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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. /**
  30.  * @file    thread.c
  31.  * @brief   Thread management functions.
  32.  */
  33.  
  34. #include <proc/scheduler.h>
  35. #include <proc/thread.h>
  36. #include <proc/task.h>
  37. #include <proc/uarg.h>
  38. #include <mm/frame.h>
  39. #include <mm/page.h>
  40. #include <arch/asm.h>
  41. #include <arch.h>
  42. #include <synch/synch.h>
  43. #include <synch/spinlock.h>
  44. #include <synch/waitq.h>
  45. #include <synch/rwlock.h>
  46. #include <cpu.h>
  47. #include <func.h>
  48. #include <context.h>
  49. #include <adt/btree.h>
  50. #include <adt/list.h>
  51. #include <typedefs.h>
  52. #include <time/clock.h>
  53. #include <config.h>
  54. #include <arch/interrupt.h>
  55. #include <smp/ipi.h>
  56. #include <arch/faddr.h>
  57. #include <atomic.h>
  58. #include <memstr.h>
  59. #include <print.h>
  60. #include <mm/slab.h>
  61. #include <debug.h>
  62. #include <main/uinit.h>
  63. #include <syscall/copy.h>
  64. #include <errno.h>
  65.  
  66.  
  67. /** Thread states */
  68. char *thread_states[] = {
  69.     "Invalid",
  70.     "Running",
  71.     "Sleeping",
  72.     "Ready",
  73.     "Entering",
  74.     "Exiting",
  75.     "Undead"
  76. };
  77.  
  78. /** Lock protecting the threads_btree B+tree. For locking rules, see declaration thereof. */
  79. SPINLOCK_INITIALIZE(threads_lock);
  80.  
  81. /** B+tree of all threads.
  82.  *
  83.  * When a thread is found in the threads_btree B+tree, it is guaranteed to exist as long
  84.  * as the threads_lock is held.
  85.  */
  86. btree_t threads_btree;     
  87.  
  88. SPINLOCK_INITIALIZE(tidlock);
  89. __u32 last_tid = 0;
  90.  
  91. static slab_cache_t *thread_slab;
  92. #ifdef ARCH_HAS_FPU
  93. slab_cache_t *fpu_context_slab;
  94. #endif
  95.  
  96. /** Thread wrapper
  97.  *
  98.  * This wrapper is provided to ensure that every thread
  99.  * makes a call to thread_exit() when its implementing
  100.  * function returns.
  101.  *
  102.  * interrupts_disable() is assumed.
  103.  *
  104.  */
  105. static void cushion(void)
  106. {
  107.     void (*f)(void *) = THREAD->thread_code;
  108.     void *arg = THREAD->thread_arg;
  109.  
  110.     /* this is where each thread wakes up after its creation */
  111.     spinlock_unlock(&THREAD->lock);
  112.     interrupts_enable();
  113.  
  114.     f(arg);
  115.     thread_exit();
  116.     /* not reached */
  117. }
  118.  
  119. /** Initialization and allocation for thread_t structure */
  120. static int thr_constructor(void *obj, int kmflags)
  121. {
  122.     thread_t *t = (thread_t *)obj;
  123.     pfn_t pfn;
  124.     int status;
  125.  
  126.     spinlock_initialize(&t->lock, "thread_t_lock");
  127.     link_initialize(&t->rq_link);
  128.     link_initialize(&t->wq_link);
  129.     link_initialize(&t->th_link);
  130.    
  131. #ifdef ARCH_HAS_FPU
  132. #  ifdef CONFIG_FPU_LAZY
  133.     t->saved_fpu_context = NULL;
  134. #  else
  135.     t->saved_fpu_context = slab_alloc(fpu_context_slab,kmflags);
  136.     if (!t->saved_fpu_context)
  137.         return -1;
  138. #  endif
  139. #endif 
  140.  
  141.     pfn = frame_alloc_rc(STACK_FRAMES, FRAME_KA | kmflags,&status);
  142.     if (status) {
  143. #ifdef ARCH_HAS_FPU
  144.         if (t->saved_fpu_context)
  145.             slab_free(fpu_context_slab,t->saved_fpu_context);
  146. #endif
  147.         return -1;
  148.     }
  149.     t->kstack = (__u8 *)PA2KA(PFN2ADDR(pfn));
  150.  
