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696caf1d00
This patch adds support for the ELFv2 ABI feature to remove function descriptors. See this GCC patch for in-depth discussion: http://gcc.gnu.org/ml/gcc-patches/2013-11/msg01141.html This mostly involves two types of changes: updating assembler source files to the new logic, and updating the dynamic loader. After the refactoring in the previous patch, most of the assembler source changes can be handled simply by providing ELFv2 versions of the macros in sysdep.h. One somewhat non-obvious change is in __GI__setjmp: this used to "fall through" to the immediately following __setjmp ENTRY point. This is no longer safe in the ELFv2 since ENTRY defines both a global and a local entry point, and you cannot simply fall through to a global entry point as it requires r12 to be set up. Also, makecontext needs to be updated to set up registers according to the new ABI for calling into the context's start routine. The dynamic linker changes mostly consist of removing special code to handle function descriptors. We also need to support the new PLT and glink format used by the the ELFv2 linker, see: https://sourceware.org/ml/binutils/2013-10/msg00376.html In addition, the dynamic linker now verifies that the dynamic libraries it loads match its own ABI. The hack in VDSO_IFUNC_RET to "synthesize" a function descriptor for vDSO routines is also no longer necessary for ELFv2.
89 lines
2.8 KiB
ArmAsm
89 lines
2.8 KiB
ArmAsm
/* Special .init and .fini section support for PowerPC64.
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Copyright (C) 2012-2013 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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In addition to the permissions in the GNU Lesser General Public
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License, the Free Software Foundation gives you unlimited
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permission to link the compiled version of this file with other
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programs, and to distribute those programs without any restriction
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coming from the use of this file. (The GNU Lesser General Public
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License restrictions do apply in other respects; for example, they
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cover modification of the file, and distribution when not linked
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into another program.)
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Note that people who make modified versions of this file are not
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obligated to grant this special exception for their modified
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versions; it is their choice whether to do so. The GNU Lesser
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General Public License gives permission to release a modified
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version without this exception; this exception also makes it
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possible to release a modified version which carries forward this
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exception.
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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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/* crti.S puts a function prologue at the beginning of the .init and
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.fini sections and defines global symbols for those addresses, so
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they can be called as functions. The symbols _init and _fini are
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magic and cause the linker to emit DT_INIT and DT_FINI. */
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#include <libc-symbols.h>
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#include <sysdep.h>
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#ifndef PREINIT_FUNCTION
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# define PREINIT_FUNCTION __gmon_start__
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#endif
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#ifndef PREINIT_FUNCTION_WEAK
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# define PREINIT_FUNCTION_WEAK 1
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#endif
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#if PREINIT_FUNCTION_WEAK
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weak_extern (PREINIT_FUNCTION)
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#else
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.hidden PREINIT_FUNCTION
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#endif
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#if PREINIT_FUNCTION_WEAK
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.section ".toc", "aw"
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.LC0:
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.tc PREINIT_FUNCTION[TC], PREINIT_FUNCTION
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#endif
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.section ".init", "ax", @progbits
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ENTRY_2(_init)
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.align ALIGNARG (2)
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BODY_LABEL (_init):
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LOCALENTRY(_init)
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mflr 0
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std 0, 16(r1)
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stdu r1, -112(r1)
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#if PREINIT_FUNCTION_WEAK
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addis r9, r2, .LC0@toc@ha
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ld r0, .LC0@toc@l(r9)
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cmpdi cr7, r0, 0
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beq+ cr7, 1f
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#endif
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bl JUMPTARGET (PREINIT_FUNCTION)
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nop
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1:
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.section ".fini", "ax", @progbits
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ENTRY_2(_fini)
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.align ALIGNARG (2)
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BODY_LABEL (_fini):
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LOCALENTRY(_fini)
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mflr 0
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std 0, 16(r1)
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stdu r1, -112(r1)
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