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authorAlan Modra <amodra@gmail.com>2017-06-14 10:47:25 +0930
committerAlan Modra <amodra@gmail.com>2017-06-14 10:47:25 +0930
commit0572433b5beb636de1a49ec6b4fdab830c38cdc5 (patch)
tree718b3b7cd3011961b409a8233dfac4f2b0c6c487 /elf/dl-runtime.c
parentd5b411854f0a3135c931921dfa8a33af395acfd3 (diff)
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PowerPC64 ELFv2 PPC64_OPT_LOCALENTRY
ELFv2 functions with localentry:0 are those with a single entry point,
ie. global entry == local entry, that have no requirement on r2 or
r12 and guarantee r2 is unchanged on return.  Such an external
function can be called via the PLT without saving r2 or restoring it
on return, avoiding a common load-hit-store for small functions.

This patch implements the ld.so changes necessary for this
optimization.  ld.so needs to check that an optimized plt call
sequence is in fact calling a function implemented with localentry:0,
end emit a fatal error otherwise.

The elf/testobj6.c change is to stop "error while loading shared
libraries: expected localentry:0 `preload'" when running
elf/preloadtest, which we'd get otherwise.

	* elf/elf.h (PPC64_OPT_LOCALENTRY): Define.
	* sysdeps/alpha/dl-machine.h (elf_machine_fixup_plt): Add
	refsym and sym parameters.  Adjust callers.
	* sysdeps/aarch64/dl-machine.h (elf_machine_fixup_plt): Likewise.
	* sysdeps/arm/dl-machine.h (elf_machine_fixup_plt): Likewise.
	* sysdeps/generic/dl-machine.h (elf_machine_fixup_plt): Likewise.
	* sysdeps/hppa/dl-machine.h (elf_machine_fixup_plt): Likewise.
	* sysdeps/i386/dl-machine.h (elf_machine_fixup_plt): Likewise.
	* sysdeps/ia64/dl-machine.h (elf_machine_fixup_plt): Likewise.
	* sysdeps/m68k/dl-machine.h (elf_machine_fixup_plt): Likewise.
	* sysdeps/microblaze/dl-machine.h (elf_machine_fixup_plt): Likewise.
	* sysdeps/mips/dl-machine.h (elf_machine_fixup_plt): Likewise.
	* sysdeps/nios2/dl-machine.h (elf_machine_fixup_plt): Likewise.
	* sysdeps/powerpc/powerpc32/dl-machine.h (elf_machine_fixup_plt):
	Likewise.
	* sysdeps/s390/s390-32/dl-machine.h (elf_machine_fixup_plt): Likewise.
	* sysdeps/s390/s390-64/dl-machine.h (elf_machine_fixup_plt): Likewise.
	* sysdeps/sh/dl-machine.h (elf_machine_fixup_plt): Likewise.
	* sysdeps/sparc/sparc32/dl-machine.h (elf_machine_fixup_plt): Likewise.
	* sysdeps/sparc/sparc64/dl-machine.h (elf_machine_fixup_plt): Likewise.
	* sysdeps/tile/dl-machine.h (elf_machine_fixup_plt): Likewise.
	* sysdeps/x86_64/dl-machine.h (elf_machine_fixup_plt): Likewise.
	* sysdeps/powerpc/powerpc64/dl-machine.c (_dl_error_localentry): New.
	(_dl_reloc_overflow): Increase buffser size.  Formatting.
	* sysdeps/powerpc/powerpc64/dl-machine.h (ppc64_local_entry_offset):
	Delete reloc param, add refsym and sym.  Check optimized plt
	call stubs for localentry:0 functions.  Adjust callers.
	(elf_machine_fixup_plt, elf_machine_plt_conflict): Add refsym
	and sym parameters.  Adjust callers.
	(_dl_reloc_overflow): Move attribute.
	(_dl_error_localentry): Declare.
	* elf/dl-runtime.c (_dl_fixup): Save original sym.  Pass
	refsym and sym to elf_machine_fixup_plt.
	* elf/testobj6.c (preload): Call printf.
Diffstat (limited to 'elf/dl-runtime.c')
-rw-r--r--elf/dl-runtime.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/elf/dl-runtime.c b/elf/dl-runtime.c
index 7d1d240403..51d3819d4a 100644
--- a/elf/dl-runtime.c
+++ b/elf/dl-runtime.c
@@ -71,6 +71,7 @@ _dl_fixup (
   const PLTREL *const reloc
     = (const void *) (D_PTR (l, l_info[DT_JMPREL]) + reloc_offset);
   const ElfW(Sym) *sym = &symtab[ELFW(R_SYM) (reloc->r_info)];
+  const ElfW(Sym) *refsym = sym;
   void *const rel_addr = (void *)(l->l_addr + reloc->r_offset);
   lookup_t result;
   DL_FIXUP_VALUE_TYPE value;
@@ -145,7 +146,7 @@ _dl_fixup (
   if (__glibc_unlikely (GLRO(dl_bind_not)))
     return value;
 
-  return elf_machine_fixup_plt (l, result, reloc, rel_addr, value);
+  return elf_machine_fixup_plt (l, result, refsym, sym, reloc, rel_addr, value);
 }
 
 #ifndef PROF