  151.     return 0;
  152. }
  153.  
  154. /** Destruction of thread_t object */
  155. static int thr_destructor(void *obj)
  156. {
  157.     thread_t *t = (thread_t *)obj;
  158.  
  159.     frame_free(ADDR2PFN(KA2PA(t->kstack)));
  160. #ifdef ARCH_HAS_FPU
  161.     if (t->saved_fpu_context)
  162.         slab_free(fpu_context_slab,t->saved_fpu_context);
  163. #endif
  164.     return 1; /* One page freed */
  165. }
  166.  
  167. /** Initialize threads
  168.  *
  169.  * Initialize kernel threads support.
  170.  *
  171.  */
  172. void thread_init(void)
  173. {
  174.     THREAD = NULL;
  175.     atomic_set(&nrdy,0);
  176.     thread_slab = slab_cache_create("thread_slab",
  177.                     sizeof(thread_t),0,
  178.                     thr_constructor, thr_destructor, 0);
  179. #ifdef ARCH_HAS_FPU
  180.     fpu_context_slab = slab_cache_create("fpu_slab",
  181.                          sizeof(fpu_context_t),
  182.                          FPU_CONTEXT_ALIGN,
  183.                          NULL, NULL, 0);
  184. #endif
  185.  
  186.     btree_create(&threads_btree);
  187. }
  188.  
  189. /** Make thread ready
  190.  *
  191.  * Switch thread t to the ready state.
  192.  *
  193.  * @param t Thread to make ready.
  194.  *
  195.  */
  196. void thread_ready(thread_t *t)
  197. {
  198.     cpu_t *cpu;
  199.     runq_t *r;
  200.     ipl_t ipl;
  201.     int i, avg;
  202.  
  203.     ipl = interrupts_disable();
  204.  
  205.     spinlock_lock(&t->lock);
  206.  
  207.     ASSERT(! (t->state == Ready));
  208.  
  209.     i = (t->priority < RQ_COUNT -1) ? ++t->priority : t->priority;
  210.    
  211.     cpu = CPU;
  212.     if (t->flags & X_WIRED) {
  213.         cpu = t->cpu;
  214.     }
  215.     t->state = Ready;
  216.     spinlock_unlock(&t->lock);
  217.    
  218.     /*
  219.      * Append t to respective ready queue on respective processor.
  220.      */
  221.     r = &cpu->rq[i];
  222.     spinlock_lock(&r->lock);
  223.     list_append(&t->rq_link, &r->rq_head);
  224.     r->n++;
  225.     spinlock_unlock(&r->lock);
  226.  
  227.     atomic_inc(&nrdy);
  228.     avg = atomic_get(&nrdy) / config.cpu_active;
  229.     atomic_inc(&cpu->nrdy);
  230.  
  231.     interrupts_restore(ipl);
  232. }
  233.  
  234. /** Destroy thread memory structure
  235.  *
  236.  * Detach thread from all queues, cpus etc. and destroy it.
  237.  *
  238.  * Assume thread->lock is held!!
  239.  */
  240. void thread_destroy(thread_t *t)
  241. {
  242.     bool destroy_task = false; 
  243.  
  244.     ASSERT(t->state == Exiting || t->state == Undead);
  245.     ASSERT(t->task);
  246.     ASSERT(t->cpu);
  247.  
  248.     spinlock_lock(&t->cpu->lock);
  249.     if(t->cpu->fpu_owner==t)
  250.         t->cpu->fpu_owner=NULL;
  251.     spinlock_unlock(&t->cpu->lock);
  252.  
  253.     spinlock_unlock(&t->lock);
  254.  
  255.     spinlock_lock(&threads_lock);
  256.     btree_remove(&threads_btree, (btree_key_t) ((__address ) t), NULL);
  257.     spinlock_unlock(&threads_lock);
  258.  
  259.     /*
  260.      * Detach from the containing task.
