1 // SPDX-License-Identifier: GPL-2.0+
3 * Copyright (C) 2017 Andes Technology
4 * Chih-Mao Chen <cmchen@andestech.com>
6 * Statically process runtime relocations on RISC-V ELF images
7 * so that it can be directly executed when loaded at LMA
8 * without fixup. Both RV32 and RV64 are supported.
11 #define CONCAT_IMPL(x, y) x##y
12 #define CONCAT(x, y) CONCAT_IMPL(x, y)
13 #define CONCAT3(x, y, z) CONCAT(CONCAT(x, y), z)
15 #define prelink_nn CONCAT(prelink, PRELINK_INC_BITS)
16 #define uintnn_t CONCAT3(uint, PRELINK_INC_BITS, _t)
17 #define get_offset_nn CONCAT(get_offset_, PRELINK_INC_BITS)
18 #define Elf_Ehdr CONCAT3(Elf, PRELINK_INC_BITS, _Ehdr)
19 #define Elf_Phdr CONCAT3(Elf, PRELINK_INC_BITS, _Phdr)
20 #define Elf_Rela CONCAT3(Elf, PRELINK_INC_BITS, _Rela)
21 #define Elf_Sym CONCAT3(Elf, PRELINK_INC_BITS, _Sym)
22 #define Elf_Dyn CONCAT3(Elf, PRELINK_INC_BITS, _Dyn)
23 #define Elf_Addr CONCAT3(Elf, PRELINK_INC_BITS, _Addr)
24 #define ELF_R_TYPE CONCAT3(ELF, PRELINK_INC_BITS, _R_TYPE)
25 #define ELF_R_SYM CONCAT3(ELF, PRELINK_INC_BITS, _R_SYM)
26 #define lenn_to_cpu CONCAT3(le, PRELINK_INC_BITS, _to_cpu)
28 static void* get_offset_nn (void* data, Elf_Phdr* phdrs, size_t phnum, Elf_Addr addr)
32 for (p = phdrs; p < phdrs + phnum; ++p)
33 if (lenn_to_cpu(p->p_vaddr) <= addr && lenn_to_cpu(p->p_vaddr) + lenn_to_cpu(p->p_memsz) > addr)
34 return data + lenn_to_cpu(p->p_offset) + (addr - lenn_to_cpu(p->p_vaddr));
39 static void prelink_nn(void *data)
41 Elf_Ehdr *ehdr = data;
46 if (le16_to_cpu(ehdr->e_machine) != EM_RISCV)
47 die("Machine type is not RISC-V");
49 Elf_Phdr *phdrs = data + lenn_to_cpu(ehdr->e_phoff);
52 for (p = phdrs; p < phdrs + le16_to_cpu(ehdr->e_phnum); ++p) {
53 if (le32_to_cpu(p->p_type) == PT_DYNAMIC) {
54 dyns = data + lenn_to_cpu(p->p_offset);
60 die("No dynamic section found");
62 Elf_Rela *rela_dyn = NULL;
63 size_t rela_count = 0;
64 Elf_Sym *dynsym = NULL;
65 for (dyn = dyns;; ++dyn) {
66 if (lenn_to_cpu(dyn->d_tag) == DT_NULL)
68 else if (lenn_to_cpu(dyn->d_tag) == DT_RELA)
69 rela_dyn = get_offset_nn(data, phdrs, le16_to_cpu(ehdr->e_phnum), + lenn_to_cpu(dyn->d_un.d_ptr));
70 else if (lenn_to_cpu(dyn->d_tag) == DT_RELASZ)
71 rela_count = lenn_to_cpu(dyn->d_un.d_val) / sizeof(Elf_Rela);
72 else if (lenn_to_cpu(dyn->d_tag) == DT_SYMTAB)
73 dynsym = get_offset_nn(data, phdrs, le16_to_cpu(ehdr->e_phnum), + lenn_to_cpu(dyn->d_un.d_ptr));
78 die("No .rela.dyn found");
81 die("No .dynsym found");
83 for (r = rela_dyn; r < rela_dyn + rela_count; ++r) {
84 void* buf = get_offset_nn(data, phdrs, le16_to_cpu(ehdr->e_phnum), lenn_to_cpu(r->r_offset));
89 if (ELF_R_TYPE(lenn_to_cpu(r->r_info)) == R_RISCV_RELATIVE)
90 *((uintnn_t*) buf) = r->r_addend;
91 else if (ELF_R_TYPE(lenn_to_cpu(r->r_info)) == R_RISCV_32)
92 *((uint32_t*) buf) = dynsym[ELF_R_SYM(lenn_to_cpu(r->r_info))].st_value;
93 else if (ELF_R_TYPE(lenn_to_cpu(r->r_info)) == R_RISCV_64)
94 *((uint64_t*) buf) = dynsym[ELF_R_SYM(lenn_to_cpu(r->r_info))].st_value;