e83f7ba2c9
. file- and functionality-compatible with previous situation
(FreeBSD csu) (with a crt1.o -> crt0.o symlink in /usr/lib)
. harmonizes source with netbsd
. harmonizes linker invocation (e.g. clang) with netbsd
. helpful to get some arm code in there for the arm port project
232 lines
7 KiB
ArmAsm
232 lines
7 KiB
ArmAsm
/* $NetBSD: rtld_start.S,v 1.9 2010/09/30 19:32:40 skrll Exp $ */
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/*-
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* Copyright (c) 2002 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Matt Fredette.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <machine/asm.h>
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#include <machine/frame.h>
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.import _GLOBAL_OFFSET_TABLE_
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ENTRY($rtld_start,HPPA_FRAME_SIZE)
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/* Start stack calling convention. */
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copy %r3, %r1
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copy %sp, %r3
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stw,ma %r1, HPPA_FRAME_SIZE(%sp)
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/*
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* Save our single argument, the ps_strings pointer. We'll need this
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* twice later: once to call _rtld, and again to transfer to the
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* program's entry point.
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*/
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stw %arg0, HPPA_FRAME_ARG(0)(%r3)
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/*
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* We can't move to C until we relocate at least the
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* Global Offset Table. Even finding the GOT is tricky
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* without inadvertently causing the linker to make
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* relocations for this part of the text segment.
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*/
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bl L$lpc1, %r19
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depi 0, 31, 2, %r19
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L$lpc1: addil L'_DYNAMIC - ($PIC_pcrel$0 - 8), %r19
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ldo R'_DYNAMIC - ($PIC_pcrel$0 - 12)(%r1),%arg0
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/*
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* Load the absolute address of the beginning of the GOT into %r19, the
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* shared library linkage table register, leaving it ready-to-use by
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* the dynamic linker C code.
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*/
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addil L'_GLOBAL_OFFSET_TABLE_ - ($PIC_pcrel$0 - 16), %r19
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ldo R'_GLOBAL_OFFSET_TABLE_ - ($PIC_pcrel$0 - 20)(%r1),%r19
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/*
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* The linker sets the first entry in the GOT to the unrelocated
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* address of _DYNAMIC. Subtract this from the absolute address of
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* _DYNAMIC to get our relocbase.
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*/
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ldw 0(%r19), %arg1
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sub %arg0, %arg1, %arg1 ; %arg1 = relocbase
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bl _rtld_relocate_nonplt_self, %rp
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copy %arg1, %r4 ; save for later
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/*
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* Recover the ps_strings pointer, and take out the
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* ps_argvstr member.
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*/
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ldw HPPA_FRAME_ARG(0)(%r3), %arg0 ; ps_strings
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ldw 0(%arg0), %arg0 ; ps_argvstr member first in struct
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/*
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* ps_argvstr - 4 would get us a pointer to argc, comparable to the
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* initial stack pointer on architectures where the stack grows down.
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* Subtracting an additional eight creates the storage for obj and
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* cleanup that _rtld needs.
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*/
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ldo -12(%arg0), %arg0
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stw %arg0, HPPA_FRAME_ARG(1)(%r3)
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/* Call _rtld, copying relocbase into arg1. */
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bl _rtld, %rp
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copy %r4, %arg1 ; %arg1 = relocbase
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/* Prepare the arguments for the entry point. */
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ldw HPPA_FRAME_ARG(1)(%r3), %r1
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ldw HPPA_FRAME_ARG(0)(%r3), %arg0 ; ps_strings
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ldw 0(%r1), %arg1 ; cleanup
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ldw 4(%r1), %arg2 ; obj
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/* End stack calling convention. */
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ldo HPPA_FRAME_SIZE(%r3), %sp
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ldw,mb -HPPA_FRAME_SIZE(%sp), %r3
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/* Go for it. */
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bv %r0(%ret0)
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copy %r0, %rp
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EXIT($rtld_start)
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/*
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* This does our setup for an object's GOT. %arg0 is the Obj_Entry * for the
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* object, and %arg1 is its GOT pointer.
