b567aa1258
* sysdeps/alpha/dl-machine.h (elf_machine_rela): Fix arguments in call to elf_machine_fixup_plt. * sysdeps/sparc/sparc32/dl-machine.h (elf_machine_rela): Likewise. * sysdeps/sparc/sparc64/dl-machine.h (elf_machine_rela): Likewise.
546 lines
16 KiB
C
546 lines
16 KiB
C
/* Machine-dependent ELF dynamic relocation inline functions. Alpha version.
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Copyright (C) 1996, 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Richard Henderson <rth@tamu.edu>.
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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 Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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/* This was written in the absence of an ABI -- don't expect
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it to remain unchanged. */
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#ifndef dl_machine_h
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#define dl_machine_h 1
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#define ELF_MACHINE_NAME "alpha"
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#include <string.h>
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/* Return nonzero iff E_MACHINE is compatible with the running host. */
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static inline int
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elf_machine_matches_host (Elf64_Word e_machine)
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{
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return e_machine == EM_ALPHA;
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}
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/* Return the link-time address of _DYNAMIC. The multiple-got-capable
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linker no longer allocates the first .got entry for this. But not to
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worry, no special tricks are needed. */
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static inline Elf64_Addr
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elf_machine_dynamic (void)
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{
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#ifndef NO_AXP_MULTI_GOT_LD
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return (Elf64_Addr) &_DYNAMIC;
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#else
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register Elf64_Addr *gp __asm__ ("$29");
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return gp[-4096];
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#endif
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}
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/* Return the run-time load address of the shared object. */
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static inline Elf64_Addr
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elf_machine_load_address (void)
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{
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/* NOTE: While it is generally unfriendly to put data in the text
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segment, it is only slightly less so when the "data" is an
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instruction. While we don't have to worry about GLD just yet, an
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optimizing linker might decide that our "data" is an unreachable
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instruction and throw it away -- with the right switches, DEC's
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linker will do this. What ought to happen is we should add
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something to GAS to allow us access to the new GPREL_HI32/LO32
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relocation types stolen from OSF/1 3.0. */
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/* This code relies on the fact that BRADDR relocations do not
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appear in dynamic relocation tables. Not that that would be very
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useful anyway -- br/bsr has a 4MB range and the shared libraries
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are usually many many terabytes away. */
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Elf64_Addr dot;
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long int zero_disp;
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asm("br %0, 1f\n\t"
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".weak __load_address_undefined\n\t"
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"br $0, __load_address_undefined\n"
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"1:"
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: "=r"(dot));
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zero_disp = *(int *)dot;
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zero_disp = (zero_disp << 43) >> 41;
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return dot + 4 + zero_disp;
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}
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/* Set up the loaded object described by L so its unrelocated PLT
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entries will jump to the on-demand fixup code in dl-runtime.c. */
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static inline int
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elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
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{
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Elf64_Addr plt;
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extern void _dl_runtime_resolve (void);
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extern void _dl_runtime_profile (void);
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if (l->l_info[DT_JMPREL] && lazy)
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{
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/* The GOT entries for the functions in the PLT have not been
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filled in yet. Their initial contents are directed to the
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PLT which arranges for the dynamic linker to be called. */
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plt = D_PTR (l, l_info[DT_PLTGOT]);
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/* This function will be called to perform the relocation. */
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if (!profile)
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*(Elf64_Addr *)(plt + 16) = (Elf64_Addr) &_dl_runtime_resolve;
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else
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{
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*(Elf64_Addr *)(plt + 16) = (Elf64_Addr) &_dl_runtime_profile;
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if (_dl_name_match_p (_dl_profile, l))
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{
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/* This is the object we are looking for. Say that we really
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want profiling and the timers are started. */
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_dl_profile_map = l;
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}
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}
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/* Identify this shared object */
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*(Elf64_Addr *)(plt + 24) = (Elf64_Addr) l;
