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.

1 files changed, 20 insertions, 4 deletions

diff --git a/sysdeps/powerpc/powerpc64/dl-machine.c b/sysdeps/powerpc/powerpc64/dl-machine.c
index 0eccc6621a..2cfd43b21b 100644
--- a/sysdeps/powerpc/powerpc64/dl-machine.c
+++ b/sysdeps/powerpc/powerpc64/dl-machine.c
@@ -24,11 +24,11 @@
 
 void
 _dl_reloc_overflow (struct link_map *map,
-		   const char *name,
-		   Elf64_Addr *const reloc_addr,
-		   const Elf64_Sym *refsym)
+		    const char *name,
+		    Elf64_Addr *const reloc_addr,
+		    const Elf64_Sym *refsym)
 {
-  char buffer[128];
+  char buffer[1024];
   char *t;
   t = stpcpy (buffer, name);
   t = stpcpy (t, " reloc at 0x");
@@ -45,3 +45,19 @@ _dl_reloc_overflow (struct link_map *map,
   t = stpcpy (t, " out of range");
   _dl_signal_error (0, map->l_name, NULL, buffer);
 }
+
+#if _CALL_ELF == 2
+void
+_dl_error_localentry (struct link_map *map, const Elf64_Sym *refsym)
+{
+  char buffer[1024];
+  char *t;
+  const char *strtab;
+
+  strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
+  t = stpcpy (buffer, "expected localentry:0 `");
+  t = stpcpy (t, strtab + refsym->st_name);
+  t = stpcpy (t, "'");
+  _dl_signal_error (0, map->l_name, NULL, buffer);
+}
+#endif