1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* Copyright (C) 2017 Andes Technology Corporation */ 3 4 #ifndef _ASM_RISCV_MODULE_H 5 #define _ASM_RISCV_MODULE_H 6 7 #include <asm-generic/module.h> 8 9 #define MODULE_ARCH_VERMAGIC "riscv" 10 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); 14 15 #ifdef CONFIG_MODULE_SECTIONS 16 struct mod_section { 17 Elf_Shdr *shdr; 18 int num_entries; 19 int max_entries; 20 }; 21 22 struct mod_arch_specific { 23 struct mod_section got; 24 struct mod_section plt; 25 struct mod_section got_plt; 26 }; 27 28 struct got_entry { 29 unsigned long symbol_addr; /* the real variable address */ 30 }; 31 32 static inline struct got_entry emit_got_entry(unsigned long val) 33 { 34 return (struct got_entry) {val}; 35 } 36 37 static inline struct got_entry *get_got_entry(unsigned long val, 38 const struct mod_section *sec) 39 { 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]; 45 } 46 return NULL; 47 } 48 49 struct plt_entry { 50 /* 51 * Trampoline code to real target address. The return address 52 * should be the original (pc+4) before entring plt entry. 53 */ 54 u32 insn_auipc; /* auipc t0, 0x0 */ 55 u32 insn_ld; /* ld t1, 0x10(t0) */ 56 u32 insn_jr; /* jr t1 */ 57 }; 58 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 64 65 static inline struct plt_entry emit_plt_entry(unsigned long val, 66 unsigned long plt, 67 unsigned long got_plt) 68 { 69 /* 70 * U-Type encoding: 71 * +------------+----------+----------+ 72 * | imm[31:12] | rd[11:7] | opc[6:0] | 73 * +------------+----------+----------+ 74 * 75 * I-Type encoding: 76 * +------------+------------+--------+----------+----------+ 77 * | imm[31:20] | rs1[19:15] | funct3 | rd[11:7] | opc[6:0] | 78 * +------------+------------+--------+----------+----------+ 79 * 80 */ 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) 88 }; 89 } 90 91 static inline int get_got_plt_idx(unsigned long val, const struct mod_section *sec) 92 { 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; 98 } 99 return -1; 100 } 101 102 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) 105 { 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; 112 } 113 114 #endif /* CONFIG_MODULE_SECTIONS */ 115 116 #endif /* _ASM_RISCV_MODULE_H */ 117