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/* $NetBSD: rtld_start.S,v 1.12 2012/01/06 10:38:57 skrll Exp $ */
/*-
* Copyright (c) 2002 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Matt Fredette.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <machine/asm.h>
#include <machine/frame.h>
.import _GLOBAL_OFFSET_TABLE_
ENTRY($rtld_start,HPPA_FRAME_SIZE)
/* Start stack calling convention. */
copy %r3, %r1
copy %sp, %r3
stw,ma %r1, HPPA_FRAME_SIZE(%sp)
/*
* Save our single argument, the ps_strings pointer. We'll need this
* twice later: once to call _rtld, and again to transfer to the
* program's entry point.
*/
stw %arg0, HPPA_FRAME_ARG(0)(%r3)
/*
* We can't move to C until we relocate at least the
* Global Offset Table. Even finding the GOT is tricky
* without inadvertently causing the linker to make
* relocations for this part of the text segment.
*/
bl L$lpc1, %r19
depi 0, 31, 2, %r19
L$lpc1: addil L'_DYNAMIC - ($PIC_pcrel$0 - 8), %r19
ldo R'_DYNAMIC - ($PIC_pcrel$0 - 12)(%r1),%arg0
/*
* Load the absolute address of the beginning of the GOT into %r19, the
* shared library linkage table register, leaving it ready-to-use by
* the dynamic linker C code.
*/
addil L'_GLOBAL_OFFSET_TABLE_ - ($PIC_pcrel$0 - 16), %r19
ldo R'_GLOBAL_OFFSET_TABLE_ - ($PIC_pcrel$0 - 20)(%r1),%r19
/*
* The linker sets the first entry in the GOT to the unrelocated
* address of _DYNAMIC. Subtract this from the absolute address of
* _DYNAMIC to get our relocbase.
*/
ldw 0(%r19), %arg1
sub %arg0, %arg1, %arg1 ; %arg1 = relocbase
bl _rtld_relocate_nonplt_self, %rp
copy %arg1, %r4 ; save for later
/*
* Recover the ps_strings pointer, and take out the
* ps_argvstr member.
*/
ldw HPPA_FRAME_ARG(0)(%r3), %arg0 ; ps_strings
ldw 0(%arg0), %arg0 ; ps_argvstr member first in struct
/*
* ps_argvstr - 4 would get us a pointer to argc, comparable to the
* initial stack pointer on architectures where the stack grows down.
* Subtracting an additional eight creates the storage for obj and
* cleanup that _rtld needs.
*/
ldo -12(%arg0), %arg0
stw %arg0, HPPA_FRAME_ARG(1)(%r3)
/* Call _rtld, copying relocbase into arg1. */
bl _rtld, %rp
copy %r4, %arg1 ; %arg1 = relocbase
/* Prepare the arguments for the entry point. */
ldw HPPA_FRAME_ARG(1)(%r3), %r1
ldw HPPA_FRAME_ARG(0)(%r3), %arg0 ; ps_strings
ldw 0(%r1), %arg1 ; cleanup
ldw 4(%r1), %arg2 ; obj
/* End stack calling convention. */
ldo HPPA_FRAME_SIZE(%r3), %sp
ldw,mb -HPPA_FRAME_SIZE(%sp), %r3
/* Go for it. */
bv %r0(%ret0)
copy %r0, %rp
EXIT($rtld_start)
/*
* This does our setup for an object's GOT. %arg0 is the Obj_Entry * for the
* object, and %arg1 is its GOT pointer.
*/
LEAF_ENTRY(__rtld_setup_hppa_pltgot)
/*
* The second entry of the GOT is reserved for the dynamic linker. We
* put the Obj_Entry * for the object in there.
*/
stw %arg0, 4(%arg1)
/*
* Fill the fixup_func and fixup_ltp members of the PLT stub. This
* stub is inserted by the linker immediately before the GOT. We use
* this stub to enter our binder.
*/
bl L$lpc2, %arg0
depi 0, 31, 2, %arg0
L$lpc2: addil L'_rtld_bind_start - ($PIC_pcrel$0 - 8), %arg0
ldo R'_rtld_bind_start - ($PIC_pcrel$0 - 12)(%r1),%arg0
stw %arg0, -8(%arg1)
bv %r0(%rp)
stw %r19, -4(%arg1)
EXIT(__rtld_setup_hppa_pltgot)
/*
* In order to support lazy binding, this implementation of _rtld_bind_start is
* very closely tied to the shared-library call stub and the PLT stub, both
* inserted by the linker.
*/
/*
* This is a magic branch instruction that is used by GCC's
* __canonicalize_funcptr_for_compare() function to fixup relocations
* in order to do function pointer comparisons.
*/
bl _rtld_bind, %rp
ENTRY(_rtld_bind_start,HPPA_FRAME_SIZE)
/* Start stack calling convention. */
copy %r3, %r1
copy %sp, %r3
stw,ma %r1, HPPA_FRAME_SIZE(%sp)
/*
* We have to save all calling convention registers that are set by the
* caller, because we have to restore them before transferring to the
* bound function. Note that this includes %ret0, %ret1, and %t1.
*
* %ret0 and %ret1 because they can have meaning on entry to a
* function.
*
* %t1 because it's used by libc to pass on errno values to cerror.
*/
stw %rp, HPPA_FRAME_CRP(%r3)
stw %arg0, HPPA_FRAME_ARG(0)(%r3)
stw %arg1, HPPA_FRAME_ARG(1)(%r3)
stw %arg2, HPPA_FRAME_ARG(2)(%r3)
stw %arg3, HPPA_FRAME_ARG(3)(%r3)
/* 0(%r3) is filled with the saved %r3 above */
stw %ret0, 4(%r3)
stw %ret1, 8(%r3)
stw %t1, 12(%r3) /* %r22 */
/*
* The linker PLT stub loads %r20 with (GOT - 8) for the object that
* needs binding done. The second entry of the GOT is reserved for the
* dynamic linker's use, and we previously stashed the object's
* Obj_Entry * there.
*/
ldw 12(%r20), %arg0
/*
* The linker shared-library call stub loads %r19 from the shared
* linkage member of the PLT entry. We previously stashed the reloff
* of the relocation there.
*/
copy %r19, %arg1
/*
* The linker PLT stub loads %r21 with the fixup_ltp word in itself.
* We previously stashed our %r19 value there.
*/
bl _rtld_bind, %rp
copy %r21, %r19
/*
* Our hppa version of _rtld_bind returns to us the address of the PLT
* entry that it fixed up. Load the function address and shared
* linkage for the newly bound function.
*/
ldw 0(%ret0), %r21
ldw 4(%ret0), %r19
/* Restore registers saved above. */
ldw HPPA_FRAME_CRP(%r3), %rp
ldw HPPA_FRAME_ARG(0)(%r3), %arg0
ldw HPPA_FRAME_ARG(1)(%r3), %arg1
ldw HPPA_FRAME_ARG(2)(%r3), %arg2
ldw HPPA_FRAME_ARG(3)(%r3), %arg3
ldw 4(%r3), %ret0
ldw 8(%r3), %ret1
ldw 12(%r3), %t1 /* %r22 */
/* End stack calling convention. */
ldo HPPA_FRAME_SIZE(%r3), %sp
ldw,mb -HPPA_FRAME_SIZE(%sp), %r3
/* Transfer to the function. */
bv %r0(%r21)
nop
EXIT(_rtld_bind_start)
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