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1fae5a6800
_dl_tlsdesc_resolve_hold calls into a C function that clobbers r0, but it assumes the original argument is still in r0 after the call. This can cause crash in case of concurrent TLS access when TLSDESC is in use (-mtls-dialect=gnu2). Run into this while fixing BZ 18572. Both r0 and r1 are saved/restored so the stack remains 8 byte aligned. [BZ #19129] * sysdeps/arm/dl-tlsdesc.S (_dl_tlsdesc_resolve_hold): Save and restore r0 and r1.
229 lines
6.0 KiB
ArmAsm
229 lines
6.0 KiB
ArmAsm
/* Thread-local storage handling in the ELF dynamic linker. ARM version.
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Copyright (C) 2006-2015 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<http://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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#include <arm-features.h>
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#include <tls.h>
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#include "tlsdesc.h"
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.text
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@ emit debug information with cfi
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@ use arm-specific pseudos for unwinding itself
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CFI_SECTIONS
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.hidden _dl_tlsdesc_return
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.global _dl_tlsdesc_return
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.type _dl_tlsdesc_return,#function
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cfi_startproc
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eabi_fnstart
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.align 2
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_dl_tlsdesc_return:
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sfi_breg r0, \
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ldr r0, [\B]
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BX (lr)
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eabi_fnend
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cfi_endproc
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.size _dl_tlsdesc_return, .-_dl_tlsdesc_return
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.hidden _dl_tlsdesc_undefweak
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.global _dl_tlsdesc_undefweak
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.type _dl_tlsdesc_undefweak,#function
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cfi_startproc
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eabi_fnstart
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.align 2
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_dl_tlsdesc_undefweak:
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GET_TLS (r1)
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rsb r0, r0, #0
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BX (lr)
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cfi_endproc
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eabi_fnend
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.size _dl_tlsdesc_undefweak, .-_dl_tlsdesc_undefweak
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#ifdef SHARED
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.hidden _dl_tlsdesc_dynamic
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.global _dl_tlsdesc_dynamic
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.type _dl_tlsdesc_dynamic,#function
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/*
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The assembly code that follows is a rendition of the following
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C code, hand-optimized a little bit.
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ptrdiff_t
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_dl_tlsdesc_dynamic(struct tlsdesc *tdp)
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{
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struct tlsdesc_dynamic_arg *td = tdp->argument.pointer;
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dtv_t *dtv = (dtv_t *)THREAD_DTV();
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if (__builtin_expect (td->gen_count <= dtv[0].counter
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&& dtv[td->tlsinfo.ti_module].pointer.val
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!= TLS_DTV_UNALLOCATED,
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1))
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return dtv[td->tlsinfo.ti_module].pointer.val +
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td->tlsinfo.ti_offset - __builtin_thread_pointer();
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return __tls_get_addr (&td->tlsinfo) - __builtin_thread_pointer();
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}
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*/
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cfi_startproc
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eabi_fnstart
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.align 2
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_dl_tlsdesc_dynamic:
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/* Our calling convention is to clobber r0, r1 and the processor
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flags. All others that are modified must be saved */
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eabi_save ({r2,r3,r4,lr})
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push {r2,r3,r4,lr}
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cfi_adjust_cfa_offset (16)
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cfi_rel_offset (r2,0)
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cfi_rel_offset (r3,4)
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cfi_rel_offset (r4,8)
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cfi_rel_offset (lr,12)
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sfi_breg r0, \
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ldr r1, [\B] /* td */
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GET_TLS (lr)
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mov r4, r0 /* r4 = tp */
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sfi_breg r0, \
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ldr r0, [\B]
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sfi_breg r1, \
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ldr r2, [\B, #8] /* gen_count */
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sfi_breg r0, \
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ldr r3, [\B]
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cmp r2, r3
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bhi 1f
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sfi_breg r1, \
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ldr r3, [\B]
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#ifndef ARM_NO_INDEX_REGISTER
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ldr r2, [r0, r3, lsl #3]
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#else
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add lr, r0, r3, lsl #3
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sfi_breg lr, \
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ldr r2, [\B]
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#endif
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cmn r2, #1
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ittt ne
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sfi_breg r1, \
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ldrne r3, [r1, #4]
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addne r3, r2, r3
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rsbne r0, r4, r3
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bne 2f
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1: mov r0, r1
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bl __tls_get_addr
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rsb r0, r4, r0
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2:
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#if ((defined (__ARM_ARCH_4T__) && defined (__THUMB_INTERWORK__)) \
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|| defined (ARM_ALWAYS_BX))
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pop {r2,r3,r4, lr}
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cfi_adjust_cfa_offset (-16)
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cfi_restore (lr)
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cfi_restore (r4)
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cfi_restore (r3)
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cfi_restore (r2)
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bx lr
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#else
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pop {r2,r3,r4, pc}
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#endif
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eabi_fnend
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cfi_endproc
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.size _dl_tlsdesc_dynamic, .-_dl_tlsdesc_dynamic
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#endif /* SHARED */
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/* lazy resolved for tls descriptors. */
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.hidden _dl_tlsdesc_lazy_resolver
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.global _dl_tlsdesc_lazy_resolver
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.type _dl_tlsdesc_lazy_resolver,#function
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cfi_startproc
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eabi_fnstart
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.align 2
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_dl_tlsdesc_lazy_resolver:
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/* r0 points at the tlsdesc,
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r1 points at the GOT
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r2 was pushed by the trampoline and used as a temp,
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we need to pop it here.
