blob: c07d930f7ed24da4f16409565fdca03b06a4492f [file] [log] [blame]
Rick Chen42ac26f2017-12-26 13:55:56 +08001/*
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
28static 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
39static 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