eb9053b12f
kernel #defines to figure out where the stack is located. This stops libc_r from exploding when the kernel is compiled with a different KVM size. IMHO this is all kinda bogus, it would be better to just check %esp and work from that.
238 lines
8.6 KiB
C
238 lines
8.6 KiB
C
/*
|
|
* Copyright (c) 2001 Daniel Eischen <deischen@freebsd.org>
|
|
* Copyright (c) 2000-2001 Jason Evans <jasone@freebsd.org>
|
|
* All rights reserved.
|
|
*
|
|
* 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.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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.
|
|
*
|
|
* $FreeBSD$
|
|
*/
|
|
#include <sys/types.h>
|
|
#include <sys/mman.h>
|
|
#include <sys/param.h>
|
|
#include <sys/queue.h>
|
|
#include <sys/user.h>
|
|
#include <stdlib.h>
|
|
#include <pthread.h>
|
|
#include "pthread_private.h"
|
|
|
|
/* Spare thread stack. */
|
|
struct stack {
|
|
LIST_ENTRY(stack) qe; /* Stack queue linkage. */
|
|
size_t stacksize; /* Stack size (rounded up). */
|
|
size_t guardsize; /* Guard size. */
|
|
void *stackaddr; /* Stack address. */
|
|
};
|
|
|
|
/*
|
|
* Default sized (stack and guard) spare stack queue. Stacks are cached to
|
|
* avoid additional complexity managing mmap()ed stack regions. Spare stacks
|
|
* are used in LIFO order to increase cache locality.
|
|
*/
|
|
static LIST_HEAD(, stack) _dstackq = LIST_HEAD_INITIALIZER(_dstackq);
|
|
|
|
/*
|
|
* Miscellaneous sized (non-default stack and/or guard) spare stack queue.
|
|
* Stacks are cached to avoid additional complexity managing mmap()ed stack
|
|
* regions. This list is unordered, since ordering on both stack size and guard
|
|
* size would be more trouble than it's worth. Stacks are allocated from this
|
|
* cache on a first size match basis.
|
|
*/
|
|
static LIST_HEAD(, stack) _mstackq = LIST_HEAD_INITIALIZER(_mstackq);
|
|
|
|
/**
|
|
* Base address of the last stack allocated (including its red zone, if there is
|
|
* one). Stacks are allocated contiguously, starting beyond the top of the main
|
|
* stack. When a new stack is created, a red zone is typically created
|
|
* (actually, the red zone is simply left unmapped) above the top of the stack,
|
|
* such that the stack will not be able to grow all the way to the bottom of the
|
|
* next stack. This isn't fool-proof. It is possible for a stack to grow by a
|
|
* large amount, such that it grows into the next stack, and as long as the
|
|
* memory within the red zone is never accessed, nothing will prevent one thread
|
|
* stack from trouncing all over the next.
|
|
*
|
|
* low memory
|
|
* . . . . . . . . . . . . . . . . . .
|
|
* | |
|
|
* | stack 3 | start of 3rd thread stack
|
|
* +-----------------------------------+
|
|
* | |
|
|
* | Red Zone (guard page) | red zone for 2nd thread
|
|
* | |
|
|
* +-----------------------------------+
|
|
* | stack 2 - PTHREAD_STACK_DEFAULT | top of 2nd thread stack
|
|
* | |
|
|
* | |
|
|
* | |
|
|
* | |
|
|
* | stack 2 |
|
|
* +-----------------------------------+ <-- start of 2nd thread stack
|
|
* | |
|
|
* | Red Zone | red zone for 1st thread
|
|
* | |
|
|
* +-----------------------------------+
|
|
* | stack 1 - PTHREAD_STACK_DEFAULT | top of 1st thread stack
|
|
* | |
|
|
* | |
|
|
* | |
|
|
* | |
|
|
* | stack 1 |
|
|
* +-----------------------------------+ <-- start of 1st thread stack
|
|
* | | (initial value of last_stack)
|
|
* | Red Zone |
|
|
* | | red zone for main thread
|
|
* +-----------------------------------+
|
|
* | USRSTACK - PTHREAD_STACK_INITIAL | top of main thread stack
|
|
* | | ^
|
|
* | | |
|
|
* | | |
|
|
* | | | stack growth
|
|
* | |
|
|
* +-----------------------------------+ <-- start of main thread stack
|
|
* (USRSTACK)
|
|
* high memory
|
|
*
|
|
*/
|
|
static void * last_stack;
|
|
|
|
void *
|
|
_thread_stack_alloc(size_t stacksize, size_t guardsize)
|
|
{
|
|
void *stack = NULL;
|
|
struct stack *spare_stack;
|
|
size_t stack_size;
|
|
|
|
/*
|
|
* Round up stack size to nearest multiple of PAGE_SIZE, so that mmap()
|
|
* will work. If the stack size is not an even multiple, we end up
|
|
* initializing things such that there is unused space above the
|
|
* beginning of the stack, so the stack sits snugly against its guard.
