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 /* ARC specific section quirks - before relocation loop in generic loader
26 *
27 * For dwarf unwinding out of modules, this needs to
28 * 1. Ensure the .debug_frame is allocatable (ARC Linker bug: despite
29 * -fasynchronous-unwind-tables it doesn't).
30 * 2. Since we are iterating thru sec hdr tbl anyways, make a note of
31 * the exact section index, for later use.
32 */
module_frob_arch_sections(Elf_Ehdr * hdr,Elf_Shdr * sechdrs,char * secstr,struct module * mod)33 int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
34 char *secstr, struct module *mod)
35 {
36 #ifdef CONFIG_ARC_DW2_UNWIND
37 int i;
38
39 mod->arch.unw_sec_idx = 0;
40 mod->arch.unw_info = NULL;
41
42 for (i = 1; i < hdr->e_shnum; i++) {
43 if (strcmp(secstr+sechdrs[i].sh_name, ".debug_frame") == 0) {
44 sechdrs[i].sh_flags |= SHF_ALLOC;
45 mod->arch.unw_sec_idx = i;
46 break;
47 }
48 }
49 #endif
50 return 0;
51 }
52
module_arch_cleanup(struct module * mod)53 void module_arch_cleanup(struct module *mod)
54 {
55 #ifdef CONFIG_ARC_DW2_UNWIND
56 if (mod->arch.unw_info)
57 unwind_remove_table(mod->arch.unw_info, 0);
58 #endif
59 }
60
apply_relocate_add(Elf32_Shdr * sechdrs,const char * strtab,unsigned int symindex,unsigned int relsec,struct module * module)61 int apply_relocate_add(Elf32_Shdr *sechdrs,
62 const char *strtab,
63 unsigned int symindex, /* sec index for sym tbl */
64 unsigned int relsec, /* sec index for relo sec */
65 struct module *module)
66 {
67 int i, n;
68 Elf32_Rela *rel_entry = (void *)sechdrs[relsec].sh_addr;
69 Elf32_Sym *sym_entry, *sym_sec;
70 Elf32_Addr relocation;
71 Elf32_Addr location;
72 Elf32_Addr sec_to_patch;
73 int relo_type;
74
75 sec_to_patch = sechdrs[sechdrs[relsec].sh_info].sh_addr;
76 sym_sec = (Elf32_Sym *) sechdrs[symindex].sh_addr;
77 n = sechdrs[relsec].sh_size / sizeof(*rel_entry);
78
79 pr_debug("\n========== Module Sym reloc ===========================\n");
80 pr_debug("Section to fixup %x\n", sec_to_patch);
81 pr_debug("=========================================================\n");
82 pr_debug("rela->r_off | rela->addend | sym->st_value | ADDR | VALUE\n");
83 pr_debug("=========================================================\n");
84
85 /* Loop thru entries in relocation section */
86 for (i = 0; i < n; i++) {
87
88 /* This is where to make the change */
89 location = sec_to_patch + rel_entry[i].r_offset;
90
91 /* This is the symbol it is referring to. Note that all
92 undefined symbols have been resolved. */
93 sym_entry = sym_sec + ELF32_R_SYM(rel_entry[i].r_info);
94
95 relocation = sym_entry->st_value + rel_entry[i].r_addend;
96
97 pr_debug("\t%x\t\t%x\t\t%x %x %x [%s]\n",
98 rel_entry[i].r_offset, rel_entry[i].r_addend,
99 sym_entry->st_value, location, relocation,
100 strtab + sym_entry->st_name);
101
102 /* This assumes modules are built with -mlong-calls
103 * so any branches/jumps are absolute 32 bit jmps
104 * global data access again is abs 32 bit.
105 * Both of these are handled by same relocation type
106 */
107 relo_type = ELF32_R_TYPE(rel_entry[i].r_info);
108
109 if (likely(R_ARC_32_ME == relo_type))
110 arc_write_me((unsigned short *)location, relocation);
111 else if (R_ARC_32 == relo_type)
112 *((Elf32_Addr *) location) = relocation;
113 else
114 goto relo_err;
115
116 }
117 return 0;
118
119 relo_err:
120 pr_err("%s: unknown relocation: %u\n",
121 module->name, ELF32_R_TYPE(rel_entry[i].r_info));
122 return -ENOEXEC;
123
124 }
125
126 /* Just before lift off: After sections have been relocated, we add the
127 * dwarf section to unwinder table pool
128 * This couldn't be done in module_frob_arch_sections() because
129 * relocations had not been applied by then
130 */
module_finalize(const Elf32_Ehdr * hdr,const Elf_Shdr * sechdrs,struct module * mod)131 int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
132 struct module *mod)
133 {
134 #ifdef CONFIG_ARC_DW2_UNWIND
135 void *unw;
136 int unwsec = mod->arch.unw_sec_idx;
137
138 if (unwsec) {
139 unw = unwind_add_table(mod, (void *)sechdrs[unwsec].sh_addr,
140 sechdrs[unwsec].sh_size);
141 mod->arch.unw_info = unw;
142 }
143 #endif
144 return 0;
145 }
146