include/linux/codetag.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * code tagging framework
   4  */
   5 #ifndef _LINUX_CODETAG_H
   6 #define _LINUX_CODETAG_H
   7
   8 #include <linux/types.h>
   9
  10 struct codetag_iterator;
  11 struct codetag_type;
  12 struct codetag_module;
  13 struct seq_buf;
  14 struct module;
  15
  16 #define CODETAG_SECTION_START_PREFIX    "__start_"
  17 #define CODETAG_SECTION_STOP_PREFIX     "__stop_"
  18
  19 /*
  20  * An instance of this structure is created in a special ELF section at every
  21  * code location being tagged.  At runtime, the special section is treated as
  22  * an array of these.
  23  */
  24 struct codetag {
  25         unsigned int flags; /* used in later patches */
  26         unsigned int lineno;
  27         const char *modname;
  28         const char *function;
  29         const char *filename;
  30 } __aligned(8);
  31
  32 union codetag_ref {
  33         struct codetag *ct;
  34 };
  35
  36 struct codetag_type_desc {
  37         const char *section;
  38         size_t tag_size;
  39         void (*module_load)(struct codetag_type *cttype,
  40                             struct codetag_module *cmod);
  41         void (*module_unload)(struct codetag_type *cttype,
  42                               struct codetag_module *cmod);
  43 #ifdef CONFIG_MODULES
  44         void (*module_replaced)(struct module *mod, struct module *new_mod);
  45         bool (*needs_section_mem)(struct module *mod, unsigned long size);
  46         void *(*alloc_section_mem)(struct module *mod, unsigned long size,
  47                                    unsigned int prepend, unsigned long align);
  48         void (*free_section_mem)(struct module *mod, bool used);
  49 #endif
  50 };
  51
  52 struct codetag_iterator {
  53         struct codetag_type *cttype;
  54         struct codetag_module *cmod;
  55         unsigned long mod_id;
  56         struct codetag *ct;
  57 };
  58
  59 #ifdef MODULE
  60 #define CT_MODULE_NAME KBUILD_MODNAME
  61 #else
  62 #define CT_MODULE_NAME NULL
  63 #endif
  64
  65 #define CODE_TAG_INIT {                                 \
  66         .modname        = CT_MODULE_NAME,               \
  67         .function       = __func__,                     \
  68         .filename       = __FILE__,                     \
  69         .lineno         = __LINE__,                     \
  70         .flags          = 0,                            \
  71 }
  72
  73 void codetag_lock_module_list(struct codetag_type *cttype, bool lock);
  74 bool codetag_trylock_module_list(struct codetag_type *cttype);
  75 struct codetag_iterator codetag_get_ct_iter(struct codetag_type *cttype);
  76 struct codetag *codetag_next_ct(struct codetag_iterator *iter);
  77
  78 void codetag_to_text(struct seq_buf *out, struct codetag *ct);
  79
  80 struct codetag_type *
  81 codetag_register_type(const struct codetag_type_desc *desc);
  82
  83 #if defined(CONFIG_CODE_TAGGING) && defined(CONFIG_MODULES)
  84
  85 bool codetag_needs_module_section(struct module *mod, const char *name,
  86                                   unsigned long size);
  87 void *codetag_alloc_module_section(struct module *mod, const char *name,
  88                                    unsigned long size, unsigned int prepend,
  89                                    unsigned long align);
  90 void codetag_free_module_sections(struct module *mod);
  91 void codetag_module_replaced(struct module *mod, struct module *new_mod);
  92 void codetag_load_module(struct module *mod);
  93 void codetag_unload_module(struct module *mod);
  94
  95 #else /* defined(CONFIG_CODE_TAGGING) && defined(CONFIG_MODULES) */
  96
  97 static inline bool
  98 codetag_needs_module_section(struct module *mod, const char *name,
  99                              unsigned long size) { return false; }
 100 static inline void *
 101 codetag_alloc_module_section(struct module *mod, const char *name,
 102                              unsigned long size, unsigned int prepend,
 103                              unsigned long align) { return NULL; }
 104 static inline void codetag_free_module_sections(struct module *mod) {}
 105 static inline void codetag_module_replaced(struct module *mod, struct module *new_mod) {}
 106 static inline void codetag_load_module(struct module *mod) {}
 107 static inline void codetag_unload_module(struct module *mod) {}
 108
 109 #endif /* defined(CONFIG_CODE_TAGGING) && defined(CONFIG_MODULES) */
 110
 111 #endif /* _LINUX_CODETAG_H */