kmodsrc/ksplice.h

   1 /**
   2  * struct ksplice_symbol - Ksplice's analogue of an ELF symbol
   3  * @name:       The ELF name of the symbol
   4  * @label:      A unique Ksplice name for the symbol
   5  **/
   6 struct ksplice_symbol {
   7         const char *name;
   8         const char *label;
   9 };
  10
  11 /**
  12  * struct ksplice_reloc - Ksplice's analogue of an ELF relocation
  13  * @blank_addr:         The address of the relocation's storage unit
  14  * @blank_offset:       The offset (from the start of the section) of the
  15  *                      relocation's storage unit
  16  * @symbol:             The ksplice_symbol associated with this relocation
  17  * @pcrel:              Is the relocation PC relative?
  18  * @addend:             The ELF addend of the relocation
  19  * @size:               The size, in bytes, of the item to be relocated
  20  * @dst_mask:           Bitmask for which parts of the instruction or data are
  21  *                      replaced with the relocated value
  22  *                      (based on dst_mask from GNU BFD's reloc_howto_struct)
  23  * @rightshift:         The value the final relocation is shifted right by;
  24  *                      used to drop unwanted data from the relocation
  25  *                      (based on rightshift from GNU BFD's reloc_howto_struct)
  26  * @signed_addend:      Should the addend be interpreted as a signed value?
  27  **/
  28 struct ksplice_reloc {
  29         unsigned long blank_addr;
  30         long blank_offset;
  31         const struct ksplice_symbol *symbol;
  32         int pcrel;
  33         long addend;
  34         int size;
  35         long dst_mask;
  36         unsigned int rightshift;
  37         int signed_addend;
  38 };
  39
  40 /**
  41  * struct ksplice_section - Ksplice's analogue of an ELF section
  42  * @symbol:             The ksplice_symbol associated with this section
  43  * @size:               The length, in bytes, of this section
  44  * @thismod_addr:       The address of the section
  45  * @flags:              Specifies whether this section contains text, read-only
  46  *                      data, or data
  47  **/
  48 struct ksplice_section {
  49         const struct ksplice_symbol *symbol;
  50         unsigned long size;
  51         unsigned long thismod_addr;
  52         unsigned int flags;
  53 };
  54 #define KSPLICE_SECTION_TEXT 0x00000001
  55 #define KSPLICE_SECTION_RODATA 0x00000002
  56 #define KSPLICE_SECTION_DATA 0x00000004
  57
  58 #define MAX_TRAMPOLINE_SIZE 5
  59
  60 /**
  61  * struct ksplice_trampoline - A trampoline Ksplice should insert
  62  * @repladdr:           The address of the replacement function
  63  * @oldaddr:            The address of the obsolete function
  64  * @trampoline:         The bytes of the trampoline itself
  65  * @saved:              The bytes of the original function which were
  66  *                      overwritten by the trampoline
  67  * @size:               The size of the trampoline
  68  *
  69  * Any value put into a private field by user space will be ignored.
  70  **/
  71 struct ksplice_trampoline {
  72         unsigned long repladdr;
  73 /* private: */
  74         unsigned long oldaddr;
  75         char trampoline[MAX_TRAMPOLINE_SIZE];
  76         char saved[MAX_TRAMPOLINE_SIZE];
  77         unsigned int size;
  78 };
  79
  80 /**
  81  * struct ksplice_patch - A function replacement that Ksplice should perform
  82  * @label:              The unique Ksplice name for the obsolete function
  83  * @trampoline:         A trampoline to insert over the obsolete function
  84  * @reverse_trampoline: A trampoline to insert over the repladdr of any
  85  *                      trampoline previously installed at the start of the
  86  *                      obsolete function (if the function has been previously
  87  *                      patched)
  88  *
  89  * Any value put into a private field by user space will be ignored.
  90  **/
  91 struct ksplice_patch {
  92         const char *label;
  93         struct ksplice_trampoline trampoline;
  94 /* private: */
  95         struct ksplice_trampoline reverse_trampoline;
  96 };
  97
  98 /**
  99  * struct ksplice_export - A change to be made to the exported symbol table
 100  * @name:               The obsolete name of the exported symbol
 101  * @new_name:           The new name of the exported symbol
 102  * @sym:                The kernel_symbol being changed
 103  * @saved_name:         The pointer to the original name of the kernel_symbol
 104  *
 105  * Any value put into a private field by user space will be ignored.
 106  **/
 107 struct ksplice_export {
 108         const char *name;
 109         const char *new_name;
 110 /* private: */
 111         struct kernel_symbol *sym;
 112         const char *saved_name;
 113 };
 114
 115 #ifdef KSPLICE_STANDALONE
 116 struct ksplice_system_map {
 117         const char *label;
 118         unsigned long nr_candidates;
 119         const unsigned long *candidates;
 120 };
 121 #endif /* KSPLICE_STANDALONE */
 122
 123 #ifdef __KERNEL__
 124 #include <linux/module.h>
 125 #include <linux/version.h>
 126
 127 #if defined(CONFIG_PARAVIRT) && defined(CONFIG_X86_64) &&       \
 128     LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,25) &&             \
 129     LINUX_VERSION_CODE < KERNEL_VERSION(2,6,27)
 130 /* Linux 2.6.25 and 2.6.26 apply paravirt replacements to the core
 131  * kernel but not modules on x86-64.  If we are patching the core
 132  * kernel, we need to apply the same replacements to our update
 133  * modules in order for run-pre matching to succeed.
