kmodsrc/ksplice.h

   1 #include <linux/types.h>
   2
   3 /**
   4  * struct ksplice_symbol - Ksplice's analogue of an ELF symbol
   5  * @name:               The ELF name of the symbol
   6  * @label:              A unique Ksplice name for the symbol
   7  * @candidate_vals:     A linked list of possible values for the symbol, or NULL
   8  * @value:              The value of the symbol (valid when vals is NULL)
   9  **/
  10 struct ksplice_symbol {
  11         const char *name;
  12         const char *label;
  13 /* private: */
  14         struct list_head *candidate_vals;
  15         unsigned long value;
  16 };
  17
  18 /**
  19  * struct ksplice_reloc - Ksplice's analogue of an ELF relocation
  20  * @blank_addr:         The address of the relocation's storage unit
  21  * @symbol:             The ksplice_symbol associated with this relocation
  22  * @howto:              The information regarding the relocation type
  23  * @insn_addend:        The part of the ELF addend resulting from quirks of
  24  *                      the instruction one of whose operands is the relocation.
  25  *                      For example, this is -4 on x86 pc-relative jumps.
  26  * @target_addend:      The rest of the ELF addend.  This is equal to the offset
  27  *                      against the symbol that the relocation refers to.
  28  **/
  29 struct ksplice_reloc {
  30         unsigned long blank_addr;
  31         struct ksplice_symbol *symbol;
  32         const struct ksplice_reloc_howto *howto;
  33         long insn_addend;
  34         long target_addend;
  35 };
  36
  37 enum ksplice_reloc_howto_type {
  38         KSPLICE_HOWTO_RELOC,
  39         KSPLICE_HOWTO_RELOC_PATCH,
  40         KSPLICE_HOWTO_DATE,
  41         KSPLICE_HOWTO_TIME,
  42         KSPLICE_HOWTO_BUG,
  43         KSPLICE_HOWTO_EXTABLE,
  44         KSPLICE_HOWTO_SYMBOL,
  45 };
  46
  47 /**
  48  * struct ksplice_reloc_howto - Ksplice's relocation type information
  49  * @type:               The type of the relocation
  50  * @pcrel:              Is the relocation PC relative?
  51  * @size:               The size, in bytes, of the item to be relocated
  52  * @dst_mask:           Bitmask for which parts of the instruction or data are
  53  *                      replaced with the relocated value
  54  *                      (based on dst_mask from GNU BFD's reloc_howto_struct)
  55  * @rightshift:         The value the final relocation is shifted right by;
  56  *                      used to drop unwanted data from the relocation
  57  *                      (based on rightshift from GNU BFD's reloc_howto_struct)
  58  * @signed_addend:      Should the addend be interpreted as a signed value?
  59  **/
  60 struct ksplice_reloc_howto {
  61         enum ksplice_reloc_howto_type type;
  62         int pcrel;
  63         int size;
  64         long dst_mask;
  65         unsigned int rightshift;
  66         int signed_addend;
  67 };
  68
  69 #if BITS_PER_LONG == 32
  70 #define KSPLICE_CANARY 0x77777777UL
  71 #elif BITS_PER_LONG == 64
  72 #define KSPLICE_CANARY 0x7777777777777777UL
  73 #endif /* BITS_PER_LONG */
  74
  75 /**
  76  * struct ksplice_section - Ksplice's analogue of an ELF section
  77  * @symbol:             The ksplice_symbol associated with this section
  78  * @size:               The length, in bytes, of this section
  79  * @address:            The address of the section
  80  * @flags:              Flags indicating the type of the section, whether or
  81  *                      not it has been matched, etc.
