include/linux/moduleloader.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_MODULELOADER_H
   3 #define _LINUX_MODULELOADER_H
   4 /* The stuff needed for archs to support modules. */
   5
   6 #include <linux/module.h>
   7 #include <linux/elf.h>
   8
   9 /* These may be implemented by architectures that need to hook into the
  10  * module loader code.  Architectures that don't need to do anything special
  11  * can just rely on the 'weak' default hooks defined in kernel/module.c.
  12  * Note, however, that at least one of apply_relocate or apply_relocate_add
  13  * must be implemented by each architecture.
  14  */
  15
  16 /* arch may override to do additional checking of ELF header architecture */
  17 bool module_elf_check_arch(Elf_Ehdr *hdr);
  18
  19 /* Adjust arch-specific sections.  Return 0 on success.  */
  20 int module_frob_arch_sections(Elf_Ehdr *hdr,
  21                               Elf_Shdr *sechdrs,
  22                               char *secstrings,
  23                               struct module *mod);
  24
  25 /* Additional bytes needed by arch in front of individual sections */
  26 unsigned int arch_mod_section_prepend(struct module *mod, unsigned int section);
  27
  28 /* Determines if the section name is an init section (that is only used during
  29  * module loading).
  30  */
  31 bool module_init_section(const char *name);
  32
  33 /* Determines if the section name is an exit section (that is only used during
  34  * module unloading)
  35  */
  36 bool module_exit_section(const char *name);
  37
  38 /* Describes whether within_module_init() will consider this an init section
  39  * or not. This behaviour changes with CONFIG_MODULE_UNLOAD.
  40  */
  41 bool module_init_layout_section(const char *sname);
  42
  43 /*
  44  * Apply the given relocation to the (simplified) ELF.  Return -error
  45  * or 0.
  46  */
  47 #ifdef CONFIG_MODULES_USE_ELF_REL
  48 int apply_relocate(Elf_Shdr *sechdrs,
  49                    const char *strtab,
  50                    unsigned int symindex,
  51                    unsigned int relsec,
  52                    struct module *mod);
  53 #else
  54 static inline int apply_relocate(Elf_Shdr *sechdrs,
  55                                  const char *strtab,
  56                                  unsigned int symindex,
  57                                  unsigned int relsec,
  58                                  struct module *me)
  59 {
  60         printk(KERN_ERR "module %s: REL relocation unsupported\n",
  61                module_name(me));
  62         return -ENOEXEC;
  63 }
  64 #endif
  65
  66 /*
  67  * Apply the given add relocation to the (simplified) ELF.  Return
  68  * -error or 0
  69  */
  70 #ifdef CONFIG_MODULES_USE_ELF_RELA
  71 int apply_relocate_add(Elf_Shdr *sechdrs,
  72                        const char *strtab,
  73                        unsigned int symindex,
  74                        unsigned int relsec,
  75                        struct module *mod);
  76 #ifdef CONFIG_LIVEPATCH
  77 /*
  78  * Some architectures (namely x86_64 and ppc64) perform sanity checks when
  79  * applying relocations.  If a patched module gets unloaded and then later
  80  * reloaded (and re-patched), klp re-applies relocations to the replacement
  81  * function(s).  Any leftover relocations from the previous loading of the
  82  * patched module might trigger the sanity checks.
  83  *
  84  * To prevent that, when unloading a patched module, clear out any relocations
  85  * that might trigger arch-specific sanity checks on a future module reload.
  86  */
  87 void clear_relocate_add(Elf_Shdr *sechdrs,
  88                    const char *strtab,
  89                    unsigned int symindex,
  90                    unsigned int relsec,
  91                    struct module *me);
  92 #endif
  93 #else
  94 static inline int apply_relocate_add(Elf_Shdr *sechdrs,
  95                                      const char *strtab,
  96                                      unsigned int symindex,
  97                                      unsigned int relsec,
  98                                      struct module *me)
  99 {
 100         printk(KERN_ERR "module %s: REL relocation unsupported\n",
 101                module_name(me));
 102         return -ENOEXEC;
 103 }
 104 #endif
 105
 106 /* Any final processing of module before access.  Return -error or 0. */
 107 int module_finalize(const Elf_Ehdr *hdr,
 108                     const Elf_Shdr *sechdrs,
 109                     struct module *mod);
 110
 111 int module_post_finalize(const Elf_Ehdr *hdr,
 112                          const Elf_Shdr *sechdrs,
 113                          struct module *mod);
 114
 115 #ifdef CONFIG_MODULES
 116 void flush_module_init_free_work(void);
 117 #else
 118 static inline void flush_module_init_free_work(void)
 119 {
 120 }
 121 #endif
 122
 123 /* Any cleanup needed when module leaves. */
 124 void module_arch_cleanup(struct module *mod);
 125
 126 /* Any cleanup before freeing mod->module_init */
 127 void module_arch_freeing_init(struct module *mod);
 128
 129 #endif