mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-22 13:00:06 +00:00
7f507ee17a
ChangeLog: 2014-01-03 Andrew Hunter <ahh@google.com> * elf/dl-open.c (): New comment. * elf/dl-reloc.c (_dl_try_allocate_static_tls): Use atomic_compare_and_exchange_bool_acq (_dl_allocate_static_tls): Block signals. * elf/dl-tls.c (allocate_and_init): Return void. (_dl_update_slotinfo): Block signals, use atomic update. nptl/ChangeLog: 2014-01-03 Andrew Hunter <ahh@google.com> * nptl/Makefile (tst-tls7): New test. * nptl/tst-tls7.c: New file. * nptl/tst-tls7mod.c: New file. * nptl/allocatestack.c (init_one_static_tls): Use atomic barrier.
1264 lines
34 KiB
C
1264 lines
34 KiB
C
/* Copyright (C) 2002-2014 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library 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
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#include <assert.h>
|
|
#include <errno.h>
|
|
#include <signal.h>
|
|
#include <stdint.h>
|
|
#include <string.h>
|
|
#include <unistd.h>
|
|
#include <sys/mman.h>
|
|
#include <sys/param.h>
|
|
#include <dl-sysdep.h>
|
|
#include <dl-tls.h>
|
|
#include <tls.h>
|
|
#include <list.h>
|
|
#include <lowlevellock.h>
|
|
#include <kernel-features.h>
|
|
|
|
|
|
#ifndef NEED_SEPARATE_REGISTER_STACK
|
|
|
|
/* Most architectures have exactly one stack pointer. Some have more. */
|
|
# define STACK_VARIABLES void *stackaddr = NULL
|
|
|
|
/* How to pass the values to the 'create_thread' function. */
|
|
# define STACK_VARIABLES_ARGS stackaddr
|
|
|
|
/* How to declare function which gets there parameters. */
|
|
# define STACK_VARIABLES_PARMS void *stackaddr
|
|
|
|
/* How to declare allocate_stack. */
|
|
# define ALLOCATE_STACK_PARMS void **stack
|
|
|
|
/* This is how the function is called. We do it this way to allow
|
|
other variants of the function to have more parameters. */
|
|
# define ALLOCATE_STACK(attr, pd) allocate_stack (attr, pd, &stackaddr)
|
|
|
|
#else
|
|
|
|
/* We need two stacks. The kernel will place them but we have to tell
|
|
the kernel about the size of the reserved address space. */
|
|
# define STACK_VARIABLES void *stackaddr = NULL; size_t stacksize = 0
|
|
|
|
/* How to pass the values to the 'create_thread' function. */
|
|
# define STACK_VARIABLES_ARGS stackaddr, stacksize
|
|
|
|
/* How to declare function which gets there parameters. */
|
|
# define STACK_VARIABLES_PARMS void *stackaddr, size_t stacksize
|
|
|
|
/* How to declare allocate_stack. */
|
|
# define ALLOCATE_STACK_PARMS void **stack, size_t *stacksize
|
|
|
|
/* This is how the function is called. We do it this way to allow
|
|
other variants of the function to have more parameters. */
|
|
# define ALLOCATE_STACK(attr, pd) \
|
|
allocate_stack (attr, pd, &stackaddr, &stacksize)
|
|
|
|
#endif
|
|
|
|
|
|
/* Default alignment of stack. */
|
|
#ifndef STACK_ALIGN
|
|
# define STACK_ALIGN __alignof__ (long double)
|
|
#endif
|
|
|
|
/* Default value for minimal stack size after allocating thread
|
|
descriptor and guard. */
|
|
#ifndef MINIMAL_REST_STACK
|
|
# define MINIMAL_REST_STACK 4096
|
|
#endif
|
|
|
|
|
|
/* Newer kernels have the MAP_STACK flag to indicate a mapping is used for
|
|
a stack. Use it when possible. */
|
|
#ifndef MAP_STACK
|
|
# define MAP_STACK 0
|
|
#endif
|
|
|
|
/* This yields the pointer that TLS support code calls the thread pointer. */
|
|
#if TLS_TCB_AT_TP
|
|
# define TLS_TPADJ(pd) (pd)
|
|
#elif TLS_DTV_AT_TP
|
|
# define TLS_TPADJ(pd) ((struct pthread *)((char *) (pd) + TLS_PRE_TCB_SIZE))
|
|
#endif
|
|
|
|
/* Cache handling for not-yet free stacks. */
|
|
|
|
/* Maximum size in kB of cache. */
|
|
static size_t stack_cache_maxsize = 40 * 1024 * 1024; /* 40MiBi by default. */
|
|
static size_t stack_cache_actsize;
|
|
|
|
/* Mutex protecting this variable. */
|
|
static int stack_cache_lock = LLL_LOCK_INITIALIZER;
|
|
|
|
/* List of queued stack frames. */
|
|
static LIST_HEAD (stack_cache);
|
|
|
|
/* List of the stacks in use. */
|
|
static LIST_HEAD (stack_used);
|
|
|
|
/* We need to record what list operations we are going to do so that,
|
|
in case of an asynchronous interruption due to a fork() call, we
|
|
can correct for the work. */
|
|
static uintptr_t in_flight_stack;
|
|
|
|
/* List of the threads with user provided stacks in use. No need to
|
|
initialize this, since it's done in __pthread_initialize_minimal. */
|
|
list_t __stack_user __attribute__ ((nocommon));
|
|
hidden_data_def (__stack_user)
|
|
|
|
#if COLORING_INCREMENT != 0
|
|
/* Number of threads created. */
|
|
static unsigned int nptl_ncreated;
|
|
#endif
|
|
|
|
|
|
/* Check whether the stack is still used or not. */
|
|
#define FREE_P(descr) ((descr)->tid <= 0)
|
|
|
|
|
|
static void
|
|
stack_list_del (list_t *elem)
|
|
{
|
|
in_flight_stack = (uintptr_t) elem;
|
|
|
|
atomic_write_barrier ();
|
|
|
|
list_del (elem);
|
|
|
|
atomic_write_barrier ();
|
|
|
|
in_flight_stack = 0;
|
|
}
|
|
|
|
|
|
static void
|
|
stack_list_add (list_t *elem, list_t *list)
|
|
{
|
|
in_flight_stack = (uintptr_t) elem | 1;
|
|
|
|
atomic_write_barrier ();
|
|
|
|
list_add (elem, list);
|
|
|
|
atomic_write_barrier ();
|
|
|
|
in_flight_stack = 0;
|
|
}
|
|
|
|
|
|
/* We create a double linked list of all cache entries. Double linked
|
|
because this allows removing entries from the end. */
|
|
|
|
|
|
/* Get a stack frame from the cache. We have to match by size since
|
|
some blocks might be too small or far too large. */
|
|
static struct pthread *
|
|
get_cached_stack (size_t *sizep, void **memp)
|
|
{
|
|
size_t size = *sizep;
|
|
struct pthread *result = NULL;
|
|
list_t *entry;
|
|
|
|
lll_lock (stack_cache_lock, LLL_PRIVATE);
|
|
|
|
/* Search the cache for a matching entry. We search for the
|
|
smallest stack which has at least the required size. Note that
|
|
in normal situations the size of all allocated stacks is the
|
|
same. As the very least there are only a few different sizes.