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/* If the first instruction of the plt entry is not
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"br $28, plt0", we cannot do lazy relocation. */
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lazy = (*(unsigned int *)(plt + 32) == 0xc39ffff7);
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}
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return lazy;
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}
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/* This code is used in dl-runtime.c to call the `fixup' function
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and then redirect to the address it returns. */
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#define TRAMPOLINE_TEMPLATE(tramp_name, fixup_name, IMB) \
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extern void tramp_name (void); \
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asm ( "\
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.globl " #tramp_name "
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.ent " #tramp_name "
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" #tramp_name ":
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lda $sp, -44*8($sp)
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.frame $sp, 44*8, $26
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/* Preserve all integer registers that C normally doesn't. */
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stq $26, 0*8($sp)
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stq $0, 1*8($sp)
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stq $1, 2*8($sp)
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stq $2, 3*8($sp)
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stq $3, 4*8($sp)
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stq $4, 5*8($sp)
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stq $5, 6*8($sp)
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stq $6, 7*8($sp)
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stq $7, 8*8($sp)
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stq $8, 9*8($sp)
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stq $16, 10*8($sp)
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stq $17, 11*8($sp)
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stq $18, 12*8($sp)
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stq $19, 13*8($sp)
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stq $20, 14*8($sp)
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stq $21, 15*8($sp)
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stq $22, 16*8($sp)
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stq $23, 17*8($sp)
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stq $24, 18*8($sp)
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stq $25, 19*8($sp)
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stq $29, 20*8($sp)
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stt $f0, 21*8($sp)
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stt $f1, 22*8($sp)
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stt $f10, 23*8($sp)
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stt $f11, 24*8($sp)
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stt $f12, 25*8($sp)
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stt $f13, 26*8($sp)
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stt $f14, 27*8($sp)
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stt $f15, 28*8($sp)
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stt $f16, 29*8($sp)
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stt $f17, 30*8($sp)
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stt $f18, 31*8($sp)
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stt $f19, 32*8($sp)
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stt $f20, 33*8($sp)
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stt $f21, 34*8($sp)
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stt $f22, 35*8($sp)
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stt $f23, 36*8($sp)
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stt $f24, 37*8($sp)
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stt $f25, 38*8($sp)
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stt $f26, 39*8($sp)
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stt $f27, 40*8($sp)
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stt $f28, 41*8($sp)
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stt $f29, 42*8($sp)
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stt $f30, 43*8($sp)
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.mask 0x27ff01ff, -44*8
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.fmask 0xfffffc03, -(44-21)*8
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/* Set up our $gp */
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br $gp, .+4
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ldgp $gp, 0($gp)
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.prologue 0
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/* Set up the arguments for fixup: */
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/* $16 = link_map out of plt0 */
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/* $17 = offset of reloc entry = ($28 - $27 - 20) /12 * 24 */
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/* $18 = return address */
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subq $28, $27, $17
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ldq $16, 8($27)
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subq $17, 20, $17
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mov $26, $18
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addq $17, $17, $17
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/* Do the fixup */
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bsr $26, " ASM_ALPHA_NG_SYMBOL_PREFIX #fixup_name "..ng
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/* Move the destination address into position. */
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mov $0, $27
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/* Restore program registers. */
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ldq $26, 0*8($sp)
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ldq $0, 1*8($sp)
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ldq $1, 2*8($sp)
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ldq $2, 3*8($sp)
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ldq $3, 4*8($sp)
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ldq $4, 5*8($sp)
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ldq $5, 6*8($sp)
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ldq $6, 7*8($sp)
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ldq $7, 8*8($sp)
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ldq $8, 9*8($sp)
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ldq $16, 10*8($sp)
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ldq $17, 11*8($sp)
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ldq $18, 12*8($sp)
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ldq $19, 13*8($sp)
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ldq $20, 14*8($sp)
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ldq $21, 15*8($sp)
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ldq $22, 16*8($sp)
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ldq $23, 17*8($sp)
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ldq $24, 18*8($sp)
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ldq $25, 19*8($sp)
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ldq $29, 20*8($sp)
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ldt $f0, 21*8($sp)
