2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License as published by
4 * the Free Software Foundation; either version 2 of the License, or
5 * (at your option) any later version.
7 * This program is distributed in the hope that it will be useful,
8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 * GNU General Public License for more details.
12 * Copyright (C) 2017 Zihao Yu
15 #include <linux/elf.h>
16 #include <linux/err.h>
17 #include <linux/errno.h>
18 #include <linux/moduleloader.h>
19 #include <linux/vmalloc.h>
20 #include <linux/sizes.h>
21 #include <asm/pgtable.h>
22 #include <asm/sections.h>
25 * The auipc+jalr instruction pair can reach any PC-relative offset
26 * in the range [-2^31 - 2^11, 2^31 - 2^11)
28 static bool riscv_insn_valid_32bit_offset(ptrdiff_t val)
33 return (-(1L << 31) - (1L << 11)) <= val && val < ((1L << 31) - (1L << 11));
37 static int apply_r_riscv_32_rela(struct module *me, u32 *location, Elf_Addr v)
40 pr_err("%s: value %016llx out of range for 32-bit field\n",
41 me->name, (long long)v);
48 static int apply_r_riscv_64_rela(struct module *me, u32 *location, Elf_Addr v)
54 static int apply_r_riscv_branch_rela(struct module *me, u32 *location,
57 ptrdiff_t offset = (void *)v - (void *)location;
58 u32 imm12 = (offset & 0x1000) << (31 - 12);
59 u32 imm11 = (offset & 0x800) >> (11 - 7);
60 u32 imm10_5 = (offset & 0x7e0) << (30 - 10);
61 u32 imm4_1 = (offset & 0x1e) << (11 - 4);
63 *location = (*location & 0x1fff07f) | imm12 | imm11 | imm10_5 | imm4_1;
67 static int apply_r_riscv_jal_rela(struct module *me, u32 *location,
70 ptrdiff_t offset = (void *)v - (void *)location;
71 u32 imm20 = (offset & 0x100000) << (31 - 20);
72 u32 imm19_12 = (offset & 0xff000);
73 u32 imm11 = (offset & 0x800) << (20 - 11);
74 u32 imm10_1 = (offset & 0x7fe) << (30 - 10);
76 *location = (*location & 0xfff) | imm20 | imm19_12 | imm11 | imm10_1;
80 static int apply_r_riscv_rcv_branch_rela(struct module *me, u32 *location,
83 ptrdiff_t offset = (void *)v - (void *)location;
84 u16 imm8 = (offset & 0x100) << (12 - 8);
85 u16 imm7_6 = (offset & 0xc0) >> (6 - 5);
86 u16 imm5 = (offset & 0x20) >> (5 - 2);
87 u16 imm4_3 = (offset & 0x18) << (12 - 5);
88 u16 imm2_1 = (offset & 0x6) << (12 - 10);
90 *(u16 *)location = (*(u16 *)location & 0xe383) |
91 imm8 | imm7_6 | imm5 | imm4_3 | imm2_1;
95 static int apply_r_riscv_rvc_jump_rela(struct module *me, u32 *location,
98 ptrdiff_t offset = (void *)v - (void *)location;
99 u16 imm11 = (offset & 0x800) << (12 - 11);
100 u16 imm10 = (offset & 0x400) >> (10 - 8);
101 u16 imm9_8 = (offset & 0x300) << (12 - 11);
102 u16 imm7 = (offset & 0x80) >> (7 - 6);
103 u16 imm6 = (offset & 0x40) << (12 - 11);
104 u16 imm5 = (offset & 0x20) >> (5 - 2);
105 u16 imm4 = (offset & 0x10) << (12 - 5);
106 u16 imm3_1 = (offset & 0xe) << (12 - 10);
108 *(u16 *)location = (*(u16 *)location & 0xe003) |
109 imm11 | imm10 | imm9_8 | imm7 | imm6 | imm5 | imm4 | imm3_1;
113 static int apply_r_riscv_pcrel_hi20_rela(struct module *me, u32 *location,
116 ptrdiff_t offset = (void *)v - (void *)location;
119 if (!riscv_insn_valid_32bit_offset(offset)) {
121 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
122 me->name, (long long)v, location);
126 hi20 = (offset + 0x800) & 0xfffff000;
127 *location = (*location & 0xfff) | hi20;
131 static int apply_r_riscv_pcrel_lo12_i_rela(struct module *me, u32 *location,
135 * v is the lo12 value to fill. It is calculated before calling this