|
|
Therefore this loop will exit early most of the time with an
|
|
exact match. */
|
|
list_for_each (entry, &stack_cache)
|
|
{
|
|
struct pthread *curr;
|
|
|
|
curr = list_entry (entry, struct pthread, list);
|
|
if (FREE_P (curr) && curr->stackblock_size >= size)
|
|
{
|
|
if (curr->stackblock_size == size)
|
|
{
|
|
result = curr;
|
|
break;
|
|
}
|
|
|
|
if (result == NULL
|
|
|| result->stackblock_size > curr->stackblock_size)
|
|
result = curr;
|
|
}
|
|
}
|
|
|
|
if (__builtin_expect (result == NULL, 0)
|
|
/* Make sure the size difference is not too excessive. In that
|
|
case we do not use the block. */
|
|
|| __builtin_expect (result->stackblock_size > 4 * size, 0))
|
|
{
|
|
/* Release the lock. */
|
|
lll_unlock (stack_cache_lock, LLL_PRIVATE);
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/* Don't allow setxid until cloned. */
|
|
result->setxid_futex = -1;
|
|
|
|
/* Dequeue the entry. */
|
|
stack_list_del (&result->list);
|
|
|
|
/* And add to the list of stacks in use. */
|
|
stack_list_add (&result->list, &stack_used);
|
|
|
|
/* And decrease the cache size. */
|
|
stack_cache_actsize -= result->stackblock_size;
|
|
|
|
/* Release the lock early. */
|
|
lll_unlock (stack_cache_lock, LLL_PRIVATE);
|
|
|
|
/* Report size and location of the stack to the caller. */
|
|
*sizep = result->stackblock_size;
|
|
*memp = result->stackblock;
|
|
|
|
/* Cancellation handling is back to the default. */
|
|
result->cancelhandling = 0;
|
|
result->cleanup = NULL;
|
|
|
|
/* No pending event. */
|
|
result->nextevent = NULL;
|
|
|
|
/* Clear the DTV. */
|
|
dtv_t *dtv = GET_DTV (TLS_TPADJ (result));
|
|
_dl_clear_dtv (dtv);
|
|
|
|
/* Re-initialize the TLS. */
|
|
_dl_allocate_tls_init (TLS_TPADJ (result));
|
|
|
|
return result;
|
|
}
|
|
|
|
|
|
/* Free stacks until cache size is lower than LIMIT. */
|
|
void
|
|
__free_stacks (size_t limit)
|
|
{
|
|
/* We reduce the size of the cache. Remove the last entries until
|
|
the size is below the limit. */
|
|
list_t *entry;
|
|
list_t *prev;
|
|
|
|
/* Search from the end of the list. */
|
|
list_for_each_prev_safe (entry, prev, &stack_cache)
|
|
{
|
|
struct pthread *curr;
|
|
|
|
curr = list_entry (entry, struct pthread, list);
|
|
if (FREE_P (curr))
|
|
{
|
|
/* Unlink the block. */
|
|
stack_list_del (entry);
|
|
|
|
/* Account for the freed memory. */
|
|
stack_cache_actsize -= curr->stackblock_size;
|
|
|
|
/* Free the memory associated with the ELF TLS. */
|
|
_dl_deallocate_tls (TLS_TPADJ (curr), false);
|
|
|
|
/* Remove this block. This should never fail. If it does
|
|
something is really wrong. */
|
|
if (munmap (curr->stackblock, curr->stackblock_size) != 0)
|
|
abort ();
|
|
|
|
/* Maybe we have freed enough. */
|
|
if (stack_cache_actsize <= limit)
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/* Add a stack frame which is not used anymore to the stack. Must be
|
|
called with the cache lock held. */
|
|
static inline void
|
|
__attribute ((always_inline))
|
|
queue_stack (struct pthread *stack)
|
|
{
|
|
/* We unconditionally add the stack to the list. The memory may
|
|
still be in use but it will not be reused until the kernel marks
|
|
the stack as not used anymore. */
|
|
stack_list_add (&stack->list, &stack_cache);
|
|
|
|
stack_cache_actsize += stack->stackblock_size;
|
|
if (__builtin_expect (stack_cache_actsize > stack_cache_maxsize, 0))
|
|
__free_stacks (stack_cache_maxsize);
|
|
}
|
|
|
|
|
|
static int
|
|
internal_function
|
|
change_stack_perm (struct pthread *pd
|
|
#ifdef NEED_SEPARATE_REGISTER_STACK
|
|
, size_t pagemask
|
|
#endif
|
|
)
|
|
{
|
|
#ifdef NEED_SEPARATE_REGISTER_STACK
|
|
void *stack = (pd->stackblock
|
|
+ (((((pd->stackblock_size - pd->guardsize) / 2)
|
|
& pagemask) + pd->guardsize) & pagemask));
|
|
size_t len = pd->stackblock + pd->stackblock_size - stack;
|
|
#elif _STACK_GROWS_DOWN
|
|
void *stack = pd->stackblock + pd->guardsize;
|
|
size_t len = pd->stackblock_size - pd->guardsize;
|
|
#elif _STACK_GROWS_UP
|
|
void *stack = pd->stackblock;
|
|
size_t len = (uintptr_t) pd - pd->guardsize - (uintptr_t) pd->stackblock;
|
|
#else
|
|
# error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
|
|
#endif
|
|
if (mprotect (stack, len, PROT_READ | PROT_WRITE | PROT_EXEC) != 0)
|
|
return errno;
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
/* Returns a usable stack for a new thread either by allocating a
|
|
new stack or reusing a cached stack of sufficient size.
