xref: /openbmc/u-boot/arch/arc/lib/relocate.c (revision c978b524)
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 	memcpy((void *)gd->relocaddr, (void *)&__image_copy_start, len);
21 
22 	return 0;
23 }
24 
25 int clear_bss(void)
26 {
27 	ulong dst_addr = (ulong)&__bss_start + gd->reloc_off;
28 	size_t len = (size_t)&__bss_end - (size_t)&__bss_start;
29 
30 	memset((void *)dst_addr, 0x00, len);
31 
32 	return 0;
33 }
34 
35 /*
36  * Base functionality is taken from x86 version with added ARC-specifics
37  */
38 int do_elf_reloc_fixups(void)
39 {
40 	Elf32_Rela *re_src = (Elf32_Rela *)(&__rel_dyn_start);
41 	Elf32_Rela *re_end = (Elf32_Rela *)(&__rel_dyn_end);
42 
43 	debug("Section .rela.dyn is located at %08x-%08x\n",
44 	      (unsigned int)re_src, (unsigned int)re_end);
45 
46 	Elf32_Addr *offset_ptr_rom, *last_offset = NULL;
47 	Elf32_Addr *offset_ptr_ram;
48 
49 	do {
50 		/* Get the location from the relocation entry */
51 		offset_ptr_rom = (Elf32_Addr *)re_src->r_offset;
52 
53 		/* Check that the location of the relocation is in .text */
54 		if (offset_ptr_rom >= (Elf32_Addr *)&__image_copy_start &&
55 		    offset_ptr_rom > last_offset) {
56 			unsigned int val;
57 			/* Switch to the in-RAM version */
58 			offset_ptr_ram = (Elf32_Addr *)((ulong)offset_ptr_rom +
59 							gd->reloc_off);
60 
61 			debug("Patching value @ %08x (relocated to %08x)\n",
62 			      (unsigned int)offset_ptr_rom,
63 			      (unsigned int)offset_ptr_ram);
64 
65 			/*
66 			 * Use "memcpy" because target location might be
67 			 * 16-bit aligned on ARC so we may need to read
68 			 * byte-by-byte. On attempt to read entire word by
69 			 * CPU throws an exception
70 			 */
71 			memcpy(&val, offset_ptr_ram, sizeof(int));
72 
73 #ifdef __LITTLE_ENDIAN__
74 			/* If location in ".text" section swap value */
75 			if ((unsigned int)offset_ptr_rom <
76 			    (unsigned int)&__ivt_end)
77 				val = (val << 16) | (val >> 16);
78 #endif
79 
80 			/* Check that the target points into executable */
81 			if (val >= (unsigned int)&__image_copy_start && val <=
82 			    (unsigned int)&__image_copy_end) {
83 				val += gd->reloc_off;
84 #ifdef __LITTLE_ENDIAN__
85 				/* If location in ".text" section swap value */
86 				if ((unsigned int)offset_ptr_rom <
87 				    (unsigned int)&__ivt_end)
88 					val = (val << 16) | (val >> 16);
89 #endif
90 				memcpy(offset_ptr_ram, &val, sizeof(int));
91 			}
92 		}
93 		last_offset = offset_ptr_rom;
94 
95 	} while (++re_src < re_end);
96 
97 	return 0;
98 }
99