.ipl = interrupts_read();
  318.     interrupts_restore(ipl);
  319.    
  320.     memcpy(t->name, name, THREAD_NAME_BUFLEN);
  321.    
  322.     t->thread_code = func;
  323.     t->thread_arg = arg;
  324.     t->ticks = -1;
  325.     t->priority = -1;       /* start in rq[0] */
  326.     t->cpu = NULL;
  327.     t->flags = 0;
  328.     t->state = Entering;
  329.     t->call_me = NULL;
  330.     t->call_me_with = NULL;
  331.    
  332.     timeout_initialize(&t->sleep_timeout);
  333.     t->sleep_interruptible = false;
  334.     t->sleep_queue = NULL;
  335.     t->timeout_pending = 0;
  336.  
  337.     t->in_copy_from_uspace = false;
  338.     t->in_copy_to_uspace = false;
  339.  
  340.     t->interrupted = false;
  341.     t->join_type = None;
  342.     t->detached = false;
  343.     waitq_initialize(&t->join_wq);
  344.    
  345.     t->rwlock_holder_type = RWLOCK_NONE;
  346.        
  347.     t->task = task;
  348.    
  349.     t->fpu_context_exists = 0;
  350.     t->fpu_context_engaged = 0;
  351.    
  352.     /*
  353.      * Attach to the containing task.
  354.      */
  355.     ipl = interrupts_disable();  
  356.     spinlock_lock(&task->lock);
  357.     if (!task->accept_new_threads) {
  358.         spinlock_unlock(&task->lock);
  359.         slab_free(thread_slab, t);
  360.         interrupts_restore(ipl);
  361.         return NULL;
  362.     }
  363.     list_append(&t->th_link, &task->th_head);
  364.     if (task->refcount++ == 0)
  365.         task->main_thread = t;
  366.     spinlock_unlock(&task->lock);
  367.  
  368.     /*
  369.      * Register this thread in the system-wide list.
  370.      */
  371.     spinlock_lock(&threads_lock);
  372.     btree_insert(&threads_btree, (btree_key_t) ((__address) t), (void *) t, NULL);
  373.     spinlock_unlock(&threads_lock);
  374.    
  375.     interrupts_restore(ipl);
  376.    
  377.     return t;
  378. }
  379.  
  380. /** Terminate thread.
  381.  *
  382.  * End current thread execution and switch it to the exiting
  383.  * state. All pending timeouts are executed.
  384.  *
  385.  */
  386. void thread_exit(void)
  387. {
  388.     ipl_t ipl;
  389.  
  390. restart:
  391.     ipl = interrupts_disable();
  392.     spinlock_lock(&THREAD->lock);
  393.     if (THREAD->timeout_pending) { /* busy waiting for timeouts in progress */
  394.         spinlock_unlock(&THREAD->lock);
  395.         interrupts_restore(ipl);
  396.         goto restart;
  397.     }
  398.     THREAD->state = Exiting;
  399.     spinlock_unlock(&THREAD->lock);
  400.     scheduler();
  401.  
  402.     /* Not reached */
  403.     while (1)
  404.         ;
  405. }
  406.  
  407.  
  408. /** Thread sleep
  409.  *
  410.  * Suspend execution of the current thread.
  411.  *
  412.  * @param sec Number of seconds to sleep.
  413.  *
  414.  */
  415. void thread_sleep(__u32 sec)
  416. {
  417.     thread_usleep(sec*1000000);
  418. }
  419.  
  420. /** Wait for another thread to exit.
  421.  *
  422.  * @param t Thread to join on exit.
  423.  * @param usec Timeout in microseconds.
  424.  * @param flags Mode of operation.
  425.  *
  426.  * @return An error code from errno.h or an error code from synch.h.
  427.  */
  428. int thread_join_timeout(thread_t *t, __u32 usec, int flags)
  429. {
  430.     ipl_t ipl;
  431.     int rc;
  432.  
  433.     if (t == THREAD)
  434.         return EINVAL;
  435.  
  436.     /*
  437.      * Since thread join can only be called once on an undetached thread,
  438.      * the thread pointer is guaranteed to be still valid.
  439.      */
  440.    
  441.     ipl = interrupts_disable();
  442.     spinlock_lock(&t->lock);
  443.     ASSERT(!t->detached);
  444.     spinlock_unlock(&t->lock);
  445.     interrupts_restore(ipl);
  446.    
  447.     rc = waitq_sleep_timeout(&t->join_wq, usec, flags);
  448.    
  449.     return rc; 
  450. }
  451.  
  452. /** Detach thread.
  453.  *
  454.  * Mark the thread as detached, if the thread is already in the Undead state,
  455.  * deallocate its resources.
  456.  *
  457.  * @param t Thread to be detached.
  458.  */
  459. void thread_detach(thread_t *t)
  460. {
  461.     ipl_t ipl;
  462.  
  463.     /*
  464.      * Since the thread is expected to not be already detached,
  465.      * pointer to it must be still valid.
