2015-10-15 10:25:28 +02:00

117 lines
3.8 KiB
ArmAsm

/* $NetBSD: rtld_start.S,v 1.2 2015/03/27 23:14:53 matt Exp $ */
/*-
* Copyright (c) 2014 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Matt Thomas of 3am Software Foundry.
*
* 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>
.globl _C_LABEL(_rtld_relocate_nonplt_self)
.globl _C_LABEL(_rtld)
/*
* void
* ___start(void (*cleanup)(void),
* const Obj_Entry *obj,
* struct ps_strings *ps_strings)
*/
ENTRY(_rtld_start)
move s0, sp # save stack pointer
addi sp, sp, -4*__SIZEOF_POINTER__
# adjust stack pointer
# -> 2*PTR_SIZE(sp) for atexit
# -> 3*PTR_SIZE(sp) for obj_main
move s1, a2 # save ps_strings pointer
.L0: auipc gp, %pcrel_hi(_GLOBAL_OFFSET_TABLE_)
PTR_L t0, %pcrel_lo(.L0)(gp) # &_DYNAMIC
.L1: auipc a0, %pcrel_hi(_DYNAMIC)
addi a0, a0, %pcrel_lo(.L1)
sub s2, a0, t0 # save for _rtld
move a1, s2
call _C_LABEL(_rtld_relocate_nonplt_self)
move a1, s2 # relocbase
addi a0, sp, 2*__SIZEOF_POINTER__ # sp
call _C_LABEL(_rtld) # a0 = _rtld(sp, relocbase)
mv t0, a0
PTR_L a0, 2*__SIZEOF_POINTER__(sp) # cleanup function
PTR_L a1, 3*__SIZEOF_POINTER__(sp) # obj_main entry
move a2, s1 # restore ps_strings
move sp, s0 # readjust stack
move s0, zero # break stack chain
jr t0 # _start(cleanup, obj_main, ps_strings);
END(_rtld_start)
#define XCALLFRAME_SIZ (12*SZREG)
#define XCALLFRAME_RA (8*SZREG)
#define XCALLFRAME_A7 (7*SZREG)
#define XCALLFRAME_A6 (6*SZREG)
#define XCALLFRAME_A5 (5*SZREG)
#define XCALLFRAME_A4 (4*SZREG)
#define XCALLFRAME_A3 (3*SZREG)
#define XCALLFRAME_A2 (2*SZREG)
#define XCALLFRAME_A1 (1*SZREG)
#define XCALLFRAME_A0 (0*SZREG)
/*
* t0 = obj pointer
* t1 = reloc offset
*/
ENTRY_NP(_rtld_bind_start)
addi sp, sp, -XCALLFRAME_SIZ // save arguments on stack
REG_S a0, XCALLFRAME_A0(sp)
REG_S a1, XCALLFRAME_A1(sp)
REG_S a2, XCALLFRAME_A2(sp)
REG_S a3, XCALLFRAME_A3(sp)
REG_S a4, XCALLFRAME_A4(sp)
REG_S a5, XCALLFRAME_A5(sp)
REG_S a6, XCALLFRAME_A6(sp)
REG_S a7, XCALLFRAME_A7(sp)
REG_S ra, XCALLFRAME_RA(sp)
mv a0, t0 /* object from got.plt[1] */
mv a1, t1 /* reloc offset */
call _C_LABEL(_rtld_bind)
mv t0, a0 /* save function pointer */
REG_L a0, XCALLFRAME_A0(sp)
REG_L a1, XCALLFRAME_A1(sp)
REG_L a2, XCALLFRAME_A2(sp)
REG_L a3, XCALLFRAME_A3(sp)
REG_L a4, XCALLFRAME_A4(sp)
REG_L a5, XCALLFRAME_A5(sp)
REG_L a6, XCALLFRAME_A6(sp)
REG_L a7, XCALLFRAME_A7(sp)
REG_L ra, XCALLFRAME_RA(sp)
addi sp, sp, XCALLFRAME_SIZ
jr t0
END(_rtld_bind_start)