  261.      */
  262.     spinlock_lock(&t->task->lock);
  263.     list_remove(&t->th_link);
  264.     if (--t->task->refcount == 0) {
  265.         t->task->accept_new_threads = false;
  266.         destroy_task = true;
  267.     }
  268.     spinlock_unlock(&t->task->lock);   
  269.    
  270.     if (destroy_task)
  271.         task_destroy(t->task);
  272.    
  273.     slab_free(thread_slab, t);
  274. }
  275.  
  276. /** Create new thread
  277.  *
  278.  * Create a new thread.
  279.  *
  280.  * @param func  Thread's implementing function.
  281.  * @param arg   Thread's implementing function argument.
  282.  * @param task  Task to which the thread belongs.
  283.  * @param flags Thread flags.
  284.  * @param name  Symbolic name.
  285.  *
  286.  * @return New thread's structure on success, NULL on failure.
  287.  *
  288.  */
  289. thread_t *thread_create(void (* func)(void *), void *arg, task_t *task, int flags, char *name)
  290. {
  291.     thread_t *t;
  292.     ipl_t ipl;
  293.    
  294.     t = (thread_t *) slab_alloc(thread_slab, 0);
  295.     if (!t)
  296.         return NULL;
  297.  
  298.     thread_create_arch(t);
  299.    
  300.     /* Not needed, but good for debugging */
  301.     memsetb((__address)t->kstack, THREAD_STACK_SIZE * 1<<STACK_FRAMES, 0);
  302.    
  303.     ipl = interrupts_disable();
  304.     spinlock_lock(&tidlock);
  305.     t->tid = ++last_tid;
  306.     spinlock_unlock(&tidlock);
  307.     interrupts_restore(ipl);
  308.    
  309.     context_save(&t->saved_context);
  310.     context_set(&t->saved_context, FADDR(cushion), (__address) t->kstack, THREAD_STACK_SIZE);
  311.    
  312.     the_initialize((the_t *) t->kstack);
  313.    
  314.     ipl = interrupts_disable();
  315.     t->saved_context.ipl = interrupts_read();
  316.     interrupts_restore(ipl);
  317.    
  318.     memcpy(t->name, name, THREAD_NAME_BUFLEN);
  319.    
  320.     t->thread_code = func;
  321.     t->thread_arg = arg;
  322.     t->ticks = -1;
  323.     t->priority = -1;       /* start in rq[0] */
  324.     t->cpu = NULL;
  325.     t->flags = 0;
  326.     t->state = Entering;
  327.     t->call_me = NULL;
  328.     t->call_me_with = NULL;
  329.    
  330.     timeout_initialize(&t->sleep_timeout);
  331.     t->sleep_interruptible = false;
  332.     t->sleep_queue = NULL;
  333.     t->timeout_pending = 0;
  334.  
  335.     t->in_copy_from_uspace = false;
  336.     t->in_copy_to_uspace = false;
  337.  
  338.     t->interrupted = false;
  339.     t->join_type = None;
  340.     t->detached = false;
  341.     waitq_initialize(&t->join_wq);
  342.    
  343.     t->rwlock_holder_type = RWLOCK_NONE;
  344.        
  345.     t->task = task;
  346.    
  347.     t->fpu_context_exists = 0;
  348.     t->fpu_context_engaged = 0;
  349.    
  350.     /*
  351.      * Attach to the containing task.
  352.      */
  353.     ipl = interrupts_disable();  
  354.     spinlock_lock(&task->lock);
  355.     if (!task->accept_new_threads) {
  356.         spinlock_unlock(&task->lock);
  357.         slab_free(thread_slab, t);
  358.         interrupts_restore(ipl);
  359.         return NULL;
  360.     }
  361.     list_append(&t->th_link, &task->th_head);
  362.     if (task->refcount++ == 0)
  363.         task->main_thread = t;
  364.     spinlock_unlock(&task->lock);
  365.  
  366.     /*
  367.      * Register this thread in the system-wide list.
  368.      */
  369.     spinlock_lock(&threads_lock);
  370.     btree_insert(&threads_btree, (btree_key_t) ((__address) t), (void *) t, NULL);
  371.     spinlock_unlock(&threads_lock);
  372.    
