xref: /openbmc/u-boot/arch/arc/lib/relocate.c (revision 70ad375e)
1 /*
2  * Copyright (C) 2013-2014 Synopsys, Inc. All rights reserved.
3  *
4  * SPDX-License-Identifier:	GPL-2.0+
5  */
6 
7 #include <common.h>
8 #include <elf.h>
9 #include <asm/sections.h>
10 
11 DECLARE_GLOBAL_DATA_PTR;
12 
13 /*
14  * Base functionality is taken from x86 version with added ARC-specifics
15  */
16 int do_elf_reloc_fixups(void)
17 {
18 	Elf32_Rela *re_src = (Elf32_Rela *)(&__rel_dyn_start);
19 	Elf32_Rela *re_end = (Elf32_Rela *)(&__rel_dyn_end);
20 
21 	Elf32_Addr *offset_ptr_rom, *last_offset = NULL;
22 	Elf32_Addr *offset_ptr_ram;
23 
24 	do {
25 		/* Get the location from the relocation entry */
26 		offset_ptr_rom = (Elf32_Addr *)re_src->r_offset;
27 
28 		/* Check that the location of the relocation is in .text */
29 		if (offset_ptr_rom >= (Elf32_Addr *)CONFIG_SYS_TEXT_BASE &&
30 		    offset_ptr_rom > last_offset) {
31 			unsigned int val;
32 			/* Switch to the in-RAM version */
33 			offset_ptr_ram = (Elf32_Addr *)((ulong)offset_ptr_rom +
34 							gd->reloc_off);
35 
36 			/*
37 			 * Use "memcpy" because target location might be
38 			 * 16-bit aligned on ARC so we may need to read
39 			 * byte-by-byte. On attempt to read entire word by
40 			 * CPU throws an exception
41 			 */
42 			memcpy(&val, offset_ptr_ram, sizeof(int));
43 
44 #ifdef __LITTLE_ENDIAN__
45 			/* If location in ".text" section swap value */
46 			if ((unsigned int)offset_ptr_rom <
47 			    (unsigned int)&__text_end)
48 				val = (val << 16) | (val >> 16);
49 #endif
50 
51 			/* Check that the target points into .text */
52 			if (val >= CONFIG_SYS_TEXT_BASE && val <=
53 			    (unsigned int)&__bss_end) {
54 				val += gd->reloc_off;
55 #ifdef __LITTLE_ENDIAN__
56 				/* If location in ".text" section swap value */
57 				if ((unsigned int)offset_ptr_rom <
58 				    (unsigned int)&__text_end)
59 					val = (val << 16) | (val >> 16);
60 #endif
61 				memcpy(offset_ptr_ram, &val, sizeof(int));
62 			} else {
63 				debug("   %p: rom reloc %x, ram %p, value %x, limit %x\n",
64 				      re_src, re_src->r_offset, offset_ptr_ram,
65 				      val, (unsigned int)&__bss_end);
66 			}
67 		} else {
68 			debug("   %p: rom reloc %x, last %p\n", re_src,
69 			      re_src->r_offset, last_offset);
70 		}
71 		last_offset = offset_ptr_rom;
72 
73 	} while (++re_src < re_end);
74 
75 	return 0;
76 }
77