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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.     pfn_t pfn;
  128.     int status;
  129.  
  130.     spinlock_initialize(&t->lock, "thread_t_lock");
  131.     link_initialize(&t->rq_link);
  132.     link_initialize(&t->wq_link);
  133.     link_initialize(&t->th_link);
  134.    
  135. #ifdef ARCH_HAS_FPU
  136. #  ifdef CONFIG_FPU_LAZY
  137.     t->saved_fpu_context = NULL;
  138. #  else
  139.     t->saved_fpu_context = slab_alloc(fpu_context_slab,kmflags);
  140.     if (!t->saved_fpu_context)
  141.         return -1;
  142. #  endif
  143. #endif 
  144.  
  145.     pfn = frame_alloc_rc(STACK_FRAMES, FRAME_KA | kmflags,&status);
  146.     if (status) {
  147. #ifdef ARCH_HAS_FPU
  148.         if (t->saved_fpu_context)
  149.             slab_free(fpu_context_slab,t->saved_fpu_context);
  150. #endif
  151.         return -1;
  152.     }
  153.     t->kstack = (__u8 *)PA2KA(PFN2ADDR(pfn));
  154.  
  155.     return 0;
  156. }
  157.  
  158. /** Destruction of thread_t object */
  159. static int thr_destructor(void *obj)
  160. {
  161.     thread_t *t = (thread_t *)obj;
  162.  
  163.     frame_free(ADDR2PFN(KA2PA(t->kstack)));
  164. #ifdef ARCH_HAS_FPU
  165.     if (t->saved_fpu_context)
  166.         slab_free(fpu_context_slab,t->saved_fpu_context);
  167. #endif
  168.     return 1; /* One page freed */
  169. }
  170.  
  171. /** Initialize threads
  172.  *
  173.  * Initialize kernel threads support.
  174.  *
  175.  */
  176. void thread_init(void)
  177. {
  178.     THREAD = NULL;
  179.     atomic_set(&nrdy,0);
  180.     thread_slab = slab_cache_create("thread_slab",
  181.                     sizeof(thread_t),0,
  182.                     thr_constructor, thr_destructor, 0);
  183. #ifdef ARCH_HAS_FPU
  184.     fpu_context_slab = slab_cache_create("fpu_slab",
  185.                          sizeof(fpu_context_t),
  186.                          FPU_CONTEXT_ALIGN,
  187.                          NULL, NULL, 0);
  188. #endif
  189.  
  190.     btree_create(&threads_btree);
  191. }
  192.  
  193. /** Make thread ready
  194.  *
  195.  * Switch thread t to the ready state.
  196.  *
  197.  * @param t Thread to make ready.
  198.  *
  199.  */
  200. void thread_ready(thread_t *t)
  201. {
  202.     cpu_t *cpu;
  203.     runq_t *r;
  204.     ipl_t ipl;
  205.     int i, avg;
  206.  
  207.     ipl = interrupts_disable();
  208.  
  209.     spinlock_lock(&t->lock);
  210.  
  211.     ASSERT(! (t->state == Ready));
  212.  
  213.     i = (t->priority < RQ_COUNT -1) ? ++t->priority : t->priority;
  214.    
  215.     cpu = CPU;
  216.     if (t->flags & X_WIRED) {
  217.         cpu = t->cpu;
  218.     }
  219.     t->state = Ready;
  220.     spinlock_unlock(&t->lock);
  221.    
  222.     /*
  223.      * Append t to respective ready queue on respective processor.
  224.      */
  225.     r = &cpu->rq[i];
  226.     spinlock_lock(&r->lock);
  227.     list_append(&t->rq_link, &r->rq_head);
  228.     r->n++;
  229.     spinlock_unlock(&r->lock);
  230.  
  231.     atomic_inc(&nrdy);
  232.     avg = atomic_get(&nrdy) / config.cpu_active;
  233.     atomic_inc(&cpu->nrdy);
  234.  
  235.     interrupts_restore(ipl);
  236. }
  237.  
  238. /** Destroy thread memory structure
  239.  *
  240.  * Detach thread from all queues, cpus etc. and destroy it.
  241.  *
  242.  * Assume thread->lock is held!!
  243.  */
  244. void thread_destroy(thread_t *t)
  245. {
  246.     bool destroy_task = false; 
  247.  