|
|
ATTR must be non-NULL and point to a valid pthread_attr.
|
|
PDP must be non-NULL. */
|
|
static int
|
|
allocate_stack (const struct pthread_attr *attr, struct pthread **pdp,
|
|
ALLOCATE_STACK_PARMS)
|
|
{
|
|
struct pthread *pd;
|
|
size_t size;
|
|
size_t pagesize_m1 = __getpagesize () - 1;
|
|
void *stacktop;
|
|
|
|
assert (powerof2 (pagesize_m1 + 1));
|
|
assert (TCB_ALIGNMENT >= STACK_ALIGN);
|
|
|
|
/* Get the stack size from the attribute if it is set. Otherwise we
|
|
use the default we determined at start time. */
|
|
if (attr->stacksize != 0)
|
|
size = attr->stacksize;
|
|
else
|
|
{
|
|
lll_lock (__default_pthread_attr_lock, LLL_PRIVATE);
|
|
size = __default_pthread_attr.stacksize;
|
|
lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE);
|
|
}
|
|
|
|
/* Get memory for the stack. */
|
|
if (__builtin_expect (attr->flags & ATTR_FLAG_STACKADDR, 0))
|
|
{
|
|
uintptr_t adj;
|
|
|
|
/* If the user also specified the size of the stack make sure it
|
|
is large enough. */
|
|
if (attr->stacksize != 0
|
|
&& attr->stacksize < (__static_tls_size + MINIMAL_REST_STACK))
|
|
return EINVAL;
|
|
|
|
/* Adjust stack size for alignment of the TLS block. */
|
|
#if TLS_TCB_AT_TP
|
|
adj = ((uintptr_t) attr->stackaddr - TLS_TCB_SIZE)
|
|
& __static_tls_align_m1;
|
|
assert (size > adj + TLS_TCB_SIZE);
|
|
#elif TLS_DTV_AT_TP
|
|
adj = ((uintptr_t) attr->stackaddr - __static_tls_size)
|
|
& __static_tls_align_m1;
|
|
assert (size > adj);
|
|
#endif
|
|
|
|
/* The user provided some memory. Let's hope it matches the
|
|
size... We do not allocate guard pages if the user provided
|
|
the stack. It is the user's responsibility to do this if it
|
|
is wanted. */
|
|
#if TLS_TCB_AT_TP
|
|
pd = (struct pthread *) ((uintptr_t) attr->stackaddr
|
|
- TLS_TCB_SIZE - adj);
|
|
#elif TLS_DTV_AT_TP
|
|
pd = (struct pthread *) (((uintptr_t) attr->stackaddr
|
|
- __static_tls_size - adj)
|
|
- TLS_PRE_TCB_SIZE);
|
|
#endif
|
|
|
|
/* The user provided stack memory needs to be cleared. */
|
|
memset (pd, '\0', sizeof (struct pthread));
|
|
|
|
/* The first TSD block is included in the TCB. */
|
|
pd->specific[0] = pd->specific_1stblock;
|
|
|
|
/* Remember the stack-related values. */
|
|
pd->stackblock = (char *) attr->stackaddr - size;
|
|
pd->stackblock_size = size;
|
|
|
|
/* This is a user-provided stack. It will not be queued in the
|
|
stack cache nor will the memory (except the TLS memory) be freed. */
|
|
pd->user_stack = true;
|
|
|
|
/* This is at least the second thread. */
|
|
pd->header.multiple_threads = 1;
|
|
#ifndef TLS_MULTIPLE_THREADS_IN_TCB
|
|
__pthread_multiple_threads = *__libc_multiple_threads_ptr = 1;
|
|
#endif
|
|
|
|
#ifndef __ASSUME_PRIVATE_FUTEX
|
|
/* The thread must know when private futexes are supported. */
|
|
pd->header.private_futex = THREAD_GETMEM (THREAD_SELF,
|
|
header.private_futex);
|
|
#endif
|
|
|
|
#ifdef NEED_DL_SYSINFO
|
|
/* Copy the sysinfo value from the parent. */
|
|
THREAD_SYSINFO(pd) = THREAD_SELF_SYSINFO;
|
|
#endif
|
|
|
|
/* The process ID is also the same as that of the caller. */
|
|
pd->pid = THREAD_GETMEM (THREAD_SELF, pid);
|
|
|
|
/* Don't allow setxid until cloned. */
|
|
pd->setxid_futex = -1;
|
|
|
|
/* Allocate the DTV for this thread. */
|
|
if (_dl_allocate_tls (TLS_TPADJ (pd)) == NULL)
|
|
{
|
|
/* Something went wrong. */
|
|
assert (errno == ENOMEM);
|
|
return errno;
|
|
}
|
|
|
|
|
|
/* Prepare to modify global data. */
|
|
lll_lock (stack_cache_lock, LLL_PRIVATE);
|
|
|
|
/* And add to the list of stacks in use. */
|
|
list_add (&pd->list, &__stack_user);
|
|
|
|
lll_unlock (stack_cache_lock, LLL_PRIVATE);
|
|
}
|
|
else
|
|
{
|
|
/* Allocate some anonymous memory. If possible use the cache. */
|
|
size_t guardsize;
|
|
size_t reqsize;
|
|
void *mem;
|
|
const int prot = (PROT_READ | PROT_WRITE
|
|
| ((GL(dl_stack_flags) & PF_X) ? PROT_EXEC : 0));
|
|
|
|
#if COLORING_INCREMENT != 0
|
|
/* Add one more page for stack coloring. Don't do it for stacks
|
|
with 16 times pagesize or larger. This might just cause
|
|
unnecessary misalignment. */
|
|
if (size <= 16 * pagesize_m1)
|
|
size += pagesize_m1 + 1;
|
|
#endif
|
|
|
|
/* Adjust the stack size for alignment. */
|
|
size &= ~__static_tls_align_m1;
|
|
assert (size != 0);
|
|
|
|
/* Make sure the size of the stack is enough for the guard and
|
|
eventually the thread descriptor. */
|
|
guardsize = (attr->guardsize + pagesize_m1) & ~pagesize_m1;
|
|
if (__builtin_expect (size < ((guardsize + __static_tls_size
|
|
+ MINIMAL_REST_STACK + pagesize_m1)
|
|
& ~pagesize_m1),
|
|
0))
|
|
/* The stack is too small (or the guard too large). */
|
|
return EINVAL;
|
|
|
|
/* Try to get a stack from the cache. */
|
|
reqsize = size;
|
|
pd = get_cached_stack (&size, &mem);
|
|
if (pd == NULL)
|
|
{
|
|
/* To avoid aliasing effects on a larger scale than pages we
|
|
adjust the allocated stack size if necessary. This way
|
|
allocations directly following each other will not have
|
|
aliasing problems. */
|
|
#if MULTI_PAGE_ALIASING != 0
|
|
if ((size % MULTI_PAGE_ALIASING) == 0)
|
|
size += pagesize_m1 + 1;
|
|
#endif
|
|
|
|
mem = mmap (NULL, size, prot,
|
|
MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
|
|
|
|
if (__builtin_expect (mem == MAP_FAILED, 0))
|
|
return errno;
|
|
|
|
/* SIZE is guaranteed to be greater than zero.
