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