linuxthreads/descr.h

   1 /* Linuxthreads - a simple clone()-based implementation of Posix        */
   2 /* threads for Linux.                                                   */
   3 /* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr)              */
   4 /*                                                                      */
   5 /* This program is free software; you can redistribute it and/or        */
   6 /* modify it under the terms of the GNU Library General Public License  */
   7 /* as published by the Free Software Foundation; either version 2       */
   8 /* of the License, or (at your option) any later version.               */
   9 /*                                                                      */
  10 /* This program is distributed in the hope that it will be useful,      */
  11 /* but WITHOUT ANY WARRANTY; without even the implied warranty of       */
  12 /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        */
  13 /* GNU Library General Public License for more details.                 */
  14
  15 #ifndef _DESCR_H
  16 #define _DESCR_H        1
  17
  18 #define __need_res_state
  19 #include <resolv.h>
  20 #include <sched.h>
  21 #include <setjmp.h>
  22 #include <signal.h>
  23 #include <stdint.h>
  24 #include <sys/types.h>
  25 #include <hp-timing.h>
  26 #include <tls.h>
  27
  28 /* Fast thread-specific data internal to libc.  */
  29 enum __libc_tsd_key_t { _LIBC_TSD_KEY_MALLOC = 0,
  30                         _LIBC_TSD_KEY_DL_ERROR,
  31                         _LIBC_TSD_KEY_RPC_VARS,
  32                         _LIBC_TSD_KEY_LOCALE,
  33                         _LIBC_TSD_KEY_CTYPE_B,
  34                         _LIBC_TSD_KEY_CTYPE_TOLOWER,
  35                         _LIBC_TSD_KEY_CTYPE_TOUPPER,
  36                         _LIBC_TSD_KEY_N };
  37
  38 /* The type of thread descriptors */
  39 typedef struct _pthread_descr_struct *pthread_descr;
  40
  41
  42 /* Some more includes.  */
  43 #include <pt-machine.h>
  44 #include <linuxthreads_db/thread_dbP.h>
  45
  46
  47 /* Arguments passed to thread creation routine */
  48 struct pthread_start_args {
  49   void *(*start_routine)(void *); /* function to run */
  50   void *arg;                      /* its argument */
  51   sigset_t mask;                  /* initial signal mask for thread */
  52   int schedpolicy;                /* initial scheduling policy (if any) */
  53   struct sched_param schedparam;  /* initial scheduling parameters (if any) */
  54 };
  55
  56
  57 /* Callback interface for removing the thread from waiting on an
  58    object if it is cancelled while waiting or about to wait.
  59    This hold a pointer to the object, and a pointer to a function
  60    which ``extricates'' the thread from its enqueued state.
  61    The function takes two arguments: pointer to the wait object,
  62    and a pointer to the thread. It returns 1 if an extrication
  63    actually occured, and hence the thread must also be signalled.
  64    It returns 0 if the thread had already been extricated. */
  65 typedef struct _pthread_extricate_struct {
  66     void *pu_object;
  67     int (*pu_extricate_func)(void *, pthread_descr);
  68 } pthread_extricate_if;
  69
  70
  71 /* Atomic counter made possible by compare_and_swap */
  72 struct pthread_atomic {
  73   long p_count;
  74   int p_spinlock;
  75 };
  76
  77
  78 /* Context info for read write locks. The pthread_rwlock_info structure
  79    is information about a lock that has been read-locked by the thread
  80    in whose list this structure appears. The pthread_rwlock_context
  81    is embedded in the thread context and contains a pointer to the
  82    head of the list of lock info structures, as well as a count of
  83    read locks that are untracked, because no info structure could be
  84    allocated for them. */
  85 struct _pthread_rwlock_t;
  86 typedef struct _pthread_rwlock_info {
  87   struct _pthread_rwlock_info *pr_next;
  88   struct _pthread_rwlock_t *pr_lock;
  89   int pr_lock_count;
  90 } pthread_readlock_info;
  91
  92
  93 /* We keep thread specific data in a special data structure, a two-level
