| Rick Chen | 93fa563 | 2017-12-26 13:55:56 +0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2017 Andes Technology |
| 3 | * Chih-Mao Chen <cmchen@andestech.com> |
| 4 | * |
| 5 | * SPDX-License-Identifier: GPL-2.0+ |
| 6 | * |
| 7 | * Statically process runtime relocations on RISC-V ELF images |
| 8 | * so that it can be directly executed when loaded at LMA |
| 9 | * without fixup. Both RV32 and RV64 are supported. |
| 10 | */ |
| 11 | |
| 12 | #define CONCAT_IMPL(x, y) x##y |
| 13 | #define CONCAT(x, y) CONCAT_IMPL(x, y) |
| 14 | #define CONCAT3(x, y, z) CONCAT(CONCAT(x, y), z) |
| 15 | |
| 16 | #define prelink_nn CONCAT(prelink, PRELINK_INC_BITS) |
| 17 | #define uintnn_t CONCAT3(uint, PRELINK_INC_BITS, _t) |
| 18 | #define get_offset_nn CONCAT(get_offset_, PRELINK_INC_BITS) |
| 19 | #define Elf_Ehdr CONCAT3(Elf, PRELINK_INC_BITS, _Ehdr) |
| 20 | #define Elf_Phdr CONCAT3(Elf, PRELINK_INC_BITS, _Phdr) |
| 21 | #define Elf_Rela CONCAT3(Elf, PRELINK_INC_BITS, _Rela) |
| 22 | #define Elf_Sym CONCAT3(Elf, PRELINK_INC_BITS, _Sym) |
| 23 | #define Elf_Dyn CONCAT3(Elf, PRELINK_INC_BITS, _Dyn) |
| 24 | #define Elf_Addr CONCAT3(Elf, PRELINK_INC_BITS, _Addr) |
| 25 | #define ELF_R_TYPE CONCAT3(ELF, PRELINK_INC_BITS, _R_TYPE) |
| 26 | #define ELF_R_SYM CONCAT3(ELF, PRELINK_INC_BITS, _R_SYM) |
| 27 | |
| 28 | static void* get_offset_nn (void* data, Elf_Phdr* phdrs, size_t phnum, Elf_Addr addr) |
| 29 | { |
| 30 | Elf_Phdr *p; |
| 31 | |
| 32 | for (p = phdrs; p < phdrs + phnum; ++p) |
| 33 | if (p->p_vaddr <= addr && p->p_vaddr + p->p_memsz > addr) |
| 34 | return data + p->p_offset + (addr - p->p_vaddr); |
| 35 | |
| 36 | return NULL; |
| 37 | } |
| 38 | |
| 39 | static void prelink_nn(void *data) |
| 40 | { |
| 41 | Elf_Ehdr *ehdr = data; |
| 42 | Elf_Phdr *p; |
| 43 | Elf_Dyn *dyn; |
| 44 | Elf_Rela *r; |
| 45 | |
| 46 | if (ehdr->e_machine != EM_RISCV) |
| 47 | die("Machine type is not RISC-V"); |
| 48 | |
| 49 | Elf_Phdr *phdrs = data + ehdr->e_phoff; |
| 50 | |
| 51 | Elf_Dyn *dyns = NULL; |
| 52 | for (p = phdrs; p < phdrs + ehdr->e_phnum; ++p) { |
| 53 | if (p->p_type == PT_DYNAMIC) { |
| 54 | dyns = data + p->p_offset; |
| 55 | break; |
| 56 | } |
| 57 | } |
| 58 | |
| 59 | if (dyns == NULL) |
| 60 | die("No dynamic section found"); |
| 61 | |
| 62 | Elf_Rela *rela_dyn = NULL; |
| 63 | size_t rela_count = 0; |
| 64 | Elf_Sym *dynsym = NULL; |
| 65 | for (dyn = dyns;; ++dyn) { |
| 66 | if (dyn->d_tag == DT_NULL) |
| 67 | break; |
| 68 | else if (dyn->d_tag == DT_RELA) |
| 69 | rela_dyn = get_offset_nn(data, phdrs, ehdr->e_phnum, + dyn->d_un.d_ptr); |
| 70 | else if (dyn->d_tag == DT_RELASZ) |
| 71 | rela_count = dyn->d_un.d_val / sizeof(Elf_Rela); |
| 72 | else if (dyn->d_tag == DT_SYMTAB) |
| 73 | dynsym = get_offset_nn(data, phdrs, ehdr->e_phnum, + dyn->d_un.d_ptr); |
| 74 | |
| 75 | } |
| 76 | |
| 77 | if (rela_dyn == NULL) |
| 78 | die("No .rela.dyn found"); |
| 79 | |
| 80 | if (dynsym == NULL) |
| 81 | die("No .dynsym found"); |
| 82 | |
| 83 | for (r = rela_dyn; r < rela_dyn + rela_count; ++r) { |
| 84 | void* buf = get_offset_nn(data, phdrs, ehdr->e_phnum, r->r_offset); |
| 85 | |
| 86 | if (buf == NULL) |
| 87 | continue; |
| 88 | |
| 89 | if (ELF_R_TYPE(r->r_info) == R_RISCV_RELATIVE) |
| 90 | *((uintnn_t*) buf) = r->r_addend; |
| 91 | else if (ELF_R_TYPE(r->r_info) == R_RISCV_32) |
| 92 | *((uint32_t*) buf) = dynsym[ELF_R_SYM(r->r_info)].st_value; |
| 93 | else if (ELF_R_TYPE(r->r_info) == R_RISCV_64) |
| 94 | *((uint64_t*) buf) = dynsym[ELF_R_SYM(r->r_info)].st_value; |
| 95 | } |
| 96 | } |
| 97 | |
| 98 | #undef prelink_nn |
| 99 | #undef uintnn_t |
| 100 | #undef get_offset_nn |
| 101 | #undef Elf_Ehdr |
| 102 | #undef Elf_Phdr |
| 103 | #undef Elf_Rela |
| 104 | #undef Elf_Sym |
| 105 | #undef Elf_Dyn |
| 106 | #undef Elf_Addr |
| 107 | #undef ELF_R_TYPE |
| 108 | #undef ELF_R_SYM |
| 109 | |
| 110 | #undef CONCAT_IMPL |
| 111 | #undef CONCAT |
| 112 | #undef CONCAT3 |