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/* $NetBSD: rtld_start.S,v 1.5 2001/08/14 22:17:48 eeh Exp $ */
/*-
* Copyright (c) 2001 Jake Burkholder.
* Copyright (c) 2000 Eduardo Horvath.
* Copyright (c) 1999 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Christos Zoulas and Paul Kranenburg.
*
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* 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.
*
* $FreeBSD$
*/
#include <machine/asm.h>
/*
* ELF:
* On startup the stack should contain 16 extended word register save
* area, followed by the arg count, etc.
*/
ENTRY(.rtld_start)
clr %fp
mov %o0, %l0
mov %o3, %l1
sub %sp, 16, %sp
add %sp, SPOFF + CCFSZ + 0x0, %o1
call _rtld
add %sp, SPOFF + CCFSZ + 0x8, %o2
ldx [%sp + SPOFF + CCFSZ + 0x0], %o1
ldx [%sp + SPOFF + CCFSZ + 0x8], %o2
add %sp, 16, %sp
mov %l1, %o3
jmp %o0
mov %l0, %o0
END(.rtld_start)
/*
* Find the address of _DYNAMIC by disassembling a call instruction to it.
* Binutils may not fill in the GOT as expected on other architectures.
*/
.weak _DYNAMIC
ENTRY(rtld_dynamic_addr)
save %sp, -CCFSZ, %sp
call 1f
nop
call _DYNAMIC + 8
1: lduw [%o7 + 8], %o0
sll %o0, 2, %o0
sra %o0, 0, %o0
ret
restore %o0, %o7, %o0
END(rtld_dynamic_addr)
/*
* We have two separate entry points to the runtime linker.
* I'm implementing this following the SPARC v9 ABI spec.
*
* _rtld_bind_start_0(x, y) is called from .PLT0, and is used for
* PLT entries above 32768.
*
* _rtld_bind_start_1(x, y) is called from .PLT1, and is used for
* PLT entries below 32768.
*
* The first two entries of PLT2 contain the xword object pointer.
*
* These routines are called with two longword arguments,
* x and y. To calculate the address of the entry,
* _rtld_bind_start_1(x, y) does:
*
* n = x >> 15;
*
* and _rtld_bind_start_0(x, y) should do, according to the SCD:
*
* i = x - y - 1048596;
* n = 32768 + (i/5120)*160 + (i%5120)/24;
*
* Note that the number of 1048596 from above is incorrect; rather,
* we need to use HIPLTOFFS as defined below.
*
* Neither routine needs to issue a save since it's already been
* done in the PLT entry.
*/
#define NPLTLOSLOTS 32768
#define PLTSLOTSZ 32
/*
* - 16 to compensate for the difference of the positions of the jumps that
* generate the arguments in .PLT0 and the high plt entry.
*/
#define HIPLTOFFS (NPLTLOSLOTS * PLTSLOTSZ - 16)
ENTRY(_rtld_bind_start_0)
sethi %hi(HIPLTOFFS), %l1
or %l1, %lo(HIPLTOFFS), %l1
sub %o0, %o1, %l0 /* x - y */
sub %l0, %l1, %l0 /* i = x - y - HIPLTOFFS */
sethi %hi(5120), %l7
sdivx %l0, %l7, %l1 /* Calculate i / 5120 */
mulx %l1, %l7, %l3
sub %l0, %l3, %l2 /* And i % 5120 */
mulx %l1, 160, %l5 /* (i / 5120) * 160 */
sdivx %l2, 24, %l4 /* (i % 5120) / 24 */
sethi %hi(NPLTLOSLOTS), %l6
add %l4, %l5, %l4 /* (i / 5120) * 160 + (i % 5120) / 24 */
add %l4, %l6, %l4 /* + NPLTLOSLOTS */
sub %l4, 4, %l4 /* XXX: 4 entries are reserved */
sllx %l4, 1, %l5 /* Each element is an Elf_Rela which */
add %l5, %l4, %l4 /* is 3 longwords or 24 bytes. */
sllx %l4, 3, %l4 /* So multiply by 24. */
ldx [%o1 + (10*4)], %o0 /* Load object pointer from PLT2 */
call _rtld_bind /* Call _rtld_bind(obj, offset) */
mov %l4, %o1
jmp %o0 /* return value == function address */
restore /* Dump our stack frame */
END(_rtld_bind_start_0)
ENTRY(_rtld_bind_start_1)
srax %o0, 15, %o2 /* %o0 is the index to our PLT slot */
sub %o2, 4, %o2 /* XXX: 4 entries are reserved */
sllx %o2, 1, %o3 /* Each element is an Elf_Rela which */
add %o3, %o2, %o2 /* is 3 longwords or 24 bytes. */
sllx %o2, 3, %o2 /* So multiply by 24. */
ldx [%o1 + 8], %o0 /* The object pointer is at [%o1 + 8] */
call _rtld_bind /* Call _rtld_bind(obj, offset) */
mov %o2, %o1
jmp %o0 /* return value == function address */
restore /* Dump our stack frame */
END(_rtld_bind_start_1)
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