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_MATCH_DATA_EARLY 0x00000100
  96 #define KSPLICE_SECTION_MATCHED 0x10000000
  97
  98 #define MAX_TRAMPOLINE_SIZE 5
  99
 100 enum ksplice_patch_type {
 101         KSPLICE_PATCH_TEXT,
 102         KSPLICE_PATCH_DATA,
 103         KSPLICE_PATCH_EXPORT,
 104 };
 105
 106 /**
 107  * struct ksplice_patch - A replacement that Ksplice should perform
 108  * @oldaddr:            The address of the obsolete function or structure
 109  * @repladdr:           The address of the replacement function
 110  * @type:               The type of the ksplice patch
 111  * @size:               The size of the patch
 112  * @contents:           The bytes to be installed at oldaddr
 113  * @vaddr               The address of the page mapping used to write at oldaddr
 114  * @saved:              The bytes originally at oldaddr which were
 115  *                      overwritten by the patch
 116  **/
 117 struct ksplice_patch {
 118         unsigned long oldaddr;
 119         unsigned long repladdr;
 120         enum ksplice_patch_type type;
 121         unsigned int size;
 122         void *contents;
 123 /* private: */
 124         void *vaddr;
 125         void *saved;
 126 };
 127
 128 #ifdef KSPLICE_STANDALONE
 129 struct ksplice_system_map {
 130         const char *label;
 131         unsigned long nr_candidates;
 132         const unsigned long *candidates;
 133 };
 134 #endif /* KSPLICE_STANDALONE */
 135
 136 #ifdef __KERNEL__
 137 #include <linux/module.h>
 138 #include <linux/stringify.h>
 139 #include <linux/version.h>
 140
 141 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19)
 142 /* 6e21828743247270d09a86756a0c11702500dbfb was after 2.6.18 */
 143 #define bool _Bool
 144 #define false 0
 145 #define true 1
 146 #endif /* LINUX_VERSION_CODE */
 147
 148 #if defined(CONFIG_PARAVIRT) && defined(CONFIG_X86_64) &&       \
 149     LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,25) &&             \
 150     LINUX_VERSION_CODE < KERNEL_VERSION(2,6,27)
 151 /* Linux 2.6.25 and 2.6.26 apply paravirt replacements to the core
 152  * kernel but not modules on x86-64.  If we are patching the core
 153  * kernel, we need to apply the same replacements to our update
 154  * modules in order for run-pre matching to succeed.
 155  */
 156 #define KSPLICE_NEED_PARAINSTRUCTIONS 1
 157 #endif /* KSPLICE_NEED_PARAINSTRUCTIONS */
 158
 159 #define _PASTE(x, y) x##y
 160 #define PASTE(x, y) _PASTE(x, y)
 161 #define KSPLICE_UNIQ(s) PASTE(s##_, KSPLICE_MID)
 162 #define KSPLICE_KID_UNIQ(s) PASTE(s##_, KSPLICE_KID)
 163 #ifdef KSPLICE_STANDALONE
 164 #define init_ksplice_mod_change KSPLICE_KID_UNIQ(init_ksplice_mod_change)
 165 #define cleanup_ksplice_mod_change KSPLICE_KID_UNIQ(cleanup_ksplice_mod_change)
 166 #endif
 167
 168 /**
 169  * struct ksplice_module_list_entry - A record of a ksplice_mod_change's target
 170  * @target_mod_name:    The name of the ksplice_mod_change's target module
 171  * @new_code_mod_name:  The name of the ksplice_mod_change's new_code module
 172  * @applied:            Whether the ksplice_mod_change was applied or not (this
 173  *                      will be false for ksplice_mod_changes patching targets
 174  *                      that are not loaded when the partial flag is set)
 175  **/
 176 struct ksplice_module_list_entry {
 177         const char *target_mod_name;
 178         const char *new_code_mod_name;
 179         const char *kid;
 180         bool applied;
 181 /* private: */
 182         struct list_head update_list;   /* list head for this is per-update */
 183         struct list_head list;  /* list head for this is global */
 184 };
 185
 186 /* List of all ksplice modules and the module they patch */
 187 extern struct list_head ksplice_modules;
