Messages in this thread Patch in this message | | | Date | Wed, 25 Feb 2009 16:07:05 +0100 | From | Martin Schwidefsky <> | Subject | [patch/s390 43/46] module function call optimization |
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From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Avoid the detour over the PLT if the branch target of a function call in a module is in the range of the bras (16-bit) or brasl (32-bit) instruction. The PLT is still generated but it is unused.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> ---
arch/s390/kernel/module.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-)
Index: quilt-2.6/arch/s390/kernel/module.c =================================================================== --- quilt-2.6.orig/arch/s390/kernel/module.c +++ quilt-2.6/arch/s390/kernel/module.c @@ -310,15 +310,20 @@ apply_rela(Elf_Rela *rela, Elf_Addr base info->plt_initialized = 1; } if (r_type == R_390_PLTOFF16 || - r_type == R_390_PLTOFF32 - || r_type == R_390_PLTOFF64 - ) + r_type == R_390_PLTOFF32 || + r_type == R_390_PLTOFF64) val = me->arch.plt_offset - me->arch.got_offset + info->plt_offset + rela->r_addend; - else - val = (Elf_Addr) me->module_core + - me->arch.plt_offset + info->plt_offset + - rela->r_addend - loc; + else { + if (!((r_type == R_390_PLT16DBL && + val - loc + 0xffffUL < 0x1ffffeUL) || + (r_type == R_390_PLT32DBL && + val - loc + 0xffffffffULL < 0x1fffffffeULL))) + val = (Elf_Addr) me->module_core + + me->arch.plt_offset + + info->plt_offset; + val += rela->r_addend - loc; + } if (r_type == R_390_PLT16DBL) *(unsigned short *) loc = val >> 1; else if (r_type == R_390_PLTOFF16) -- blue skies, Martin.
"Reality continues to ruin my life." - Calvin.
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