371 lines
10 KiB
C
371 lines
10 KiB
C
/* Copyright (C) 2002-2015 Free Software Foundation, Inc.
|
|
Contributed by Zack Weinberg <zack@codesourcery.com>
|
|
|
|
This file is part of GCC.
|
|
|
|
GCC is free software; you can redistribute it and/or modify it under
|
|
the terms of the GNU General Public License as published by the Free
|
|
Software Foundation; either version 3, or (at your option) any later
|
|
version.
|
|
|
|
GCC 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 General Public License
|
|
for more details.
|
|
|
|
Under Section 7 of GPL version 3, you are granted additional
|
|
permissions described in the GCC Runtime Library Exception, version
|
|
3.1, as published by the Free Software Foundation.
|
|
|
|
You should have received a copy of the GNU General Public License and
|
|
a copy of the GCC Runtime Library Exception along with this program;
|
|
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
/* Threads compatibility routines for libgcc2 for VxWorks.
|
|
These are out-of-line routines called from gthr-vxworks.h.
|
|
|
|
This file provides the TLS related support routines, calling specific
|
|
VxWorks kernel entry points for this purpose. The base VxWorks 5.x kernels
|
|
don't feature these entry points, and we provide gthr_supp_vxw_5x.c as an
|
|
option to fill this gap. Asking users to rebuild a kernel is not to be
|
|
taken lightly, still, so we have isolated these routines from the rest of
|
|
vxlib to ensure that the kernel dependencies are only dragged when really
|
|
necessary. */
|
|
|
|
#include "tconfig.h"
|
|
#include "tsystem.h"
|
|
#include "gthr.h"
|
|
|
|
#if defined(__GTHREADS)
|
|
#include <vxWorks.h>
|
|
#ifndef __RTP__
|
|
#include <vxLib.h>
|
|
#endif
|
|
#include <taskLib.h>
|
|
#ifndef __RTP__
|
|
#include <taskHookLib.h>
|
|
#else
|
|
# include <errno.h>
|
|
#endif
|
|
|
|
/* Thread-local storage.
|
|
|
|
We reserve a field in the TCB to point to a dynamically allocated
|
|
array which is used to store TLS values. A TLS key is simply an
|
|
offset in this array. The exact location of the TCB field is not
|
|
known to this code nor to vxlib.c -- all access to it indirects
|
|
through the routines __gthread_get_tls_data and
|
|
__gthread_set_tls_data, which are provided by the VxWorks kernel.
|
|
|
|
There is also a global array which records which keys are valid and
|
|
which have destructors.
|
|
|
|
A task delete hook is installed to execute key destructors. The
|
|
routines __gthread_enter_tls_dtor_context and
|
|
__gthread_leave_tls_dtor_context, which are also provided by the
|
|
kernel, ensure that it is safe to call free() on memory allocated
|
|
by the task being deleted. (This is a no-op on VxWorks 5, but
|
|
a major undertaking on AE.)
|
|
|
|
The task delete hook is only installed when at least one thread
|
|
has TLS data. This is a necessary precaution, to allow this module
|
|
to be unloaded - a module with a hook can not be removed.
|
|
|
|
Since this interface is used to allocate only a small number of
|
|
keys, the table size is small and static, which simplifies the
|
|
code quite a bit. Revisit this if and when it becomes necessary. */
|
|
|
|
#define MAX_KEYS 4
|
|
|
|
/* This is the structure pointed to by the pointer returned
|
|
by __gthread_get_tls_data. */
|
|
struct tls_data
|
|
{
|
|
int *owner;
|
|
void *values[MAX_KEYS];
|
|
unsigned int generation[MAX_KEYS];
|
|
};
|
|
|
|
/* To make sure we only delete TLS data associated with this object,
|
|
include a pointer to a local variable in the TLS data object. */
|
|
static int self_owner;
|
|
|
|
/* Flag to check whether the delete hook is installed. Once installed
|
|
it is only removed when unloading this module. */
|
|
static volatile int delete_hook_installed;
|
|
|
|
/* kernel provided routines */
|
|
extern void *__gthread_get_tls_data (void);
|
|
extern void __gthread_set_tls_data (void *data);
|
|
|
|
extern void __gthread_enter_tls_dtor_context (void);
|
|
extern void __gthread_leave_tls_dtor_context (void);
|
|
|
|
#ifndef __RTP__
|
|
|
|
extern void *__gthread_get_tsd_data (WIND_TCB *tcb);
|
|
extern void __gthread_set_tsd_data (WIND_TCB *tcb, void *data);
|
|
extern void __gthread_enter_tsd_dtor_context (WIND_TCB *tcb);
|
|
extern void __gthread_leave_tsd_dtor_context (WIND_TCB *tcb);
|
|
|
|
#endif /* __RTP__ */
|
|
|
|
/* This is a global structure which records all of the active keys.