|
|
So we can never get a null pointer back from mmap. */
|
|
assert (mem != NULL);
|
|
|
|
#if COLORING_INCREMENT != 0
|
|
/* Atomically increment NCREATED. */
|
|
unsigned int ncreated = atomic_increment_val (&nptl_ncreated);
|
|
|
|
/* We chose the offset for coloring by incrementing it for
|
|
every new thread by a fixed amount. The offset used
|
|
module the page size. Even if coloring would be better
|
|
relative to higher alignment values it makes no sense to
|
|
do it since the mmap() interface does not allow us to
|
|
specify any alignment for the returned memory block. */
|
|
size_t coloring = (ncreated * COLORING_INCREMENT) & pagesize_m1;
|
|
|
|
/* Make sure the coloring offsets does not disturb the alignment
|
|
of the TCB and static TLS block. */
|
|
if (__builtin_expect ((coloring & __static_tls_align_m1) != 0, 0))
|
|
coloring = (((coloring + __static_tls_align_m1)
|
|
& ~(__static_tls_align_m1))
|
|
& ~pagesize_m1);
|
|
#else
|
|
/* Unless specified we do not make any adjustments. */
|
|
# define coloring 0
|
|
#endif
|
|
|
|
/* Place the thread descriptor at the end of the stack. */
|
|
#if TLS_TCB_AT_TP
|
|
pd = (struct pthread *) ((char *) mem + size - coloring) - 1;
|
|
#elif TLS_DTV_AT_TP
|
|
pd = (struct pthread *) ((((uintptr_t) mem + size - coloring
|
|
- __static_tls_size)
|
|
& ~__static_tls_align_m1)
|
|
- TLS_PRE_TCB_SIZE);
|
|
#endif
|
|
|
|
/* Remember the stack-related values. */
|
|
pd->stackblock = mem;
|
|
pd->stackblock_size = size;
|
|
|
|
/* We allocated the first block thread-specific data array.
|
|
This address will not change for the lifetime of this
|
|
descriptor. */
|
|
pd->specific[0] = pd->specific_1stblock;
|
|
|
|
/* This is at least the second thread. */
|
|
pd->header.multiple_threads = 1;
|
|
#ifndef TLS_MULTIPLE_THREADS_IN_TCB
|
|
__pthread_multiple_threads = *__libc_multiple_threads_ptr = 1;
|
|
#endif
|
|
|
|
#ifndef __ASSUME_PRIVATE_FUTEX
|
|
/* The thread must know when private futexes are supported. */
|
|
pd->header.private_futex = THREAD_GETMEM (THREAD_SELF,
|
|
header.private_futex);
|
|
#endif
|
|
|
|
#ifdef NEED_DL_SYSINFO
|
|
/* Copy the sysinfo value from the parent. */
|
|
THREAD_SYSINFO(pd) = THREAD_SELF_SYSINFO;
|
|
#endif
|
|
|
|
/* Don't allow setxid until cloned. */
|
|
pd->setxid_futex = -1;
|
|
|
|
/* The process ID is also the same as that of the caller. */
|
|
pd->pid = THREAD_GETMEM (THREAD_SELF, pid);
|
|
|
|
/* Allocate the DTV for this thread. */
|
|
if (_dl_allocate_tls (TLS_TPADJ (pd)) == NULL)
|
|
{
|
|
/* Something went wrong. */
|
|
assert (errno == ENOMEM);
|
|
|
|
/* Free the stack memory we just allocated. */
|
|
(void) munmap (mem, size);
|
|
|
|
return errno;
|
|
}
|
|
|
|
|
|
/* Prepare to modify global data. */
|
|
lll_lock (stack_cache_lock, LLL_PRIVATE);
|
|
|
|
/* And add to the list of stacks in use. */
|
|
stack_list_add (&pd->list, &stack_used);
|
|
|
|
lll_unlock (stack_cache_lock, LLL_PRIVATE);
|
|
|
|
|
|
/* There might have been a race. Another thread might have
|
|
caused the stacks to get exec permission while this new
|
|
stack was prepared. Detect if this was possible and
|
|
change the permission if necessary. */
|
|
if (__builtin_expect ((GL(dl_stack_flags) & PF_X) != 0
|
|
&& (prot & PROT_EXEC) == 0, 0))
|
|
{
|
|
int err = change_stack_perm (pd
|
|
#ifdef NEED_SEPARATE_REGISTER_STACK
|
|
, ~pagesize_m1
|
|
#endif
|
|
);
|
|
if (err != 0)
|
|
{
|
|
/* Free the stack memory we just allocated. */
|
|
(void) munmap (mem, size);
|
|
|
|
return err;
|
|
}
|
|
}
|
|
|
|
|
|
/* Note that all of the stack and the thread descriptor is
|
|
zeroed. This means we do not have to initialize fields
|
|
with initial value zero. This is specifically true for
|
|
the 'tid' field which is always set back to zero once the
|
|
stack is not used anymore and for the 'guardsize' field
|
|
which will be read next. */
|
|
}
|
|
|
|
/* Create or resize the guard area if necessary. */
|
|
if (__builtin_expect (guardsize > pd->guardsize, 0))
|
|
{
|
|
#ifdef NEED_SEPARATE_REGISTER_STACK
|
|
char *guard = mem + (((size - guardsize) / 2) & ~pagesize_m1);
|
|
#elif _STACK_GROWS_DOWN
|
|
char *guard = mem;
|
|
# elif _STACK_GROWS_UP
|
|
char *guard = (char *) (((uintptr_t) pd - guardsize) & ~pagesize_m1);
|
|
#endif
|
|
