/* 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> #define MODULE_ARCH_VERMAGIC "riscv" 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 */ #endif /* _ASM_RISCV_MODULE_H */