xref: /openbmc/u-boot/arch/arc/lib/relocate.c (revision 699c4e59)
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 int copy_uboot_to_ram(void)
14 {
15 	size_t len = (size_t)&__image_copy_end - (size_t)&__image_copy_start;
16 
17 	memcpy((void *)gd->relocaddr, (void *)&__image_copy_start, len);
18 
19 	return 0;
20 }
21 
22 int clear_bss(void)
23 {
24 	ulong dst_addr = (ulong)&__bss_start + gd->reloc_off;
25 	size_t len = (size_t)&__bss_end - (size_t)&__bss_start;
26 
27 	memset((void *)dst_addr, 0x00, len);
28 
29 	return 0;
30 }
31 
32 /*
33  * Base functionality is taken from x86 version with added ARC-specifics
34  */
35 int do_elf_reloc_fixups(void)
36 {
37 	Elf32_Rela *re_src = (Elf32_Rela *)(&__rel_dyn_start);
38 	Elf32_Rela *re_end = (Elf32_Rela *)(&__rel_dyn_end);
39 
40 	debug("Section .rela.dyn is located at %08x-%08x\n",
41 	      (unsigned int)re_src, (unsigned int)re_end);
42 
43 	Elf32_Addr *offset_ptr_rom, *last_offset = NULL;
44 	Elf32_Addr *offset_ptr_ram;
45 
46 	do {
47 		/* Get the location from the relocation entry */
48 		offset_ptr_rom = (Elf32_Addr *)re_src->r_offset;
49 
50 		/* Check that the location of the relocation is in .text */
51 		if (offset_ptr_rom >= (Elf32_Addr *)&__image_copy_start &&
52 		    offset_ptr_rom > last_offset) {
53 			unsigned int val;
54 			/* Switch to the in-RAM version */
55 			offset_ptr_ram = (Elf32_Addr *)((ulong)offset_ptr_rom +
56 							gd->reloc_off);
57 
58 			debug("Patching value @ %08x (relocated to %08x)\n",
59 			      (unsigned int)offset_ptr_rom,
60 			      (unsigned int)offset_ptr_ram);
61 
62 			/*
63 			 * Use "memcpy" because target location might be
64 			 * 16-bit aligned on ARC so we may need to read
65 			 * byte-by-byte. On attempt to read entire word by
66 			 * CPU throws an exception
67 			 */
68 			memcpy(&val, offset_ptr_ram, sizeof(int));
69 
70 #ifdef __LITTLE_ENDIAN__
71 			/* If location in ".text" section swap value */
72 			if ((unsigned int)offset_ptr_rom <
73 			    (unsigned int)&__ivt_end)
74 				val = (val << 16) | (val >> 16);
75 #endif
76 
77 			/* Check that the target points into executable */
78 			if (val >= (unsigned int)&__image_copy_start && val <=
79 			    (unsigned int)&__image_copy_end) {
80 				val += gd->reloc_off;
81 #ifdef __LITTLE_ENDIAN__
82 				/* If location in ".text" section swap value */
83 				if ((unsigned int)offset_ptr_rom <
84 				    (unsigned int)&__ivt_end)
85 					val = (val << 16) | (val >> 16);
86 #endif
87 				memcpy(offset_ptr_ram, &val, sizeof(int));
88 			}
89 		}
90 		last_offset = offset_ptr_rom;
91 
92 	} while (++re_src < re_end);
93 
94 	return 0;
95 }
96