if (mprotect (guard, guardsize, PROT_NONE) != 0)
|
|
{
|
|
mprot_error:
|
|
lll_lock (stack_cache_lock, LLL_PRIVATE);
|
|
|
|
/* Remove the thread from the list. */
|
|
stack_list_del (&pd->list);
|
|
|
|
lll_unlock (stack_cache_lock, LLL_PRIVATE);
|
|
|
|
/* Get rid of the TLS block we allocated. */
|
|
_dl_deallocate_tls (TLS_TPADJ (pd), false);
|
|
|
|
/* Free the stack memory regardless of whether the size
|
|
of the cache is over the limit or not. If this piece
|
|
of memory caused problems we better do not use it
|
|
anymore. Uh, and we ignore possible errors. There
|
|
is nothing we could do. */
|
|
(void) munmap (mem, size);
|
|
|
|
return errno;
|
|
}
|
|
|
|
pd->guardsize = guardsize;
|
|
}
|
|
else if (__builtin_expect (pd->guardsize - guardsize > size - reqsize,
|
|
0))
|
|
{
|
|
/* The old guard area is too large. */
|
|
|
|
#ifdef NEED_SEPARATE_REGISTER_STACK
|
|
char *guard = mem + (((size - guardsize) / 2) & ~pagesize_m1);
|
|
char *oldguard = mem + (((size - pd->guardsize) / 2) & ~pagesize_m1);
|
|
|
|
if (oldguard < guard
|
|
&& mprotect (oldguard, guard - oldguard, prot) != 0)
|
|
goto mprot_error;
|
|
|
|
if (mprotect (guard + guardsize,
|
|
oldguard + pd->guardsize - guard - guardsize,
|
|
prot) != 0)
|
|
goto mprot_error;
|
|
#elif _STACK_GROWS_DOWN
|
|
if (mprotect ((char *) mem + guardsize, pd->guardsize - guardsize,
|
|
prot) != 0)
|
|
goto mprot_error;
|
|
#elif _STACK_GROWS_UP
|
|
if (mprotect ((char *) pd - pd->guardsize,
|
|
pd->guardsize - guardsize, prot) != 0)
|
|
goto mprot_error;
|
|
#endif
|
|
|
|
pd->guardsize = guardsize;
|
|
}
|
|
/* The pthread_getattr_np() calls need to get passed the size
|
|
requested in the attribute, regardless of how large the
|
|
actually used guardsize is. */
|
|
pd->reported_guardsize = guardsize;
|
|
}
|
|
|
|
/* Initialize the lock. We have to do this unconditionally since the
|
|
stillborn thread could be canceled while the lock is taken. */
|
|
pd->lock = LLL_LOCK_INITIALIZER;
|
|
|
|
/* The robust mutex lists also need to be initialized
|
|
unconditionally because the cleanup for the previous stack owner
|
|
might have happened in the kernel. */
|
|
pd->robust_head.futex_offset = (offsetof (pthread_mutex_t, __data.__lock)
|
|
- offsetof (pthread_mutex_t,
|
|
__data.__list.__next));
|
|
pd->robust_head.list_op_pending = NULL;
|
|
#ifdef __PTHREAD_MUTEX_HAVE_PREV
|
|
pd->robust_prev = &pd->robust_head;
|
|
#endif
|
|
pd->robust_head.list = &pd->robust_head;
|
|
|
|
/* We place the thread descriptor at the end of the stack. */
|
|
*pdp = pd;
|
|
|
|
#if TLS_TCB_AT_TP
|
|
/* The stack begins before the TCB and the static TLS block. */
|
|
stacktop = ((char *) (pd + 1) - __static_tls_size);
|
|
#elif TLS_DTV_AT_TP
|
|
stacktop = (char *) (pd - 1);
|
|
#endif
|
|
|
|
#ifdef NEED_SEPARATE_REGISTER_STACK
|
|
*stack = pd->stackblock;
|
|
*stacksize = stacktop - *stack;
|
|
#elif _STACK_GROWS_DOWN
|
|
*stack = stacktop;
|
|
#elif _STACK_GROWS_UP
|
|
*stack = pd->stackblock;
|
|
assert (*stack > 0);
|
|
#endif
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
void
|
|
internal_function
|
|
__deallocate_stack (struct pthread *pd)
|
|
{
|
|
lll_lock (stack_cache_lock, LLL_PRIVATE);
|
|
|
|
/* Remove the thread from the list of threads with user defined
|
|
stacks. */
|
|
stack_list_del (&pd->list);
|
|
|
|
/* Not much to do. Just free the mmap()ed memory. Note that we do
|
|
not reset the 'used' flag in the 'tid' field. This is done by
|
|
the kernel. If no thread has been created yet this field is
|
|
still zero. */
|
|
if (__builtin_expect (! pd->user_stack, 1))
|
|
(void) queue_stack (pd);
|
|
else
|
|
/* Free the memory associated with the ELF TLS. */
|
|
_dl_deallocate_tls (TLS_TPADJ (pd), false);
|
|
|
|
lll_unlock (stack_cache_lock, LLL_PRIVATE);
|
|
}
|
|
|
|
|
|
int
|
|
internal_function
|
|
__make_stacks_executable (void **stack_endp)
|
|
{
|
|
/* First the main thread's stack. */
|
|
int err = _dl_make_stack_executable (stack_endp);
|
|
if (err != 0)
|
|
return err;
|
|
|
|
#ifdef NEED_SEPARATE_REGISTER_STACK
|
|
const size_t pagemask = ~(__getpagesize () - 1);
|
|
#endif
|
|
|
|
lll_lock (stack_cache_lock, LLL_PRIVATE);
|
|
|
|
list_t *runp;
|
|
list_for_each (runp, &stack_used)
|
|
{
|
|
err = change_stack_perm (list_entry (runp, struct pthread, list)