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ldt $f1, 22*8($sp)
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ldt $f10, 23*8($sp)
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ldt $f11, 24*8($sp)
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ldt $f12, 25*8($sp)
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ldt $f13, 26*8($sp)
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ldt $f14, 27*8($sp)
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ldt $f15, 28*8($sp)
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ldt $f16, 29*8($sp)
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ldt $f17, 30*8($sp)
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ldt $f18, 31*8($sp)
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ldt $f19, 32*8($sp)
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ldt $f20, 33*8($sp)
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ldt $f21, 34*8($sp)
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ldt $f22, 35*8($sp)
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ldt $f23, 36*8($sp)
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ldt $f24, 37*8($sp)
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ldt $f25, 38*8($sp)
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ldt $f26, 39*8($sp)
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ldt $f27, 40*8($sp)
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ldt $f28, 41*8($sp)
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ldt $f29, 42*8($sp)
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ldt $f30, 43*8($sp)
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/* Flush the Icache after having modified the .plt code. */
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" #IMB "
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/* Clean up and turn control to the destination */
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lda $sp, 44*8($sp)
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jmp $31, ($27)
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.end " #tramp_name)
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#ifndef PROF
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#define ELF_MACHINE_RUNTIME_TRAMPOLINE \
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TRAMPOLINE_TEMPLATE (_dl_runtime_resolve, fixup, imb); \
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TRAMPOLINE_TEMPLATE (_dl_runtime_profile, profile_fixup, /* nop */);
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#else
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#define ELF_MACHINE_RUNTIME_TRAMPOLINE \
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TRAMPOLINE_TEMPLATE (_dl_runtime_resolve, fixup, imb); \
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strong_alias (_dl_runtime_resolve, _dl_runtime_profile);
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#endif
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/* Initial entry point code for the dynamic linker.
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The C function `_dl_start' is the real entry point;
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its return value is the user program's entry point. */
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#define RTLD_START asm ("\
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.text
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.set at
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.globl _start
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.ent _start
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_start:
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br $gp, 0f
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0: ldgp $gp, 0($gp)
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.prologue 0
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/* Pass pointer to argument block to _dl_start. */
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mov $sp, $16
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bsr $26, "ASM_ALPHA_NG_SYMBOL_PREFIX"_dl_start..ng
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.end _start
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/* FALLTHRU */
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.globl _dl_start_user
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.ent _dl_start_user
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_dl_start_user:
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.frame $30,0,$31,0
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.prologue 0
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/* Save the user entry point address in s0. */
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mov $0, $9
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/* Store the highest stack address. */
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stq $30, __libc_stack_end
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/* See if we were run as a command with the executable file
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name as an extra leading argument. */
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ldl $1, _dl_skip_args
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bne $1, $fixup_stack
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$fixup_stack_ret:
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/* The special initializer gets called with the stack just
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as the application's entry point will see it; it can
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switch stacks if it moves these contents over. */
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" RTLD_START_SPECIAL_INIT "
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/* Call _dl_init(_dl_loaded, argc, argv, envp) to run initializers. */
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ldq $16, _dl_loaded
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ldq $17, 0($sp)
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lda $18, 8($sp)
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s8addq $17, 8, $19
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addq $19, $18, $19
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jsr $26, _dl_init
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/* Pass our finalizer function to the user in $0. */
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lda $0, _dl_fini
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/* Jump to the user's entry point. */
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mov $9, $27
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jmp ($9)
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$fixup_stack:
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/* Adjust the stack pointer to skip _dl_skip_args words. This
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involves copying everything down, since the stack pointer must
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always be 16-byte aligned. */
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ldq $2, 0($sp)
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subq $2, $1, $2
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mov $sp, $4
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s8addq $1, $sp, $3
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stq $2, 0($sp)
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/* Copy down argv. */
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0: ldq $5, 8($3)
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addq $4, 8, $4
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addq $3, 8, $3
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stq $5, 0($4)
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bne $5, 0b
