/* * Copyright (C) 2017 Andes Technology * Chih-Mao Chen * * SPDX-License-Identifier: GPL-2.0+ * * Statically process runtime relocations on RISC-V ELF images * so that it can be directly executed when loaded at LMA * without fixup. Both RV32 and RV64 are supported. */ #define CONCAT_IMPL(x, y) x##y #define CONCAT(x, y) CONCAT_IMPL(x, y) #define CONCAT3(x, y, z) CONCAT(CONCAT(x, y), z) #define prelink_nn CONCAT(prelink, PRELINK_INC_BITS) #define uintnn_t CONCAT3(uint, PRELINK_INC_BITS, _t) #define get_offset_nn CONCAT(get_offset_, PRELINK_INC_BITS) #define Elf_Ehdr CONCAT3(Elf, PRELINK_INC_BITS, _Ehdr) #define Elf_Phdr CONCAT3(Elf, PRELINK_INC_BITS, _Phdr) #define Elf_Rela CONCAT3(Elf, PRELINK_INC_BITS, _Rela) #define Elf_Sym CONCAT3(Elf, PRELINK_INC_BITS, _Sym) #define Elf_Dyn CONCAT3(Elf, PRELINK_INC_BITS, _Dyn) #define Elf_Addr CONCAT3(Elf, PRELINK_INC_BITS, _Addr) #define ELF_R_TYPE CONCAT3(ELF, PRELINK_INC_BITS, _R_TYPE) #define ELF_R_SYM CONCAT3(ELF, PRELINK_INC_BITS, _R_SYM) static void* get_offset_nn (void* data, Elf_Phdr* phdrs, size_t phnum, Elf_Addr addr) { Elf_Phdr *p; for (p = phdrs; p < phdrs + phnum; ++p) if (p->p_vaddr <= addr && p->p_vaddr + p->p_memsz > addr) return data + p->p_offset + (addr - p->p_vaddr); return NULL; } static void prelink_nn(void *data) { Elf_Ehdr *ehdr = data; Elf_Phdr *p; Elf_Dyn *dyn; Elf_Rela *r; if (ehdr->e_machine != EM_RISCV) die("Machine type is not RISC-V"); Elf_Phdr *phdrs = data + ehdr->e_phoff; Elf_Dyn *dyns = NULL; for (p = phdrs; p < phdrs + ehdr->e_phnum; ++p) { if (p->p_type == PT_DYNAMIC) { dyns = data + p->p_offset; break; } } if (dyns == NULL) die("No dynamic section found"); Elf_Rela *rela_dyn = NULL; size_t rela_count = 0; Elf_Sym *dynsym = NULL; for (dyn = dyns;; ++dyn) { if (dyn->d_tag == DT_NULL) break; else if (dyn->d_tag == DT_RELA) rela_dyn = get_offset_nn(data, phdrs, ehdr->e_phnum, + dyn->d_un.d_ptr); else if (dyn->d_tag == DT_RELASZ) rela_count = dyn->d_un.d_val / sizeof(Elf_Rela); else if (dyn->d_tag == DT_SYMTAB) dynsym = get_offset_nn(data, phdrs, ehdr->e_phnum, + dyn->d_un.d_ptr); } if (rela_dyn == NULL) die("No .rela.dyn found"); if (dynsym == NULL) die("No .dynsym found"); for (r = rela_dyn; r < rela_dyn + rela_count; ++r) { void* buf = get_offset_nn(data, phdrs, ehdr->e_phnum, r->r_offset); if (buf == NULL) continue; if (ELF_R_TYPE(r->r_info) == R_RISCV_RELATIVE) *((uintnn_t*) buf) = r->r_addend; else if (ELF_R_TYPE(r->r_info) == R_RISCV_32) *((uint32_t*) buf) = dynsym[ELF_R_SYM(r->r_info)].st_value; else if (ELF_R_TYPE(r->r_info) == R_RISCV_64) *((uint64_t*) buf) = dynsym[ELF_R_SYM(r->r_info)].st_value; } } #undef prelink_nn #undef uintnn_t #undef get_offset_nn #undef Elf_Ehdr #undef Elf_Phdr #undef Elf_Rela #undef Elf_Sym #undef Elf_Dyn #undef Elf_Addr #undef ELF_R_TYPE #undef ELF_R_SYM #undef CONCAT_IMPL #undef CONCAT #undef CONCAT3