|
|
#ifdef NEED_SEPARATE_REGISTER_STACK
|
|
, pagemask
|
|
#endif
|
|
);
|
|
if (err != 0)
|
|
break;
|
|
}
|
|
|
|
/* Also change the permission for the currently unused stacks. This
|
|
might be wasted time but better spend it here than adding a check
|
|
in the fast path. */
|
|
if (err == 0)
|
|
list_for_each (runp, &stack_cache)
|
|
{
|
|
err = change_stack_perm (list_entry (runp, struct pthread, list)
|
|
#ifdef NEED_SEPARATE_REGISTER_STACK
|
|
, pagemask
|
|
#endif
|
|
);
|
|
if (err != 0)
|
|
break;
|
|
}
|
|
|
|
lll_unlock (stack_cache_lock, LLL_PRIVATE);
|
|
|
|
return err;
|
|
}
|
|
|
|
|
|
/* In case of a fork() call the memory allocation in the child will be
|
|
the same but only one thread is running. All stacks except that of
|
|
the one running thread are not used anymore. We have to recycle
|
|
them. */
|
|
void
|
|
__reclaim_stacks (void)
|
|
{
|
|
struct pthread *self = (struct pthread *) THREAD_SELF;
|
|
|
|
/* No locking necessary. The caller is the only stack in use. But
|
|
we have to be aware that we might have interrupted a list
|
|
operation. */
|
|
|
|
if (in_flight_stack != 0)
|
|
{
|
|
bool add_p = in_flight_stack & 1;
|
|
list_t *elem = (list_t *) (in_flight_stack & ~(uintptr_t) 1);
|
|
|
|
if (add_p)
|
|
{
|
|
/* We always add at the beginning of the list. So in this
|
|
case we only need to check the beginning of these lists. */
|
|
int check_list (list_t *l)
|
|
{
|
|
if (l->next->prev != l)
|
|
{
|
|
assert (l->next->prev == elem);
|
|
|
|
elem->next = l->next;
|
|
elem->prev = l;
|
|
l->next = elem;
|
|
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
if (check_list (&stack_used) == 0)
|
|
(void) check_list (&stack_cache);
|
|
}
|
|
else
|
|
{
|
|
/* We can simply always replay the delete operation. */
|
|
elem->next->prev = elem->prev;
|
|
elem->prev->next = elem->next;
|
|
}
|
|
}
|
|
|
|
/* Mark all stacks except the still running one as free. */
|
|
list_t *runp;
|
|
list_for_each (runp, &stack_used)
|
|
{
|
|
struct pthread *curp = list_entry (runp, struct pthread, list);
|
|
if (curp != self)
|
|
{
|
|
/* This marks the stack as free. */
|
|
curp->tid = 0;
|
|
|
|
/* The PID field must be initialized for the new process. */
|
|
curp->pid = self->pid;
|
|
|
|
/* Account for the size of the stack. */
|
|
stack_cache_actsize += curp->stackblock_size;
|
|
|
|
if (curp->specific_used)
|
|
{
|
|
/* Clear the thread-specific data. */
|
|
memset (curp->specific_1stblock, '\0',
|
|
sizeof (curp->specific_1stblock));
|
|
|
|
curp->specific_used = false;
|
|
|
|
for (size_t cnt = 1; cnt < PTHREAD_KEY_1STLEVEL_SIZE; ++cnt)
|
|
if (curp->specific[cnt] != NULL)
|
|
{
|
|
memset (curp->specific[cnt], '\0',
|
|
sizeof (curp->specific_1stblock));
|
|
|
|
/* We have allocated the block which we do not
|
|
free here so re-set the bit. */
|
|
curp->specific_used = true;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Reset the PIDs in any cached stacks. */
|
|
list_for_each (runp, &stack_cache)
|
|
{
|
|
struct pthread *curp = list_entry (runp, struct pthread, list);
|
|
curp->pid = self->pid;
|
|
}
|
|
|
|
/* Add the stack of all running threads to the cache. */
|
|
list_splice (&stack_used, &stack_cache);
|
|
|
|
/* Remove the entry for the current thread to from the cache list
|
|
and add it to the list of running threads. Which of the two
|
|
lists is decided by the user_stack flag. */
|
|
stack_list_del (&self->list);
|
|
|
|
/* Re-initialize the lists for all the threads. */
|
|
INIT_LIST_HEAD (&stack_used);
|
|
INIT_LIST_HEAD (&__stack_user);
|
|
|
|
if (__builtin_expect (THREAD_GETMEM (self, user_stack), 0))
|
|
list_add (&self->list, &__stack_user);
|
|
else
|
|
list_add (&self->list, &stack_used);
|
|
|
|
/* There is one thread running. */
|
|
__nptl_nthreads = 1;
|
|
|
|
in_flight_stack = 0;
|
|
|
|
/* Initialize locks. */
|
|
stack_cache_lock = LLL_LOCK_INITIALIZER;
|
|
__default_pthread_attr_lock = LLL_LOCK_INITIALIZER;
|
|
}
|
|
|
|
|
|
#if HP_TIMING_AVAIL
|
|
# undef __find_thread_by_id
|
|
/* Find a thread given the thread ID. */
|
|
attribute_hidden
|
|
struct pthread *
|
|
__find_thread_by_id (pid_t tid)
|
|
{
|
|
struct pthread *result = NULL;
|
|
|
|
lll_lock (stack_cache_lock, LLL_PRIVATE);
|
|
|
|
/* Iterate over the list with system-allocated threads first. */