  466.      */
  467.     ipl = interrupts_disable();
  468.     spinlock_lock(&t->lock);
  469.     ASSERT(!t->detached);
  470.     if (t->state == Undead) {
  471.         thread_destroy(t);  /* unlocks &t->lock */
  472.         interrupts_restore(ipl);
  473.         return;
  474.     } else {
  475.         t->detached = true;
  476.     }
  477.     spinlock_unlock(&t->lock);
  478.     interrupts_restore(ipl);
  479. }
  480.  
  481. /** Thread usleep
  482.  *
  483.  * Suspend execution of the current thread.
  484.  *
  485.  * @param usec Number of microseconds to sleep.
  486.  *
  487.  */
  488. void thread_usleep(__u32 usec)
  489. {
  490.     waitq_t wq;
  491.                  
  492.     waitq_initialize(&wq);
  493.  
  494.     (void) waitq_sleep_timeout(&wq, usec, SYNCH_FLAGS_NON_BLOCKING);
  495. }
  496.  
  497. /** Register thread out-of-context invocation
  498.  *
  499.  * Register a function and its argument to be executed
  500.  * on next context switch to the current thread.
  501.  *
  502.  * @param call_me      Out-of-context function.
  503.  * @param call_me_with Out-of-context function argument.
  504.  *
  505.  */
  506. void thread_register_call_me(void (* call_me)(void *), void *call_me_with)
  507. {
  508.     ipl_t ipl;
  509.    
  510.     ipl = interrupts_disable();
  511.     spinlock_lock(&THREAD->lock);
  512.     THREAD->call_me = call_me;
  513.     THREAD->call_me_with = call_me_with;
  514.     spinlock_unlock(&THREAD->lock);
  515.     interrupts_restore(ipl);
  516. }
  517.  
  518. /** Print list of threads debug info */
  519. void thread_print_list(void)
  520. {
  521.     link_t *cur;
  522.     ipl_t ipl;
  523.    
  524.     /* Messing with thread structures, avoid deadlock */
  525.     ipl = interrupts_disable();
  526.     spinlock_lock(&threads_lock);
  527.  
  528.     for (cur = threads_btree.leaf_head.next; cur != &threads_btree.leaf_head; cur = cur->next) {
  529.         btree_node_t *node;
  530.         int i;
  531.  
  532.         node = list_get_instance(cur, btree_node_t, leaf_link);
  533.         for (i = 0; i < node->keys; i++) {
  534.             thread_t *t;
  535.        
  536.             t = (thread_t *) node->value[i];
  537.             printf("%s: address=%#zx, tid=%zd, state=%s, task=%#zx, code=%#zx, stack=%#zx, cpu=",
  538.                 t->name, t, t->tid, thread_states[t->state], t->task, t->thread_code, t->kstack);
  539.             if (t->cpu)
  540.                 printf("cpu%zd", t->cpu->id);
  541.             else
  542.                 printf("none");
  543.             if (t->state == Sleeping) {
  544.                 printf(", kst=%#zx", t->kstack);
  545.                 printf(", wq=%#zx", t->sleep_queue);
  546.             }
  547.             printf("\n");
  548.         }
  549.     }
  550.  
  551.     spinlock_unlock(&threads_lock);
  552.     interrupts_restore(ipl);
  553. }
  554.  
  555. /** Check whether thread exists.
  556.  *
  557.  * Note that threads_lock must be already held and
  558.  * interrupts must be already disabled.
  559.  *
  560.  * @param t Pointer to thread.
  561.  *
  562.  * @return True if thread t is known to the system, false otherwise.
  563.  */
  564. bool thread_exists(thread_t *t)
  565. {
  566.     btree_node_t *leaf;
  567.    
  568.     return btree_search(&threads_btree, (btree_key_t) ((__address) t), &leaf) != NULL;
  569. }
  570.  
  571. /** Process syscall to create new thread.
  572.  *
  573.  */
  574. __native sys_thread_create(uspace_arg_t *uspace_uarg, char *uspace_name)
  575. {
  576.     thread_t *t;
  577.     char namebuf[THREAD_NAME_BUFLEN];
  578.     uspace_arg_t *kernel_uarg;
  579.     __u32 tid;
  580.     int rc;
  581.  
  582.     rc = copy_from_uspace(namebuf, uspace_name, THREAD_NAME_BUFLEN);
  583.     if (rc != 0)
  584.         return (__native) rc;
  585.  
  586.     kernel_uarg = (uspace_arg_t *) malloc(sizeof(uspace_arg_t), 0);
  587.     rc = copy_from_uspace(kernel_uarg, uspace_uarg, sizeof(uspace_arg_t));
  588.     if (rc != 0) {
  589.         free(kernel_uarg);
  590.         return (__native) rc;
  591.     }
  592.  
  593.     if ((t = thread_create(uinit, kernel_uarg, TASK, 0, namebuf))) {
  594.         tid = t->tid;
  595.         thread_ready(t);
  596.         return (__native) tid;
  597.     } else {
  598.         free(kernel_uarg);
  599.     }
  600.  
  601.     return (__native) ENOMEM;
  602. }
  603.  
  604. /** Process syscall to terminate thread.
  605.  *
  606.  */
  607. __native sys_thread_exit(int uspace_status)
  608. {
  609.     thread_exit();
  610.     /* Unreachable */
  611.     return 0;
  612. }
  613.  
  614. /** @}
  615.  */
  616.