summaryrefslogtreecommitdiff
path: root/arch/loongarch/kernel/module.c
blob: 638427ff0d5150cbffacef7d9ac75c0f10b661b8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
// SPDX-License-Identifier: GPL-2.0+
/*
 * Author: Hanlu Li <lihanlu@loongson.cn>
 *         Huacai Chen <chenhuacai@loongson.cn>
 *
 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
 */

#define pr_fmt(fmt) "kmod: " fmt

#include <linux/moduleloader.h>
#include <linux/elf.h>
#include <linux/mm.h>
#include <linux/numa.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/kernel.h>

static inline bool signed_imm_check(long val, unsigned int bit)
{
	return -(1L << (bit - 1)) <= val && val < (1L << (bit - 1));
}

static inline bool unsigned_imm_check(unsigned long val, unsigned int bit)
{
	return val < (1UL << bit);
}

static int rela_stack_push(s64 stack_value, s64 *rela_stack, size_t *rela_stack_top)
{
	if (*rela_stack_top >= RELA_STACK_DEPTH)
		return -ENOEXEC;

	rela_stack[(*rela_stack_top)++] = stack_value;
	pr_debug("%s stack_value = 0x%llx\n", __func__, stack_value);

	return 0;
}

static int rela_stack_pop(s64 *stack_value, s64 *rela_stack, size_t *rela_stack_top)
{
	if (*rela_stack_top == 0)
		return -ENOEXEC;

	*stack_value = rela_stack[--(*rela_stack_top)];
	pr_debug("%s stack_value = 0x%llx\n", __func__, *stack_value);

	return 0;
}

static int apply_r_larch_none(struct module *mod, u32 *location, Elf_Addr v,
			s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
	return 0;
}

static int apply_r_larch_error(struct module *me, u32 *location, Elf_Addr v,
			s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
	pr_err("%s: Unsupport relocation type %u, please add its support.\n", me->name, type);
	return -EINVAL;
}

static int apply_r_larch_32(struct module *mod, u32 *location, Elf_Addr v,
			s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
	*location = v;
	return 0;
}

static int apply_r_larch_64(struct module *mod, u32 *location, Elf_Addr v,
			s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
	*(Elf_Addr *)location = v;
	return 0;
}

static int apply_r_larch_sop_push_pcrel(struct module *mod, u32 *location, Elf_Addr v,
			s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
	return rela_stack_push(v - (u64)location, rela_stack, rela_stack_top);
}

static int apply_r_larch_sop_push_absolute(struct module *mod, u32 *location, Elf_Addr v,
			s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
	return rela_stack_push(v, rela_stack, rela_stack_top);
}

static int apply_r_larch_sop_push_dup(struct module *mod, u32 *location, Elf_Addr v,
			s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
	int err = 0;
	s64 opr1;

	err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
	if (err)
		return err;
	err = rela_stack_push(opr1, rela_stack, rela_stack_top);
	if (err)
		return err;
	err = rela_stack_push(opr1, rela_stack, rela_stack_top);
	if (err)
		return err;

	return 0;
}

static int apply_r_larch_sop_push_plt_pcrel(struct module *mod, u32 *location, Elf_Addr v,
			s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
	ptrdiff_t offset = (void *)v - (void *)location;

	if (offset >= SZ_128M)
		v = module_emit_plt_entry(mod, v);

	if (offset < -SZ_128M)
		v = module_emit_plt_entry(mod, v);

	return apply_r_larch_sop_push_pcrel(mod, location, v, rela_stack, rela_stack_top, type);
}

static int apply_r_larch_sop(struct module *mod, u32 *location, Elf_Addr v,
			s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
	int err = 0;
	s64 opr1, opr2, opr3;

	if (type == R_LARCH_SOP_IF_ELSE) {
		err = rela_stack_pop(&opr3, rela_stack, rela_stack_top);
		if (err)
			return err;
	}

	err = rela_stack_pop(&opr2, rela_stack, rela_stack_top);
	if (err)
		return err;
	err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
	if (err)
		return err;