|
|
*/
|
|
if (stacksize % PAGE_SIZE != 0)
|
|
stack_size = ((stacksize / PAGE_SIZE) + 1) * PAGE_SIZE;
|
|
else
|
|
stack_size = stacksize;
|
|
|
|
/*
|
|
* If the stack and guard sizes are default, try to allocate a stack
|
|
* from the default-size stack cache:
|
|
*/
|
|
if (stack_size == PTHREAD_STACK_DEFAULT &&
|
|
guardsize == PTHREAD_GUARD_DEFAULT) {
|
|
/*
|
|
* Use the garbage collector mutex for synchronization of the
|
|
* spare stack list.
|
|
*/
|
|
if (pthread_mutex_lock(&_gc_mutex) != 0)
|
|
PANIC("Cannot lock gc mutex");
|
|
|
|
if ((spare_stack = LIST_FIRST(&_dstackq)) != NULL) {
|
|
/* Use the spare stack. */
|
|
LIST_REMOVE(spare_stack, qe);
|
|
stack = spare_stack->stackaddr;
|
|
}
|
|
|
|
/* Unlock the garbage collector mutex. */
|
|
if (pthread_mutex_unlock(&_gc_mutex) != 0)
|
|
PANIC("Cannot unlock gc mutex");
|
|
}
|
|
/*
|
|
* The user specified a non-default stack and/or guard size, so try to
|
|
* allocate a stack from the non-default size stack cache, using the
|
|
* rounded up stack size (stack_size) in the search:
|
|
*/
|
|
else {
|
|
/*
|
|
* Use the garbage collector mutex for synchronization of the
|
|
* spare stack list.
|
|
*/
|
|
if (pthread_mutex_lock(&_gc_mutex) != 0)
|
|
PANIC("Cannot lock gc mutex");
|
|
|
|
LIST_FOREACH(spare_stack, &_mstackq, qe) {
|
|
if (spare_stack->stacksize == stack_size &&
|
|
spare_stack->guardsize == guardsize) {
|
|
LIST_REMOVE(spare_stack, qe);
|
|
stack = spare_stack->stackaddr;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Unlock the garbage collector mutex. */
|
|
if (pthread_mutex_unlock(&_gc_mutex) != 0)
|
|
PANIC("Cannot unlock gc mutex");
|
|
}
|
|
|
|
/* Check if a stack was not allocated from a stack cache: */
|
|
if (stack == NULL) {
|
|
|
|
if (last_stack == NULL)
|
|
last_stack = _usrstack - PTHREAD_STACK_INITIAL -
|
|
PTHREAD_GUARD_DEFAULT;
|
|
|
|
/* Allocate a new stack. */
|
|
stack = last_stack - stack_size;
|
|
|
|
/*
|
|
* Even if stack allocation fails, we don't want to try to use
|
|
* this location again, so unconditionally decrement
|
|
* last_stack. Under normal operating conditions, the most
|
|
* likely reason for an mmap() error is a stack overflow of the
|
|
* adjacent thread stack.
|
|
*/
|
|
last_stack -= (stack_size + guardsize);
|
|
|
|
/* Stack: */
|
|
if (mmap(stack, stack_size, PROT_READ | PROT_WRITE, MAP_STACK,
|
|
-1, 0) == MAP_FAILED)
|
|
stack = NULL;
|
|
}
|
|
|
|
return (stack);
|
|
}
|
|
|
|
/* This function must be called with _gc_mutex held. */
|
|
void
|
|
_thread_stack_free(void *stack, size_t stacksize, size_t guardsize)
|
|
{
|
|
struct stack *spare_stack;
|
|
|
|
spare_stack = (stack + stacksize - sizeof(struct stack));
|
|
/* Round stacksize up to nearest multiple of PAGE_SIZE. */
|
|
if (stacksize % PAGE_SIZE != 0) {
|
|
spare_stack->stacksize = ((stacksize / PAGE_SIZE) + 1) *
|
|
PAGE_SIZE;
|
|
} else
|
|
spare_stack->stacksize = stacksize;
|
|
spare_stack->guardsize = guardsize;
|
|
spare_stack->stackaddr = stack;
|
|
|
|
if (spare_stack->stacksize == PTHREAD_STACK_DEFAULT &&
|
|
spare_stack->guardsize == PTHREAD_GUARD_DEFAULT) {
|
|
/* Default stack/guard size. */
|
|
LIST_INSERT_HEAD(&_dstackq, spare_stack, qe);
|
|
} else {
|
|
/* Non-default stack/guard size. */
|
|
LIST_INSERT_HEAD(&_mstackq, spare_stack, qe);
|
|
}
|
|
}
|