arch/arm64/include/asm/module.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Copyright (C) 2012 ARM Ltd.
   4  */
   5 #ifndef __ASM_MODULE_H
   6 #define __ASM_MODULE_H
   7
   8 #include <asm-generic/module.h>
   9
  10 struct mod_plt_sec {
  11         int                     plt_shndx;
  12         int                     plt_num_entries;
  13         int                     plt_max_entries;
  14 };
  15
  16 struct mod_arch_specific {
  17         struct mod_plt_sec      core;
  18         struct mod_plt_sec      init;
  19
  20         /* for CONFIG_DYNAMIC_FTRACE */
  21         struct plt_entry        *ftrace_trampolines;
  22 };
  23
  24 u64 module_emit_plt_entry(struct module *mod, Elf64_Shdr *sechdrs,
  25                           void *loc, const Elf64_Rela *rela,
  26                           Elf64_Sym *sym);
  27
  28 u64 module_emit_veneer_for_adrp(struct module *mod, Elf64_Shdr *sechdrs,
  29                                 void *loc, u64 val);
  30
  31 struct plt_entry {
  32         /*
  33          * A program that conforms to the AArch64 Procedure Call Standard
  34          * (AAPCS64) must assume that a veneer that alters IP0 (x16) and/or
  35          * IP1 (x17) may be inserted at any branch instruction that is
  36          * exposed to a relocation that supports long branches. Since that
  37          * is exactly what we are dealing with here, we are free to use x16
  38          * as a scratch register in the PLT veneers.
  39          */
  40         __le32  adrp;   /* adrp x16, ....                       */
  41         __le32  add;    /* add  x16, x16, #0x....               */
  42         __le32  br;     /* br   x16                             */
  43 };
  44
  45 static inline bool is_forbidden_offset_for_adrp(void *place)
  46 {
  47         return cpus_have_final_cap(ARM64_WORKAROUND_843419) &&
  48                ((u64)place & 0xfff) >= 0xff8;
  49 }
  50
  51 struct plt_entry get_plt_entry(u64 dst, void *pc);
  52
  53 static inline const Elf_Shdr *find_section(const Elf_Ehdr *hdr,
  54                                     const Elf_Shdr *sechdrs,
  55                                     const char *name)
  56 {
  57         const Elf_Shdr *s, *se;
  58         const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
  59
  60         for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) {
  61                 if (strcmp(name, secstrs + s->sh_name) == 0)
  62                         return s;
  63         }
  64
  65         return NULL;
  66 }
  67
  68 #endif /* __ASM_MODULE_H */