1/*
2 *  linux/arch/arm/kernel/module.c
3 *
4 *  Copyright (C) 2002 Russell King.
5 *  Modified for nommu by Hyok S. Choi
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * Module allocation method suggested by Andi Kleen.
12 */
13#include <linux/module.h>
14#include <linux/moduleloader.h>
15#include <linux/kernel.h>
16#include <linux/mm.h>
17#include <linux/elf.h>
18#include <linux/vmalloc.h>
19#include <linux/fs.h>
20#include <linux/string.h>
21#include <linux/gfp.h>
22
23#include <asm/pgtable.h>
24#include <asm/sections.h>
25#include <asm/smp_plat.h>
26#include <asm/unwind.h>
27#include <asm/opcodes.h>
28
29#ifdef CONFIG_XIP_KERNEL
30/*
31 * The XIP kernel text is mapped in the module area for modules and
32 * some other stuff to work without any indirect relocations.
33 * MODULES_VADDR is redefined here and not in asm/memory.h to avoid
34 * recompiling the whole kernel when CONFIG_XIP_KERNEL is turned on/off.
35 */
36#undef MODULES_VADDR
37#define MODULES_VADDR	(((unsigned long)_etext + ~PMD_MASK) & PMD_MASK)
38#endif
39
40#ifdef CONFIG_MMU
41void *module_alloc(unsigned long size)
42{
43	return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
44				GFP_KERNEL, PAGE_KERNEL_EXEC, NUMA_NO_NODE,
45				__builtin_return_address(0));
46}
47#endif
48
49int
50apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
51	       unsigned int relindex, struct module *module)
52{
53	Elf32_Shdr *symsec = sechdrs + symindex;
54	Elf32_Shdr *relsec = sechdrs + relindex;
55	Elf32_Shdr *dstsec = sechdrs + relsec->sh_info;
56	Elf32_Rel *rel = (void *)relsec->sh_addr;
57	unsigned int i;
58
59	for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) {
60		unsigned long loc;
61		Elf32_Sym *sym;
62		const char *symname;
63		s32 offset;
64		u32 tmp;
65#ifdef CONFIG_THUMB2_KERNEL
66		u32 upper, lower, sign, j1, j2;
67#endif
68
69		offset = ELF32_R_SYM(rel->r_info);
70		if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) {
71			pr_err("%s: section %u reloc %u: bad relocation sym offset\n",
72				module->name, relindex, i);
73			return -ENOEXEC;
74		}
75
76		sym = ((Elf32_Sym *)symsec->sh_addr) + offset;
77		symname = strtab + sym->st_name;
78
79		if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) {
80			pr_err("%s: section %u reloc %u sym '%s': out of bounds relocation, offset %d size %u\n",
81			       module->name, relindex, i, symname,
82			       rel->r_offset, dstsec->sh_size);
83			return -ENOEXEC;
84		}
85
86		loc = dstsec->sh_addr + rel->r_offset;
87
88		switch (ELF32_R_TYPE(rel->r_info)) {
89		case R_ARM_NONE:
90			/* ignore */
91			break;
92
93		case R_ARM_ABS32:
94		case R_ARM_TARGET1:
95			*(u32 *)loc += sym->st_value;
96			break;
97
98		case R_ARM_PC24:
99		case R_ARM_CALL:
100		case R_ARM_JUMP24:
101			offset = __mem_to_opcode_arm(*(u32 *)loc);
102			offset = (offset & 0x00ffffff) << 2;
103			if (offset & 0x02000000)
104				offset -= 0x04000000;
105
106			offset += sym->st_value - loc;
107			if (offset & 3 ||
108			    offset <= (s32)0xfe000000 ||
109			    offset >= (s32)0x02000000) {
110				pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
111				       module->name, relindex, i, symname,
112				       ELF32_R_TYPE(rel->r_info), loc,
113				       sym->st_value);
114				return -ENOEXEC;
115			}
116
117			offset >>= 2;
118			offset &= 0x00ffffff;
119
120			*(u32 *)loc &= __opcode_to_mem_arm(0xff000000);
121			*(u32 *)loc |= __opcode_to_mem_arm(offset);
122			break;
123
124	       case R_ARM_V4BX:
125		       /* Preserve Rm and the condition code. Alter
126			* other bits to re-code instruction as
127			* MOV PC,Rm.