|
|
list_t *runp;
|
|
list_for_each (runp, &stack_used)
|
|
{
|
|
struct pthread *curp;
|
|
|
|
curp = list_entry (runp, struct pthread, list);
|
|
|
|
if (curp->tid == tid)
|
|
{
|
|
result = curp;
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
/* Now the list with threads using user-allocated stacks. */
|
|
list_for_each (runp, &__stack_user)
|
|
{
|
|
struct pthread *curp;
|
|
|
|
curp = list_entry (runp, struct pthread, list);
|
|
|
|
if (curp->tid == tid)
|
|
{
|
|
result = curp;
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
out:
|
|
lll_unlock (stack_cache_lock, LLL_PRIVATE);
|
|
|
|
return result;
|
|
}
|
|
#endif
|
|
|
|
|
|
static void
|
|
internal_function
|
|
setxid_mark_thread (struct xid_command *cmdp, struct pthread *t)
|
|
{
|
|
int ch;
|
|
|
|
/* Wait until this thread is cloned. */
|
|
if (t->setxid_futex == -1
|
|
&& ! atomic_compare_and_exchange_bool_acq (&t->setxid_futex, -2, -1))
|
|
do
|
|
lll_futex_wait (&t->setxid_futex, -2, LLL_PRIVATE);
|
|
while (t->setxid_futex == -2);
|
|
|
|
/* Don't let the thread exit before the setxid handler runs. */
|
|
t->setxid_futex = 0;
|
|
|
|
do
|
|
{
|
|
ch = t->cancelhandling;
|
|
|
|
/* If the thread is exiting right now, ignore it. */
|
|
if ((ch & EXITING_BITMASK) != 0)
|
|
{
|
|
/* Release the futex if there is no other setxid in
|
|
progress. */
|
|
if ((ch & SETXID_BITMASK) == 0)
|
|
{
|
|
t->setxid_futex = 1;
|
|
lll_futex_wake (&t->setxid_futex, 1, LLL_PRIVATE);
|
|
}
|
|
return;
|
|
}
|
|
}
|
|
while (atomic_compare_and_exchange_bool_acq (&t->cancelhandling,
|
|
ch | SETXID_BITMASK, ch));
|
|
}
|
|
|
|
|
|
static void
|
|
internal_function
|
|
setxid_unmark_thread (struct xid_command *cmdp, struct pthread *t)
|
|
{
|
|
int ch;
|
|
|
|
do
|
|
{
|
|
ch = t->cancelhandling;
|
|
if ((ch & SETXID_BITMASK) == 0)
|
|
return;
|
|
}
|
|
while (atomic_compare_and_exchange_bool_acq (&t->cancelhandling,
|
|
ch & ~SETXID_BITMASK, ch));
|
|
|
|
/* Release the futex just in case. */
|
|
t->setxid_futex = 1;
|
|
lll_futex_wake (&t->setxid_futex, 1, LLL_PRIVATE);
|
|
}
|
|
|
|
|
|
static int
|
|
internal_function
|
|
setxid_signal_thread (struct xid_command *cmdp, struct pthread *t)
|
|
{
|
|
if ((t->cancelhandling & SETXID_BITMASK) == 0)
|
|
return 0;
|
|
|
|
int val;
|
|
INTERNAL_SYSCALL_DECL (err);
|
|
val = INTERNAL_SYSCALL (tgkill, err, 3, THREAD_GETMEM (THREAD_SELF, pid),
|
|
t->tid, SIGSETXID);
|
|
|
|
/* If this failed, it must have had not started yet or else exited. */
|
|
if (!INTERNAL_SYSCALL_ERROR_P (val, err))
|
|
{
|
|
atomic_increment (&cmdp->cntr);
|
|
return 1;
|
|
}
|
|
else
|
|
return 0;
|
|
}
|
|
|
|
|
|
int
|
|
attribute_hidden
|
|
__nptl_setxid (struct xid_command *cmdp)
|
|
{
|
|
int signalled;
|
|
int result;
|
|
lll_lock (stack_cache_lock, LLL_PRIVATE);
|
|
|
|
__xidcmd = cmdp;
|
|
cmdp->cntr = 0;
|
|
|
|
struct pthread *self = THREAD_SELF;
|
|
|
|
/* Iterate over the list with system-allocated threads first. */
|
|
list_t *runp;
|
|
list_for_each (runp, &stack_used)
|
|
{
|
|
struct pthread *t = list_entry (runp, struct pthread, list);
|
|
if (t == self)
|
|
continue;
|
|
|
|
setxid_mark_thread (cmdp, t);
|
|
}
|
|
|
|
/* Now the list with threads using user-allocated stacks. */
|
|
list_for_each (runp, &__stack_user)
|
|
{
|
|
struct pthread *t = list_entry (runp, struct pthread, list);
|
|
if (t == self)
|
|
continue;
|
|
|
|
setxid_mark_thread (cmdp, t);
|
|
}
|
|
|
|
/* Iterate until we don't succeed in signalling anyone. That means
|
|
we have gotten all running threads, and their children will be
|
|
automatically correct once started. */
|
|
do
|
|
{
|
|
signalled = 0;
|
|
|
|
list_for_each (runp, &stack_used)
|
|
{
|
|
struct pthread *t = list_entry (runp, struct pthread, list);
|
|
if (t == self)
|
|
continue;
|
|
|
|
signalled += setxid_signal_thread (cmdp, t);
|
|
}
|
|
|
|
list_for_each (runp, &__stack_user)
|
|
{
|
|
struct pthread *t = list_entry (runp, struct pthread, list);
|
|
if (t == self)
|
|
continue;
|
|
|
|
signalled += setxid_signal_thread (cmdp, t);
|
|
}
|
|
|
|
int cur = cmdp->cntr;
|
|
while (cur != 0)
|
|
{
|
|
lll_futex_wait (&cmdp->cntr, cur, LLL_PRIVATE);
|
|
cur = cmdp->cntr;
|
|
}
|
|
}
|
|
while (signalled != 0);
|
|
|
|