138 *location = (*location & 0xfffff) | ((v & 0xfff) << 20);
142 static int apply_r_riscv_pcrel_lo12_s_rela(struct module *me, u32 *location,
146 * v is the lo12 value to fill. It is calculated before calling this
149 u32 imm11_5 = (v & 0xfe0) << (31 - 11);
150 u32 imm4_0 = (v & 0x1f) << (11 - 4);
152 *location = (*location & 0x1fff07f) | imm11_5 | imm4_0;
156 static int apply_r_riscv_hi20_rela(struct module *me, u32 *location,
161 if (IS_ENABLED(CMODEL_MEDLOW)) {
163 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
164 me->name, (long long)v, location);
168 hi20 = ((s32)v + 0x800) & 0xfffff000;
169 *location = (*location & 0xfff) | hi20;
173 static int apply_r_riscv_lo12_i_rela(struct module *me, u32 *location,
176 /* Skip medlow checking because of filtering by HI20 already */
177 s32 hi20 = ((s32)v + 0x800) & 0xfffff000;
178 s32 lo12 = ((s32)v - hi20);
179 *location = (*location & 0xfffff) | ((lo12 & 0xfff) << 20);
183 static int apply_r_riscv_lo12_s_rela(struct module *me, u32 *location,
186 /* Skip medlow checking because of filtering by HI20 already */
187 s32 hi20 = ((s32)v + 0x800) & 0xfffff000;
188 s32 lo12 = ((s32)v - hi20);
189 u32 imm11_5 = (lo12 & 0xfe0) << (31 - 11);
190 u32 imm4_0 = (lo12 & 0x1f) << (11 - 4);
191 *location = (*location & 0x1fff07f) | imm11_5 | imm4_0;
195 static int apply_r_riscv_got_hi20_rela(struct module *me, u32 *location,
198 ptrdiff_t offset = (void *)v - (void *)location;
201 /* Always emit the got entry */
202 if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) {
203 offset = module_emit_got_entry(me, v);
204 offset = (void *)offset - (void *)location;
207 "%s: can not generate the GOT entry for symbol = %016llx from PC = %p\n",
208 me->name, (long long)v, location);
212 hi20 = (offset + 0x800) & 0xfffff000;
213 *location = (*location & 0xfff) | hi20;
217 static int apply_r_riscv_call_plt_rela(struct module *me, u32 *location,
220 ptrdiff_t offset = (void *)v - (void *)location;
223 if (!riscv_insn_valid_32bit_offset(offset)) {
224 /* Only emit the plt entry if offset over 32-bit range */
225 if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) {
226 offset = module_emit_plt_entry(me, v);
227 offset = (void *)offset - (void *)location;
230 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
231 me->name, (long long)v, location);
236 hi20 = (offset + 0x800) & 0xfffff000;
237 lo12 = (offset - hi20) & 0xfff;
238 *location = (*location & 0xfff) | hi20;
239 *(location + 1) = (*(location + 1) & 0xfffff) | (lo12 << 20);
243 static int apply_r_riscv_call_rela(struct module *me, u32 *location,
246 ptrdiff_t offset = (void *)v - (void *)location;
249 if (!riscv_insn_valid_32bit_offset(offset)) {
251 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
252 me->name, (long long)v, location);
256 hi20 = (offset + 0x800) & 0xfffff000;
257 lo12 = (offset - hi20) & 0xfff;
258 *location = (*location & 0xfff) | hi20;
259 *(location + 1) = (*(location + 1) & 0xfffff) | (lo12 << 20);
263 static int apply_r_riscv_relax_rela(struct module *me, u32 *location,
269 static int apply_r_riscv_align_rela(struct module *me, u32 *location,
273 "%s: The unexpected relocation type 'R_RISCV_ALIGN' from PC = %p\n",
278 static int apply_r_riscv_add32_rela(struct module *me, u32 *location,
281 *(u32 *)location += (u32)v;
285 static int apply_r_riscv_sub32_rela(struct module *me, u32 *location,
288 *(u32 *)location -= (u32)v;