128			*/
129		       *(u32 *)loc &= __opcode_to_mem_arm(0xf000000f);
130		       *(u32 *)loc |= __opcode_to_mem_arm(0x01a0f000);
131		       break;
132
133		case R_ARM_PREL31:
134			offset = *(u32 *)loc + sym->st_value - loc;
135			*(u32 *)loc = offset & 0x7fffffff;
136			break;
137
138		case R_ARM_MOVW_ABS_NC:
139		case R_ARM_MOVT_ABS:
140			offset = tmp = __mem_to_opcode_arm(*(u32 *)loc);
141			offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff);
142			offset = (offset ^ 0x8000) - 0x8000;
143
144			offset += sym->st_value;
145			if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_ABS)
146				offset >>= 16;
147
148			tmp &= 0xfff0f000;
149			tmp |= ((offset & 0xf000) << 4) |
150				(offset & 0x0fff);
151
152			*(u32 *)loc = __opcode_to_mem_arm(tmp);
153			break;
154
155#ifdef CONFIG_THUMB2_KERNEL
156		case R_ARM_THM_CALL:
157		case R_ARM_THM_JUMP24:
158			upper = __mem_to_opcode_thumb16(*(u16 *)loc);
159			lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2));
160
161			/*
162			 * 25 bit signed address range (Thumb-2 BL and B.W
163			 * instructions):
164			 *   S:I1:I2:imm10:imm11:0
165			 * where:
166			 *   S     = upper[10]   = offset[24]
167			 *   I1    = ~(J1 ^ S)   = offset[23]
168			 *   I2    = ~(J2 ^ S)   = offset[22]
169			 *   imm10 = upper[9:0]  = offset[21:12]
170			 *   imm11 = lower[10:0] = offset[11:1]
171			 *   J1    = lower[13]
172			 *   J2    = lower[11]
173			 */
174			sign = (upper >> 10) & 1;
175			j1 = (lower >> 13) & 1;
176			j2 = (lower >> 11) & 1;
177			offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) |
178				((~(j2 ^ sign) & 1) << 22) |
179				((upper & 0x03ff) << 12) |
180				((lower & 0x07ff) << 1);
181			if (offset & 0x01000000)
182				offset -= 0x02000000;
183			offset += sym->st_value - loc;
184
185			/*
186			 * For function symbols, only Thumb addresses are
187			 * allowed (no interworking).
188			 *
189			 * For non-function symbols, the destination
190			 * has no specific ARM/Thumb disposition, so
191			 * the branch is resolved under the assumption
192			 * that interworking is not required.
193			 */
194			if ((ELF32_ST_TYPE(sym->st_info) == STT_FUNC &&
195				!(offset & 1)) ||
196			    offset <= (s32)0xff000000 ||
197			    offset >= (s32)0x01000000) {
198				pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
199				       module->name, relindex, i, symname,
200				       ELF32_R_TYPE(rel->r_info), loc,
201				       sym->st_value);
202				return -ENOEXEC;
203			}
204
205			sign = (offset >> 24) & 1;
206			j1 = sign ^ (~(offset >> 23) & 1);
207			j2 = sign ^ (~(offset >> 22) & 1);
208			upper = (u16)((upper & 0xf800) | (sign << 10) |
209					    ((offset >> 12) & 0x03ff));
210			lower = (u16)((lower & 0xd000) |
211				      (j1 << 13) | (j2 << 11) |
212				      ((offset >> 1) & 0x07ff));
213
214			*(u16 *)loc = __opcode_to_mem_thumb16(upper);
215			*(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower);
216			break;
217
218		case R_ARM_THM_MOVW_ABS_NC:
219		case R_ARM_THM_MOVT_ABS:
220			upper = __mem_to_opcode_thumb16(*(u16 *)loc);
221			lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2));
222
223			/*
224			 * MOVT/MOVW instructions encoding in Thumb-2:
225			 *
226			 * i	= upper[10]
227			 * imm4	= upper[3:0]
228			 * imm3	= lower[14:12]
229			 * imm8	= lower[7:0]
230			 *
231			 * imm16 = imm4:i:imm3:imm8
232			 */
233			offset = ((upper & 0x000f) << 12) |
234				((upper & 0x0400) << 1) |
235				((lower & 0x7000) >> 4) | (lower & 0x00ff);
236			offset = (offset ^ 0x8000) - 0x8000;
237			offset += sym->st_value;
238
