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[linux/fpc-iii.git] / arch / riscv / include / asm / module.h
blob46202dad365d0631175998eec030194354cd4d57
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* Copyright (C) 2017 Andes Technology Corporation */
4 #ifndef _ASM_RISCV_MODULE_H
5 #define _ASM_RISCV_MODULE_H
7 #include <asm-generic/module.h>
9 #define MODULE_ARCH_VERMAGIC "riscv"
11 struct module;
12 unsigned long module_emit_got_entry(struct module *mod, unsigned long val);
13 unsigned long module_emit_plt_entry(struct module *mod, unsigned long val);
15 #ifdef CONFIG_MODULE_SECTIONS
16 struct mod_section {
17 Elf_Shdr *shdr;
18 int num_entries;
19 int max_entries;
22 struct mod_arch_specific {
23 struct mod_section got;
24 struct mod_section plt;
25 struct mod_section got_plt;
28 struct got_entry {
29 unsigned long symbol_addr; /* the real variable address */
32 static inline struct got_entry emit_got_entry(unsigned long val)
34 return (struct got_entry) {val};
37 static inline struct got_entry *get_got_entry(unsigned long val,
38 const struct mod_section *sec)
40 struct got_entry *got = (struct got_entry *)(sec->shdr->sh_addr);
41 int i;
42 for (i = 0; i < sec->num_entries; i++) {
43 if (got[i].symbol_addr == val)
44 return &got[i];
46 return NULL;
49 struct plt_entry {
51 * Trampoline code to real target address. The return address
52 * should be the original (pc+4) before entring plt entry.
54 u32 insn_auipc; /* auipc t0, 0x0 */
55 u32 insn_ld; /* ld t1, 0x10(t0) */
56 u32 insn_jr; /* jr t1 */
59 #define OPC_AUIPC 0x0017
60 #define OPC_LD 0x3003
61 #define OPC_JALR 0x0067
62 #define REG_T0 0x5
63 #define REG_T1 0x6
65 static inline struct plt_entry emit_plt_entry(unsigned long val,
66 unsigned long plt,
67 unsigned long got_plt)
70 * U-Type encoding:
71 * +------------+----------+----------+
72 * | imm[31:12] | rd[11:7] | opc[6:0] |
73 * +------------+----------+----------+
75 * I-Type encoding:
76 * +------------+------------+--------+----------+----------+
77 * | imm[31:20] | rs1[19:15] | funct3 | rd[11:7] | opc[6:0] |
78 * +------------+------------+--------+----------+----------+
81 unsigned long offset = got_plt - plt;
82 u32 hi20 = (offset + 0x800) & 0xfffff000;
83 u32 lo12 = (offset - hi20);
84 return (struct plt_entry) {
85 OPC_AUIPC | (REG_T0 << 7) | hi20,
86 OPC_LD | (lo12 << 20) | (REG_T0 << 15) | (REG_T1 << 7),
87 OPC_JALR | (REG_T1 << 15)
91 static inline int get_got_plt_idx(unsigned long val, const struct mod_section *sec)
93 struct got_entry *got_plt = (struct got_entry *)sec->shdr->sh_addr;
94 int i;
95 for (i = 0; i < sec->num_entries; i++) {
96 if (got_plt[i].symbol_addr == val)
97 return i;
99 return -1;
102 static inline struct plt_entry *get_plt_entry(unsigned long val,
103 const struct mod_section *sec_plt,
104 const struct mod_section *sec_got_plt)
106 struct plt_entry *plt = (struct plt_entry *)sec_plt->shdr->sh_addr;
107 int got_plt_idx = get_got_plt_idx(val, sec_got_plt);
108 if (got_plt_idx >= 0)
109 return plt + got_plt_idx;
110 else
111 return NULL;
114 #endif /* CONFIG_MODULE_SECTIONS */
116 #endif /* _ASM_RISCV_MODULE_H */