1/* Special .init and .fini section support for HPPA 2 Copyright (C) 2000-2022 Free Software Foundation, Inc. 3 This file is part of the GNU C Library. 4 5 The GNU C Library is free software; you can redistribute it and/or 6 modify it under the terms of the GNU Lesser General Public 7 License as published by the Free Software Foundation; either 8 version 2.1 of the License, or (at your option) any later version. 9 10 In addition to the permissions in the GNU Lesser General Public 11 License, the Free Software Foundation gives you unlimited 12 permission to link the compiled version of this file with other 13 programs, and to distribute those programs without any restriction 14 coming from the use of this file. (The GNU Lesser General Public 15 License restrictions do apply in other respects; for example, they 16 cover modification of the file, and distribution when not linked 17 into another program.) 18 19 Note that people who make modified versions of this file are not 20 obligated to grant this special exception for their modified 21 versions; it is their choice whether to do so. The GNU Lesser 22 General Public License gives permission to release a modified 23 version without this exception; this exception also makes it 24 possible to release a modified version which carries forward this 25 exception. 26 27 The GNU C Library is distributed in the hope that it will be useful, 28 but WITHOUT ANY WARRANTY; without even the implied warranty of 29 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 30 Lesser General Public License for more details. 31 32 You should have received a copy of the GNU Lesser General Public 33 License along with the GNU C Library. If not, see 34 <https://www.gnu.org/licenses/>. */ 35 36/* crti.S puts a function prologue at the beginning of the .init and 37 .fini sections and defines global symbols for those addresses, so 38 they can be called as functions. The symbols _init and _fini are 39 magic and cause the linker to emit DT_INIT and DT_FINI. */ 40 41#include <libc-symbols.h> 42#include <sysdep.h> 43 44#ifndef PREINIT_FUNCTION 45# define PREINIT_FUNCTION __gmon_start__ 46#endif 47 48#ifndef PREINIT_FUNCTION_WEAK 49# define PREINIT_FUNCTION_WEAK 1 50#endif 51 52#if PREINIT_FUNCTION_WEAK 53 weak_extern (PREINIT_FUNCTION) 54#else 55 .hidden PREINIT_FUNCTION 56#endif 57 58 59/* If we have working .init_array support, we want to keep the .init 60 section empty (apart from the mandatory prologue/epilogue. This 61 ensures that the default unwind conventions (return-pointer in b0, 62 frame state in ar.pfs, etc.) will do the Right Thing. To ensure 63 an empty .init section, we register gmon_initializer() via the 64 .init_array. 65 66 --davidm 02/10/29 */ 67 68#if PREINIT_FUNCTION_WEAK 69/* This blob of assembly code is one simple C function: 70 71static void 72__attribute__ ((used)) 73gmon_initializer (void) 74{ 75 extern void weak_function __gmon_start__ (void); 76 77 if (__gmon_start__) 78 (*__gmon_start__)(); 79} 80 81In a final executable, PLABEL32 relocations for function pointers are 82resolved at link time. Typically, binutils/ld resolves __gmon_start__ 83using an external shared library. __gmon_start__ is always called if 84it is found at link time. If __gmon_start__ is not found at runtime 85due to a library update, then the function pointer will point at a null 86function descriptor and calling it will cause a segmentation fault. 87So, we call __canonicalize_funcptr_for_compare to obtain the canonicalized 88address of __gmon_start__ and skip calling __gmon_start__ if it is zero. 89 90 */ 91 .type __canonicalize_funcptr_for_compare,@function 92 .type $$dyncall,@function 93 94 .section .data.rel.ro,"aw",@progbits 95 .align 4 96.LC0: 97 .type __gmon_start__,@function 98 .word P%__gmon_start__ 99 100 .text 101 .align 4 102 .type gmon_initializer,@function 103gmon_initializer: 104 .PROC 105 .CALLINFO FRAME=64,CALLS,SAVE_RP,ENTRY_GR=4 106 .ENTRY 107 stw %r2,-20(%r30) 108 stwm %r4,64(%r30) 109 stw %r3,-60(%r30) 110 addil LT'.LC0,%r19 111 ldw RT'.LC0(%r1),%r28 112 ldw 0(%r28),%r3 113 comib,= 0,%r3,1f 114 copy %r19,%r4 115 stw %r19,-32(%r30) 116 bl __canonicalize_funcptr_for_compare,%r2 117 copy %r3,%r26 118 comib,= 0,%r28,1f 119 copy %r4,%r19 120 copy %r3,%r22 121 .CALL ARGW0=GR 122 bl $$dyncall,%r31 123 copy %r31,%r2 1241: 125 ldw -84(%r30),%r2 126 ldw -60(%r30),%r3 127 bv %r0(%r2) 128 ldwm -64(%r30),%r4 129 .EXIT 130 .PROCEND 131 .size gmon_initializer, .-gmon_initializer 132 133# undef PREINIT_FUNCTION 134# define PREINIT_FUNCTION gmon_initializer 135#endif 136 137 .section .init_array, "aw" 138 .word P% PREINIT_FUNCTION 139 140 141/* _init prologue. */ 142 .section .init, "ax", %progbits 143 .align 4 144 .globl _init 145 .hidden _init 146 .type _init,@function 147_init: 148 stw %rp,-20(%sp) 149 stwm %r4,64(%sp) 150 stw %r19,-32(%sp) 151 152/* _fini prologue. */ 153 .section .fini,"ax",%progbits 154 .align 4 155 .globl _fini 156 .hidden _fini 157 .type _fini,@function 158_fini: 159 stw %rp,-20(%sp) 160 stwm %r4,64(%sp) 161 stw %r19,-32(%sp) 162 copy %r19,%r4 163