uclibc-ng/libpthread/linuxthreads/descr.h

/* Linuxthreads - a simple clone()-based implementation of Posix        */
/* threads for Linux.                                                   */
/* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr)              */
/*                                                                      */
/* This program is free software; you can redistribute it and/or        */
/* modify it under the terms of the GNU Library General Public License  */
/* as published by the Free Software Foundation; either version 2       */
/* of the License, or (at your option) any later version.               */
/*                                                                      */
/* This program is distributed in the hope that it will be useful,      */
/* but WITHOUT ANY WARRANTY; without even the implied warranty of       */
/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        */
/* GNU Library General Public License for more details.                 */

#ifndef _DESCR_H
#define _DESCR_H	1

#include <features.h>
#include <sched.h>
#include <setjmp.h>
#include <signal.h>
#include <stdint.h>
#include <sys/types.h>
#include <tls.h>

#if 1
# include <bits/libc-tsd.h>
#else
/* Fast thread-specific data internal to libc.  */
enum __libc_tsd_key_t { _LIBC_TSD_KEY_MALLOC = 0,
			_LIBC_TSD_KEY_DL_ERROR,
			_LIBC_TSD_KEY_RPC_VARS,
			_LIBC_TSD_KEY_LOCALE,
			_LIBC_TSD_KEY_CTYPE_B,
			_LIBC_TSD_KEY_CTYPE_TOLOWER,
			_LIBC_TSD_KEY_CTYPE_TOUPPER,
			_LIBC_TSD_KEY_N };
#endif

/* The type of thread descriptors */
typedef struct _pthread_descr_struct *pthread_descr;


/* Some more includes.  */
#include <pt-machine.h>
#include "../linuxthreads_db/thread_dbP.h"


/* Arguments passed to thread creation routine */
struct pthread_start_args {
  void *(*start_routine)(void *); /* function to run */
  void *arg;                      /* its argument */
  sigset_t mask;                  /* initial signal mask for thread */
  int schedpolicy;                /* initial scheduling policy (if any) */
  struct sched_param schedparam;  /* initial scheduling parameters (if any) */
};


/* Callback interface for removing the thread from waiting on an
   object if it is cancelled while waiting or about to wait.
   This hold a pointer to the object, and a pointer to a function
   which ``extricates'' the thread from its enqueued state.
   The function takes two arguments: pointer to the wait object,
   and a pointer to the thread. It returns 1 if an extrication
   actually occured, and hence the thread must also be signalled.
   It returns 0 if the thread had already been extricated. */
typedef struct _pthread_extricate_struct {
    void *pu_object;
    int (*pu_extricate_func)(void *, pthread_descr);
} pthread_extricate_if;


/* Atomic counter made possible by compare_and_swap */
struct pthread_atomic {
  long p_count;
  int p_spinlock;
};


/* Context info for read write locks. The pthread_rwlock_info structure
   is information about a lock that has been read-locked by the thread
   in whose list this structure appears. The pthread_rwlock_context
   is embedded in the thread context and contains a pointer to the
   head of the list of lock info structures, as well as a count of
   read locks that are untracked, because no info structure could be
   allocated for them. */
struct _pthread_rwlock_t;
typedef struct _pthread_rwlock_info {
  struct _pthread_rwlock_info *pr_next;
  struct _pthread_rwlock_t *pr_lock;
  int pr_lock_count;
} pthread_readlock_info;


/* We keep thread specific data in a special data structure, a two-level
   array.  The top-level array contains pointers to dynamically allocated
   arrays of a certain number of data pointers.  So we can implement a
   sparse array.  Each dynamic second-level array has
	PTHREAD_KEY_2NDLEVEL_SIZE
   entries.  This value shouldn't be too large.  */
#define PTHREAD_KEY_2NDLEVEL_SIZE	32

