tools/prelink-riscv.inc

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2017 Andes Technology
   4  * Chih-Mao Chen <cmchen@andestech.com>
   5  *
   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.
   9  */
  10
  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)
  14
  15 #define prelink_bonn    CONCAT3(prelink_, PRELINK_BYTEORDER, PRELINK_INC_BITS)
  16 #define uintnn_t        CONCAT3(uint, PRELINK_INC_BITS, _t)
  17 #define get_offset_bonn CONCAT3(get_offset_, PRELINK_BYTEORDER, 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 target16_to_cpu CONCAT(PRELINK_BYTEORDER, 16_to_cpu)
  27 #define target32_to_cpu CONCAT(PRELINK_BYTEORDER, 32_to_cpu)
  28 #define target64_to_cpu CONCAT(PRELINK_BYTEORDER, 64_to_cpu)
  29 #define targetnn_to_cpu CONCAT3(PRELINK_BYTEORDER, PRELINK_INC_BITS, _to_cpu)
  30
  31 static void* get_offset_bonn (void* data, Elf_Phdr* phdrs, size_t phnum, Elf_Addr addr)
  32 {
  33         Elf_Phdr *p;
  34
  35         for (p = phdrs; p < phdrs + phnum; ++p)
  36                 if (targetnn_to_cpu(p->p_vaddr) <= addr && targetnn_to_cpu(p->p_vaddr) + targetnn_to_cpu(p->p_memsz) > addr)
  37                         return data + targetnn_to_cpu(p->p_offset) + (addr - targetnn_to_cpu(p->p_vaddr));
  38
  39         return NULL;
  40 }
  41
  42 static void prelink_bonn(void *data)
  43 {
  44         Elf_Ehdr *ehdr = data;
  45         Elf_Phdr *p;
  46         Elf_Dyn *dyn;
  47         Elf_Rela *r;
  48
  49         if (target16_to_cpu(ehdr->e_machine) != EM_RISCV)
  50                 die("Machine type is not RISC-V");
  51
  52         Elf_Phdr *phdrs = data + targetnn_to_cpu(ehdr->e_phoff);
  53
  54         Elf_Dyn *dyns = NULL;
  55         for (p = phdrs; p < phdrs + target16_to_cpu(ehdr->e_phnum); ++p) {
  56                 if (target32_to_cpu(p->p_type) == PT_DYNAMIC) {
  57                         dyns = data + targetnn_to_cpu(p->p_offset);
  58                         break;
  59                 }
  60         }
  61
  62         if (dyns == NULL)
  63                 die("No dynamic section found");
  64
  65         Elf_Rela *rela_dyn = NULL;
  66         size_t rela_count = 0;
  67         Elf_Sym *dynsym = NULL;
  68         for (dyn = dyns;; ++dyn) {
  69                 if (targetnn_to_cpu(dyn->d_tag) == DT_NULL)
  70                         break;
  71                 else if (targetnn_to_cpu(dyn->d_tag) == DT_RELA)
  72                         rela_dyn = get_offset_bonn(data, phdrs, target16_to_cpu(ehdr->e_phnum), + targetnn_to_cpu(dyn->d_un.d_ptr));
  73                 else if (targetnn_to_cpu(dyn->d_tag) == DT_RELASZ)
  74                   rela_count = targetnn_to_cpu(dyn->d_un.d_val) / sizeof(Elf_Rela);
  75                 else if (targetnn_to_cpu(dyn->d_tag) == DT_SYMTAB)
  76                         dynsym = get_offset_bonn(data, phdrs, target16_to_cpu(ehdr->e_phnum), + targetnn_to_cpu(dyn->d_un.d_ptr));
  77
  78         }
  79
  80         if (rela_dyn == NULL)
  81                 die("No .rela.dyn found");
  82
  83         if (dynsym == NULL)
  84                 die("No .dynsym found");
  85
  86         for (r = rela_dyn; r < rela_dyn + rela_count; ++r) {
  87                 void* buf = get_offset_bonn(data, phdrs, target16_to_cpu(ehdr->e_phnum), targetnn_to_cpu(r->r_offset));
  88
  89                 if (buf == NULL)
  90                         continue;
  91
  92                 if (ELF_R_TYPE(targetnn_to_cpu(r->r_info)) == R_RISCV_RELATIVE)
  93                         *((uintnn_t*) buf) = r->r_addend;
  94                 else if (ELF_R_TYPE(targetnn_to_cpu(r->r_info)) == R_RISCV_32)
  95                         *((uint32_t*) buf) = dynsym[ELF_R_SYM(targetnn_to_cpu(r->r_info))].st_value;
  96                 else if (ELF_R_TYPE(targetnn_to_cpu(r->r_info)) == R_RISCV_64)
  97                         *((uint64_t*) buf) = dynsym[ELF_R_SYM(targetnn_to_cpu(r->r_info))].st_value;
  98         }
  99 }
 100
 101 #undef prelink_bonn
 102 #undef uintnn_t
 103 #undef get_offset_bonn
 104 #undef Elf_Ehdr
 105 #undef Elf_Phdr
 106 #undef Elf_Rela
 107 #undef Elf_Sym
 108 #undef Elf_Dyn
 109 #undef Elf_Addr
 110 #undef ELF_R_TYPE
 111 #undef ELF_R_SYM
 112 #undef target16_to_cpu
 113 #undef target32_to_cpu
 114 #undef target64_to_cpu
 115 #undef targetnn_to_cpu
 116
 117 #undef CONCAT_IMPL
 118 #undef CONCAT
 119 #undef CONCAT3