|
|
|
|
A key is potentially valid (i.e. has been handed out by
|
|
__gthread_key_create) iff its generation count in this structure is
|
|
even. In that case, the matching entry in the dtors array is a
|
|
routine to be called when a thread terminates with a valid,
|
|
non-NULL specific value for that key.
|
|
|
|
A key is actually valid in a thread T iff the generation count
|
|
stored in this structure is equal to the generation count stored in
|
|
T's specific-value structure. */
|
|
|
|
typedef void (*tls_dtor) (void *);
|
|
|
|
struct tls_keys
|
|
{
|
|
tls_dtor dtor[MAX_KEYS];
|
|
unsigned int generation[MAX_KEYS];
|
|
};
|
|
|
|
#define KEY_VALID_P(key) !(tls_keys.generation[key] & 1)
|
|
|
|
/* Note: if MAX_KEYS is increased, this initializer must be updated
|
|
to match. All the generation counts begin at 1, which means no
|
|
key is valid. */
|
|
static struct tls_keys tls_keys =
|
|
{
|
|
{ 0, 0, 0, 0 },
|
|
{ 1, 1, 1, 1 }
|
|
};
|
|
|
|
/* This lock protects the tls_keys structure. */
|
|
static __gthread_mutex_t tls_lock;
|
|
|
|
static __gthread_once_t tls_init_guard = __GTHREAD_ONCE_INIT;
|
|
|
|
/* Internal routines. */
|
|
|
|
/* The task TCB has just been deleted. Call the destructor
|
|
function for each TLS key that has both a destructor and
|
|
a non-NULL specific value in this thread.
|
|
|
|
This routine does not need to take tls_lock; the generation
|
|
count protects us from calling a stale destructor. It does
|
|
need to read tls_keys.dtor[key] atomically. */
|
|
|
|
static void
|
|
tls_delete_hook (void *tcb ATTRIBUTE_UNUSED)
|
|
{
|
|
struct tls_data *data;
|
|
__gthread_key_t key;
|
|
|
|
#ifdef __RTP__
|
|
data = __gthread_get_tls_data ();
|
|
#else
|
|
/* In kernel mode, we can be called in the context of the thread
|
|
doing the killing, so must use the TCB to determine the data of
|
|
the thread being killed. */
|
|
data = __gthread_get_tsd_data (tcb);
|
|
#endif
|
|
|
|
if (data && data->owner == &self_owner)
|
|
{
|
|
#ifdef __RTP__
|
|
__gthread_enter_tls_dtor_context ();
|
|
#else
|
|
__gthread_enter_tsd_dtor_context (tcb);
|
|
#endif
|
|
for (key = 0; key < MAX_KEYS; key++)
|
|
{
|
|
if (data->generation[key] == tls_keys.generation[key])
|
|
{
|
|
tls_dtor dtor = tls_keys.dtor[key];
|
|
|
|
if (dtor)
|
|
dtor (data->values[key]);
|
|
}
|
|
}
|
|
free (data);
|
|
#ifdef __RTP__
|
|
__gthread_leave_tls_dtor_context ();
|
|
#else
|
|
__gthread_leave_tsd_dtor_context (tcb);
|
|
#endif
|
|
|
|
#ifdef __RTP__
|
|
__gthread_set_tls_data (0);
|
|
#else
|
|
__gthread_set_tsd_data (tcb, 0);
|
|
#endif
|
|
}
|
|
}
|
|
|
|
/* Initialize global data used by the TLS system. */
|
|
static void
|
|
tls_init (void)
|
|
{
|
|
__GTHREAD_MUTEX_INIT_FUNCTION (&tls_lock);
|
|
}
|
|
|
|
static void tls_destructor (void) __attribute__ ((destructor));
|
|
static void
|
|
tls_destructor (void)
|
|
{
|
|
#ifdef __RTP__
|
|
/* All threads but this one should have exited by now. */
|
|
tls_delete_hook (NULL);
|
|
#endif
|
|
/* Unregister the hook. */
|
|
if (delete_hook_installed)
|
|
taskDeleteHookDelete ((FUNCPTR)tls_delete_hook);
|
|
|
|
if (tls_init_guard.done && __gthread_mutex_lock (&tls_lock) != ERROR)
|
|
semDelete (tls_lock);
|
|
}
|
|
|
|
/* External interface */
|
|
|
|
/* Store in KEYP a value which can be passed to __gthread_setspecific/
|
|
__gthread_getspecific to store and retrieve a value which is
|
|
specific to each calling thread. If DTOR is not NULL, it will be
|
|
