1 /*
2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8
9 #include <linux/module.h>
10 #include <linux/moduleloader.h>
11 #include <linux/kernel.h>
12 #include <linux/elf.h>
13 #include <linux/vmalloc.h>
14 #include <linux/slab.h>
15 #include <linux/fs.h>
16 #include <linux/string.h>
17 #include <asm/unwind.h>
18
arc_write_me(unsigned short * addr,unsigned long value)19 static inline void arc_write_me(unsigned short *addr, unsigned long value)
20 {
21 *addr = (value & 0xffff0000) >> 16;
22 *(addr + 1) = (value & 0xffff);
23 }
24
25 /*
26 * This gets called before relocation loop in generic loader
27 * Make a note of the section index of unwinding section
28 */
module_frob_arch_sections(Elf_Ehdr * hdr,Elf_Shdr * sechdrs,char * secstr,struct module * mod)29 int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
30 char *secstr, struct module *mod)
31 {
32 #ifdef CONFIG_ARC_DW2_UNWIND
33 mod->arch.unw_sec_idx = 0;
34 mod->arch.unw_info = NULL;
35 #endif
36 mod->arch.secstr = secstr;
37 return 0;
38 }
39
module_arch_cleanup(struct module * mod)40 void module_arch_cleanup(struct module *mod)
41 {
42 #ifdef CONFIG_ARC_DW2_UNWIND
43 if (mod->arch.unw_info)
44 unwind_remove_table(mod->arch.unw_info, 0);
45 #endif
46 }
47
apply_relocate_add(Elf32_Shdr * sechdrs,const char * strtab,unsigned int symindex,unsigned int relsec,struct module * module)48 int apply_relocate_add(Elf32_Shdr *sechdrs,
49 const char *strtab,
50 unsigned int symindex, /* sec index for sym tbl */
51 unsigned int relsec, /* sec index for relo sec */
52 struct module *module)
53 {
54 int i, n, relo_type;
55 Elf32_Rela *rel_entry = (void *)sechdrs[relsec].sh_addr;
56 Elf32_Sym *sym_entry, *sym_sec;
57 Elf32_Addr relocation, location, tgt_addr;
58 unsigned int tgtsec;
59
60 /*
61 * @relsec has relocations e.g. .rela.init.text
62 * @tgtsec is section to patch e.g. .init.text
63 */
64 tgtsec = sechdrs[relsec].sh_info;
65 tgt_addr = sechdrs[tgtsec].sh_addr;
66 sym_sec = (Elf32_Sym *) sechdrs[symindex].sh_addr;
67 n = sechdrs[relsec].sh_size / sizeof(*rel_entry);
68
69 pr_debug("\nSection to fixup %s @%x\n",
70 module->arch.secstr + sechdrs[tgtsec].sh_name, tgt_addr);
71 pr_debug("=========================================================\n");
72 pr_debug("r_off\tr_add\tst_value ADDRESS VALUE\n");
73 pr_debug("=========================================================\n");
74
75 /* Loop thru entries in relocation section */
76 for (i = 0; i < n; i++) {
77 const char *s;
78
79 /* This is where to make the change */
80 location = tgt_addr + rel_entry[i].r_offset;
81
82 /* This is the symbol it is referring to. Note that all
83 undefined symbols have been resolved. */
84 sym_entry = sym_sec + ELF32_R_SYM(rel_entry[i].r_info);
85
86 relocation = sym_entry->st_value + rel_entry[i].r_addend;
87
88 if (sym_entry->st_name == 0 && ELF_ST_TYPE (sym_entry->st_info) == STT_SECTION) {
89 s = module->arch.secstr + sechdrs[sym_entry->st_shndx].sh_name;
90 } else {
91 s = strtab + sym_entry->st_name;
92 }
93
94 pr_debug(" %x\t%x\t%x %x %x [%s]\n",
95 rel_entry[i].r_offset, rel_entry[i].r_addend,
96 sym_entry->st_value, location, relocation, s);
97
98 /* This assumes modules are built with -mlong-calls
99 * so any branches/jumps are absolute 32 bit jmps
100 * global data access again is abs 32 bit.
101 * Both of these are handled by same relocation type
102 */
103 relo_type = ELF32_R_TYPE(rel_entry[i].r_info);
104
105 if (likely(R_ARC_32_ME == relo_type)) /* ME ( S + A ) */
106 arc_write_me((unsigned short *)location, relocation);
107 else if (R_ARC_32 == relo_type) /* ( S + A ) */
108 *((Elf32_Addr *) location) = relocation;
109 else if (R_ARC_32_PCREL == relo_type) /* ( S + A ) - PDATA ) */
110 *((Elf32_Addr *) location) = relocation - location;
111 else
112 goto relo_err;
113
114 }
115
116 #ifdef CONFIG_ARC_DW2_UNWIND
117 if (strcmp(module->arch.secstr+sechdrs[tgtsec].sh_name, ".eh_frame") == 0)
118 module->arch.unw_sec_idx = tgtsec;
119 #endif
120
121 return 0;
122
123 relo_err:
124 pr_err("%s: unknown relocation: %u\n",
125 module->name, ELF32_R_TYPE(rel_entry[i].r_info));
126 return -ENOEXEC;
127
128 }
129
130 /* Just before lift off: After sections have been relocated, we add the
131 * dwarf section to unwinder table pool
132 * This couldn't be done in module_frob_arch_sections() because
133 * relocations had not been applied by then
134 */
module_finalize(const Elf32_Ehdr * hdr,const Elf_Shdr * sechdrs,struct module * mod)135 int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
136 struct module *mod)
137 {
138 #ifdef CONFIG_ARC_DW2_UNWIND
139 void *unw;
140 int unwsec = mod->arch.unw_sec_idx;
141
142 if (unwsec) {
143 unw = unwind_add_table(mod, (void *)sechdrs[unwsec].sh_addr,
144 sechdrs[unwsec].sh_size);
145 mod->arch.unw_info = unw;
146 }
147 #endif
148 return 0;
149 }
150