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, 0, 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			if (sym->st_value & 3) {
102				pr_err("%s: section %u reloc %u sym '%s': unsupported interworking call (ARM -> Thumb)\n",
103				       module->name, relindex, i, symname);
104				return -ENOEXEC;
105			}
106
107			offset = __mem_to_opcode_arm(*(u32 *)loc);
108			offset = (offset & 0x00ffffff) << 2;
109			if (offset & 0x02000000)
110				offset -= 0x04000000;
111
112			offset += sym->st_value - loc;
113			if (offset <= (s32)0xfe000000 ||
114			    offset >= (s32)0x02000000) {
115				pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
116				       module->name, relindex, i, symname,
117				       ELF32_R_TYPE(rel->r_info), loc,
118				       sym->st_value);
119				return -ENOEXEC;
120			}
121
122			offset >>= 2;
123			offset &= 0x00ffffff;
124
125			*(u32 *)loc &= __opcode_to_mem_arm(0xff000000);
126			*(u32 *)loc |= __opcode_to_mem_arm(offset);
127			break;
128
129	       case R_ARM_V4BX:
130		       /* Preserve Rm and the condition code. Alter
131			* other bits to re-code instruction as
132			* MOV PC,Rm.
133			*/
134		       *(u32 *)loc &= __opcode_to_mem_arm(0xf000000f);
135		       *(u32 *)loc |= __opcode_to_mem_arm(0x01a0f000);
136		       break;
137
138		case R_ARM_PREL31:
139			offset = *(u32 *)loc + sym->st_value - loc;
140			*(u32 *)loc = offset & 0x7fffffff;
141			break;
142
143		case R_ARM_MOVW_ABS_NC:
144		case R_ARM_MOVT_ABS:
145			offset = tmp = __mem_to_opcode_arm(*(u32 *)loc);
146			offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff);
147			offset = (offset ^ 0x8000) - 0x8000;
148
149			offset += sym->st_value;
150			if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_ABS)
151				offset >>= 16;
152
153			tmp &= 0xfff0f000;
154			tmp |= ((offset & 0xf000) << 4) |
155				(offset & 0x0fff);
156
157			*(u32 *)loc = __opcode_to_mem_arm(tmp);
158			break;
159
160#ifdef CONFIG_THUMB2_KERNEL
161		case R_ARM_THM_CALL:
162		case R_ARM_THM_JUMP24:
163			/*
164			 * For function symbols, only Thumb addresses are
165			 * allowed (no interworking).
166			 *
167			 * For non-function symbols, the destination
168			 * has no specific ARM/Thumb disposition, so
169			 * the branch is resolved under the assumption
170			 * that interworking is not required.
171			 */
172			if (ELF32_ST_TYPE(sym->st_info) == STT_FUNC &&
173			    !(sym->st_value & 1)) {
174				pr_err("%s: section %u reloc %u sym '%s': unsupported interworking call (Thumb -> ARM)\n",
175				       module->name, relindex, i, symname);
176				return -ENOEXEC;
177			}
178
179			upper = __mem_to_opcode_thumb16(*(u16 *)loc);
180			lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2));
181
182			/*
183			 * 25 bit signed address range (Thumb-2 BL and B.W
184			 * instructions):
185			 *   S:I1:I2:imm10:imm11:0
186			 * where:
187			 *   S     = upper[10]   = offset[24]
188			 *   I1    = ~(J1 ^ S)   = offset[23]
189			 *   I2    = ~(J2 ^ S)   = offset[22]
190			 *   imm10 = upper[9:0]  = offset[21:12]
191			 *   imm11 = lower[10:0] = offset[11:1]
192			 *   J1    = lower[13]
193			 *   J2    = lower[11]
194			 */
195			sign = (upper >> 10) & 1;
196			j1 = (lower >> 13) & 1;
197			j2 = (lower >> 11) & 1;
198			offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) |
199				((~(j2 ^ sign) & 1) << 22) |
200				((upper & 0x03ff) << 12) |
201				((lower & 0x07ff) << 1);
202			if (offset & 0x01000000)
203				offset -= 0x02000000;
204			offset += sym->st_value - loc;
205
206			if (offset <= (s32)0xff000000 ||
207			    offset >= (s32)0x01000000) {
208				pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
209				       module->name, relindex, i, symname,
210				       ELF32_R_TYPE(rel->r_info), loc,
211				       sym->st_value);
212				return -ENOEXEC;
213			}
214
215			sign = (offset >> 24) & 1;
216			j1 = sign ^ (~(offset >> 23) & 1);
217			j2 = sign ^ (~(offset >> 22) & 1);
218			upper = (u16)((upper & 0xf800) | (sign << 10) |
219					    ((offset >> 12) & 0x03ff));
220			lower = (u16)((lower & 0xd000) |
221				      (j1 << 13) | (j2 << 11) |
222				      ((offset >> 1) & 0x07ff));
223
224			*(u16 *)loc = __opcode_to_mem_thumb16(upper);
225			*(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower);