	switch (type) {
	case R_LARCH_SOP_AND:
		err = rela_stack_push(opr1 & opr2, rela_stack, rela_stack_top);
		break;
	case R_LARCH_SOP_ADD:
		err = rela_stack_push(opr1 + opr2, rela_stack, rela_stack_top);
		break;
	case R_LARCH_SOP_SUB:
		err = rela_stack_push(opr1 - opr2, rela_stack, rela_stack_top);
		break;
	case R_LARCH_SOP_SL:
		err = rela_stack_push(opr1 << opr2, rela_stack, rela_stack_top);
		break;
	case R_LARCH_SOP_SR:
		err = rela_stack_push(opr1 >> opr2, rela_stack, rela_stack_top);
		break;
	case R_LARCH_SOP_IF_ELSE:
		err = rela_stack_push(opr1 ? opr2 : opr3, rela_stack, rela_stack_top);
		break;
	default:
		pr_err("%s: Unsupport relocation type %u\n", mod->name, type);
		return -EINVAL;
	}

	return err;
}

static int apply_r_larch_sop_imm_field(struct module *mod, u32 *location, Elf_Addr v,
			s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
	int err = 0;
	s64 opr1;
	union loongarch_instruction *insn = (union loongarch_instruction *)location;

	err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
	if (err)
		return err;

	switch (type) {
	case R_LARCH_SOP_POP_32_U_10_12:
		if (!unsigned_imm_check(opr1, 12))
			goto overflow;

		/* (*(uint32_t *) PC) [21 ... 10] = opr [11 ... 0] */
		insn->reg2i12_format.immediate = opr1 & 0xfff;
		return 0;
	case R_LARCH_SOP_POP_32_S_10_12:
		if (!signed_imm_check(opr1, 12))
			goto overflow;

		insn->reg2i12_format.immediate = opr1 & 0xfff;
		return 0;
	case R_LARCH_SOP_POP_32_S_10_16:
		if (!signed_imm_check(opr1, 16))
			goto overflow;

		insn->reg2i16_format.immediate = opr1 & 0xffff;
		return 0;
	case R_LARCH_SOP_POP_32_S_10_16_S2:
		if (opr1 % 4)
			goto unaligned;

		if (!signed_imm_check(opr1, 18))
			goto overflow;

		insn->reg2i16_format.immediate = (opr1 >> 2) & 0xffff;
		return 0;
	case R_LARCH_SOP_POP_32_S_5_20:
		if (!signed_imm_check(opr1, 20))
			goto overflow;

		insn->reg1i20_format.immediate = (opr1) & 0xfffff;
		return 0;
	case R_LARCH_SOP_POP_32_S_0_5_10_16_S2:
		if (opr1 % 4)
			goto unaligned;

		if (!signed_imm_check(opr1, 23))
			goto overflow;

		opr1 >>= 2;
		insn->reg1i21_format.immediate_l = opr1 & 0xffff;
		insn->reg1i21_format.immediate_h = (opr1 >> 16) & 0x1f;
		return 0;
	case R_LARCH_SOP_POP_32_S_0_10_10_16_S2:
		if (opr1 % 4)
			goto unaligned;

		if (!signed_imm_check(opr1, 28))
			goto overflow;

		opr1 >>= 2;
		insn->reg0i26_format.immediate_l = opr1 & 0xffff;
		insn->reg0i26_format.immediate_h = (opr1 >> 16) & 0x3ff;
		return 0;
	case R_LARCH_SOP_POP_32_U:
		if (!unsigned_imm_check(opr1, 32))
			goto overflow;

		/* (*(uint32_t *) PC) = opr */
		*location = (u32)opr1;
		return 0;
	default:
		pr_err("%s: Unsupport relocation type %u\n", mod->name, type);
		return -EINVAL;
	}

overflow:
	pr_err("module %s: opr1 = 0x%llx overflow! dangerous %s (%u) relocation\n",
		mod->name, opr1, __func__, type);
	return -ENOEXEC;

unaligned:
	pr_err("module %s: opr1 = 0x%llx unaligned! dangerous %s (%u) relocation\n",
		mod->name, opr1, __func__, type);
	return -ENOEXEC;
}

static int apply_r_larch_add_sub(struct module *mod, u32 *location, Elf_Addr v,
			s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
	switch (type) {
	case R_LARCH_ADD32:
		*(s32 *)location += v;
		return 0;
	case R_LARCH_ADD64:
		*(s64 *)location += v;
		return 0;
	case R_LARCH_SUB32:
		*(s32 *)location -= v;
		return 0;
	case R_LARCH_SUB64:
		*(s64 *)location -= v;
		return 0;
	default:
		pr_err("%s: Unsupport relocation type %u\n", mod->name, type);
		return -EINVAL;
	}
}