  373.     interrupts_restore(ipl);
  374.    
  375.     return t;
  376. }
  377.  
  378. /** Terminate thread.
  379.  *
  380.  * End current thread execution and switch it to the exiting
  381.  * state. All pending timeouts are executed.
  382.  *
  383.  */
  384. void thread_exit(void)
  385. {
  386.     ipl_t ipl;
  387.  
  388. restart:
  389.     ipl = interrupts_disable();
  390.     spinlock_lock(&THREAD->lock);
  391.     if (THREAD->timeout_pending) { /* busy waiting for timeouts in progress */
  392.         spinlock_unlock(&THREAD->lock);
  393.         interrupts_restore(ipl);
  394.         goto restart;
  395.     }
  396.     THREAD->state = Exiting;
  397.     spinlock_unlock(&THREAD->lock);
  398.     scheduler();
  399.  
  400.     /* Not reached */
  401.     while (1)
  402.         ;
  403. }
  404.  
  405.  
  406. /** Thread sleep
  407.  *
  408.  * Suspend execution of the current thread.
  409.  *
  410.  * @param sec Number of seconds to sleep.
  411.  *
  412.  */
  413. void thread_sleep(__u32 sec)
  414. {
  415.     thread_usleep(sec*1000000);
  416. }
  417.  
  418. /** Wait for another thread to exit.
  419.  *
  420.  * @param t Thread to join on exit.
  421.  * @param usec Timeout in microseconds.
  422.  * @param flags Mode of operation.
  423.  *
  424.  * @return An error code from errno.h or an error code from synch.h.
  425.  */
  426. int thread_join_timeout(thread_t *t, __u32 usec, int flags)
  427. {
  428.     ipl_t ipl;
  429.     int rc;
  430.  
  431.     if (t == THREAD)
  432.         return EINVAL;
  433.  
  434.     /*
  435.      * Since thread join can only be called once on an undetached thread,
  436.      * the thread pointer is guaranteed to be still valid.
  437.      */
  438.    
  439.     ipl = interrupts_disable();
  440.     spinlock_lock(&t->lock);
  441.     ASSERT(!t->detached);
  442.     spinlock_unlock(&t->lock);
  443.     interrupts_restore(ipl);
  444.    
  445.     rc = waitq_sleep_timeout(&t->join_wq, usec, flags);
  446.    
  447.     return rc; 
  448. }
  449.  
  450. /** Detach thread.
  451.  *
  452.  * Mark the thread as detached, if the thread is already in the Undead state,
  453.  * deallocate its resources.
  454.  *
  455.  * @param t Thread to be detached.
  456.  */
  457. void thread_detach(thread_t *t)
  458. {
  459.     ipl_t ipl;
  460.  
  461.     /*
  462.      * Since the thread is expected to not be already detached,
  463.      * pointer to it must be still valid.
  464.      */
  465.     ipl = interrupts_disable();
  466.     spinlock_lock(&t->lock);
  467.     ASSERT(!t->detached);
  468.     if (t->state == Undead) {
  469.         thread_destroy(t);  /* unlocks &t->lock */
  470.         interrupts_restore(ipl);
  471.         return;
  472.     } else {
  473.         t->detached = true;
  474.     }
  475.     spinlock_unlock(&t->lock);
  476.     interrupts_restore(ipl);
  477. }
  478.  
  479. /** Thread usleep
  480.  *
  481.  * Suspend execution of the current thread.
  482.  *
  483.  * @param usec Number of microseconds to sleep.
  484.  *
  485.  */
  486. void thread_usleep(__u32 usec)
  487. {
  488.     waitq_t wq;
  489.                  
  490.     waitq_initialize(&wq);
  491.  
  492.     (void) waitq_sleep_timeout(&wq, usec, SYNCH_FLAGS_NON_BLOCKING);
  493. }
  494.  
  495. /** Register thread out-of-context invocation
  496.  *
  497.  * Register a function and its argument to be executed
  498.  * on next context switch to the current thread.
  499.  *
  500.  * @param call_me      Out-of-context function.
  501.  * @param call_me_with Out-of-context function argument.