292 static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
294 [R_RISCV_32] = apply_r_riscv_32_rela,
295 [R_RISCV_64] = apply_r_riscv_64_rela,
296 [R_RISCV_BRANCH] = apply_r_riscv_branch_rela,
297 [R_RISCV_JAL] = apply_r_riscv_jal_rela,
298 [R_RISCV_RVC_BRANCH] = apply_r_riscv_rcv_branch_rela,
299 [R_RISCV_RVC_JUMP] = apply_r_riscv_rvc_jump_rela,
300 [R_RISCV_PCREL_HI20] = apply_r_riscv_pcrel_hi20_rela,
301 [R_RISCV_PCREL_LO12_I] = apply_r_riscv_pcrel_lo12_i_rela,
302 [R_RISCV_PCREL_LO12_S] = apply_r_riscv_pcrel_lo12_s_rela,
303 [R_RISCV_HI20] = apply_r_riscv_hi20_rela,
304 [R_RISCV_LO12_I] = apply_r_riscv_lo12_i_rela,
305 [R_RISCV_LO12_S] = apply_r_riscv_lo12_s_rela,
306 [R_RISCV_GOT_HI20] = apply_r_riscv_got_hi20_rela,
307 [R_RISCV_CALL_PLT] = apply_r_riscv_call_plt_rela,
308 [R_RISCV_CALL] = apply_r_riscv_call_rela,
309 [R_RISCV_RELAX] = apply_r_riscv_relax_rela,
310 [R_RISCV_ALIGN] = apply_r_riscv_align_rela,
311 [R_RISCV_ADD32] = apply_r_riscv_add32_rela,
312 [R_RISCV_SUB32] = apply_r_riscv_sub32_rela,
315 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
316 unsigned int symindex, unsigned int relsec,
319 Elf_Rela *rel = (void *) sechdrs[relsec].sh_addr;
320 int (*handler)(struct module *me, u32 *location, Elf_Addr v);
323 unsigned int i, type;
327 pr_debug("Applying relocate section %u to %u\n", relsec,
328 sechdrs[relsec].sh_info);
330 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
331 /* This is where to make the change */
332 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
334 /* This is the symbol it is referring to */
335 sym = (Elf_Sym *)sechdrs[symindex].sh_addr
336 + ELF_RISCV_R_SYM(rel[i].r_info);
337 if (IS_ERR_VALUE(sym->st_value)) {
338 /* Ignore unresolved weak symbol */
339 if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
341 pr_warning("%s: Unknown symbol %s\n",
342 me->name, strtab + sym->st_name);
346 type = ELF_RISCV_R_TYPE(rel[i].r_info);
348 if (type < ARRAY_SIZE(reloc_handlers_rela))
349 handler = reloc_handlers_rela[type];
354 pr_err("%s: Unknown relocation type %u\n",
359 v = sym->st_value + rel[i].r_addend;
361 if (type == R_RISCV_PCREL_LO12_I || type == R_RISCV_PCREL_LO12_S) {
364 for (j = 0; j < sechdrs[relsec].sh_size / sizeof(*rel); j++) {
365 unsigned long hi20_loc =
366 sechdrs[sechdrs[relsec].sh_info].sh_addr
368 u32 hi20_type = ELF_RISCV_R_TYPE(rel[j].r_info);
370 /* Find the corresponding HI20 relocation entry */
371 if (hi20_loc == sym->st_value
372 && (hi20_type == R_RISCV_PCREL_HI20
373 || hi20_type == R_RISCV_GOT_HI20)) {
376 (Elf_Sym *)sechdrs[symindex].sh_addr
377 + ELF_RISCV_R_SYM(rel[j].r_info);
378 unsigned long hi20_sym_val =
383 size_t offset = hi20_sym_val - hi20_loc;
384 if (IS_ENABLED(CONFIG_MODULE_SECTIONS)
385 && hi20_type == R_RISCV_GOT_HI20) {
386 offset = module_emit_got_entry(
388 offset = offset - hi20_loc;
390 hi20 = (offset + 0x800) & 0xfffff000;
391 lo12 = offset - hi20;
397 if (j == sechdrs[relsec].sh_size / sizeof(*rel)) {
399 "%s: Can not find HI20 relocation information\n",
405 res = handler(me, location, v);
413 #if defined(CONFIG_MMU) && defined(CONFIG_64BIT)
414 #define VMALLOC_MODULE_START \
415 max(PFN_ALIGN((unsigned long)&_end - SZ_2G), VMALLOC_START)
416 void *module_alloc(unsigned long size)
418 return __vmalloc_node_range(size, 1, VMALLOC_MODULE_START,
419 VMALLOC_END, GFP_KERNEL,
420 PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
421 __builtin_return_address(0));