/* $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: head/libexec/rtld-elf/sparc64/rtld_start.S 130661 2004-06-18 02:01:37Z tmm $ */ #include /* * 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)