  94    array.  The top-level array contains pointers to dynamically allocated
  95    arrays of a certain number of data pointers.  So we can implement a
  96    sparse array.  Each dynamic second-level array has
  97         PTHREAD_KEY_2NDLEVEL_SIZE
  98    entries.  This value shouldn't be too large.  */
  99 #define PTHREAD_KEY_2NDLEVEL_SIZE       32
 100
 101 /* We need to address PTHREAD_KEYS_MAX key with PTHREAD_KEY_2NDLEVEL_SIZE
 102    keys in each subarray.  */
 103 #define PTHREAD_KEY_1STLEVEL_SIZE \
 104   ((PTHREAD_KEYS_MAX + PTHREAD_KEY_2NDLEVEL_SIZE - 1) \
 105    / PTHREAD_KEY_2NDLEVEL_SIZE)
 106
 107
 108 union dtv;
 109
 110 struct _pthread_descr_struct
 111 {
 112 #if !defined USE_TLS || !TLS_DTV_AT_TP
 113   /* This overlaps tcbhead_t (see tls.h), as used for TLS without threads.  */
 114   union
 115   {
 116     struct
 117     {
 118       void *tcb;                /* Pointer to the TCB.  This is not always
 119                                    the address of this thread descriptor.  */
 120       union dtv *dtvp;
 121       pthread_descr self;       /* Pointer to this structure */
 122       int multiple_threads;
 123 # ifdef NEED_DL_SYSINFO
 124       uintptr_t sysinfo;
 125 # endif
 126     } data;
 127     void *__padding[16];
 128   } p_header;
 129 # define p_multiple_threads p_header.data.multiple_threads
 130 #elif TLS_MULTIPLE_THREADS_IN_TCB
 131   int p_multiple_threads;
 132 #endif
 133
 134   pthread_descr p_nextlive, p_prevlive;
 135                                 /* Double chaining of active threads */
 136   pthread_descr p_nextwaiting;  /* Next element in the queue holding the thr */
 137   pthread_descr p_nextlock;     /* can be on a queue and waiting on a lock */
 138   pthread_t p_tid;              /* Thread identifier */
 139   int p_pid;                    /* PID of Unix process */
 140   int p_priority;               /* Thread priority (== 0 if not realtime) */
 141   struct _pthread_fastlock * p_lock; /* Spinlock for synchronized accesses */
 142   int p_signal;                 /* last signal received */
 143   sigjmp_buf * p_signal_jmp;    /* where to siglongjmp on a signal or NULL */
 144   sigjmp_buf * p_cancel_jmp;    /* where to siglongjmp on a cancel or NULL */
 145   char p_terminated;            /* true if terminated e.g. by pthread_exit */
 146   char p_detached;              /* true if detached */
 147   char p_exited;                /* true if the assoc. process terminated */
 148   void * p_retval;              /* placeholder for return value */
 149   int p_retcode;                /* placeholder for return code */
 150   pthread_descr p_joining;      /* thread joining on that thread or NULL */
 151   struct _pthread_cleanup_buffer * p_cleanup; /* cleanup functions */
 152   char p_cancelstate;           /* cancellation state */
 153   char p_canceltype;            /* cancellation type (deferred/async) */
 154   char p_canceled;              /* cancellation request pending */
 155   char * p_in_sighandler;       /* stack address of sighandler, or NULL */
 156   char p_sigwaiting;            /* true if a sigwait() is in progress */
 157   struct pthread_start_args p_start_args; /* arguments for thread creation */
 158   void ** p_specific[PTHREAD_KEY_1STLEVEL_SIZE]; /* thread-specific data */
 159 #if !(USE_TLS && HAVE___THREAD)
 160   void * p_libc_specific[_LIBC_TSD_KEY_N]; /* thread-specific data for libc */
 161   int * p_errnop;               /* pointer to used errno variable */
 162   int p_errno;                  /* error returned by last system call */
 163   int * p_h_errnop;             /* pointer to used h_errno variable */
 164   int p_h_errno;                /* error returned by last netdb function */
 165   struct __res_state *p_resp;   /* Pointer to resolver state */
 166 #endif
 167   struct __res_state p_res;     /* per-thread resolver state */
 168   int p_userstack;              /* nonzero if the user provided the stack */
 169   void *p_guardaddr;            /* address of guard area or NULL */
 170   size_t p_guardsize;           /* size of guard area */
 171   int p_nr;                     /* Index of descriptor in __pthread_handles */
