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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. uint32_t 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.  
  128.     spinlock_initialize(&t->lock, "thread_t_lock");
  129.     link_initialize(&t->rq_link);
  130.     link_initialize(&t->wq_link);
  131.     link_initialize(&t->th_link);
  132.    
  133. #ifdef ARCH_HAS_FPU
  134. #  ifdef CONFIG_FPU_LAZY
  135.     t->saved_fpu_context = NULL;
  136. #  else
  137.     t->saved_fpu_context = slab_alloc(fpu_context_slab,kmflags);
  138.     if (!t->saved_fpu_context)
  139.         return -1;
  140. #  endif
  141. #endif 
  142.  
  143.     t->kstack = frame_alloc(STACK_FRAMES, FRAME_KA | kmflags);
  144.     if (! t->kstack) {
  145. #ifdef ARCH_HAS_FPU
  146.         if (t->saved_fpu_context)
  147.             slab_free(fpu_context_slab,t->saved_fpu_context);
  148. #endif
  149.         return -1;
  150.     }
  151.  
  152.     return 0;
  153. }
  154.  
  155. /** Destruction of thread_t object */
  156. static int thr_destructor(void *obj)
  157. {
  158.     thread_t *t = (thread_t *) obj;
  159.  
  160.     frame_free(KA2PA(t->kstack));
  161. #ifdef ARCH_HAS_FPU
  162.     if (t->saved_fpu_context)
  163.         slab_free(fpu_context_slab,t->saved_fpu_context);
  164. #endif
  165.     return 1; /* One page freed */
  166. }
  167.  
  168. /** Initialize threads
  169.  *
  170.  * Initialize kernel threads support.
  171.  *
  172.  */
  173. void thread_init(void)
  174. {
  175.     THREAD = NULL;
  176.     atomic_set(&nrdy,0);
  177.     thread_slab = slab_cache_create("thread_slab",
  178.                     sizeof(thread_t),0,
  179.                     thr_constructor, thr_destructor, 0);
  180. #ifdef ARCH_HAS_FPU
  181.     fpu_context_slab = slab_cache_create("fpu_slab",
  182.                          sizeof(fpu_context_t),
  183.                          FPU_CONTEXT_ALIGN,
  184.                          NULL, NULL, 0);
  185. #endif
  186.  
  187.     btree_create(&threads_btree);
  188. }
  189.  
  190. /** Make thread ready
  191.  *
  192.  * Switch thread t to the ready state.
  193.  *
  194.  * @param t Thread to make ready.
  195.  *
  196.  */
  197. void thread_ready(thread_t *t)
  198. {
  199.     cpu_t *cpu;
  200.     runq_t *r;
  201.     ipl_t ipl;
  202.     int i, avg;
  203.  
  204.     ipl = interrupts_disable();
  205.  
  206.     spinlock_lock(&t->lock);
  207.  
  208.     ASSERT(! (t->state == Ready));
  209.  
  210.     i = (t->priority < RQ_COUNT -1) ? ++t->priority : t->priority;
  211.    
  212.     cpu = CPU;
  213.     if (t->flags & X_WIRED) {
  214.         cpu = t->cpu;
  215.     }
  216.     t->state = Ready;
  217.     spinlock_unlock(&t->lock);
  218.    
  219.     /*
  220.      * Append t to respective ready queue on respective processor.
  221.      */
  222.     r = &cpu->rq[i];
  223.     spinlock_lock(&r->lock);
  224.     list_append(&t->rq_link, &r->rq_head);
  225.     r->n++;
  226.     spinlock_unlock(&r->lock);
  227.  
  228.     atomic_inc(&nrdy);
  229.     avg = atomic_get(&nrdy) / config.cpu_active;
  230.     atomic_inc(&cpu->nrdy);
  231.  
  232.     interrupts_restore(ipl);
  233. }
  234.  
  235. /** Destroy thread memory structure
  236.  *
  237.  * Detach thread from all queues, cpus etc. and destroy it.
  238.  *
  239.  * Assume thread->lock is held!!
  240.  */
  241. void thread_destroy(thread_t *t)
  242. {
  243.     bool destroy_task = false; 
  244.  
  245.     ASSERT(t->state == Exiting || t->state == Undead);
  246.     ASSERT(t->task);
  247.     ASSERT(t->cpu);
  248.  