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/* Copy down envp. */
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1: ldq $5, 8($3)
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addq $4, 8, $4
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addq $3, 8, $3
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stq $5, 0($4)
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bne $5, 1b
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/* Copy down auxiliary table. */
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2: ldq $5, 8($3)
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ldq $6, 16($3)
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addq $4, 16, $4
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addq $3, 16, $3
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stq $5, -8($4)
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stq $6, 0($4)
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bne $5, 2b
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br $fixup_stack_ret
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.end _dl_start_user
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.set noat
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.previous");
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#ifndef RTLD_START_SPECIAL_INIT
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#define RTLD_START_SPECIAL_INIT /* nothing */
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#endif
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/* Nonzero iff TYPE describes relocation of a PLT entry, so
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PLT entries should not be allowed to define the value. */
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#define elf_machine_lookup_noplt_p(type) ((type) == R_ALPHA_JMP_SLOT)
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/* Nonzero iff TYPE should not be allowed to resolve to one of
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the main executable's symbols, as for a COPY reloc, which we don't use. */
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#define elf_machine_lookup_noexec_p(type) (0)
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/* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
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#define ELF_MACHINE_JMP_SLOT R_ALPHA_JMP_SLOT
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/* The alpha never uses Elf64_Rel relocations. */
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#define ELF_MACHINE_NO_REL 1
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/* Fix up the instructions of a PLT entry to invoke the function
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rather than the dynamic linker. */
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static inline Elf64_Addr
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elf_machine_fixup_plt (struct link_map *l, lookup_t t,
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const Elf64_Rela *reloc,
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Elf64_Addr *got_addr, Elf64_Addr value)
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{
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const Elf64_Rela *rela_plt;
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Elf64_Word *plte;
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long int edisp;
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/* Store the value we are going to load. */
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*got_addr = value;
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/* Recover the PLT entry address by calculating reloc's index into the
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.rela.plt, and finding that entry in the .plt. */
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rela_plt = (void *) D_PTR (l, l_info[DT_JMPREL]);
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plte = (void *) (D_PTR (l, l_info[DT_PLTGOT]) + 32);
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plte += 3 * (reloc - rela_plt);
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/* Find the displacement from the plt entry to the function. */
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edisp = (long int) (value - (Elf64_Addr)&plte[3]) / 4;
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if (edisp >= -0x100000 && edisp < 0x100000)
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{
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/* If we are in range, use br to perfect branch prediction and
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elide the dependency on the address load. This case happens,
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e.g., when a shared library call is resolved to the same library. */
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int hi, lo;
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hi = value - (Elf64_Addr)&plte[0];
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lo = (short int) hi;
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hi = (hi - lo) >> 16;
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/* Emit "lda $27,lo($27)" */
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plte[1] = 0x237b0000 | (lo & 0xffff);
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/* Emit "br $31,function" */
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plte[2] = 0xc3e00000 | (edisp & 0x1fffff);
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/* Think about thread-safety -- the previous instructions must be
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committed to memory before the first is overwritten. */
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__asm__ __volatile__("wmb" : : : "memory");
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/* Emit "ldah $27,hi($27)" */
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plte[0] = 0x277b0000 | (hi & 0xffff);
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}
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else
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{
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/* Don't bother with the hint since we already know the hint is
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wrong. Eliding it prevents the wrong page from getting pulled
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into the cache. */
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int hi, lo;
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hi = (Elf64_Addr)got_addr - (Elf64_Addr)&plte[0];
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lo = (short)hi;
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hi = (hi - lo) >> 16;
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/* Emit "ldq $27,lo($27)" */
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plte[1] = 0xa77b0000 | (lo & 0xffff);
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/* Emit "jmp $31,($27)" */
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plte[2] = 0x6bfb0000;
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/* Think about thread-safety -- the previous instructions must be
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committed to memory before the first is overwritten. */
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__asm__ __volatile__("wmb" : : : "memory");
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/* Emit "ldah $27,hi($27)" */
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plte[0] = 0x277b0000 | (hi & 0xffff);
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}
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/* At this point, if we've been doing runtime resolution, Icache is dirty.
