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freebsd/lib/libc/gen/tls.c
2010-02-16 02:22:59 +00:00

316 lines
7.2 KiB
C

/*-
* Copyright (c) 2004 Doug Rabson
* 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 AUTHOR 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 AUTHOR 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.
*
* $FreeBSD$
*/
/*
* Define stubs for TLS internals so that programs and libraries can
* link. These functions will be replaced by functional versions at
* runtime from ld-elf.so.1.
*/
#include <sys/cdefs.h>
#include <stdlib.h>
#include <string.h>
#include <elf.h>
#include "libc_private.h"
__weak_reference(__libc_allocate_tls, _rtld_allocate_tls);
__weak_reference(__libc_free_tls, _rtld_free_tls);
#ifdef __i386__
__weak_reference(___libc_tls_get_addr, ___tls_get_addr);
__attribute__((__regparm__(1))) void * ___libc_tls_get_addr(void *);
#endif
void * __libc_tls_get_addr(void *);
__weak_reference(__libc_tls_get_addr, __tls_get_addr);
void *_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign);
void _rtld_free_tls(void *tls, size_t tcbsize, size_t tcbalign);
void *__libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign);
void __libc_free_tls(void *tls, size_t tcbsize, size_t tcbalign);
#if defined(__ia64__) || defined(__amd64__)
#define TLS_TCB_ALIGN 16
#elif defined(__powerpc__) || defined(__i386__) || defined(__arm__) || \
defined(__sparc64__) || defined(__mips__)
#define TLS_TCB_ALIGN sizeof(void *)
#else
#error TLS_TCB_ALIGN undefined for target architecture
#endif
#if defined(__ia64__) || defined(__powerpc__)
#define TLS_VARIANT_I
#endif
#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \
defined(__arm__) || defined(__mips__)
#define TLS_VARIANT_II
#endif
#ifndef PIC
#define round(size, align) \
(((size) + (align) - 1) & ~((align) - 1))
static size_t tls_static_space;
static size_t tls_init_size;
static void *tls_init;
#endif
#ifdef __i386__
/* GNU ABI */
__attribute__((__regparm__(1)))
void *
___libc_tls_get_addr(void *ti __unused)
{
return (0);
}
#endif
void *
__libc_tls_get_addr(void *ti __unused)
{
return (0);
}
#ifndef PIC
#ifdef TLS_VARIANT_I
#define TLS_TCB_SIZE (2 * sizeof(void *))
/*
* Free Static TLS using the Variant I method.
*/
void
__libc_free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
{
Elf_Addr *dtv;
Elf_Addr **tls;
tls = (Elf_Addr **)((Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE);
dtv = tls[0];
free(dtv);
free(tcb);
}
/*
* Allocate Static TLS using the Variant I method.
*/
void *
__libc_allocate_tls(void *oldtcb, size_t tcbsize, size_t tcbalign __unused)
{
Elf_Addr *dtv;
Elf_Addr **tls;
char *tcb;
if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
return (oldtcb);
tcb = calloc(1, tls_static_space + tcbsize - TLS_TCB_SIZE);
tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
if (oldtcb != NULL) {
memcpy(tls, oldtcb, tls_static_space);
free(oldtcb);
/* Adjust the DTV. */
dtv = tls[0];
dtv[2] = (Elf_Addr)tls + TLS_TCB_SIZE;
} else {
dtv = malloc(3 * sizeof(Elf_Addr));
tls[0] = dtv;
dtv[0] = 1;
dtv[1] = 1;
dtv[2] = (Elf_Addr)tls + TLS_TCB_SIZE;
if (tls_init_size > 0)
memcpy((void*)dtv[2], tls_init, tls_init_size);
if (tls_static_space > tls_init_size)
memset((void*)(dtv[2] + tls_init_size), 0,
tls_static_space - tls_init_size);
}
return(tcb);
}
#endif
#ifdef TLS_VARIANT_II
#define TLS_TCB_SIZE (3 * sizeof(Elf_Addr))
/*
* Free Static TLS using the Variant II method.
*/
void
__libc_free_tls(void *tcb, size_t tcbsize __unused, size_t tcbalign)
{
size_t size;
Elf_Addr* dtv;
Elf_Addr tlsstart, tlsend;
/*
* Figure out the size of the initial TLS block so that we can
* find stuff which ___tls_get_addr() allocated dynamically.
*/
size = round(tls_static_space, tcbalign);
dtv = ((Elf_Addr**)tcb)[1];
tlsend = (Elf_Addr) tcb;
tlsstart = tlsend - size;
free((void*) tlsstart);
free(dtv);
}
/*
* Allocate Static TLS using the Variant II method.
*/
void *
__libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
{
size_t size;
char *tls;
Elf_Addr *dtv;
Elf_Addr segbase, oldsegbase;
size = round(tls_static_space, tcbalign);
if (tcbsize < 2 * sizeof(Elf_Addr))
tcbsize = 2 * sizeof(Elf_Addr);
tls = calloc(1, size + tcbsize);
dtv = malloc(3 * sizeof(Elf_Addr));
segbase = (Elf_Addr)(tls + size);
((Elf_Addr*)segbase)[0] = segbase;
((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
dtv[0] = 1;
dtv[1] = 1;
dtv[2] = segbase - tls_static_space;
if (oldtls) {
/*
* Copy the static TLS block over whole.
*/
oldsegbase = (Elf_Addr) oldtls;
memcpy((void *)(segbase - tls_static_space),
(const void *)(oldsegbase - tls_static_space),
tls_static_space);
/*
* We assume that this block was the one we created with
* allocate_initial_tls().
*/
_rtld_free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
} else {
memcpy((void *)(segbase - tls_static_space),
tls_init, tls_init_size);
memset((void *)(segbase - tls_static_space + tls_init_size),
0, tls_static_space - tls_init_size);
}
return (void*) segbase;
}
#endif /* TLS_VARIANT_II */
#else
void *
__libc_allocate_tls(void *oldtls __unused, size_t tcbsize __unused,
size_t tcbalign __unused)
{
return (0);
}
void
__libc_free_tls(void *tcb __unused, size_t tcbsize __unused,
size_t tcbalign __unused)
{
}
#endif /* PIC */
extern char **environ;
void
_init_tls()
{
#ifndef PIC
Elf_Addr *sp;
Elf_Auxinfo *aux, *auxp;
Elf_Phdr *phdr;
size_t phent, phnum;
int i;
void *tls;
sp = (Elf_Addr *) environ;
while (*sp++ != 0)
;
aux = (Elf_Auxinfo *) sp;
phdr = 0;
phent = phnum = 0;
for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
switch (auxp->a_type) {
case AT_PHDR:
phdr = auxp->a_un.a_ptr;
break;
case AT_PHENT:
phent = auxp->a_un.a_val;
break;
case AT_PHNUM:
phnum = auxp->a_un.a_val;
break;
}
}
if (phdr == 0 || phent != sizeof(Elf_Phdr) || phnum == 0)
return;
for (i = 0; (unsigned) i < phnum; i++) {
if (phdr[i].p_type == PT_TLS) {
tls_static_space = round(phdr[i].p_memsz,
phdr[i].p_align);
tls_init_size = phdr[i].p_filesz;
tls_init = (void*) phdr[i].p_vaddr;
}
}
tls = _rtld_allocate_tls(NULL, TLS_TCB_SIZE, TLS_TCB_ALIGN);
_set_tp(tls);
#endif
}