src/patches/suse-2.6.27.25/patches.suse/genksyms-override.diff

   1 From: Andreas Gruenbacher <agruen@suse.de>
   2 Subject: genksyms: allow to ignore symbol checksum changes
   3
   4 This adds an "override" keyword for use in *.symvers / *.symref files.  When a
   5 symbol is overridden, the symbol's old definition will be used for computing
   6 checksums instead of the new one, preserving the previous checksum.  (Genksyms
   7 will still warn about the change.)
   8
   9 This is meant to allow distributions to hide minor actual as well as fake ABI
  10 changes. (For example, when extra type information becomes available because
  11 additional headers are included, this may change checksums even though none of
  12 the types used have actully changed.)
  13
  14 This approach also allows to get rid of "#ifdef __GENKSYMS__" hacks in the code,
  15 which are currently used in some vendor kernels to work around checksum changes.
  16
  17 Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
  18
  19 ---
  20  scripts/genksyms/genksyms.c |   34 ++++++++++++++++++++++++++++++----
  21  scripts/genksyms/genksyms.h |    1 +
  22  2 files changed, 31 insertions(+), 4 deletions(-)
  23
  24 --- a/scripts/genksyms/genksyms.c
  25 +++ b/scripts/genksyms/genksyms.c
  26 @@ -191,11 +191,26 @@ struct symbol *__add_symbol(const char *
  27                                 /* fall through */ ;
  28                         else if (sym->type == type &&
  29                                  equal_list(sym->defn, defn)) {
  30 +                               if (!sym->is_declared && sym->is_override) {
  31 +                                       print_location();
  32 +                                       print_type_name(type, name);
  33 +                                       fprintf(stderr, " modversion is "
  34 +                                               "unchanged\n");
  35 +                               }
  36                                 sym->is_declared = 1;
  37                                 return sym;
  38                         } else if (!sym->is_declared) {
  39 -                               status = is_unknown_symbol(sym) ?
  40 -                                       STATUS_DEFINED : STATUS_MODIFIED;
  41 +                               if (sym->is_override && flag_preserve) {
  42 +                                       print_location();
  43 +                                       fprintf(stderr, "ignoring ");
  44 +                                       print_type_name(type, name);
  45 +                                       fprintf(stderr, " modversion change\n");
  46 +                                       sym->is_declared = 1;
  47 +                                       return sym;
  48 +                               } else {
  49 +                                       status = is_unknown_symbol(sym) ?
  50 +                                               STATUS_DEFINED : STATUS_MODIFIED;
  51 +                               }
  52                         } else {
  53                                 error_with_pos("redefinition of %s", name);
  54                                 return sym;
  55 @@ -229,6 +244,7 @@ struct symbol *__add_symbol(const char *
  56
  57         sym->is_declared = !is_reference;
  58         sym->status = status;
  59 +       sym->is_override = 0;
  60
  61         if (flag_debug) {
  62                 fprintf(debugfile, "Defn for %s %s == <",
  63 @@ -348,9 +364,16 @@ static void read_reference(FILE *f)
  64         while (!feof(f)) {
  65                 struct string_list *defn = NULL;
  66                 struct string_list *sym, *def;
  67 -               int is_extern = 0;
  68 +               int is_extern = 0, is_override = 0;
  69 +               struct symbol *subsym;
  70
  71                 sym = read_node(f);
  72 +               if (sym && sym->tag == SYM_NORMAL &&
  73 +                   !strcmp(sym->string, "override")) {
  74 +                       is_override = 1;
  75 +                       free_node(sym);
  76 +                       sym = read_node(f);
  77 +               }
  78                 if (!sym)
  79                         continue;
  80                 def = read_node(f);
  81 @@ -365,8 +388,9 @@ static void read_reference(FILE *f)
  82                         defn = def;
  83                         def = read_node(f);
  84                 }
  85 -               add_reference_symbol(xstrdup(sym->string), sym->tag,
  86 +               subsym = add_reference_symbol(xstrdup(sym->string), sym->tag,
  87                                               defn, is_extern);
  88 +               subsym->is_override = is_override;
  89                 free_node(sym);
  90         }
  91  }
  92 @@ -743,6 +767,8 @@ int main(int argc, char **argv)
  93                 while (visited_symbols != (struct symbol *)-1L) {
  94                         struct symbol *sym = visited_symbols;
  95
  96 +                       if (sym->is_override)
  97 +                               fputs("override ", dumpfile);
  98                         if (sym->type != SYM_NORMAL) {
  99                                 putc(symbol_type_name[sym->type][0], dumpfile);
 100                                 putc('#', dumpfile);
 101 --- a/scripts/genksyms/genksyms.h
 102 +++ b/scripts/genksyms/genksyms.h
 103 @@ -49,6 +49,7 @@ struct symbol {
 104         int is_extern;
 105         int is_declared;
 106         enum symbol_status status;
 107 +       int is_override;
 108  };
 109
 110  typedef struct string_list **yystype;