 134  */
 135 #define KSPLICE_NEED_PARAINSTRUCTIONS 1
 136 #endif /* KSPLICE_NEED_PARAINSTRUCTIONS */
 137
 138 #undef _STR
 139 #define _STR(x) #x
 140 #undef STR
 141 #define STR(x) _STR(x)
 142 #define _PASTE(x, y) x##y
 143 #define PASTE(x, y) _PASTE(x, y)
 144 #define KSPLICE_UNIQ(s) PASTE(s##_, KSPLICE_MID)
 145 #define KSPLICE_KID_UNIQ(s) PASTE(s##_, KSPLICE_KID)
 146 #ifdef KSPLICE_STANDALONE
 147 #define init_ksplice_pack KSPLICE_KID_UNIQ(init_ksplice_pack)
 148 #define cleanup_ksplice_pack KSPLICE_KID_UNIQ(cleanup_ksplice_pack)
 149 #endif
 150
 151 /**
 152  * struct ksplice_module_list_entry - A record of a Ksplice pack's target
 153  * @target:     A module that is patched
 154  * @primary:    A Ksplice module that patches target
 155  **/
 156 struct ksplice_module_list_entry {
 157         struct module *target;
 158         struct module *primary;
 159 /* private: */
 160         struct list_head list;
 161 };
 162
 163 /* List of all ksplice modules and the module they patch */
 164 extern struct list_head ksplice_module_list;
 165
 166 /**
 167  * struct ksplice_pack - Data for one module modified by a Ksplice update
 168  * @name:                       The name of the primary module for the pack
 169  * @kid:                        The Ksplice unique identifier for the pack
 170  * @target_name:                The name of the module modified by the pack
 171  * @primary:                    The primary module associated with the pack
 172  * @primary_relocs:             The relocations for the primary module
 173  * @primary_relocs_end:         The end pointer for primary_relocs
 174  * @primary_sections:           The sections in the primary module
 175  * @primary_sections_end:       The end pointer for primary_sections array
 176  * @helper_relocs:              The relocations for the helper module
 177  * @helper_relocs_end:          The end pointer for helper_relocs array
 178  * @helper_sections:            The sections in the helper module
 179  * @helper_sections_end:        The end pointer for helper_sections array
 180  * @patches:                    The function replacements in the pack
 181  * @patches_end:                The end pointer for patches array
 182  * @exports:                    The exported symbol changes in the pack
 183  * @exports_end:                The end pointer for the exports array
 184  * @update:                     The atomic update the pack is part of
 185  * @target:                     The module modified by the pack
 186  * @reloc_namevals:             The mapping between Ksplice symbol labels and
 187  *                              their values
 188  * @safety_records:             The ranges of addresses that must not be on a
 189  *                              kernel stack for the patch to apply safely
 190  **/
 191 struct ksplice_pack {
 192         const char *name;
 193         const char *kid;
 194         const char *target_name;
 195 #ifdef KSPLICE_STANDALONE
 196         unsigned long map_printk;
 197 #endif /* KSPLICE_STANDALONE */
 198         struct module *primary;
 199         const struct ksplice_reloc *primary_relocs, *primary_relocs_end;
 200         const struct ksplice_section *primary_sections, *primary_sections_end;
 201         const struct ksplice_reloc *helper_relocs, *helper_relocs_end;
 202         const struct ksplice_section *helper_sections, *helper_sections_end;
 203         struct ksplice_patch *patches, *patches_end;
 204         struct ksplice_export *exports, *exports_end;
 205 #ifdef KSPLICE_NEED_PARAINSTRUCTIONS
 206         struct paravirt_patch_site
 207             *primary_parainstructions, *primary_parainstructions_end,
 208             *helper_parainstructions, *helper_parainstructions_end;
 209 #endif /* KSPLICE_NEED_PARAINSTRUCTIONS */
 210 #ifdef KSPLICE_STANDALONE
 211         struct ksplice_system_map
 212             *primary_system_map, *primary_system_map_end,
 213             *helper_system_map, *helper_system_map_end;
 214 #endif /* KSPLICE_STANDALONE */
 215 /* private: */
 216         struct ksplice_module_list_entry module_list_entry;
 217         struct update *update;
 218         struct module *target;
 219         struct list_head reloc_namevals;
 220         struct list_head safety_records;
 221         struct list_head list;
 222 };
 223
 224
 225 /**
 226  * init_ksplice_pack() - Initializes a pack
 227  * @pack:       The pack to be initialized.  The non-private fields should
 228  *              already be filled when this is called.
 229  **/
 230 int init_ksplice_pack(struct ksplice_pack *pack);
 231
 232 /**
 233  * cleanup_ksplice_pack() - Cleans up a pack
 234  * @pack:       The pack to be cleaned up
 235  */
 236 void cleanup_ksplice_pack(struct ksplice_pack *pack);
 237
 238 #endif /* __KERNEL__ */