/* We need to address PTHREAD_KEYS_MAX key with PTHREAD_KEY_2NDLEVEL_SIZE
   keys in each subarray.  */
#define PTHREAD_KEY_1STLEVEL_SIZE \
  ((PTHREAD_KEYS_MAX + PTHREAD_KEY_2NDLEVEL_SIZE - 1) \
   / PTHREAD_KEY_2NDLEVEL_SIZE)


union dtv;

struct _pthread_descr_struct
{
#if !defined USE_TLS || !TLS_DTV_AT_TP
  /* This overlaps tcbhead_t (see tls.h), as used for TLS without threads.  */
  union
  {
    struct
    {
      void *tcb;		/* Pointer to the TCB.  This is not always
				   the address of this thread descriptor.  */
      union dtv *dtvp;
      pthread_descr self;	/* Pointer to this structure */
      int multiple_threads;
# ifdef NEED_DL_SYSINFO
      uintptr_t sysinfo;
# endif
    } data;
    void *__padding[16];
  } p_header;
# define p_multiple_threads p_header.data.multiple_threads
#elif TLS_MULTIPLE_THREADS_IN_TCB
  int p_multiple_threads;
#endif

  pthread_descr p_nextlive, p_prevlive;
                                /* Double chaining of active threads */
  pthread_descr p_nextwaiting;  /* Next element in the queue holding the thr */
  pthread_descr p_nextlock;	/* can be on a queue and waiting on a lock */
  pthread_t p_tid;              /* Thread identifier */
  int p_pid;                    /* PID of Unix process */
  int p_priority;               /* Thread priority (== 0 if not realtime) */
  struct _pthread_fastlock * p_lock; /* Spinlock for synchronized accesses */
  int p_signal;                 /* last signal received */
  sigjmp_buf * p_signal_jmp;    /* where to siglongjmp on a signal or NULL */
  sigjmp_buf * p_cancel_jmp;    /* where to siglongjmp on a cancel or NULL */
  char p_terminated;            /* true if terminated e.g. by pthread_exit */
  char p_detached;              /* true if detached */
  char p_exited;                /* true if the assoc. process terminated */
  void * p_retval;              /* placeholder for return value */
  int p_retcode;                /* placeholder for return code */
  pthread_descr p_joining;      /* thread joining on that thread or NULL */
  struct _pthread_cleanup_buffer * p_cleanup; /* cleanup functions */
  char p_cancelstate;           /* cancellation state */
  char p_canceltype;            /* cancellation type (deferred/async) */
  char p_canceled;              /* cancellation request pending */
  char * p_in_sighandler;       /* stack address of sighandler, or NULL */
  char p_sigwaiting;            /* true if a sigwait() is in progress */
  struct pthread_start_args p_start_args; /* arguments for thread creation */
  void ** p_specific[PTHREAD_KEY_1STLEVEL_SIZE]; /* thread-specific data */
#if !(USE_TLS && HAVE___THREAD)
  void * p_libc_specific[_LIBC_TSD_KEY_N]; /* thread-specific data for libc */
  int * p_errnop;               /* pointer to used errno variable */
  int p_errno;                  /* error returned by last system call */
  int * p_h_errnop;             /* pointer to used h_errno variable */
  int p_h_errno;                /* error returned by last netdb function */
#endif
  int p_userstack;		/* nonzero if the user provided the stack */
  void *p_guardaddr;		/* address of guard area or NULL */
  size_t p_guardsize;		/* size of guard area */
  pthread_descr p_self;		/* Pointer to this structure */
  int p_nr;                     /* Index of descriptor in __pthread_handles */
  int p_report_events;		/* Nonzero if events must be reported.  */
  td_eventbuf_t p_eventbuf;     /* Data for event.  */
  struct pthread_atomic p_resume_count; /* number of times restart() was
					   called on thread */
  char p_woken_by_cancel;       /* cancellation performed wakeup */
  char p_condvar_avail;		/* flag if conditional variable became avail */
  char p_sem_avail;             /* flag if semaphore became available */
  pthread_extricate_if *p_extricate; /* See above */
  pthread_readlock_info *p_readlock_list;  /* List of readlock info structs */
  pthread_readlock_info *p_readlock_free;  /* Free list of structs */
  int p_untracked_readlock_count;	/* Readlocks not tracked by list */
  int p_inheritsched;           /* copied from the thread attribute */
#if HP_TIMING_AVAIL
  hp_timing_t p_cpuclock_offset; /* Initial CPU clock for thread.  */
#endif
#ifdef USE_TLS
  char *p_stackaddr;		/* Stack address.  */
#endif
  size_t p_alloca_cutoff;	/* Maximum size which should be allocated
				   using alloca() instead of malloc().  */
  /* New elements must be added at the end.  */
#ifdef __UCLIBC_HAS_XLOCALE__
  __locale_t locale; /* thread-specific locale from uselocale() only! */
#endif /* __UCLIBC_HAS_XLOCALE__ */
} __attribute__ ((aligned(32))); /* We need to align the structure so that
				    doubles are aligned properly.  This is 8
				    bytes on MIPS and 16 bytes on MIPS64.
				    32 bytes might give better cache
				    utilization.  */



