1/*  Kernel module help for x86-64
2    Copyright (C) 2001 Rusty Russell.
3    Copyright (C) 2002,2003 Andi Kleen, SuSE Labs.
4
5    This program is free software; you can redistribute it and/or modify
6    it under the terms of the GNU General Public License as published by
7    the Free Software Foundation; either version 2 of the License, or
8    (at your option) any later version.
9
10    This program is distributed in the hope that it will be useful,
11    but WITHOUT ANY WARRANTY; without even the implied warranty of
12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13    GNU General Public License for more details.
14
15    You should have received a copy of the GNU General Public License
16    along with this program; if not, write to the Free Software
17    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18*/
19#include <linux/moduleloader.h>
20#include <linux/elf.h>
21#include <linux/vmalloc.h>
22#include <linux/fs.h>
23#include <linux/string.h>
24#include <linux/kernel.h>
25#include <linux/slab.h>
26#include <linux/bug.h>
27
28#include <asm/system.h>
29#include <asm/page.h>
30#include <asm/pgtable.h>
31
32#define DEBUGP(fmt...)
33
34#ifndef CONFIG_UML
35void module_free(struct module *mod, void *module_region)
36{
37	vfree(module_region);
38}
39
40void *module_alloc(unsigned long size)
41{
42	struct vm_struct *area;
43
44	if (!size)
45		return NULL;
46	size = PAGE_ALIGN(size);
47	if (size > MODULES_LEN)
48		return NULL;
49
50	area = __get_vm_area(size, VM_ALLOC, MODULES_VADDR, MODULES_END);
51	if (!area)
52		return NULL;
53
54	return __vmalloc_area(area, GFP_KERNEL, PAGE_KERNEL_EXEC);
55}
56#endif
57
58/* We don't need anything special. */
59int module_frob_arch_sections(Elf_Ehdr *hdr,
60			      Elf_Shdr *sechdrs,
61			      char *secstrings,
62			      struct module *mod)
63{
64	return 0;
65}
66
67int apply_relocate_add(Elf64_Shdr *sechdrs,
68		   const char *strtab,
69		   unsigned int symindex,
70		   unsigned int relsec,
71		   struct module *me)
72{
73	unsigned int i;
74	Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
75	Elf64_Sym *sym;
76	void *loc;
77	u64 val;
78
79	DEBUGP("Applying relocate section %u to %u\n", relsec,
80	       sechdrs[relsec].sh_info);
81	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
82		/* This is where to make the change */
83		loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
84			+ rel[i].r_offset;
85
86		/* This is the symbol it is referring to.  Note that all
87		   undefined symbols have been resolved.  */
88		sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
89			+ ELF64_R_SYM(rel[i].r_info);
90
91	        DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
92		       (int)ELF64_R_TYPE(rel[i].r_info),
93		       sym->st_value, rel[i].r_addend, (u64)loc);
94
95		val = sym->st_value + rel[i].r_addend;
96
97		switch (ELF64_R_TYPE(rel[i].r_info)) {
98		case R_X86_64_NONE:
99			break;
100		case R_X86_64_64:
101			*(u64 *)loc = val;
102			break;
103		case R_X86_64_32:
104			*(u32 *)loc = val;
105			if (val != *(u32 *)loc)
106				goto overflow;
107			break;
108		case R_X86_64_32S:
109			*(s32 *)loc = val;
110			if ((s64)val != *(s32 *)loc)
111				goto overflow;
112			break;
113		case R_X86_64_PC32:
114			val -= (u64)loc;
115			*(u32 *)loc = val;
116			break;
117		default:
118			printk(KERN_ERR "module %s: Unknown rela relocation: %Lu\n",
119			       me->name, ELF64_R_TYPE(rel[i].r_info));
120			return -ENOEXEC;
121		}
122	}
123	return 0;
124
125overflow:
126	printk(KERN_ERR "overflow in relocation type %d val %Lx\n",
127	       (int)ELF64_R_TYPE(rel[i].r_info), val);
128	printk(KERN_ERR "`%s' likely not compiled with -mcmodel=kernel\n",
129	       me->name);
130	return -ENOEXEC;
131}
132
133int apply_relocate(Elf_Shdr *sechdrs,
134		   const char *strtab,
135		   unsigned int symindex,
136		   unsigned int relsec,
137		   struct module *me)
138{
139	printk("non add relocation not supported\n");
140	return -ENOSYS;
141}
142
143int module_finalize(const Elf_Ehdr *hdr,
144                    const Elf_Shdr *sechdrs,
145                    struct module *me)
146{
147	const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL;
148	char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
149
150	for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
151		if (!strcmp(".text", secstrings + s->sh_name))
152			text = s;
153		if (!strcmp(".altinstructions", secstrings + s->sh_name))
154			alt = s;
155		if (!strcmp(".smp_locks", secstrings + s->sh_name))
156			locks= s;
157	}
158
159	if (alt) {
160		/* patch .altinstructions */
161		void *aseg = (void *)alt->sh_addr;
162		apply_alternatives(aseg, aseg + alt->sh_size);
163	}
164	if (locks && text) {
165		void *lseg = (void *)locks->sh_addr;
166		void *tseg = (void *)text->sh_addr;
167		alternatives_smp_module_add(me, me->name,
168					    lseg, lseg + locks->sh_size,
169					    tseg, tseg + text->sh_size);
170	}
171
172	return module_bug_finalize(hdr, sechdrs, me);
173}
174
175void module_arch_cleanup(struct module *mod)
176{
177	alternatives_smp_module_del(mod);
178	module_bug_cleanup(mod);
179}
180