NetBSD/lib/libpthread/pthread_stack.c

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/* $NetBSD: pthread_stack.c,v 1.7 2003/03/08 08:03:36 lukem Exp $ */
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/*-
* Copyright (c) 2001 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Nathan J. Williams.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
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#include <sys/cdefs.h>
__RCSID("$NetBSD: pthread_stack.c,v 1.7 2003/03/08 08:03:36 lukem Exp $");
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#include <err.h>
#include <errno.h>
#include <signal.h>
#include <stdint.h>
#include <stdlib.h>
#include <ucontext.h>
#include <unistd.h>
#include <sys/queue.h>
#include <sys/mman.h>
#include <sched.h>
#include "pthread.h"
#include "pthread_int.h"
static pthread_t
pthread__stackid_setup(void *base, int size);
/* Allocate a stack for a thread, and set it up. It needs to be aligned, so
* that a thread can find itself by its stack pointer.
*/
int
pthread__stackalloc(pthread_t *newt)
{
void *addr;
int ret;
vaddr_t a, b, c, d;
/* The mmap() interface doesn't let us specify alignment,
* so we work around it by mmap()'ing twice the needed space,
* then unmapping the unaligned stuff on the edges.
*/
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addr = mmap(NULL, 2 * PT_STACKSIZE, PROT_READ|PROT_WRITE,
MAP_ANON|MAP_PRIVATE, -1, (off_t)0);
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if (addr == MAP_FAILED)
return ENOMEM;
a = (vaddr_t) addr;
if ((a & PT_STACKMASK) != 0) {
b = (a & ~PT_STACKMASK) + PT_STACKSIZE;
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ret = munmap((void *)a, (size_t)(b-a));
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if (ret == -1)
return ENOMEM;
} else {
b = a;
}
c = b + PT_STACKSIZE;
d = a + 2*PT_STACKSIZE;
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ret = munmap((void *)c, (size_t)(d-c));
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if (ret == -1)
return ENOMEM;
*newt = pthread__stackid_setup((void *)b, PT_STACKSIZE);
return 0;
}
/*
* Set up the slightly special stack for the "initial" thread, which
* runs on the normal system stack, and thus gets slightly different
* treatment.
*/
void
pthread__initmain(pthread_t *newt)
{
void *base;
base = (void *) (pthread__sp() & ~PT_STACKMASK);
*newt = pthread__stackid_setup(base, PT_STACKSIZE);
}
static pthread_t
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/*ARGSUSED*/
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pthread__stackid_setup(void *base, int size)
{
pthread_t t;
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size_t pagesize;
int ret;
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/* Protect the next-to-bottom stack page as a red zone. */
/* XXX assumes that the stack grows down. */
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pagesize = (size_t)sysconf(_SC_PAGESIZE);
#ifdef __hppa__
#error "stack does not grow down"
#endif
ret = mprotect((char *)base + pagesize, pagesize, PROT_NONE);
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if (ret == -1)
err(2, "Couldn't mprotect() stack redzone at %p\n",
(char *)base + pagesize);
/*
* Put a pointer to the pthread in the bottom (but
* redzone-protected section) of the stack.
*/
t = base;
t->pt_stack.ss_sp = (char *)base + 2 * pagesize;
t->pt_stack.ss_size = PT_STACKSIZE - 2 * pagesize;
/* Set up an initial ucontext pointer to a "safe" area */
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t->pt_uc =(ucontext_t *)(void *)((char *)t->pt_stack.ss_sp +
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t->pt_stack.ss_size - (pagesize/2));
#ifdef _UC_UCONTEXT_ALIGN
t->pt_uc = (ucontext_t *)((uintptr_t)t->pt_uc & _UC_UCONTEXT_ALIGN);
#endif
return t;
}