/*
 * reloc_handlers_rela() - Apply a particular relocation to a module
 * @mod: the module to apply the reloc to
 * @location: the address at which the reloc is to be applied
 * @v: the value of the reloc, with addend for RELA-style
 * @rela_stack: the stack used for store relocation info, LOCAL to THIS module
 * @rela_stac_top: where the stack operation(pop/push) applies to
 *
 * Return: 0 upon success, else -ERRNO
 */
typedef int (*reloc_rela_handler)(struct module *mod, u32 *location, Elf_Addr v,
			s64 *rela_stack, size_t *rela_stack_top, unsigned int type);

/* The handlers for known reloc types */
static reloc_rela_handler reloc_rela_handlers[] = {
	[R_LARCH_NONE ... R_LARCH_SUB64]		     = apply_r_larch_error,

	[R_LARCH_NONE]					     = apply_r_larch_none,
	[R_LARCH_32]					     = apply_r_larch_32,
	[R_LARCH_64]					     = apply_r_larch_64,
	[R_LARCH_MARK_LA]				     = apply_r_larch_none,
	[R_LARCH_MARK_PCREL]				     = apply_r_larch_none,
	[R_LARCH_SOP_PUSH_PCREL]			     = apply_r_larch_sop_push_pcrel,
	[R_LARCH_SOP_PUSH_ABSOLUTE]			     = apply_r_larch_sop_push_absolute,
	[R_LARCH_SOP_PUSH_DUP]				     = apply_r_larch_sop_push_dup,
	[R_LARCH_SOP_PUSH_PLT_PCREL]			     = apply_r_larch_sop_push_plt_pcrel,
	[R_LARCH_SOP_SUB ... R_LARCH_SOP_IF_ELSE] 	     = apply_r_larch_sop,
	[R_LARCH_SOP_POP_32_S_10_5 ... R_LARCH_SOP_POP_32_U] = apply_r_larch_sop_imm_field,
	[R_LARCH_ADD32 ... R_LARCH_SUB64]		     = apply_r_larch_add_sub,
};

int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
		       unsigned int symindex, unsigned int relsec,
		       struct module *mod)
{
	int i, err;
	unsigned int type;
	s64 rela_stack[RELA_STACK_DEPTH];
	size_t rela_stack_top = 0;
	reloc_rela_handler handler;
	void *location;
	Elf_Addr v;
	Elf_Sym *sym;
	Elf_Rela *rel = (void *) sechdrs[relsec].sh_addr;

	pr_debug("%s: Applying relocate section %u to %u\n", __func__, relsec,
	       sechdrs[relsec].sh_info);

	rela_stack_top = 0;
	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
		/* This is where to make the change */
		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr + rel[i].r_offset;
		/* This is the symbol it is referring to */
		sym = (Elf_Sym *)sechdrs[symindex].sh_addr + ELF_R_SYM(rel[i].r_info);
		if (IS_ERR_VALUE(sym->st_value)) {
			/* Ignore unresolved weak symbol */
			if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
				continue;
			pr_warn("%s: Unknown symbol %s\n", mod->name, strtab + sym->st_name);
			return -ENOENT;
		}

		type = ELF_R_TYPE(rel[i].r_info);

		if (type < ARRAY_SIZE(reloc_rela_handlers))
			handler = reloc_rela_handlers[type];
		else
			handler = NULL;

		if (!handler) {
			pr_err("%s: Unknown relocation type %u\n", mod->name, type);
			return -EINVAL;
		}

		pr_debug("type %d st_value %llx r_addend %llx loc %llx\n",
		       (int)ELF_R_TYPE(rel[i].r_info),
		       sym->st_value, rel[i].r_addend, (u64)location);

		v = sym->st_value + rel[i].r_addend;
		err = handler(mod, location, v, rela_stack, &rela_stack_top, type);
		if (err)
			return err;
	}

	return 0;
}

void *module_alloc(unsigned long size)
{
	return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
			GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE, __builtin_return_address(0));
}