1  // SPDX-License-Identifier: GPL-2.0-or-later
2  /*
3   * OpenRISC module.c
4   *
5   * Linux architectural port borrowing liberally from similar works of
6   * others.  All original copyrights apply as per the original source
7   * declaration.
8   *
9   * Modifications for the OpenRISC architecture:
10   * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
11   */
12  
13  #include <linux/moduleloader.h>
14  #include <linux/elf.h>
15  
apply_relocate_add(Elf32_Shdr * sechdrs,const char * strtab,unsigned int symindex,unsigned int relsec,struct module * me)16  int apply_relocate_add(Elf32_Shdr *sechdrs,
17  		       const char *strtab,
18  		       unsigned int symindex,
19  		       unsigned int relsec,
20  		       struct module *me)
21  {
22  	unsigned int i;
23  	Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
24  	Elf32_Sym *sym;
25  	uint32_t *location;
26  	uint32_t value;
27  
28  	pr_debug("Applying relocate section %u to %u\n", relsec,
29  		 sechdrs[relsec].sh_info);
30  	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
31  		/* This is where to make the change */
32  		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
33  			+ rel[i].r_offset;
34  
35  		/* This is the symbol it is referring to.  Note that all
36  		   undefined symbols have been resolved.  */
37  		sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
38  			+ ELF32_R_SYM(rel[i].r_info);
39  		value = sym->st_value + rel[i].r_addend;
40  
41  		switch (ELF32_R_TYPE(rel[i].r_info)) {
42  		case R_OR1K_32:
43  			*location = value;
44  			break;
45  		case R_OR1K_LO_16_IN_INSN:
46  			*((uint16_t *)location + 1) = value;
47  			break;
48  		case R_OR1K_HI_16_IN_INSN:
49  			*((uint16_t *)location + 1) = value >> 16;
50  			break;
51  		case R_OR1K_INSN_REL_26:
52  			value -= (uint32_t)location;
53  			value >>= 2;
54  			value &= 0x03ffffff;
55  			value |= *location & 0xfc000000;
56  			*location = value;
57  			break;
58  		case R_OR1K_AHI16:
59  			/* Adjust the operand to match with a signed LO16.  */
60  			value += 0x8000;
61  			*((uint16_t *)location + 1) = value >> 16;
62  			break;
63  		case R_OR1K_SLO16:
64  			/* Split value lower 16-bits.  */
65  			value = ((value & 0xf800) << 10) | (value & 0x7ff);
66  			*location = (*location & ~0x3e007ff) | value;
67  			break;
68  		default:
69  			pr_err("module %s: Unknown relocation: %u\n",
70  			       me->name, ELF32_R_TYPE(rel[i].r_info));
71  			break;
72  		}
73  	}
74  
75  	return 0;
76  }
77