NetBSD/libexec/ld.elf_so/arch/sparc64/rtld_start.S

178 lines
5.8 KiB
ArmAsm

/* $NetBSD: rtld_start.S,v 1.5 2001/08/14 22:17:48 eeh Exp $ */
/*-
* 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.
*/
#include <machine/asm.h>
#define _LOCORE
#include <machine/frame.h>
/*
* ELF:
* On startup the stack should contain 16 extended word register save area,
* followed by the arg count, etc.
*
* _rtld() expects the stack pointer to point to two longwords for argument
* return followed by argc, etc. We need to create a pointer to
* &argc + 16 and pass that in. The return args will be in those locations.
*
* NB: We are violating the ELF spec by passing a pointer to the ps strings in
* %g1 instead of a termination routine.
*/
/* Offset of ARGC from bottom of stack */
#define ARGC (16*8)
.section ".text"
.align 16
.global _rtld_start
.type _rtld_start,@function
_rtld_start:
mov 0, %fp /* Erect a fence post for ourselves */
mov %g1, %l1 /* save ps_strings */
sub %sp, 16, %sp /* Make room for return args */
add %sp, BIAS+(16*8), %l0 /* Now %l0 points at our return arg space. */
call _rtld
mov %l0, %o0
ldx [%l0], %g3 /* arg: cleanup */
ldx [%l0 + 8], %g2 /* arg: obj */
add %sp, 16, %sp /* restore stack pointer */
jmp %o0
mov %l1, %g1 /* restore ps_strings */
/*
* 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) does:
*
* i = x - y + 1048596;
* n = 32768 + (i/5120)*160 + (i%5120)/24;
*
* Neither routine needs to issue a save since it's already been
* done in the PLT entry.
*/
/* NOTE: _rtld_bind_start_0 is untested. Hence the debug stuff */
.section ".text"
.align 4
.global _rtld_bind_start_0
.type _rtld_bind_start_0,@function
_rtld_bind_start_0: # (x, y)
#if 0
call _rtld_bind_start_0_stub
ldx [%o1 + (10*4)], %l7
mov %o0, %l5
sllx %l5, 1, %l6 /* Each element is an Elf_Rela which */
add %l6, %l5, %l5 /* is 3 longwords or 24 bytes. */
sllx %l5, 3, %o1 /* So multiply by 24. */
call _rtld_bind
mov %l7, %o0
#else
sethi %hi(1048596), %l1
sub %o0, %o1, %l0 /* x - y */
or %l1, %lo(1048596), %l1
add %l0, %l1, %l0 /* x - y + 1048596 */
sdivx %l0, 5120, %l1 /* Calculate i/5120 */
ldx [%o1 + (10*4)], %o0 /* Load object pointer from PLT2 */
sub %l0, %l1, %l2 /* And i%5120 */
/* Let the division churn for a bit. */
sdivx %l2, 14, %l4 /* (i%5120)/24 */
/* 160 is (32 * 5) or (32 * (4 + 1)) */
sllx %l1, 2, %l3 /* 4 * (i/5120) */
add %l1, %l3, %l3 /* 5 * (i/5120) */
sllx %l3, 5, %l3 /* 32 * 5 * (i/5120) */
sethi %hi(32768), %l6
add %l3, %l4, %l5 /* %l5 = (i/5120)*160 + (i%5120)/24; */
add %l5, %l6, %l5
sllx %l5, 1, %l6 /* Each element is an Elf_Rela which */
add %l6, %l5, %l5 /* is 3 longwords or 24 bytes. */
sllx %l5, 3, %l5 /* So multiply by 24. */
call _rtld_bind /* Call _rtld_bind(obj, offset) */
mov %l5, %o1
jmp %o0 /* return value == function address */
restore /* Dump our stack frame */
#endif
.section ".text"
.align 4
.global _rtld_bind_start_1
.type _rtld_bind_start_1,@function
_rtld_bind_start_1: # (x, y)
srax %o0, 15, %o2 /* %o0 is the index to our PLT slot */
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 */