glibc/sysdeps/arm/dl-tlsdesc.S
Will Newton 36ffe7398a ARM: Fix handling of concurrent TLS descriptor resolution
The current code for handling concurrent resolution says that the
ABI for _dl_tlsdesc_resolve_hold is the same as that of
_dl_tlsdesc_lazy_resolver. However _dl_tlsdesc_resolve_hold is
called from the trampoline directly rather than the lazy resolver
stub so, for example, r2 has not been pushed so does not needed
to be restored.

This fixes an intermittent failure in nptl/tst-tls3 when building
glibc for arm-linux-gnueabihf with -mtls-dialect=gnu2.

ChangeLog:

2014-05-27  Will Newton  <will.newton@linaro.org>

	[BZ #16990]
	* sysdeps/arm/dl-tlsdesc.S (_dl_tlsdesc_resolve_hold): Save
	and restore r2 rather than just restoring.
2014-05-27 10:39:18 +01:00

220 lines
5.6 KiB
ArmAsm

/* Thread-local storage handling in the ELF dynamic linker. ARM version.
Copyright (C) 2006-2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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 <sysdep.h>
#include <arm-features.h>
#include <tls.h>
#include "tlsdesc.h"
.text
@ emit debug information with cfi
@ use arm-specific pseudos for unwinding itself
CFI_SECTIONS
.hidden _dl_tlsdesc_return
.global _dl_tlsdesc_return
.type _dl_tlsdesc_return,#function
cfi_startproc
eabi_fnstart
.align 2
_dl_tlsdesc_return:
sfi_breg r0, \
ldr r0, [\B]
BX (lr)
eabi_fnend
cfi_endproc
.size _dl_tlsdesc_return, .-_dl_tlsdesc_return
.hidden _dl_tlsdesc_undefweak
.global _dl_tlsdesc_undefweak
.type _dl_tlsdesc_undefweak,#function
cfi_startproc
eabi_fnstart
.align 2
_dl_tlsdesc_undefweak:
GET_TLS (r1)
rsb r0, r0, #0
BX (lr)
cfi_endproc
eabi_fnend
.size _dl_tlsdesc_undefweak, .-_dl_tlsdesc_undefweak
#ifdef SHARED
.hidden _dl_tlsdesc_dynamic
.global _dl_tlsdesc_dynamic
.type _dl_tlsdesc_dynamic,#function
/*
The assembly code that follows is a rendition of the following
C code, hand-optimized a little bit.
ptrdiff_t
_dl_tlsdesc_dynamic(struct tlsdesc *tdp)
{
struct tlsdesc_dynamic_arg *td = tdp->argument.pointer;
dtv_t *dtv = (dtv_t *)THREAD_DTV();
if (__builtin_expect (td->gen_count <= dtv[0].counter
&& dtv[td->tlsinfo.ti_module].pointer.val
!= TLS_DTV_UNALLOCATED,
1))
return dtv[td->tlsinfo.ti_module].pointer.val +
td->tlsinfo.ti_offset - __builtin_thread_pointer();
return __tls_get_addr (&td->tlsinfo) - __builtin_thread_pointer();
}
*/
cfi_startproc
eabi_fnstart
.align 2
_dl_tlsdesc_dynamic:
/* Our calling convention is to clobber r0, r1 and the processor
flags. All others that are modified must be saved */
eabi_save ({r2,r3,r4,lr})
push {r2,r3,r4,lr}
cfi_adjust_cfa_offset (16)
cfi_rel_offset (r2,0)
cfi_rel_offset (r3,4)
cfi_rel_offset (r4,8)
cfi_rel_offset (lr,12)
sfi_breg r0, \
ldr r1, [\B] /* td */
GET_TLS (lr)
