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 | |
16 | static 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 | */ |
26 | int 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 | |
37 | void 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 | |
45 | int 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(addr: (unsigned short *)location, value: 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 | |
120 | relo_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 | */ |
132 | int 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 | } |
147 | |