  249.     spinlock_lock(&t->cpu->lock);
  250.     if(t->cpu->fpu_owner==t)
  251.         t->cpu->fpu_owner=NULL;
  252.     spinlock_unlock(&t->cpu->lock);
  253.  
  254.     spinlock_unlock(&t->lock);
  255.  
  256.     spinlock_lock(&threads_lock);
  257.     btree_remove(&threads_btree, (btree_key_t) ((uintptr_t ) t), NULL);
  258.     spinlock_unlock(&threads_lock);
  259.  
  260.     /*
  261.      * Detach from the containing task.
  262.      */
  263.     spinlock_lock(&t->task->lock);
  264.     list_remove(&t->th_link);
  265.     if (--t->task->refcount == 0) {
  266.         t->task->accept_new_threads = false;
  267.         destroy_task = true;
  268.     }
  269.     spinlock_unlock(&t->task->lock);   
  270.    
  271.     if (destroy_task)
  272.         task_destroy(t->task);
  273.    
  274.     slab_free(thread_slab, t);
  275. }
  276.  
  277. /** Create new thread
  278.  *
  279.  * Create a new thread.
  280.  *
  281.  * @param func  Thread's implementing function.
  282.  * @param arg   Thread's implementing function argument.
  283.  * @param task  Task to which the thread belongs.
  284.  * @param flags Thread flags.
  285.  * @param name  Symbolic name.
  286.  *
  287.  * @return New thread's structure on success, NULL on failure.
  288.  *
  289.  */
  290. thread_t *thread_create(void (* func)(void *), void *arg, task_t *task, int flags, char *name)
  291. {
  292.     thread_t *t;
  293.     ipl_t ipl;
  294.    
  295.     t = (thread_t *) slab_alloc(thread_slab, 0);
  296.     if (!t)
  297.         return NULL;
  298.  
  299.     thread_create_arch(t);
  300.    
  301.     /* Not needed, but good for debugging */
  302.     memsetb((uintptr_t) t->kstack, THREAD_STACK_SIZE * 1 << STACK_FRAMES, 0);
  303.    
  304.     ipl = interrupts_disable();
  305.     spinlock_lock(&tidlock);
  306.     t->tid = ++last_tid;
  307.     spinlock_unlock(&tidlock);
  308.     interrupts_restore(ipl);
  309.    
  310.     context_save(&t->saved_context);
  311.     context_set(&t->saved_context, FADDR(cushion), (uintptr_t) t->kstack, THREAD_STACK_SIZE);
  312.    
  313.     the_initialize((the_t *) t->kstack);
  314.    
  315.     ipl = interrupts_disable();
  316.     t->saved_context.ipl = interrupts_read();
  317.     interrupts_restore(ipl);
  318.    
  319.     memcpy(t->name, name, THREAD_NAME_BUFLEN);
  320.    
  321.     t->context = THE->context;
  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) ((uintptr_t) 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(uint32_t 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, uint32_t 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(uint32_t 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, context=%ld, state=%s, task=%#zx, code=%#zx, stack=%#zx, cpu=",
  538.                 t->name, t, t->tid, t->context, 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) ((uintptr_t) t), &leaf) != NULL;
  569. }
  570.  
  571. /** Process syscall to create new thread.
  572.  *
  573.  */
  574. unative_t 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.     uint32_t tid;
  580.     int rc;
  581.  
  582.     rc = copy_from_uspace(namebuf, uspace_name, THREAD_NAME_BUFLEN);
  583.     if (rc != 0)
  584.         return (unative_t) 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 (unative_t) rc;
  591.     }
  592.  
  593.     if ((t = thread_create(uinit, kernel_uarg, TASK, 0, namebuf))) {
  594.         tid = t->tid;
  595.         thread_ready(t);
  596.         return (unative_t) tid;
  597.     } else {
  598.         free(kernel_uarg);
  599.     }
  600.  
  601.     return (unative_t) ENOMEM;
  602. }
  603.  
  604. /** Process syscall to terminate thread.
  605.  *
  606.  */
  607. unative_t sys_thread_exit(int uspace_status)
  608. {
  609.     thread_exit();
  610.     /* Unreachable */
  611.     return 0;
  612. }
  613.  
  614. /** @}
  615.  */
  616.