226			break;
227
228		case R_ARM_THM_MOVW_ABS_NC:
229		case R_ARM_THM_MOVT_ABS:
230			upper = __mem_to_opcode_thumb16(*(u16 *)loc);
231			lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2));
232
233			/*
234			 * MOVT/MOVW instructions encoding in Thumb-2:
235			 *
236			 * i	= upper[10]
237			 * imm4	= upper[3:0]
238			 * imm3	= lower[14:12]
239			 * imm8	= lower[7:0]
240			 *
241			 * imm16 = imm4:i:imm3:imm8
242			 */
243			offset = ((upper & 0x000f) << 12) |
244				((upper & 0x0400) << 1) |
245				((lower & 0x7000) >> 4) | (lower & 0x00ff);
246			offset = (offset ^ 0x8000) - 0x8000;
247			offset += sym->st_value;
248
249			if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS)
250				offset >>= 16;
251
252			upper = (u16)((upper & 0xfbf0) |
253				      ((offset & 0xf000) >> 12) |
254				      ((offset & 0x0800) >> 1));
255			lower = (u16)((lower & 0x8f00) |
256				      ((offset & 0x0700) << 4) |
257				      (offset & 0x00ff));
258			*(u16 *)loc = __opcode_to_mem_thumb16(upper);
259			*(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower);
260			break;
261#endif
262
263		default:
264			pr_err("%s: unknown relocation: %u\n",
265			       module->name, ELF32_R_TYPE(rel->r_info));
266			return -ENOEXEC;
267		}
268	}
269	return 0;
270}
271
272struct mod_unwind_map {
273	const Elf_Shdr *unw_sec;
274	const Elf_Shdr *txt_sec;
275};
276
277static const Elf_Shdr *find_mod_section(const Elf32_Ehdr *hdr,
278	const Elf_Shdr *sechdrs, const char *name)
279{
280	const Elf_Shdr *s, *se;
281	const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
282
283	for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++)
284		if (strcmp(name, secstrs + s->sh_name) == 0)
285			return s;
286
287	return NULL;
288}
289
290extern void fixup_pv_table(const void *, unsigned long);
291extern void fixup_smp(const void *, unsigned long);
292
293int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
294		    struct module *mod)
295{
296	const Elf_Shdr *s = NULL;
297#ifdef CONFIG_ARM_UNWIND
298	const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
299	const Elf_Shdr *sechdrs_end = sechdrs + hdr->e_shnum;
300	struct mod_unwind_map maps[ARM_SEC_MAX];
301	int i;
302
303	memset(maps, 0, sizeof(maps));
304
305	for (s = sechdrs; s < sechdrs_end; s++) {
306		const char *secname = secstrs + s->sh_name;
307
308		if (!(s->sh_flags & SHF_ALLOC))
309			continue;
310
311		if (strcmp(".ARM.exidx.init.text", secname) == 0)
312			maps[ARM_SEC_INIT].unw_sec = s;
313		else if (strcmp(".ARM.exidx", secname) == 0)
314			maps[ARM_SEC_CORE].unw_sec = s;
315		else if (strcmp(".ARM.exidx.exit.text", secname) == 0)
316			maps[ARM_SEC_EXIT].unw_sec = s;
317		else if (strcmp(".ARM.exidx.text.unlikely", secname) == 0)
318			maps[ARM_SEC_UNLIKELY].unw_sec = s;
319		else if (strcmp(".ARM.exidx.text.hot", secname) == 0)
320			maps[ARM_SEC_HOT].unw_sec = s;
321		else if (strcmp(".init.text", secname) == 0)
322			maps[ARM_SEC_INIT].txt_sec = s;
323		else if (strcmp(".text", secname) == 0)
324			maps[ARM_SEC_CORE].txt_sec = s;
325		else if (strcmp(".exit.text", secname) == 0)
326			maps[ARM_SEC_EXIT].txt_sec = s;
327		else if (strcmp(".text.unlikely", secname) == 0)
328			maps[ARM_SEC_UNLIKELY].txt_sec = s;
329		else if (strcmp(".text.hot", secname) == 0)
330			maps[ARM_SEC_HOT].txt_sec = s;
331	}
332
333	for (i = 0; i < ARM_SEC_MAX; i++)
334		if (maps[i].unw_sec && maps[i].txt_sec)
335			mod->arch.unwind[i] =
336				unwind_table_add(maps[i].unw_sec->sh_addr,
337					         maps[i].unw_sec->sh_size,
338					         maps[i].txt_sec->sh_addr,
339					         maps[i].txt_sec->sh_size);
340#endif
341#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
342	s = find_mod_section(hdr, sechdrs, ".pv_table");
343	if (s)
344		fixup_pv_table((void *)s->sh_addr, s->sh_size);
345#endif
346	s = find_mod_section(hdr, sechdrs, ".alt.smp.init");
347	if (s && !is_smp())
348#ifdef CONFIG_SMP_ON_UP
349		fixup_smp((void *)s->sh_addr, s->sh_size);
350#else
351		return -EINVAL;
352#endif
353	return 0;
354}
355
356void
357module_arch_cleanup(struct module *mod)
358{
359#ifdef CONFIG_ARM_UNWIND
360	int i;
361
362	for (i = 0; i < ARM_SEC_MAX; i++)
363		if (mod->arch.unwind[i])
364			unwind_table_del(mod->arch.unwind[i]);
365#endif
366}
367