mov r4, r0 /* r4 = tp */
sfi_breg r0, \
ldr r0, [\B]
sfi_breg r1, \
ldr r2, [\B, #8] /* gen_count */
sfi_breg r0, \
ldr r3, [\B]
cmp r2, r3
bhi 1f
sfi_breg r1, \
ldr r3, [\B]
#ifndef ARM_NO_INDEX_REGISTER
ldr r2, [r0, r3, lsl #3]
#else
add lr, r0, r3, lsl #3
sfi_breg lr, \
ldr r2, [\B]
#endif
cmn r2, #1
ittt ne
sfi_breg r1, \
ldrne r3, [r1, #4]
addne r3, r2, r3
rsbne r0, r4, r3
bne 2f
1: mov r0, r1
bl __tls_get_addr
rsb r0, r4, r0
2:
#if ((defined (__ARM_ARCH_4T__) && defined (__THUMB_INTERWORK__)) \
|| defined (ARM_ALWAYS_BX))
pop {r2,r3,r4, lr}
cfi_adjust_cfa_offset (-16)
cfi_restore (lr)
cfi_restore (r4)
cfi_restore (r3)
cfi_restore (r2)
bx lr
#else
pop {r2,r3,r4, pc}
#endif
eabi_fnend
cfi_endproc
.size _dl_tlsdesc_dynamic, .-_dl_tlsdesc_dynamic
#endif /* SHARED */
/* lazy resolved for tls descriptors. */
.hidden _dl_tlsdesc_lazy_resolver
.global _dl_tlsdesc_lazy_resolver
.type _dl_tlsdesc_lazy_resolver,#function
cfi_startproc
eabi_fnstart
.align 2
_dl_tlsdesc_lazy_resolver:
/* r0 points at the tlsdesc,
r1 points at the GOT
r2 was pushed by the trampoline and used as a temp,
we need to pop it here.
We push the remaining call-clobbered registers here, and also
R1 -- to keep the stack correctly aligned. */
/* Tell the unwinder that r2 has already been pushed. */
eabi_save ({r2})
cfi_adjust_cfa_offset (4)
cfi_rel_offset (r2, 0)
eabi_save ({r0,r1,r3,ip,lr})
push {r0, r1, r3, ip, lr}
cfi_adjust_cfa_offset (20)
cfi_rel_offset (r0, 0)
cfi_rel_offset (r1, 4)
cfi_rel_offset (r3, 8)
cfi_rel_offset (ip, 12)
cfi_rel_offset (lr, 16)
bl _dl_tlsdesc_lazy_resolver_fixup
pop {r0, r1, r3, ip, lr}
cfi_adjust_cfa_offset (-20)
cfi_restore (lr)
cfi_restore (ip)
cfi_restore (r3)
cfi_restore (r1)
cfi_restore (r0)
pop {r2}
cfi_adjust_cfa_offset (-4)
cfi_restore (r2)
sfi_breg r0, \
ldr r1, [\B, #4]
BX (r1)
eabi_fnend
cfi_endproc
.size _dl_tlsdesc_lazy_resolver, .-_dl_tlsdesc_lazy_resolver
/* Holder for lazy tls descriptors being resolve in another thread.
Our calling convention is to clobber r0, r1 and the processor
flags. All others that are modified must be saved */
.hidden _dl_tlsdesc_resolve_hold
.global _dl_tlsdesc_resolve_hold
.type _dl_tlsdesc_resolve_hold,#function
cfi_startproc
eabi_fnstart
.align 2
_dl_tlsdesc_resolve_hold:
eabi_save ({r2,r3,ip,lr})
push {r2, r3, ip, lr}
cfi_adjust_cfa_offset (16)
cfi_rel_offset (r2, 0)
cfi_rel_offset (r3, 4)
cfi_rel_offset (ip, 8)
cfi_rel_offset (lr, 12)
adr r1, _dl_tlsdesc_resolve_hold
bl _dl_tlsdesc_resolve_hold_fixup
pop {r2, r3, ip, lr}
cfi_adjust_cfa_offset (-16)
cfi_restore (lr)
cfi_restore (ip)
cfi_restore (r3)
cfi_restore (r2)
sfi_breg r0, \
ldr r1, [\B, #4]
BX (r1)
eabi_fnend
cfi_endproc
.size _dl_tlsdesc_resolve_hold, .-_dl_tlsdesc_resolve_hold