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This will be taken care of in _dl_runtime_resolve. If instead we are
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doing this as part of non-lazy startup relocation, that bit of code
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hasn't made it into Icache yet, so there's nothing to clean up. */
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return value;
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}
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/* Return the final value of a plt relocation. */
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static inline Elf64_Addr
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elf_machine_plt_value (struct link_map *map, const Elf64_Rela *reloc,
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Elf64_Addr value)
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{
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return value + reloc->r_addend;
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}
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#endif /* !dl_machine_h */
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#ifdef RESOLVE
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/* Perform the relocation specified by RELOC and SYM (which is fully resolved).
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MAP is the object containing the reloc. */
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static inline void
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elf_machine_rela (struct link_map *map,
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const Elf64_Rela *reloc,
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const Elf64_Sym *sym,
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const struct r_found_version *version,
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Elf64_Addr *const reloc_addr)
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{
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unsigned long int const r_type = ELF64_R_TYPE (reloc->r_info);
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#ifndef RTLD_BOOTSTRAP
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/* This is defined in rtld.c, but nowhere in the static libc.a; make the
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reference weak so static programs can still link. This declaration
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cannot be done when compiling rtld.c (i.e. #ifdef RTLD_BOOTSTRAP)
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because rtld.c contains the common defn for _dl_rtld_map, which is
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incompatible with a weak decl in the same file. */
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weak_extern (_dl_rtld_map);
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#endif
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/* We cannot use a switch here because we cannot locate the switch
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jump table until we've self-relocated. */
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if (r_type == R_ALPHA_RELATIVE)
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{
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#ifndef RTLD_BOOTSTRAP
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/* Already done in dynamic linker. */
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if (map != &_dl_rtld_map)
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#endif
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*reloc_addr += map->l_addr;
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}
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else if (r_type == R_ALPHA_NONE)
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return;
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else
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{
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Elf64_Addr loadbase, sym_value;
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loadbase = RESOLVE (&sym, version, r_type);
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sym_value = sym ? loadbase + sym->st_value : 0;
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sym_value += reloc->r_addend;
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if (r_type == R_ALPHA_GLOB_DAT)
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*reloc_addr = sym_value;
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else if (r_type == R_ALPHA_JMP_SLOT)
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elf_machine_fixup_plt (map, NULL, reloc, reloc_addr, sym_value);
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else if (r_type == R_ALPHA_REFQUAD)
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{
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sym_value += *reloc_addr;
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#ifndef RTLD_BOOTSTRAP
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if (map == &_dl_rtld_map)
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|
{
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/* Undo the relocation done here during bootstrapping.
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|
Now we will relocate anew, possibly using a binding
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|
found in the user program or a loaded library rather
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|
than the dynamic linker's built-in definitions used
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while loading those libraries. */
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const Elf64_Sym *const dlsymtab
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= (void *) D_PTR (map, l_info[DT_SYMTAB]);
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sym_value -= map->l_addr;
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sym_value -= dlsymtab[ELF64_R_SYM(reloc->r_info)].st_value;
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sym_value -= reloc->r_addend;
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}
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#endif
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*reloc_addr = sym_value;
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}
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else
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_dl_reloc_bad_type (map, r_type, 0);
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}
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}
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static inline void
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elf_machine_lazy_rel (struct link_map *map,
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Elf64_Addr l_addr, const Elf64_Rela *reloc)
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|
{
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Elf64_Addr * const reloc_addr = (void *)(l_addr + reloc->r_offset);
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unsigned long int const r_type = ELF64_R_TYPE (reloc->r_info);
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if (r_type == R_ALPHA_JMP_SLOT)
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{
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/* Perform a RELATIVE reloc on the .got entry that transfers
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|
to the .plt. */
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|
*reloc_addr += l_addr;
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}
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else if (r_type == R_ALPHA_NONE)
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return;
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else
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_dl_reloc_bad_type (map, r_type, 1);
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}
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#endif /* RESOLVE */
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