called when a thread terminates with a non-NULL specific value for
|
|
this key, with the value as its sole argument. */
|
|
|
|
int
|
|
__gthread_key_create (__gthread_key_t *keyp, tls_dtor dtor)
|
|
{
|
|
__gthread_key_t key;
|
|
|
|
__gthread_once (&tls_init_guard, tls_init);
|
|
|
|
if (__gthread_mutex_lock (&tls_lock) == ERROR)
|
|
return errno;
|
|
|
|
for (key = 0; key < MAX_KEYS; key++)
|
|
if (!KEY_VALID_P (key))
|
|
goto found_slot;
|
|
|
|
/* no room */
|
|
__gthread_mutex_unlock (&tls_lock);
|
|
return EAGAIN;
|
|
|
|
found_slot:
|
|
tls_keys.generation[key]++; /* making it even */
|
|
tls_keys.dtor[key] = dtor;
|
|
*keyp = key;
|
|
__gthread_mutex_unlock (&tls_lock);
|
|
return 0;
|
|
}
|
|
|
|
/* Invalidate KEY; it can no longer be used as an argument to
|
|
setspecific/getspecific. Note that this does NOT call destructor
|
|
functions for any live values for this key. */
|
|
int
|
|
__gthread_key_delete (__gthread_key_t key)
|
|
{
|
|
if (key >= MAX_KEYS)
|
|
return EINVAL;
|
|
|
|
__gthread_once (&tls_init_guard, tls_init);
|
|
|
|
if (__gthread_mutex_lock (&tls_lock) == ERROR)
|
|
return errno;
|
|
|
|
if (!KEY_VALID_P (key))
|
|
{
|
|
__gthread_mutex_unlock (&tls_lock);
|
|
return EINVAL;
|
|
}
|
|
|
|
tls_keys.generation[key]++; /* making it odd */
|
|
tls_keys.dtor[key] = 0;
|
|
|
|
__gthread_mutex_unlock (&tls_lock);
|
|
return 0;
|
|
}
|
|
|
|
/* Retrieve the thread-specific value for KEY. If it has never been
|
|
set in this thread, or KEY is invalid, returns NULL.
|
|
|
|
It does not matter if this function races with key_create or
|
|
key_delete; the worst that can happen is you get a value other than
|
|
the one that a serialized implementation would have provided. */
|
|
|
|
void *
|
|
__gthread_getspecific (__gthread_key_t key)
|
|
{
|
|
struct tls_data *data;
|
|
|
|
if (key >= MAX_KEYS)
|
|
return 0;
|
|
|
|
data = __gthread_get_tls_data ();
|
|
|
|
if (!data)
|
|
return 0;
|
|
|
|
if (data->generation[key] != tls_keys.generation[key])
|
|
return 0;
|
|
|
|
return data->values[key];
|
|
}
|
|
|
|
/* Set the thread-specific value for KEY. If KEY is invalid, or
|
|
memory allocation fails, returns -1, otherwise 0.
|
|
|
|
The generation count protects this function against races with
|
|
key_create/key_delete; the worst thing that can happen is that a
|
|
value is successfully stored into a dead generation (and then
|
|
immediately becomes invalid). However, we do have to make sure
|
|
to read tls_keys.generation[key] atomically. */
|
|
|
|
int
|
|
__gthread_setspecific (__gthread_key_t key, void *value)
|
|
{
|
|
struct tls_data *data;
|
|
unsigned int generation;
|
|
|
|
if (key >= MAX_KEYS)
|
|
return EINVAL;
|
|
|
|
data = __gthread_get_tls_data ();
|
|
if (!data)
|
|
{
|
|
if (!delete_hook_installed)
|
|
{
|
|
/* Install the delete hook. */
|
|
if (__gthread_mutex_lock (&tls_lock) == ERROR)
|
|
return ENOMEM;
|
|
if (!delete_hook_installed)
|
|
{
|
|
taskDeleteHookAdd ((FUNCPTR)tls_delete_hook);
|
|
delete_hook_installed = 1;
|
|
}
|
|
__gthread_mutex_unlock (&tls_lock);
|
|
}
|
|
|
|
data = malloc (sizeof (struct tls_data));
|
|
if (!data)
|
|
return ENOMEM;
|
|
|
|
memset (data, 0, sizeof (struct tls_data));
|
|
data->owner = &self_owner;
|
|
__gthread_set_tls_data (data);
|
|
}
|
|
|
|
generation = tls_keys.generation[key];
|
|
|
|
if (generation & 1)
|
|
return EINVAL;
|
|
|
|
data->generation[key] = generation;
|
|
data->values[key] = value;
|
|
|
|
return 0;
|
|
}
|
|
#endif /* __GTHREADS */
|