 172   int p_report_events;          /* Nonzero if events must be reported.  */
 173   td_eventbuf_t p_eventbuf;     /* Data for event.  */
 174   struct pthread_atomic p_resume_count; /* number of times restart() was
 175                                            called on thread */
 176   char p_woken_by_cancel;       /* cancellation performed wakeup */
 177   char p_condvar_avail;         /* flag if conditional variable became avail */
 178   char p_sem_avail;             /* flag if semaphore became available */
 179   pthread_extricate_if *p_extricate; /* See above */
 180   pthread_readlock_info *p_readlock_list;  /* List of readlock info structs */
 181   pthread_readlock_info *p_readlock_free;  /* Free list of structs */
 182   int p_untracked_readlock_count;       /* Readlocks not tracked by list */
 183   int p_inheritsched;           /* copied from the thread attribute */
 184 #if HP_TIMING_AVAIL
 185   hp_timing_t p_cpuclock_offset; /* Initial CPU clock for thread.  */
 186 #endif
 187 #ifdef USE_TLS
 188   char *p_stackaddr;            /* Stack address.  */
 189 #endif
 190   size_t p_alloca_cutoff;       /* Maximum size which should be allocated
 191                                    using alloca() instead of malloc().  */
 192   /* New elements must be added at the end.  */
 193 } __attribute__ ((aligned(32))); /* We need to align the structure so that
 194                                     doubles are aligned properly.  This is 8
 195                                     bytes on MIPS and 16 bytes on MIPS64.
 196                                     32 bytes might give better cache
 197                                     utilization.  */
 198
 199
 200
 201 /* Limit between the stack of the initial thread (above) and the
 202    stacks of other threads (below). Aligned on a STACK_SIZE boundary.
 203    Initially 0, meaning that the current thread is (by definition)
 204    the initial thread. */
 205
 206 extern char *__pthread_initial_thread_bos;
 207
 208 /* Descriptor of the initial thread */
 209
 210 extern struct _pthread_descr_struct __pthread_initial_thread;
 211
 212 /* Limits of the thread manager stack. */
 213
 214 extern char *__pthread_manager_thread_bos;
 215 extern char *__pthread_manager_thread_tos;
 216
 217 /* Descriptor of the manager thread */
 218
 219 extern struct _pthread_descr_struct __pthread_manager_thread;
 220 extern pthread_descr __pthread_manager_threadp attribute_hidden;
 221
 222 /* Indicate whether at least one thread has a user-defined stack (if 1),
 223    or all threads have stacks supplied by LinuxThreads (if 0). */
 224
 225 extern int __pthread_nonstandard_stacks;
 226
 227 /* The max size of the thread stack segments.  If the default
 228    THREAD_SELF implementation is used, this must be a power of two and
 229    a multiple of PAGE_SIZE.  */
 230 #ifndef STACK_SIZE
 231 #define STACK_SIZE  (2 * 1024 * 1024)
 232 #endif
 233
 234 /* Get some notion of the current stack.  Need not be exactly the top
 235    of the stack, just something somewhere in the current frame.  */
 236 #ifndef CURRENT_STACK_FRAME
 237 #define CURRENT_STACK_FRAME  ({ char __csf; &__csf; })
 238 #endif
 239
 240 /* Recover thread descriptor for the current thread */
 241
 242 extern pthread_descr __pthread_find_self (void) __attribute__ ((const));
 243
 244 static inline pthread_descr thread_self (void) __attribute__ ((const));
 245 static inline pthread_descr thread_self (void)
 246 {
 247 #ifdef THREAD_SELF
 248   return THREAD_SELF;
 249 #else
 250   char *sp = CURRENT_STACK_FRAME;
 251   if (sp >= __pthread_initial_thread_bos)
 252     return &__pthread_initial_thread;
 253   else if (sp >= __pthread_manager_thread_bos
 254            && sp < __pthread_manager_thread_tos)
 255     return &__pthread_manager_thread;
 256   else if (__pthread_nonstandard_stacks)
 257     return __pthread_find_self();
 258   else
 259 #ifdef _STACK_GROWS_DOWN
 260     return (pthread_descr)(((unsigned long)sp | (STACK_SIZE-1))+1) - 1;
 261 #else
 262     return (pthread_descr)((unsigned long)sp &~ (STACK_SIZE-1));
 263 #endif
 264 #endif
 265 }
 266
 267 #endif  /* descr.h */