  248.     ASSERT(t->state == Exiting || t->state == Undead);
  249.     ASSERT(t->task);
  250.     ASSERT(t->cpu);
  251.  
  252.     spinlock_lock(&t->cpu->lock);
  253.     if(t->cpu->fpu_owner==t)
  254.         t->cpu->fpu_owner=NULL;
  255.     spinlock_unlock(&t->cpu->lock);
  256.  
  257.     spinlock_unlock(&t->lock);
  258.  
  259.     spinlock_lock(&threads_lock);
  260.     btree_remove(&threads_btree, (btree_key_t) ((__address ) t), NULL);
  261.     spinlock_unlock(&threads_lock);
  262.  
  263.     /*
  264.      * Detach from the containing task.
  265.      */
  266.     spinlock_lock(&t->task->lock);
  267.     list_remove(&t->th_link);
  268.     if (--t->task->refcount == 0) {
  269.         t->task->accept_new_threads = false;
  270.         destroy_task = true;
  271.     }
  272.     spinlock_unlock(&t->task->lock);   
  273.    
  274.     if (destroy_task)
  275.         task_destroy(t->task);
  276.    
  277.     slab_free(thread_slab, t);
  278. }
  279.  
  280. /** Create new thread
  281.  *
  282.  * Create a new thread.
  283.  *
  284.  * @param func  Thread's implementing function.
  285.  * @param arg   Thread's implementing function argument.
  286.  * @param task  Task to which the thread belongs.
  287.  * @param flags Thread flags.
  288.  * @param name  Symbolic name.
  289.  *
  290.  * @return New thread's structure on success, NULL on failure.
  291.  *
  292.  */
  293. thread_t *thread_create(void (* func)(void *), void *arg, task_t *task, int flags, char *name)
  294. {
  295.     thread_t *t;
  296.     ipl_t ipl;
  297.    
  298.     t = (thread_t *) slab_alloc(thread_slab, 0);
  299.     if (!t)
  300.         return NULL;
  301.  
  302.     thread_create_arch(t);
  303.    
  304.     /* Not needed, but good for debugging */
  305.     memsetb((__address)t->kstack, THREAD_STACK_SIZE * 1<<STACK_FRAMES, 0);
  306.    
  307.     ipl = interrupts_disable();
  308.     spinlock_lock(&tidlock);
  309.     t->tid = ++last_tid;
  310.     spinlock_unlock(&tidlock);
  311.     interrupts_restore(ipl);
  312.    
  313.     context_save(&t->saved_context);
  314.     context_set(&t->saved_context, FADDR(cushion), (__address) t->kstack, THREAD_STACK_SIZE);
  315.    
  316.     the_initialize((the_t *) t->kstack);
  317.    
  318.     ipl = interrupts_disable();
  319.     t->saved_context.ipl = interrupts_read();
  320.     interrupts_restore(ipl);
  321.    
  322.     memcpy(t->name, name, THREAD_NAME_BUFLEN);
  323.    
  324.     t->thread_code = func;
  325.     t->thread_arg = arg;
  326.     t->ticks = -1;
  327.     t->priority = -1;       /* start in rq[0] */
  328.     t->cpu = NULL;
  329.     t->flags = 0;
  330.     t->state = Entering;
  331.     t->call_me = NULL;
  332.     t->call_me_with = NULL;
  333.    
  334.     timeout_initialize(&t->sleep_timeout);
  335.     t->sleep_interruptible = false;
  336.     t->sleep_queue = NULL;
  337.     t->timeout_pending = 0;
  338.  
  339.     t->in_copy_from_uspace = false;
  340.     t->in_copy_to_uspace = false;
  341.  
  342.     t->interrupted = false;
  343.     t->join_type = None;
  344.     t->detached = false;
  345.     waitq_initialize(&t->join_wq);
  346.    
  347.     t->rwlock_holder_type = RWLOCK_NONE;
  348.        
  349.     t->task = task;
  350.    
  351.     t->fpu_context_exists = 0;
  352.     t->fpu_context_engaged = 0;
  353.    
  354.     /*
  355.      * Attach to the containing task.
  356.      */
  357.     ipl = interrupts_disable();  
  358.     spinlock_lock(&task->lock);
  359.     if (!task->accept_new_threads) {
  360.         spinlock_unlock(&task->lock);
  361.         slab_free(thread_slab, t);
  362.         interrupts_restore(ipl);
  363.         return NULL;
  364.     }
  365.     list_append(&t->th_link, &task->th_head);
  366.     if (task->refcount++ == 0)
  367.         task->main_thread = t;
  368.     spinlock_unlock(&task->lock);
  369.  