 188
 189 /* There are two actions, apply and reverse */
 190 #define KS_ACTIONS 2
 191 enum ksplice_action {
 192         KS_APPLY,
 193         KS_REVERSE,
 194 };
 195
 196 /**
 197  * struct ksplice_hooks - Hooks to be run during an action (apply or reverse)
 198  * @pre:                        Runs before the action;
 199  *                              may return nonzero to abort the action
 200  * @check:                      Runs inside stop_machine before the action;
 201  *                              may return nonzero to abort the action
 202  * @intra:                      Runs inside stop_machine during the action
 203  * @post:                       Runs after the action is successfully performed
 204  * @fail:                       Runs if the action is aborted for any reason
 205  */
 206 struct ksplice_hooks {
 207         const typeof(int (*)(void)) *pre, *pre_end, *check, *check_end;
 208         const typeof(void (*)(void)) *intra, *intra_end, *post, *post_end,
 209             *fail, *fail_end;
 210 };
 211
 212 /**
 213  * struct ksplice_code - Ksplice metadata for an object
 214  * @relocs:             The Ksplice relocations for the object
 215  * @symbols:            The Ksplice symbols for the object
 216  * @sections:           The Ksplice sections for the object
 217  **/
 218 struct ksplice_code {
 219         struct ksplice_reloc *relocs, *relocs_end;
 220         struct ksplice_section *sections, *sections_end;
 221         struct ksplice_symbol *symbols, *symbols_end;
 222 #ifdef KSPLICE_NEED_PARAINSTRUCTIONS
 223         struct paravirt_patch_site *parainstructions, *parainstructions_end;
 224 #endif /* KSPLICE_NEED_PARAINSTRUCTIONS */
 225 #ifdef KSPLICE_STANDALONE
 226         struct ksplice_system_map *system_map, *system_map_end;
 227 #endif /* KSPLICE_STANDALONE */
 228 };
 229
 230 /**
 231  * struct ksplice_mod_change - Data for one module modified by a Ksplice update
 232  * @name:                       The name of the new_code module for the change
 233  * @kid:                        The Ksplice unique identifier for the change
 234  * @target_name:                The name of the module modified by the change
 235  * @new_code_mod:               The new_code module for the change
 236  * @old_code:                   The old code for run-pre matching
 237  * @new_code:                   The new code to switch to
 238  * @patches:                    The function replacements in the change
 239  * @patches_end:                The end pointer for patches array
 240  * @hooks:                      Hooks to be run during apply and reverse
 241  * @update:                     The atomic update the change is part of
 242  * @target:                     The module modified by the change
 243  * @safety_records:             The ranges of addresses that must not be on a
 244  *                              kernel stack for the patch to apply safely
 245  **/
 246 struct ksplice_mod_change {
 247         const char *name;
 248         const char *kid;
 249         const char *target_name;
 250 #ifdef KSPLICE_STANDALONE
 251         unsigned long map_printk;
 252 #endif /* KSPLICE_STANDALONE */
 253         struct module *new_code_mod;
 254         struct ksplice_code old_code, new_code;
 255         struct ksplice_patch *patches, *patches_end;
 256         struct ksplice_hooks hooks[KS_ACTIONS];
 257 /* private: */
 258         struct update *update;
 259         struct module *target;
 260         struct list_head temp_labelvals;
 261         struct list_head safety_records;
 262         struct list_head list;
 263 };
 264
 265
 266 int init_ksplice_mod_change(struct ksplice_mod_change *change);
 267
 268 void cleanup_ksplice_mod_change(struct ksplice_mod_change *change);
 269
 270 #endif /* __KERNEL__ */