  502.  *
  503.  */
  504. void thread_register_call_me(void (* call_me)(void *), void *call_me_with)
  505. {
  506.     ipl_t ipl;
  507.    
  508.     ipl = interrupts_disable();
  509.     spinlock_lock(&THREAD->lock);
  510.     THREAD->call_me = call_me;
  511.     THREAD->call_me_with = call_me_with;
  512.     spinlock_unlock(&THREAD->lock);
  513.     interrupts_restore(ipl);
  514. }
  515.  
  516. /** Print list of threads debug info */
  517. void thread_print_list(void)
  518. {
  519.     link_t *cur;
  520.     ipl_t ipl;
  521.    
  522.     /* Messing with thread structures, avoid deadlock */
  523.     ipl = interrupts_disable();
  524.     spinlock_lock(&threads_lock);
  525.  
  526.     for (cur = threads_btree.leaf_head.next; cur != &threads_btree.leaf_head; cur = cur->next) {
  527.         btree_node_t *node;
  528.         int i;
  529.  
  530.         node = list_get_instance(cur, btree_node_t, leaf_link);
  531.         for (i = 0; i < node->keys; i++) {
  532.             thread_t *t;
  533.        
  534.             t = (thread_t *) node->value[i];
  535.             printf("%s: address=%#zX, tid=%zd, state=%s, task=%#zX, code=%#zX, stack=%#zX, cpu=",
  536.                 t->name, t, t->tid, thread_states[t->state], t->task, t->thread_code, t->kstack);
  537.             if (t->cpu)
  538.                 printf("cpu%zd", t->cpu->id);
  539.             else
  540.                 printf("none");
  541.             if (t->state == Sleeping) {
  542.                 printf(", kst=%#zX", t->kstack);
  543.                 printf(", wq=%#zX", t->sleep_queue);
  544.             }
  545.             printf("\n");
  546.         }
  547.     }
  548.  
  549.     spinlock_unlock(&threads_lock);
  550.     interrupts_restore(ipl);
  551. }
  552.  
  553. /** Check whether thread exists.
  554.  *
  555.  * Note that threads_lock must be already held and
  556.  * interrupts must be already disabled.
  557.  *
  558.  * @param t Pointer to thread.
  559.  *
  560.  * @return True if thread t is known to the system, false otherwise.
  561.  */
  562. bool thread_exists(thread_t *t)
  563. {
  564.     btree_node_t *leaf;
  565.    
  566.     return btree_search(&threads_btree, (btree_key_t) ((__address) t), &leaf) != NULL;
  567. }
  568.  
  569. /** Process syscall to create new thread.
  570.  *
  571.  */
  572. __native sys_thread_create(uspace_arg_t *uspace_uarg, char *uspace_name)
  573. {
  574.     thread_t *t;
  575.     char namebuf[THREAD_NAME_BUFLEN];
  576.     uspace_arg_t *kernel_uarg;
  577.     __u32 tid;
  578.     int rc;
  579.  
  580.     rc = copy_from_uspace(namebuf, uspace_name, THREAD_NAME_BUFLEN);
  581.     if (rc != 0)
  582.         return (__native) rc;
  583.  
  584.     kernel_uarg = (uspace_arg_t *) malloc(sizeof(uspace_arg_t), 0);
  585.     rc = copy_from_uspace(kernel_uarg, uspace_uarg, sizeof(uspace_arg_t));
  586.     if (rc != 0) {
  587.         free(kernel_uarg);
  588.         return (__native) rc;
  589.     }
  590.  
  591.     if ((t = thread_create(uinit, kernel_uarg, TASK, 0, namebuf))) {
  592.         tid = t->tid;
  593.         thread_ready(t);
  594.         return (__native) tid;
  595.     } else {
  596.         free(kernel_uarg);
  597.     }
  598.  
  599.     return (__native) ENOMEM;
  600. }
  601.  
  602. /** Process syscall to terminate thread.
  603.  *
  604.  */
  605. __native sys_thread_exit(int uspace_status)
  606. {
  607.     thread_exit();
  608.     /* Unreachable */
  609.     return 0;
  610. }
  611.