  370.     /*
  371.      * Register this thread in the system-wide list.
  372.      */
  373.     spinlock_lock(&threads_lock);
  374.     btree_insert(&threads_btree, (btree_key_t) ((__address) t), (void *) t, NULL);
  375.     spinlock_unlock(&threads_lock);
  376.    
  377.     interrupts_restore(ipl);
  378.    
  379.     return t;
  380. }
  381.  
  382. /** Terminate thread.
  383.  *
  384.  * End current thread execution and switch it to the exiting
  385.  * state. All pending timeouts are executed.
  386.  *
  387.  */
  388. void thread_exit(void)
  389. {
  390.     ipl_t ipl;
  391.  
  392. restart:
  393.     ipl = interrupts_disable();
  394.     spinlock_lock(&THREAD->lock);
  395.     if (THREAD->timeout_pending) { /* busy waiting for timeouts in progress */
  396.         spinlock_unlock(&THREAD->lock);
  397.         interrupts_restore(ipl);
  398.         goto restart;
  399.     }
  400.     THREAD->state = Exiting;
  401.     spinlock_unlock(&THREAD->lock);
  402.     scheduler();
  403.  
  404.     /* Not reached */
  405.     while (1)
  406.         ;
  407. }
  408.  
  409.  
  410. /** Thread sleep
  411.  *
  412.  * Suspend execution of the current thread.
  413.  *
  414.  * @param sec Number of seconds to sleep.
  415.  *
  416.  */
  417. void thread_sleep(__u32 sec)
  418. {
  419.     thread_usleep(sec*1000000);
  420. }
  421.  
  422. /** Wait for another thread to exit.
  423.  *
  424.  * @param t Thread to join on exit.
  425.  * @param usec Timeout in microseconds.
  426.  * @param flags Mode of operation.
  427.  *
  428.  * @return An error code from errno.h or an error code from synch.h.
  429.  */
  430. int thread_join_timeout(thread_t *t, __u32 usec, int flags)
  431. {
  432.     ipl_t ipl;
  433.     int rc;
  434.  
  435.     if (t == THREAD)
  436.         return EINVAL;
  437.  
  438.     /*
  439.      * Since thread join can only be called once on an undetached thread,
  440.      * the thread pointer is guaranteed to be still valid.
  441.      */
  442.    
  443.     ipl = interrupts_disable();
  444.     spinlock_lock(&t->lock);
  445.     ASSERT(!t->detached);
  446.     spinlock_unlock(&t->lock);
  447.     interrupts_restore(ipl);
  448.    
  449.     rc = waitq_sleep_timeout(&t->join_wq, usec, flags);
  450.    
  451.     return rc; 
  452. }
  453.  
  454. /** Detach thread.
  455.  *
  456.  * Mark the thread as detached, if the thread is already in the Undead state,
  457.  * deallocate its resources.
  458.  *
  459.  * @param t Thread to be detached.
  460.  */
  461. void thread_detach(thread_t *t)
  462. {
  463.     ipl_t ipl;
  464.  
  465.     /*
  466.      * Since the thread is expected to not be already detached,
  467.      * pointer to it must be still valid.
  468.      */
  469.     ipl = interrupts_disable();
  470.     spinlock_lock(&t->lock);
  471.     ASSERT(!t->detached);
  472.     if (t->state == Undead) {
  473.         thread_destroy(t);  /* unlocks &t->lock */
  474.         interrupts_restore(ipl);
  475.         return;
  476.     } else {
  477.         t->detached = true;
  478.     }
  479.     spinlock_unlock(&t->lock);
  480.     interrupts_restore(ipl);
  481. }
  482.  
  483. /** Thread usleep
  484.  *
  485.  * Suspend execution of the current thread.
  486.  *
  487.  * @param usec Number of microseconds to sleep.
  488.  *
  489.  */
  490. void thread_usleep(__u32 usec)
  491. {
  492.     waitq_t wq;
  493.                  
  494.     waitq_initialize(&wq);
  495.  
  496.     (void) waitq_sleep_timeout(&wq, usec, SYNCH_FLAGS_NON_BLOCKING);
  497. }
  498.  
