xref: /openbmc/u-boot/arch/arc/lib/relocate.c (revision fdef3895)
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-generic/sections.h>
10 
11 extern ulong __image_copy_start;
12 extern ulong __ivt_end;
13 
14 DECLARE_GLOBAL_DATA_PTR;
15 
16 int copy_uboot_to_ram(void)
17 {
18 	size_t len = (size_t)&__image_copy_end - (size_t)&__image_copy_start;
19 
20 	if (gd->flags & GD_FLG_SKIP_RELOC)
21 		return 0;
22 
23 	memcpy((void *)gd->relocaddr, (void *)&__image_copy_start, len);
24 
25 	return 0;
26 }
27 
28 int clear_bss(void)
29 {
30 	ulong dst_addr = (ulong)&__bss_start + gd->reloc_off;
31 	size_t len = (size_t)&__bss_end - (size_t)&__bss_start;
32 
33 	memset((void *)dst_addr, 0x00, len);
34 
35 	return 0;
36 }
37 
38 /*
39  * Base functionality is taken from x86 version with added ARC-specifics
40  */
41 int do_elf_reloc_fixups(void)
42 {
43 	Elf32_Rela *re_src = (Elf32_Rela *)(&__rel_dyn_start);
44 	Elf32_Rela *re_end = (Elf32_Rela *)(&__rel_dyn_end);
45 
46 	if (gd->flags & GD_FLG_SKIP_RELOC)
47 		return 0;
48 
49 	debug("Section .rela.dyn is located at %08x-%08x\n",
50 	      (unsigned int)re_src, (unsigned int)re_end);
51 
52 	Elf32_Addr *offset_ptr_rom, *last_offset = NULL;
53 	Elf32_Addr *offset_ptr_ram;
54 
55 	do {
56 		/* Get the location from the relocation entry */
57 		offset_ptr_rom = (Elf32_Addr *)re_src->r_offset;
58 
59 		/* Check that the location of the relocation is in .text */
60 		if (offset_ptr_rom >= (Elf32_Addr *)&__image_copy_start &&
61 		    offset_ptr_rom > last_offset) {
62 			unsigned int val;
63 			/* Switch to the in-RAM version */
64 			offset_ptr_ram = (Elf32_Addr *)((ulong)offset_ptr_rom +
65 							gd->reloc_off);
66 
67 			debug("Patching value @ %08x (relocated to %08x)\n",
68 			      (unsigned int)offset_ptr_rom,
69 			      (unsigned int)offset_ptr_ram);
70 
71 			/*
72 			 * Use "memcpy" because target location might be
73 			 * 16-bit aligned on ARC so we may need to read
74 			 * byte-by-byte. On attempt to read entire word by
75 			 * CPU throws an exception
76 			 */
77 			memcpy(&val, offset_ptr_ram, sizeof(int));
78 
79 #ifdef __LITTLE_ENDIAN__
80 			/* If location in ".text" section swap value */
81 			if ((unsigned int)offset_ptr_rom <
82 			    (unsigned int)&__ivt_end)
83 				val = (val << 16) | (val >> 16);
84 #endif
85 
86 			/* Check that the target points into executable */
87 			if (val >= (unsigned int)&__image_copy_start && val <=
88 			    (unsigned int)&__image_copy_end) {
89 				val += gd->reloc_off;
90 #ifdef __LITTLE_ENDIAN__
91 				/* If location in ".text" section swap value */
92 				if ((unsigned int)offset_ptr_rom <
93 				    (unsigned int)&__ivt_end)
94 					val = (val << 16) | (val >> 16);
95 #endif
96 				memcpy(offset_ptr_ram, &val, sizeof(int));
97 			}
98 		}
99 		last_offset = offset_ptr_rom;
100 
101 	} while (++re_src < re_end);
102 
103 	return 0;
104 }
105