/* Limit between the stack of the initial thread (above) and the
   stacks of other threads (below). Aligned on a STACK_SIZE boundary.
   Initially 0, meaning that the current thread is (by definition)
   the initial thread. */

/* For non-MMU systems also remember to stack top of the initial thread.
 * This is adapted when other stacks are malloc'ed since we don't know
 * the bounds a-priori. -StS */

extern char *__pthread_initial_thread_bos;
#ifndef __ARCH_HAS_MMU__
extern char *__pthread_initial_thread_tos;
#define NOMMU_INITIAL_THREAD_BOUNDS(tos,bos) \
    if ((tos)>=__pthread_initial_thread_bos \
	&& (bos)<__pthread_initial_thread_tos) \
	__pthread_initial_thread_bos = (tos)+1
#else
#define NOMMU_INITIAL_THREAD_BOUNDS(tos,bos) /* empty */
#endif /* __ARCH_HAS_MMU__ */

/* Descriptor of the initial thread */

extern struct _pthread_descr_struct __pthread_initial_thread;

/* Limits of the thread manager stack. */

extern char *__pthread_manager_thread_bos;
extern char *__pthread_manager_thread_tos;

/* Descriptor of the manager thread */

extern struct _pthread_descr_struct __pthread_manager_thread;
extern pthread_descr __pthread_manager_threadp attribute_hidden;

/* Indicate whether at least one thread has a user-defined stack (if 1),
   or all threads have stacks supplied by LinuxThreads (if 0). */

extern int __pthread_nonstandard_stacks;

/* The max size of the thread stack segments.  If the default
   THREAD_SELF implementation is used, this must be a power of two and
   a multiple of PAGE_SIZE.  */
#ifndef STACK_SIZE
#ifdef __ARCH_HAS_MMU__
#define STACK_SIZE  (2 * 1024 * 1024)
#else
#define STACK_SIZE  (4 * __pagesize)
#endif
#endif

/* Get some notion of the current stack.  Need not be exactly the top
   of the stack, just something somewhere in the current frame.  */
#ifndef CURRENT_STACK_FRAME
#define CURRENT_STACK_FRAME  ({ char __csf; &__csf; })
#endif

/* Recover thread descriptor for the current thread */

extern pthread_descr __pthread_find_self (void) __attribute__ ((pure));

static inline pthread_descr thread_self (void) __attribute__ ((pure));
static inline pthread_descr thread_self (void)
{
#ifdef THREAD_SELF
  return THREAD_SELF;
#else
  char *sp = CURRENT_STACK_FRAME;
#ifdef __ARCH_HAS_MMU__
  if (sp >= __pthread_initial_thread_bos)
    return &__pthread_initial_thread;
  else if (sp >= __pthread_manager_thread_bos
	   && sp < __pthread_manager_thread_tos)
    return &__pthread_manager_thread;
  else if (__pthread_nonstandard_stacks)
    return __pthread_find_self();
  else
#ifdef _STACK_GROWS_DOWN
    return (pthread_descr)(((unsigned long)sp | (STACK_SIZE-1))+1) - 1;
#else
    return (pthread_descr)((unsigned long)sp &~ (STACK_SIZE-1));
#endif
#else /* !__ARCH_HAS_MMU__ */
  /* For non-MMU we need to be more careful about the initial thread stack.
   * We refine the initial thread stack bounds dynamically as we allocate
   * the other stack frame such that it doesn't overlap with them. Then
   * we can be sure to pick the right thread according to the current SP */

  /* Since we allow other stack frames to be above or below, we need to
   * treat this case special. When pthread_initialize() wasn't called yet,
   * only the initial thread is there. */
  if (__pthread_initial_thread_bos == NULL) {
      return &__pthread_initial_thread;
  }
  else if (sp >= __pthread_initial_thread_bos
	   && sp < __pthread_initial_thread_tos) {
      return &__pthread_initial_thread;
  }
  else if (sp >= __pthread_manager_thread_bos
	   && sp < __pthread_manager_thread_tos) {
      return &__pthread_manager_thread;
  }
  else {
      return __pthread_find_self();
  }
#endif /* __ARCH_HAS_MMU__ */
#endif
}

#endif	/* descr.h */