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/*
 26 * This gets called before relocation loop in generic loader
 27 * Make a note of the section index of unwinding section
 28 */
 29int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
 30			      char *secstr, struct module *mod)
 31{
 32#ifdef CONFIG_ARC_DW2_UNWIND
 33	mod->arch.unw_sec_idx = 0;
 34	mod->arch.unw_info = NULL;
 35#endif
 36	mod->arch.secstr = secstr;
 37	return 0;
 38}
 39
 40void module_arch_cleanup(struct module *mod)
 41{
 42#ifdef CONFIG_ARC_DW2_UNWIND
 43	if (mod->arch.unw_info)
 44		unwind_remove_table(mod->arch.unw_info, 0);
 45#endif
 46}
 47
 48int apply_relocate_add(Elf32_Shdr *sechdrs,
 49		       const char *strtab,
 50		       unsigned int symindex,	/* sec index for sym tbl */
 51		       unsigned int relsec,	/* sec index for relo sec */
 52		       struct module *module)
 53{
 54	int i, n, relo_type;
 55	Elf32_Rela *rel_entry = (void *)sechdrs[relsec].sh_addr;
 56	Elf32_Sym *sym_entry, *sym_sec;
 57	Elf32_Addr relocation, location, tgt_addr;
 58	unsigned int tgtsec;
 59
 60	/*
 61	 * @relsec has relocations e.g. .rela.init.text
 62	 * @tgtsec is section to patch e.g. .init.text
 63	 */
 64	tgtsec = sechdrs[relsec].sh_info;
 65	tgt_addr = sechdrs[tgtsec].sh_addr;
 66	sym_sec = (Elf32_Sym *) sechdrs[symindex].sh_addr;
 67	n = sechdrs[relsec].sh_size / sizeof(*rel_entry);
 68
 69	pr_debug("\nSection to fixup %s @%x\n",
 70		 module->arch.secstr + sechdrs[tgtsec].sh_name, tgt_addr);
 71	pr_debug("=========================================================\n");
 72	pr_debug("r_off\tr_add\tst_value ADDRESS  VALUE\n");
 73	pr_debug("=========================================================\n");
 74
 75	/* Loop thru entries in relocation section */
 76	for (i = 0; i < n; i++) {
 77		const char *s;
 78
 79		/* This is where to make the change */
 80		location = tgt_addr + rel_entry[i].r_offset;
 81
 82		/* This is the symbol it is referring to.  Note that all
 83		   undefined symbols have been resolved.  */
 84		sym_entry = sym_sec + ELF32_R_SYM(rel_entry[i].r_info);
 85
 86		relocation = sym_entry->st_value + rel_entry[i].r_addend;
 87
 88		if (sym_entry->st_name == 0 && ELF_ST_TYPE (sym_entry->st_info) == STT_SECTION) {
 89			s = module->arch.secstr + sechdrs[sym_entry->st_shndx].sh_name;
 90		} else {
 91			s = strtab + sym_entry->st_name;
 92		}
 93
 94		pr_debug("   %x\t%x\t%x %x %x [%s]\n",
 95			 rel_entry[i].r_offset, rel_entry[i].r_addend,
 96			 sym_entry->st_value, location, relocation, s);
 97
 98		/* This assumes modules are built with -mlong-calls
 99		 * so any branches/jumps are absolute 32 bit jmps
100		 * global data access again is abs 32 bit.
101		 * Both of these are handled by same relocation type
102		 */
103		relo_type = ELF32_R_TYPE(rel_entry[i].r_info);
104
105		if (likely(R_ARC_32_ME == relo_type))	/* ME ( S + A ) */
106			arc_write_me((unsigned short *)location, relocation);
107		else if (R_ARC_32 == relo_type)		/* ( S + A ) */
108			*((Elf32_Addr *) location) = relocation;
109		else if (R_ARC_32_PCREL == relo_type)	/* ( S + A ) - PDATA ) */
110			*((Elf32_Addr *) location) = relocation - location;
111		else
112			goto relo_err;
113
114	}
115
116#ifdef CONFIG_ARC_DW2_UNWIND
117	if (strcmp(module->arch.secstr+sechdrs[tgtsec].sh_name, ".eh_frame") == 0)
118		module->arch.unw_sec_idx = tgtsec;
119#endif
120
121	return 0;
122
123relo_err:
124	pr_err("%s: unknown relocation: %u\n",
125		module->name, ELF32_R_TYPE(rel_entry[i].r_info));
126	return -ENOEXEC;
127
128}
129
130/* Just before lift off: After sections have been relocated, we add the
131 * dwarf section to unwinder table pool
132 * This couldn't be done in module_frob_arch_sections() because
133 * relocations had not been applied by then
134 */
135int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
136		    struct module *mod)
137{
138#ifdef CONFIG_ARC_DW2_UNWIND
139	void *unw;
140	int unwsec = mod->arch.unw_sec_idx;
141
142	if (unwsec) {
143		unw = unwind_add_table(mod, (void *)sechdrs[unwsec].sh_addr,
144				       sechdrs[unwsec].sh_size);
145		mod->arch.unw_info = unw;
146	}
147#endif
148	return 0;
149}