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We push the remaining call-clobbered registers here, and also
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R1 -- to keep the stack correctly aligned. */
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/* Tell the unwinder that r2 has already been pushed. */
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eabi_save ({r2})
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cfi_adjust_cfa_offset (4)
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cfi_rel_offset (r2, 0)
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eabi_save ({r0,r1,r3,ip,lr})
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push {r0, r1, r3, ip, lr}
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cfi_adjust_cfa_offset (20)
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cfi_rel_offset (r0, 0)
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cfi_rel_offset (r1, 4)
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cfi_rel_offset (r3, 8)
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cfi_rel_offset (ip, 12)
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cfi_rel_offset (lr, 16)
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bl _dl_tlsdesc_lazy_resolver_fixup
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pop {r0, r1, r3, ip, lr}
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cfi_adjust_cfa_offset (-20)
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cfi_restore (lr)
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cfi_restore (ip)
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cfi_restore (r3)
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cfi_restore (r1)
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cfi_restore (r0)
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pop {r2}
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cfi_adjust_cfa_offset (-4)
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cfi_restore (r2)
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sfi_breg r0, \
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ldr r1, [\B, #4]
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BX (r1)
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eabi_fnend
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cfi_endproc
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.size _dl_tlsdesc_lazy_resolver, .-_dl_tlsdesc_lazy_resolver
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/* Holder for lazy tls descriptors being resolve in another thread.
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Our calling convention is to clobber r0, r1 and the processor
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flags. All others that are modified must be saved */
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.hidden _dl_tlsdesc_resolve_hold
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.global _dl_tlsdesc_resolve_hold
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.type _dl_tlsdesc_resolve_hold,#function
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cfi_startproc
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eabi_fnstart
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.align 2
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_dl_tlsdesc_resolve_hold:
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/* r0 is saved so its original value can be used after the call and
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r1 is saved only to keep the stack aligned. (r0 points to the tls
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descriptor, it is passed to _dl_tlsdesc_resolve_hold_fixup which
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is a void function that may clobber r0, later r0 is used to load
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the new resolver.) */
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eabi_save ({r0,r1,r2,r3,ip,lr})
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push {r0, r1, r2, r3, ip, lr}
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cfi_adjust_cfa_offset (24)
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cfi_rel_offset (r0, 0)
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cfi_rel_offset (r1, 4)
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cfi_rel_offset (r2, 8)
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cfi_rel_offset (r3, 12)
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cfi_rel_offset (ip, 16)
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cfi_rel_offset (lr, 20)
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adr r1, _dl_tlsdesc_resolve_hold
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bl _dl_tlsdesc_resolve_hold_fixup
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pop {r0, r1, r2, r3, ip, lr}
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cfi_adjust_cfa_offset (-24)
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cfi_restore (lr)
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cfi_restore (ip)
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cfi_restore (r3)
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cfi_restore (r2)
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cfi_restore (r1)
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cfi_restore (r0)
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sfi_breg r0, \
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ldr r1, [\B, #4]
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BX (r1)
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eabi_fnend
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cfi_endproc
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.size _dl_tlsdesc_resolve_hold, .-_dl_tlsdesc_resolve_hold
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