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}
147