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146 lines · 4.2 KiB

1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
4 */
5
6#include <linux/module.h>
7#include <linux/moduleloader.h>
8#include <linux/kernel.h>
9#include <linux/elf.h>
10#include <linux/vmalloc.h>
11#include <linux/slab.h>
12#include <linux/fs.h>
13#include <linux/string.h>
14#include <asm/unwind.h>
15
16static inline void arc_write_me(unsigned short *addr, unsigned long value)
17{
18 *addr = (value & 0xffff0000) >> 16;
19 *(addr + 1) = (value & 0xffff);
20}
21
22/*
23 * This gets called before relocation loop in generic loader
24 * Make a note of the section index of unwinding section
25 */
26int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
27 char *secstr, struct module *mod)
28{
29#ifdef CONFIG_ARC_DW2_UNWIND
30 mod->arch.unw_sec_idx = 0;
31 mod->arch.unw_info = NULL;
32#endif
33 mod->arch.secstr = secstr;
34 return 0;
35}
36
37void module_arch_cleanup(struct module *mod)
38{
39#ifdef CONFIG_ARC_DW2_UNWIND
40 if (mod->arch.unw_info)
41 unwind_remove_table(mod->arch.unw_info, 0);
42#endif
43}
44
45int apply_relocate_add(Elf32_Shdr *sechdrs,
46 const char *strtab,
47 unsigned int symindex, /* sec index for sym tbl */
48 unsigned int relsec, /* sec index for relo sec */
49 struct module *module)
50{
51 int i, n, relo_type;
52 Elf32_Rela *rel_entry = (void *)sechdrs[relsec].sh_addr;
53 Elf32_Sym *sym_entry, *sym_sec;
54 Elf32_Addr relocation, location, tgt_addr;
55 unsigned int tgtsec;
56
57 /*
58 * @relsec has relocations e.g. .rela.init.text
59 * @tgtsec is section to patch e.g. .init.text
60 */
61 tgtsec = sechdrs[relsec].sh_info;
62 tgt_addr = sechdrs[tgtsec].sh_addr;
63 sym_sec = (Elf32_Sym *) sechdrs[symindex].sh_addr;
64 n = sechdrs[relsec].sh_size / sizeof(*rel_entry);
65
66 pr_debug("\nSection to fixup %s @%x\n",
67 module->arch.secstr + sechdrs[tgtsec].sh_name, tgt_addr);
68 pr_debug("=========================================================\n");
69 pr_debug("r_off\tr_add\tst_value ADDRESS VALUE\n");
70 pr_debug("=========================================================\n");
71
72 /* Loop thru entries in relocation section */
73 for (i = 0; i < n; i++) {
74 const char *s;
75
76 /* This is where to make the change */
77 location = tgt_addr + rel_entry[i].r_offset;
78
79 /* This is the symbol it is referring to. Note that all
80 undefined symbols have been resolved. */
81 sym_entry = sym_sec + ELF32_R_SYM(rel_entry[i].r_info);
82
83 relocation = sym_entry->st_value + rel_entry[i].r_addend;
84
85 if (sym_entry->st_name == 0 && ELF_ST_TYPE (sym_entry->st_info) == STT_SECTION) {
86 s = module->arch.secstr + sechdrs[sym_entry->st_shndx].sh_name;
87 } else {
88 s = strtab + sym_entry->st_name;
89 }
90
91 pr_debug(" %x\t%x\t%x %x %x [%s]\n",
92 rel_entry[i].r_offset, rel_entry[i].r_addend,
93 sym_entry->st_value, location, relocation, s);
94
95 /* This assumes modules are built with -mlong-calls
96 * so any branches/jumps are absolute 32 bit jmps
97 * global data access again is abs 32 bit.
98 * Both of these are handled by same relocation type
99 */
100 relo_type = ELF32_R_TYPE(rel_entry[i].r_info);
101
102 if (likely(R_ARC_32_ME == relo_type)) /* ME ( S + A ) */
103 arc_write_me((unsigned short *)location, relocation);
104 else if (R_ARC_32 == relo_type) /* ( S + A ) */
105 *((Elf32_Addr *) location) = relocation;
106 else if (R_ARC_32_PCREL == relo_type) /* ( S + A ) - PDATA ) */
107 *((Elf32_Addr *) location) = relocation - location;
108 else
109 goto relo_err;
110
111 }
112
113#ifdef CONFIG_ARC_DW2_UNWIND
114 if (strcmp(module->arch.secstr+sechdrs[tgtsec].sh_name, ".eh_frame") == 0)
115 module->arch.unw_sec_idx = tgtsec;
116#endif
117
118 return 0;
119
120relo_err:
121 pr_err("%s: unknown relocation: %u\n",
122 module->name, ELF32_R_TYPE(rel_entry[i].r_info));
123 return -ENOEXEC;
124
125}
126
127/* Just before lift off: After sections have been relocated, we add the
128 * dwarf section to unwinder table pool
129 * This couldn't be done in module_frob_arch_sections() because
130 * relocations had not been applied by then
131 */
132int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
133 struct module *mod)
134{
135#ifdef CONFIG_ARC_DW2_UNWIND
136 void *unw;
137 int unwsec = mod->arch.unw_sec_idx;
138
139 if (unwsec) {
140 unw = unwind_add_table(mod, (void *)sechdrs[unwsec].sh_addr,
141 sechdrs[unwsec].sh_size);
142 mod->arch.unw_info = unw;
143 }
144#endif
145 return 0;
146}