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
19static 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 */
33int 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
53void 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
61int 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
119relo_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 */
131int 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