  82  **/
  83 struct ksplice_section {
  84         struct ksplice_symbol *symbol;
  85         unsigned long address;
  86         unsigned long size;
  87         unsigned int flags;
  88         const unsigned char **match_map;
  89         int unmatched;
  90 };
  91 #define KSPLICE_SECTION_TEXT 0x00000001
  92 #define KSPLICE_SECTION_RODATA 0x00000002
  93 #define KSPLICE_SECTION_DATA 0x00000004
  94 #define KSPLICE_SECTION_STRING 0x00000008
  95 #define KSPLICE_SECTION_MATCHED 0x10000000
  96
  97 #define MAX_TRAMPOLINE_SIZE 5
  98
  99 enum ksplice_patch_type {
 100         KSPLICE_PATCH_TEXT,
 101         KSPLICE_PATCH_DATA,
 102         KSPLICE_PATCH_EXPORT,
 103 };
 104
 105 /**
 106  * struct ksplice_patch - A replacement that Ksplice should perform
 107  * @oldaddr:            The address of the obsolete function or structure
 108  * @repladdr:           The address of the replacement function
 109  * @type:               The type of the ksplice patch
 110  * @size:               The size of the patch
 111  * @contents:           The bytes to be installed at oldaddr
 112  * @vaddr               The address of the page mapping used to write at oldaddr
 113  * @saved:              The bytes originally at oldaddr which were
 114  *                      overwritten by the patch
 115  **/
 116 struct ksplice_patch {
 117         unsigned long oldaddr;
 118         unsigned long repladdr;
 119         enum ksplice_patch_type type;
 120         unsigned int size;
 121         void *contents;
 122 /* private: */
 123         void *vaddr;
 124         void *saved;
 125 };
 126
 127 #ifdef KSPLICE_STANDALONE
 128 struct ksplice_system_map {
 129         const char *label;
 130         unsigned long nr_candidates;
 131         const unsigned long *candidates;
 132 };
 133 #endif /* KSPLICE_STANDALONE */
 134
 135 #ifdef __KERNEL__
 136 #include <linux/module.h>
 137 #include <linux/stringify.h>
 138 #include <linux/version.h>
 139
 140 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19)
 141 /* 6e21828743247270d09a86756a0c11702500dbfb was after 2.6.18 */
 142 #define bool _Bool
 143 #define false 0
 144 #define true 1
 145 #endif /* LINUX_VERSION_CODE */
 146
 147 #if defined(CONFIG_PARAVIRT) && defined(CONFIG_X86_64) &&       \
 148     LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,25) &&             \
 149     LINUX_VERSION_CODE < KERNEL_VERSION(2,6,27)
 150 /* Linux 2.6.25 and 2.6.26 apply paravirt replacements to the core
 151  * kernel but not modules on x86-64.  If we are patching the core
 152  * kernel, we need to apply the same replacements to our update
 153  * modules in order for run-pre matching to succeed.
 154  */
 155 #define KSPLICE_NEED_PARAINSTRUCTIONS 1
 156 #endif /* KSPLICE_NEED_PARAINSTRUCTIONS */
 157
 158 #define _PASTE(x, y) x##y
 159 #define PASTE(x, y) _PASTE(x, y)
 160 #define KSPLICE_UNIQ(s) PASTE(s##_, KSPLICE_MID)
 161 #define KSPLICE_KID_UNIQ(s) PASTE(s##_, KSPLICE_KID)
 162 #ifdef KSPLICE_STANDALONE
 163 #define init_ksplice_mod_change KSPLICE_KID_UNIQ(init_ksplice_mod_change)
 164 #define cleanup_ksplice_mod_change KSPLICE_KID_UNIQ(cleanup_ksplice_mod_change)
 165 #endif
 166
 167 /**
 168  * struct ksplice_module_list_entry - A record of a ksplice_mod_change's target
 169  * @target_mod_name:    The name of the ksplice_mod_change's target module
 170  * @new_code_mod_name:  The name of the ksplice_mod_change's new_code module
 171  * @applied:            Whether the ksplice_mod_change was applied or not (this
 172  *                      will be false for ksplice_mod_changes patching targets
 173  *                      that are not loaded when the partial flag is set)
 174  **/
 175 struct ksplice_module_list_entry {
 176         const char *target_mod_name;
 177         const char *new_code_mod_name;
 178         const char *kid;
 179         bool applied;
 180 /* private: */
 181         struct list_head update_list;   /* list head for this is per-update */