239			if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS)
240				offset >>= 16;
241
242			upper = (u16)((upper & 0xfbf0) |
243				      ((offset & 0xf000) >> 12) |
244				      ((offset & 0x0800) >> 1));
245			lower = (u16)((lower & 0x8f00) |
246				      ((offset & 0x0700) << 4) |
247				      (offset & 0x00ff));
248			*(u16 *)loc = __opcode_to_mem_thumb16(upper);
249			*(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower);
250			break;
251#endif
252
253		default:
254			printk(KERN_ERR "%s: unknown relocation: %u\n",
255			       module->name, ELF32_R_TYPE(rel->r_info));
256			return -ENOEXEC;
257		}
258	}
259	return 0;
260}
261
262struct mod_unwind_map {
263	const Elf_Shdr *unw_sec;
264	const Elf_Shdr *txt_sec;
265};
266
267static const Elf_Shdr *find_mod_section(const Elf32_Ehdr *hdr,
268	const Elf_Shdr *sechdrs, const char *name)
269{
270	const Elf_Shdr *s, *se;
271	const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
272
273	for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++)
274		if (strcmp(name, secstrs + s->sh_name) == 0)
275			return s;
276
277	return NULL;
278}
279
280extern void fixup_pv_table(const void *, unsigned long);
281extern void fixup_smp(const void *, unsigned long);
282
283int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
284		    struct module *mod)
285{
286	const Elf_Shdr *s = NULL;
287#ifdef CONFIG_ARM_UNWIND
288	const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
289	const Elf_Shdr *sechdrs_end = sechdrs + hdr->e_shnum;
290	struct mod_unwind_map maps[ARM_SEC_MAX];
291	int i;
292
293	memset(maps, 0, sizeof(maps));
294
295	for (s = sechdrs; s < sechdrs_end; s++) {
296		const char *secname = secstrs + s->sh_name;
297
298		if (!(s->sh_flags & SHF_ALLOC))
299			continue;
300
301		if (strcmp(".ARM.exidx.init.text", secname) == 0)
302			maps[ARM_SEC_INIT].unw_sec = s;
303		else if (strcmp(".ARM.exidx", secname) == 0)
304			maps[ARM_SEC_CORE].unw_sec = s;
305		else if (strcmp(".ARM.exidx.exit.text", secname) == 0)
306			maps[ARM_SEC_EXIT].unw_sec = s;
307		else if (strcmp(".ARM.exidx.text.unlikely", secname) == 0)
308			maps[ARM_SEC_UNLIKELY].unw_sec = s;
309		else if (strcmp(".ARM.exidx.text.hot", secname) == 0)
310			maps[ARM_SEC_HOT].unw_sec = s;
311		else if (strcmp(".init.text", secname) == 0)
312			maps[ARM_SEC_INIT].txt_sec = s;
313		else if (strcmp(".text", secname) == 0)
314			maps[ARM_SEC_CORE].txt_sec = s;
315		else if (strcmp(".exit.text", secname) == 0)
316			maps[ARM_SEC_EXIT].txt_sec = s;
317		else if (strcmp(".text.unlikely", secname) == 0)
318			maps[ARM_SEC_UNLIKELY].txt_sec = s;
319		else if (strcmp(".text.hot", secname) == 0)
320			maps[ARM_SEC_HOT].txt_sec = s;
321	}
322
323	for (i = 0; i < ARM_SEC_MAX; i++)
324		if (maps[i].unw_sec && maps[i].txt_sec)
325			mod->arch.unwind[i] =
326				unwind_table_add(maps[i].unw_sec->sh_addr,
327					         maps[i].unw_sec->sh_size,
328					         maps[i].txt_sec->sh_addr,
329					         maps[i].txt_sec->sh_size);
330#endif
331#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
332	s = find_mod_section(hdr, sechdrs, ".pv_table");
333	if (s)
334		fixup_pv_table((void *)s->sh_addr, s->sh_size);
335#endif
336	s = find_mod_section(hdr, sechdrs, ".alt.smp.init");
337	if (s && !is_smp())
338#ifdef CONFIG_SMP_ON_UP
339		fixup_smp((void *)s->sh_addr, s->sh_size);
340#else
341		return -EINVAL;
342#endif
343	return 0;
344}
345
346void
347module_arch_cleanup(struct module *mod)
348{
349#ifdef CONFIG_ARM_UNWIND
350	int i;
351
352	for (i = 0; i < ARM_SEC_MAX; i++)
353		if (mod->arch.unwind[i])
354			unwind_table_del(mod->arch.unwind[i]);
355#endif
356}
357