/* $NetBSD: rtld_start.S,v 1.14 2022/05/30 17:06:34 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) LEAF_ENTRY_NOPROFILE(_rtld_set_dp) bv %r0(%rp) copy %arg0, %dp EXIT(_rtld_set_dp)
