src/patches/suse-2.6.27.39/patches.arch/s390-17-perf-09-module-plt.patch

   1 From: Gerald Schaefer <geraldsc@de.ibm.com>
   2 Subject: [S390] module function call optimization
   3 References: bnc#532063,LTC#55526
   4
   5 commit 504665a91498f43d220b7d0942281067283a35f7
   6 Author: Martin Schwidefsky <schwidefsky@de.ibm.com>
   7 Date:   Thu Mar 26 15:24:36 2009 +0100
   8
   9     [S390] module function call optimization
  10
  11     Avoid the detour over the PLT if the branch target of a function call
  12     in a module is in the range of the bras (16-bit) or brasl (32-bit)
  13     instruction. The PLT is still generated but it is unused.
  14
  15     Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
  16
  17 Acked-by: John Jolly <jjolly@suse.de>
  18
  19 diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c
  20 index 59b4e79..eed4a00 100644
  21 --- a/arch/s390/kernel/module.c
  22 +++ b/arch/s390/kernel/module.c
  23 @@ -310,15 +310,20 @@ apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
  24                         info->plt_initialized = 1;
  25                 }
  26                 if (r_type == R_390_PLTOFF16 ||
  27 -                   r_type == R_390_PLTOFF32
  28 -                   || r_type == R_390_PLTOFF64
  29 -                       )
  30 +                   r_type == R_390_PLTOFF32 ||
  31 +                   r_type == R_390_PLTOFF64)
  32                         val = me->arch.plt_offset - me->arch.got_offset +
  33                                 info->plt_offset + rela->r_addend;
  34 -               else
  35 -                       val =  (Elf_Addr) me->module_core +
  36 -                               me->arch.plt_offset + info->plt_offset +
  37 -                               rela->r_addend - loc;
  38 +               else {
  39 +                       if (!((r_type == R_390_PLT16DBL &&
  40 +                              val - loc + 0xffffUL < 0x1ffffeUL) ||
  41 +                             (r_type == R_390_PLT32DBL &&
  42 +                              val - loc + 0xffffffffULL < 0x1fffffffeULL)))
  43 +                               val = (Elf_Addr) me->module_core +
  44 +                                       me->arch.plt_offset +
  45 +                                       info->plt_offset;
  46 +                       val += rela->r_addend - loc;
  47 +               }
  48                 if (r_type == R_390_PLT16DBL)
  49                         *(unsigned short *) loc = val >> 1;
  50                 else if (r_type == R_390_PLTOFF16)