  499. /** Register thread out-of-context invocation
  500.  *
  501.  * Register a function and its argument to be executed
  502.  * on next context switch to the current thread.
  503.  *
  504.  * @param call_me      Out-of-context function.
  505.  * @param call_me_with Out-of-context function argument.
  506.  *
  507.  */
  508. void thread_register_call_me(void (* call_me)(void *), void *call_me_with)
  509. {
  510.     ipl_t ipl;
  511.    
  512.     ipl = interrupts_disable();
  513.     spinlock_lock(&THREAD->lock);
  514.     THREAD->call_me = call_me;
  515.     THREAD->call_me_with = call_me_with;
  516.     spinlock_unlock(&THREAD->lock);
  517.     interrupts_restore(ipl);
  518. }
  519.  
  520. /** Print list of threads debug info */
  521. void thread_print_list(void)
  522. {
  523.     link_t *cur;
  524.     ipl_t ipl;
  525.    
  526.     /* Messing with thread structures, avoid deadlock */
  527.     ipl = interrupts_disable();
  528.     spinlock_lock(&threads_lock);
  529.  
  530.     for (cur = threads_btree.leaf_head.next; cur != &threads_btree.leaf_head; cur = cur->next) {
  531.         btree_node_t *node;
  532.         int i;
  533.  
  534.         node = list_get_instance(cur, btree_node_t, leaf_link);
  535.         for (i = 0; i < node->keys; i++) {
  536.             thread_t *t;
  537.        
  538.             t = (thread_t *) node->value[i];
  539.             printf("%s: address=%#zx, tid=%zd, state=%s, task=%#zx, code=%#zx, stack=%#zx, cpu=",
  540.                 t->name, t, t->tid, thread_states[t->state], t->task, t->thread_code, t->kstack);
  541.             if (t->cpu)
  542.                 printf("cpu%zd", t->cpu->id);
  543.             else
  544.                 printf("none");
  545.             if (t->state == Sleeping) {
  546.                 printf(", kst=%#zx", t->kstack);
  547.                 printf(", wq=%#zx", t->sleep_queue);
  548.             }
  549.             printf("\n");
  550.         }
  551.     }
  552.  
  553.     spinlock_unlock(&threads_lock);
  554.     interrupts_restore(ipl);
  555. }
  556.  
  557. /** Check whether thread exists.
  558.  *
  559.  * Note that threads_lock must be already held and
  560.  * interrupts must be already disabled.
  561.  *
  562.  * @param t Pointer to thread.
  563.  *
  564.  * @return True if thread t is known to the system, false otherwise.
  565.  */
  566. bool thread_exists(thread_t *t)
  567. {
  568.     btree_node_t *leaf;
  569.    
  570.     return btree_search(&threads_btree, (btree_key_t) ((__address) t), &leaf) != NULL;
  571. }
  572.  
  573. /** Process syscall to create new thread.
  574.  *
  575.  */
  576. __native sys_thread_create(uspace_arg_t *uspace_uarg, char *uspace_name)
  577. {
  578.     thread_t *t;
  579.     char namebuf[THREAD_NAME_BUFLEN];
  580.     uspace_arg_t *kernel_uarg;
  581.     __u32 tid;
  582.     int rc;
  583.  
  584.     rc = copy_from_uspace(namebuf, uspace_name, THREAD_NAME_BUFLEN);
  585.     if (rc != 0)
  586.         return (__native) rc;
  587.  
  588.     kernel_uarg = (uspace_arg_t *) malloc(sizeof(uspace_arg_t), 0);
  589.     rc = copy_from_uspace(kernel_uarg, uspace_uarg, sizeof(uspace_arg_t));
  590.     if (rc != 0) {
  591.         free(kernel_uarg);
  592.         return (__native) rc;
  593.     }
  594.  
  595.     if ((t = thread_create(uinit, kernel_uarg, TASK, 0, namebuf))) {
  596.         tid = t->tid;
  597.         thread_ready(t);
  598.         return (__native) tid;
  599.     } else {
  600.         free(kernel_uarg);
  601.     }
  602.  
  603.     return (__native) ENOMEM;
  604. }
  605.  
  606. /** Process syscall to terminate thread.
  607.  *
  608.  */
  609. __native sys_thread_exit(int uspace_status)
  610. {
  611.     thread_exit();
  612.     /* Unreachable */
  613.     return 0;
  614. }
  615.  
  616.  /** @}
  617.  */
  618.  
  619.