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*/
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LEAF_ENTRY(__rtld_setup_hppa_pltgot)
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/*
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* The second entry of the GOT is reserved for the dynamic linker. We
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* put the Obj_Entry * for the object in there.
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*/
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stw %arg0, 4(%arg1)
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/*
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* Fill the fixup_func and fixup_ltp members of the PLT stub. This
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* stub is inserted by the linker immediately before the GOT. We use
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* this stub to enter our binder.
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*/
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bl L$lpc2, %arg0
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depi 0, 31, 2, %arg0
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L$lpc2: addil L'_rtld_bind_start - ($PIC_pcrel$0 - 8), %arg0
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ldo R'_rtld_bind_start - ($PIC_pcrel$0 - 12)(%r1),%arg0
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stw %arg0, -8(%arg1)
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bv %r0(%rp)
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stw %r19, -4(%arg1)
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EXIT(__rtld_hppa_setup_pltgot)
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/*
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* In order to support lazy binding, this implementation of _rtld_bind_start is
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* very closely tied to the shared-library call stub and the PLT stub, both
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* inserted by the linker.
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*/
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/*
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* This is a magic branch instruction that is used by GCC's
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* __canonicalize_funcptr_for_compare() function to fixup relocations
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* in order to do function pointer comparisons.
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*/
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bl _rtld_bind, %rp
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ENTRY(_rtld_bind_start,HPPA_FRAME_SIZE)
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/* Start stack calling convention. */
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copy %r3, %r1
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copy %sp, %r3
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stw,ma %r1, HPPA_FRAME_SIZE(%sp)
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/*
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* We have to save all calling convention registers that are set by the
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* caller, because we have to restore them before transferring to the
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* bound function. Note that this includes %ret0, %ret1, and %t1.
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*
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* %ret0 and %ret1 because they can have meaning on entry to a
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* function.
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*
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* %t1 because it's used by libc to pass on errno values to cerror.
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*/
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stw %rp, HPPA_FRAME_CRP(%r3)
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stw %arg0, HPPA_FRAME_ARG(0)(%r3)
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stw %arg1, HPPA_FRAME_ARG(1)(%r3)
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stw %arg2, HPPA_FRAME_ARG(2)(%r3)
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stw %arg3, HPPA_FRAME_ARG(3)(%r3)
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/* 0(%r3) is filled with the saved %r3 above */
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stw %ret0, 4(%r3)
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stw %ret1, 8(%r3)
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/*
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* The linker PLT stub loads %r20 with (GOT - 8) for the object that
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* needs binding done. The second entry of the GOT is reserved for the
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* dynamic linker's use, and we previously stashed the object's
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* Obj_Entry * there.
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*/
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ldw 12(%r20), %arg0
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/*
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* The linker shared-library call stub loads %r19 from the shared
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* linkage member of the PLT entry. We previously stashed the reloff
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* of the relocation there.
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*/
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copy %r19, %arg1
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/*
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* The linker PLT stub loads %r21 with the fixup_ltp word in itself.
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* We previously stashed our %r19 value there.
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*/
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bl _rtld_bind, %rp
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copy %r21, %r19
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/*
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* Our hppa version of _rtld_bind returns to us the address of the PLT
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* entry that it fixed up. Load the function address and shared
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* linkage for the newly bound function.
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*/
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ldw 0(%ret0), %r21
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ldw 4(%ret0), %r19
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/* Restore registers saved above. */
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ldw HPPA_FRAME_CRP(%r3), %rp
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ldw HPPA_FRAME_ARG(0)(%r3), %arg0
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ldw HPPA_FRAME_ARG(1)(%r3), %arg1
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ldw HPPA_FRAME_ARG(2)(%r3), %arg2
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ldw HPPA_FRAME_ARG(3)(%r3), %arg3
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ldw 4(%r3), %ret0
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ldw 8(%r3), %ret1
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/* End stack calling convention. */
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ldo HPPA_FRAME_SIZE(%r3), %sp
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ldw,mb -HPPA_FRAME_SIZE(%sp), %r3
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/* Transfer to the function. */
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bv %r0(%r21)
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nop
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EXIT(_rtld_bind_start)
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