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 struct module; 10 unsigned long module_emit_got_entry(struct module *mod, unsigned long val); 11 unsigned long module_emit_plt_entry(struct module *mod, unsigned long val); 12 13 #ifdef CONFIG_MODULE_SECTIONS 14 struct mod_section { 15 Elf_Shdr *shdr; 16 int num_entries; 17 int max_entries; 18 }; 19 20 struct mod_arch_specific { 21 struct mod_section got; 22 struct mod_section plt; 23 struct mod_section got_plt; 24 }; 25 26 struct got_entry { 27 unsigned long symbol_addr; /* the real variable address */ 28 }; 29 30 static inline struct got_entry emit_got_entry(unsigned long val) 31 { 32 return (struct got_entry) {val}; 33 } 34 35 static inline struct got_entry *get_got_entry(unsigned long val, 36 const struct mod_section *sec) 37 { 38 struct got_entry *got = (struct got_entry *)(sec->shdr->sh_addr); 39 int i; 40 for (i = 0; i < sec->num_entries; i++) { 41 if (got[i].symbol_addr == val) 42 return &got[i]; 43 } 44 return NULL; 45 } 46 47 struct plt_entry { 48 /* 49 * Trampoline code to real target address. The return address 50 * should be the original (pc+4) before entring plt entry. 51 */ 52 u32 insn_auipc; /* auipc t0, 0x0 */ 53 u32 insn_ld; /* ld t1, 0x10(t0) */ 54 u32 insn_jr; /* jr t1 */ 55 }; 56 57 #define OPC_AUIPC 0x0017 58 #define OPC_LD 0x3003 59 #define OPC_JALR 0x0067 60 #define REG_T0 0x5 61 #define REG_T1 0x6 62 63 static inline struct plt_entry emit_plt_entry(unsigned long val, 64 unsigned long plt, 65 unsigned long got_plt) 66 { 67 /* 68 * U-Type encoding: 69 * +------------+----------+----------+ 70 * | imm[31:12] | rd[11:7] | opc[6:0] | 71 * +------------+----------+----------+ 72 * 73 * I-Type encoding: 74 * +------------+------------+--------+----------+----------+ 75 * | imm[31:20] | rs1[19:15] | funct3 | rd[11:7] | opc[6:0] | 76 * +------------+------------+--------+----------+----------+ 77 * 78 */ 79 unsigned long offset = got_plt - plt; 80 u32 hi20 = (offset + 0x800) & 0xfffff000; 81 u32 lo12 = (offset - hi20); 82 return (struct plt_entry) { 83 OPC_AUIPC | (REG_T0 << 7) | hi20, 84 OPC_LD | (lo12 << 20) | (REG_T0 << 15) | (REG_T1 << 7), 85 OPC_JALR | (REG_T1 << 15) 86 }; 87 } 88 89 static inline int get_got_plt_idx(unsigned long val, const struct mod_section *sec) 90 { 91 struct got_entry *got_plt = (struct got_entry *)sec->shdr->sh_addr; 92 int i; 93 for (i = 0; i < sec->num_entries; i++) { 94 if (got_plt[i].symbol_addr == val) 95 return i; 96 } 97 return -1; 98 } 99 100 static inline struct plt_entry *get_plt_entry(unsigned long val, 101 const struct mod_section *sec_plt, 102 const struct mod_section *sec_got_plt) 103 { 104 struct plt_entry *plt = (struct plt_entry *)sec_plt->shdr->sh_addr; 105 int got_plt_idx = get_got_plt_idx(val, sec_got_plt); 106 if (got_plt_idx >= 0) 107 return plt + got_plt_idx; 108 else 109 return NULL; 110 } 111 112 #endif /* CONFIG_MODULE_SECTIONS */ 113 114 #endif /* _ASM_RISCV_MODULE_H */ 115