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      1 /*	$NetBSD: self_reloc.c,v 1.1 2017/01/24 11:09:14 nonaka Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2008-2010 Rui Paulo <rpaulo (at) FreeBSD.org>
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #include <sys/types.h>
     30 #include <sys/exec_elf.h>
     31 
     32 #include <efi.h>
     33 
     34 void self_reloc(Elf_Addr, Elf_Dyn *);
     35 
     36 #if defined(__aarch64__)
     37 #define	USE_RELA
     38 #endif
     39 
     40 /*
     41  * A simple elf relocator.
     42  */
     43 void
     44 self_reloc(Elf_Addr baseaddr, Elf_Dyn *dynamic)
     45 {
     46 	Elf_Word relsz, relent;
     47 	Elf_Addr *newaddr;
     48 	Elf_Rel *rel = NULL;
     49 	Elf_Dyn *dynp;
     50 
     51 	/*
     52 	 * Find the relocation address, its size and the relocation entry.
     53 	 */
     54 	relsz = 0;
     55 	relent = 0;
     56 	for (dynp = dynamic; dynp->d_tag != DT_NULL; dynp++) {
     57 		switch (dynp->d_tag) {
     58 		case DT_REL:
     59 		case DT_RELA:
     60 			rel = (Elf_Rel *)(dynp->d_un.d_ptr + baseaddr);
     61 			break;
     62 		case DT_RELSZ:
     63 		case DT_RELASZ:
     64 			relsz = dynp->d_un.d_val;
     65 			break;
     66 		case DT_RELENT:
     67 		case DT_RELAENT:
     68 			relent = dynp->d_un.d_val;
     69 			break;
     70 		default:
     71 			break;
     72 		}
     73 	}
     74 
     75 	/*
     76 	 * Perform the actual relocation.
     77 	 */
     78 	for (; relsz > 0; relsz -= relent) {
     79 		switch (ELF_R_TYPE(rel->r_info)) {
     80 		case R_TYPE(NONE):
     81 			/* No relocation needs be performed. */
     82 			break;
     83 
     84 		case R_TYPE(RELATIVE):
     85 			/* Address relative to the base address. */
     86 			newaddr = (Elf_Addr *)(rel->r_offset + baseaddr);
     87 			*newaddr += baseaddr;
     88 #ifdef USE_RELA
     89 			/* Add the addend when the ABI uses them */
     90 			*newaddr += ((Elf_Rela *)rel)->r_addend;
     91 #endif
     92 			break;
     93 		default:
     94 			/* XXX: do we need other relocations ? */
     95 			break;
     96 		}
     97 		rel = (Elf_Rel *) ((char *) rel + relent);
     98 	}
     99 }
    100