/* Clean up flags, so that no thread blocks during exit waiting
|
|
for a signal which will never come. */
|
|
list_for_each (runp, &stack_used)
|
|
{
|
|
struct pthread *t = list_entry (runp, struct pthread, list);
|
|
if (t == self)
|
|
continue;
|
|
|
|
setxid_unmark_thread (cmdp, t);
|
|
}
|
|
|
|
list_for_each (runp, &__stack_user)
|
|
{
|
|
struct pthread *t = list_entry (runp, struct pthread, list);
|
|
if (t == self)
|
|
continue;
|
|
|
|
setxid_unmark_thread (cmdp, t);
|
|
}
|
|
|
|
/* This must be last, otherwise the current thread might not have
|
|
permissions to send SIGSETXID syscall to the other threads. */
|
|
INTERNAL_SYSCALL_DECL (err);
|
|
result = INTERNAL_SYSCALL_NCS (cmdp->syscall_no, err, 3,
|
|
cmdp->id[0], cmdp->id[1], cmdp->id[2]);
|
|
if (INTERNAL_SYSCALL_ERROR_P (result, err))
|
|
{
|
|
__set_errno (INTERNAL_SYSCALL_ERRNO (result, err));
|
|
result = -1;
|
|
}
|
|
|
|
lll_unlock (stack_cache_lock, LLL_PRIVATE);
|
|
return result;
|
|
}
|
|
|
|
static inline void __attribute__((always_inline))
|
|
init_one_static_tls (struct pthread *curp, struct link_map *map)
|
|
{
|
|
dtv_t *dtv = GET_DTV (TLS_TPADJ (curp));
|
|
# if TLS_TCB_AT_TP
|
|
void *dest = (char *) curp - map->l_tls_offset;
|
|
# elif TLS_DTV_AT_TP
|
|
void *dest = (char *) curp + map->l_tls_offset + TLS_PRE_TCB_SIZE;
|
|
# else
|
|
# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
|
|
# endif
|
|
|
|
/* Initialize the memory. */
|
|
memset (__mempcpy (dest, map->l_tls_initimage, map->l_tls_initimage_size),
|
|
'\0', map->l_tls_blocksize - map->l_tls_initimage_size);
|
|
|
|
/* Fill in the DTV slot so that a later LD/GD access will find it. */
|
|
dtv[map->l_tls_modid].pointer.is_static = true;
|
|
/* Pairs against the read barrier in tls_get_attr_tail, guaranteeing
|
|
any thread waiting for an update to pointer.val sees the
|
|
initimage write. */
|
|
atomic_write_barrier ();
|
|
dtv[map->l_tls_modid].pointer.val = dest;
|
|
|
|
}
|
|
|
|
void
|
|
attribute_hidden
|
|
__pthread_init_static_tls (struct link_map *map)
|
|
{
|
|
lll_lock (stack_cache_lock, LLL_PRIVATE);
|
|
|
|
/* Iterate over the list with system-allocated threads first. */
|
|
list_t *runp;
|
|
list_for_each (runp, &stack_used)
|
|
init_one_static_tls (list_entry (runp, struct pthread, list), map);
|
|
|
|
/* Now the list with threads using user-allocated stacks. */
|
|
list_for_each (runp, &__stack_user)
|
|
init_one_static_tls (list_entry (runp, struct pthread, list), map);
|
|
|
|
lll_unlock (stack_cache_lock, LLL_PRIVATE);
|
|
}
|
|
|
|
|
|
void
|
|
attribute_hidden
|
|
__wait_lookup_done (void)
|
|
{
|
|
lll_lock (stack_cache_lock, LLL_PRIVATE);
|
|
|
|
struct pthread *self = THREAD_SELF;
|
|
|
|
/* Iterate over the list with system-allocated threads first. */
|
|
list_t *runp;
|
|
list_for_each (runp, &stack_used)
|
|
{
|
|
struct pthread *t = list_entry (runp, struct pthread, list);
|
|
if (t == self || t->header.gscope_flag == THREAD_GSCOPE_FLAG_UNUSED)
|
|
continue;
|
|
|
|
int *const gscope_flagp = &t->header.gscope_flag;
|
|
|
|
/* We have to wait until this thread is done with the global
|
|
scope. First tell the thread that we are waiting and
|
|
possibly have to be woken. */
|
|
if (atomic_compare_and_exchange_bool_acq (gscope_flagp,
|
|
THREAD_GSCOPE_FLAG_WAIT,
|
|
THREAD_GSCOPE_FLAG_USED))
|
|
continue;
|
|
|
|
do
|
|
lll_futex_wait (gscope_flagp, THREAD_GSCOPE_FLAG_WAIT, LLL_PRIVATE);
|
|
while (*gscope_flagp == THREAD_GSCOPE_FLAG_WAIT);
|
|
}
|
|
|
|
/* Now the list with threads using user-allocated stacks. */
|
|
list_for_each (runp, &__stack_user)
|
|
{
|
|
struct pthread *t = list_entry (runp, struct pthread, list);
|
|
if (t == self || t->header.gscope_flag == THREAD_GSCOPE_FLAG_UNUSED)
|
|
continue;
|
|
|
|
int *const gscope_flagp = &t->header.gscope_flag;
|
|
|
|
/* We have to wait until this thread is done with the global
|
|
scope. First tell the thread that we are waiting and
|
|
possibly have to be woken. */
|
|
if (atomic_compare_and_exchange_bool_acq (gscope_flagp,
|
|
THREAD_GSCOPE_FLAG_WAIT,
|
|
THREAD_GSCOPE_FLAG_USED))
|
|
continue;
|
|
|
|
do
|
|
lll_futex_wait (gscope_flagp, THREAD_GSCOPE_FLAG_WAIT, LLL_PRIVATE);
|
|
while (*gscope_flagp == THREAD_GSCOPE_FLAG_WAIT);
|
|
}
|
|
|
|
lll_unlock (stack_cache_lock, LLL_PRIVATE);
|
|
}
|