 182         struct list_head list;  /* list head for this is global */
 183 };
 184
 185 /* List of all ksplice modules and the module they patch */
 186 extern struct list_head ksplice_modules;
 187
 188 /* There are two actions, apply and reverse */
 189 #define KS_ACTIONS 2
 190 enum ksplice_action {
 191         KS_APPLY,
 192         KS_REVERSE,
 193 };
 194
 195 /**
 196  * struct ksplice_hooks - Hooks to be run during an action (apply or reverse)
 197  * @pre:                        Runs before the action;
 198  *                              may return nonzero to abort the action
 199  * @check:                      Runs inside stop_machine before the action;
 200  *                              may return nonzero to abort the action
 201  * @intra:                      Runs inside stop_machine during the action
 202  * @post:                       Runs after the action is successfully performed
 203  * @fail:                       Runs if the action is aborted for any reason
 204  */
 205 struct ksplice_hooks {
 206         const typeof(int (*)(void)) *pre, *pre_end, *check, *check_end;
 207         const typeof(void (*)(void)) *intra, *intra_end, *post, *post_end,
 208             *fail, *fail_end;
 209 };
 210
 211 /**
 212  * struct ksplice_code - Ksplice metadata for an object
 213  * @relocs:             The Ksplice relocations for the object
 214  * @symbols:            The Ksplice symbols for the object
 215  * @sections:           The Ksplice sections for the object
 216  **/
 217 struct ksplice_code {
 218         struct ksplice_reloc *relocs, *relocs_end;
 219         struct ksplice_section *sections, *sections_end;
 220         struct ksplice_symbol *symbols, *symbols_end;
 221 #ifdef KSPLICE_NEED_PARAINSTRUCTIONS
 222         struct paravirt_patch_site *parainstructions, *parainstructions_end;
 223 #endif /* KSPLICE_NEED_PARAINSTRUCTIONS */
 224 #ifdef KSPLICE_STANDALONE
 225         struct ksplice_system_map *system_map, *system_map_end;
 226 #endif /* KSPLICE_STANDALONE */
 227 };
 228
 229 /**
 230  * struct ksplice_mod_change - Data for one module modified by a Ksplice update
 231  * @name:                       The name of the new_code module for the change
 232  * @kid:                        The Ksplice unique identifier for the change
 233  * @target_name:                The name of the module modified by the change
 234  * @new_code_mod:               The new_code module for the change
 235  * @old_code:                   The old code for run-pre matching
 236  * @new_code:                   The new code to switch to
 237  * @patches:                    The function replacements in the change
 238  * @patches_end:                The end pointer for patches array
 239  * @hooks:                      Hooks to be run during apply and reverse
 240  * @update:                     The atomic update the change is part of
 241  * @target:                     The module modified by the change
 242  * @safety_records:             The ranges of addresses that must not be on a
 243  *                              kernel stack for the patch to apply safely
 244  **/
 245 struct ksplice_mod_change {
 246         const char *name;
 247         const char *kid;
 248         const char *target_name;
 249 #ifdef KSPLICE_STANDALONE
 250         unsigned long map_printk;
 251 #endif /* KSPLICE_STANDALONE */
 252         struct module *new_code_mod;
 253         struct ksplice_code old_code, new_code;
 254         struct ksplice_patch *patches, *patches_end;
 255         struct ksplice_hooks hooks[KS_ACTIONS];
 256 /* private: */
 257         struct update *update;
 258         struct module *target;
 259         struct list_head temp_labelvals;
 260         struct list_head safety_records;
 261         struct list_head list;
 262 };
 263
 264
 265 int init_ksplice_mod_change(struct ksplice_mod_change *change);
 266
 267 void cleanup_ksplice_mod_change(struct ksplice_mod_change *change);
 268
 269 #endif /* __KERNEL__ */