1/* 2 * relocate - common relocation function for ARM U-Boot 3 * 4 * Copyright (c) 2013 Albert ARIBAUD <albert.u.boot@aribaud.net> 5 * 6 * See file CREDITS for list of people who contributed to this 7 * project. 8 * 9 * This program is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU General Public License as 11 * published by the Free Software Foundation; either version 2 of 12 * the License, or (at your option) any later version. 13 * 14 * This program is distributed in the hope that it will be useful, 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 * GNU General Public License for more details. 18 * 19 * You should have received a copy of the GNU General Public License 20 * along with this program; if not, write to the Free Software 21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 22 * MA 02111-1307 USA 23 */ 24 25#include <linux/linkage.h> 26 27/* 28 * void relocate_code(addr_moni) 29 * 30 * This function relocates the monitor code. 31 * 32 * NOTE: 33 * To prevent the code below from containing references with an R_ARM_ABS32 34 * relocation record type, we never refer to linker-defined symbols directly. 35 * Instead, we declare literals which contain their relative location with 36 * respect to relocate_code, and at run time, add relocate_code back to them. 37 */ 38 39ENTRY(relocate_code) 40 mov r6, r0 /* save addr of destination */ 41 42 ldr r0, =_start /* r0 <- SRC &_start */ 43 subs r9, r6, r0 /* r9 <- relocation offset */ 44 beq relocate_done /* skip relocation */ 45 mov r1, r6 /* r1 <- scratch for copy loop */ 46 adr r7, relocate_code /* r7 <- SRC &relocate_code */ 47 ldr r3, _image_copy_end_ofs /* r3 <- __image_copy_end local ofs */ 48 add r2, r7, r3 /* r2 <- SRC &__image_copy_end */ 49 50copy_loop: 51 ldmia r0!, {r10-r11} /* copy from source address [r0] */ 52 stmia r1!, {r10-r11} /* copy to target address [r1] */ 53 cmp r0, r2 /* until source end address [r2] */ 54 blo copy_loop 55 56 /* 57 * fix .rel.dyn relocations 58 */ 59 ldr r10, _dynsym_start_ofs /* r10 <- __dynsym_start local ofs */ 60 add r10, r10, r7 /* r10 <- SRC &__dynsym_start */ 61 ldr r2, _rel_dyn_start_ofs /* r2 <- __rel_dyn_start local ofs */ 62 add r2, r2, r7 /* r2 <- SRC &__rel_dyn_start */ 63 ldr r3, _rel_dyn_end_ofs /* r3 <- __rel_dyn_end local ofs */ 64 add r3, r3, r7 /* r3 <- SRC &__rel_dyn_end */ 65fixloop: 66 ldr r0, [r2] /* r0 <- SRC location to fix up */ 67 add r0, r0, r9 /* r0 <- DST location to fix up */ 68 ldr r1, [r2, #4] 69 and r7, r1, #0xff 70 cmp r7, #23 /* relative fixup? */ 71 beq fixrel 72 cmp r7, #2 /* absolute fixup? */ 73 beq fixabs 74 /* ignore unknown type of fixup */ 75 b fixnext 76fixabs: 77 /* absolute fix: set location to (offset) symbol value */ 78 mov r1, r1, LSR #4 /* r1 <- symbol index in .dynsym */ 79 add r1, r10, r1 /* r1 <- address of symbol in table */ 80 ldr r1, [r1, #4] /* r1 <- symbol value */ 81 add r1, r1, r9 /* r1 <- relocated sym addr */ 82 b fixnext 83fixrel: 84 /* relative fix: increase location by offset */ 85 ldr r1, [r0] 86 add r1, r1, r9 87fixnext: 88 str r1, [r0] 89 add r2, r2, #8 /* each rel.dyn entry is 8 bytes */ 90 cmp r2, r3 91 blo fixloop 92 93relocate_done: 94 95 /* ARMv4- don't know bx lr but the assembler fails to see that */ 96 97#ifdef __ARM_ARCH_4__ 98 mov pc, lr 99#else 100 bx lr 101#endif 102 103_image_copy_end_ofs: 104 .word __image_copy_end - relocate_code 105_rel_dyn_start_ofs: 106 .word __rel_dyn_start - relocate_code 107_rel_dyn_end_ofs: 108 .word __rel_dyn_end - relocate_code 109_dynsym_start_ofs: 110 .word __dynsym_start - relocate_code 111 112ENDPROC(relocate_code) 113