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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 | /* SPDX-License-Identifier: GPL-2.0 */ /* Copyright (C) 2017 Andes Technology Corporation */ #ifndef _ASM_RISCV_MODULE_H #define _ASM_RISCV_MODULE_H #include <asm-generic/module.h> #include <linux/elf.h> struct module; unsigned long module_emit_got_entry(struct module *mod, unsigned long val); unsigned long module_emit_plt_entry(struct module *mod, unsigned long val); #ifdef CONFIG_MODULE_SECTIONS struct mod_section { Elf_Shdr *shdr; int num_entries; int max_entries; }; struct mod_arch_specific { struct mod_section got; struct mod_section plt; struct mod_section got_plt; }; struct got_entry { unsigned long symbol_addr; /* the real variable address */ }; static inline struct got_entry emit_got_entry(unsigned long val) { return (struct got_entry) {val}; } static inline struct got_entry *get_got_entry(unsigned long val, const struct mod_section *sec) { struct got_entry *got = (struct got_entry *)(sec->shdr->sh_addr); int i; for (i = 0; i < sec->num_entries; i++) { if (got[i].symbol_addr == val) return &got[i]; } return NULL; } struct plt_entry { /* * Trampoline code to real target address. The return address * should be the original (pc+4) before entring plt entry. */ u32 insn_auipc; /* auipc t0, 0x0 */ u32 insn_ld; /* ld t1, 0x10(t0) */ u32 insn_jr; /* jr t1 */ }; #define OPC_AUIPC 0x0017 #define OPC_LD 0x3003 #define OPC_JALR 0x0067 #define REG_T0 0x5 #define REG_T1 0x6 static inline struct plt_entry emit_plt_entry(unsigned long val, unsigned long plt, unsigned long got_plt) { /* * U-Type encoding: * +------------+----------+----------+ * | imm[31:12] | rd[11:7] | opc[6:0] | * +------------+----------+----------+ * * I-Type encoding: * +------------+------------+--------+----------+----------+ * | imm[31:20] | rs1[19:15] | funct3 | rd[11:7] | opc[6:0] | * +------------+------------+--------+----------+----------+ * */ unsigned long offset = got_plt - plt; u32 hi20 = (offset + 0x800) & 0xfffff000; u32 lo12 = (offset - hi20); return (struct plt_entry) { OPC_AUIPC | (REG_T0 << 7) | hi20, OPC_LD | (lo12 << 20) | (REG_T0 << 15) | (REG_T1 << 7), OPC_JALR | (REG_T1 << 15) }; } static inline int get_got_plt_idx(unsigned long val, const struct mod_section *sec) { struct got_entry *got_plt = (struct got_entry *)sec->shdr->sh_addr; int i; for (i = 0; i < sec->num_entries; i++) { if (got_plt[i].symbol_addr == val) return i; } return -1; } static inline struct plt_entry *get_plt_entry(unsigned long val, const struct mod_section *sec_plt, const struct mod_section *sec_got_plt) { struct plt_entry *plt = (struct plt_entry *)sec_plt->shdr->sh_addr; int got_plt_idx = get_got_plt_idx(val, sec_got_plt); if (got_plt_idx >= 0) return plt + got_plt_idx; else return NULL; } #endif /* CONFIG_MODULE_SECTIONS */ static inline const Elf_Shdr *find_section(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, const char *name) { const Elf_Shdr *s, *se; const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) { if (strcmp(name, secstrs + s->sh_name) == 0) return s; } return NULL; } #endif /* _ASM_RISCV_MODULE_H */ |