x86; Allow IFUNC pointer defined in PDE

If IFUNC symbol is defined in position-dependent executable, we should change it to the normal function and set its address to its PLT entry which should be resolved by R_*_IRELATIVE at run-time. All external references should be resolved to its PLT in executable. bfd/ PR ld/23169 * elf-ifunc.c (_bfd_elf_allocate_ifunc_dyn_relocs): Don't issue an error on IFUNC pointer defined in PDE. * elf32-i386.c (elf_i386_finish_dynamic_symbol): Call _bfd_x86_elf_link_fixup_ifunc_symbol. * elf64-x86-64.c (elf_x86_64_finish_dynamic_symbol): Likewise. * elfxx-x86.c (_bfd_x86_elf_link_fixup_ifunc_symbol): New function. * elfxx-x86.h (_bfd_x86_elf_link_fixup_ifunc_symbol): New. ld/ PR ld/23169 * testsuite/ld-ifunc/ifunc-9-i386.d: New file. * testsuite/ld-ifunc/ifunc-9-x86-64.d: Likewise. * testsuite/ld-ifunc/pr23169a.c: Likewise. * testsuite/ld-ifunc/pr23169a.rd: Likewise. * testsuite/ld-ifunc/pr23169b.c: Likewise. * testsuite/ld-ifunc/pr23169b.c: Likewise. * testsuite/ld-ifunc/pr23169c.rd: Likewise. * testsuite/ld-ifunc/pr23169c.rd: Likewise. * testsuite/ld-ifunc/ifunc-9-x86.d: Removed. * testsuite/ld-ifunc/ifunc.exp: Run PR ld/23169 tests.
2018-05-14 03:55:37 -07:00 · 2018-05-14 03:55:37 -07:00 · 4ec0995016
commit 4ec0995016
parent 9bc935ef33
17 changed files with 290 additions and 4 deletions
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@ -1,3 +1,15 @@
+2018-05-14  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/23169
+	* elf-ifunc.c (_bfd_elf_allocate_ifunc_dyn_relocs): Don't issue
+	an error on IFUNC pointer defined in PDE.
+	* elf32-i386.c (elf_i386_finish_dynamic_symbol): Call
+	_bfd_x86_elf_link_fixup_ifunc_symbol.
+	* elf64-x86-64.c (elf_x86_64_finish_dynamic_symbol): Likewise.
+	* elfxx-x86.c (_bfd_x86_elf_link_fixup_ifunc_symbol): New
+	function.
+	* elfxx-x86.h (_bfd_x86_elf_link_fixup_ifunc_symbol): New.
+
 2018-05-14  H.J. Lu  <hongjiu.lu@intel.com>

 	PR ld/23162
--- a/bfd/elf-ifunc.c
+++ b/bfd/elf-ifunc.c
@ -131,8 +131,15 @@ _bfd_elf_allocate_ifunc_dyn_relocs (struct bfd_link_info *info,
     the resolved function may be used.  But in non-PIC executable,
     the address of its .plt slot may be used.  Pointer equality may
     not work correctly.  PIE or non-PLT reference should be used if
-     pointer equality is required here.  */
+     pointer equality is required here.
+
+     If STT_GNU_IFUNC symbol is defined in position-dependent executable,
+     backend should change it to the normal function and set its address
+     to its PLT entry which should be resolved by R_*_IRELATIVE at
+     run-time.  All external references should be resolved to its PLT in
+     executable.  */
  if (!need_dynreloc
+      && !(bfd_link_pde (info) && h->def_regular)
      && (h->dynindx != -1
 	  || info->export_dynamic)
      && h->pointer_equality_needed)
--- a/bfd/elf32-i386.c
+++ b/bfd/elf32-i386.c
@ -3805,6 +3805,8 @@ elf_i386_finish_dynamic_symbol (bfd *output_bfd,
 	sym->st_value = 0;
    }

+  _bfd_x86_elf_link_fixup_ifunc_symbol (info, htab, h, sym);
+
  /* Don't generate dynamic GOT relocation against undefined weak
     symbol in executable.  */
  if (h->got.offset != (bfd_vma) -1
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@ -4147,6 +4147,8 @@ elf_x86_64_finish_dynamic_symbol (bfd *output_bfd,
 	sym->st_value = 0;
    }

+  _bfd_x86_elf_link_fixup_ifunc_symbol (info, htab, h, sym);
+
  /* Don't generate dynamic GOT relocation against undefined weak
     symbol in executable.  */
  if (h->got.offset != (bfd_vma) -1
--- a/bfd/elfxx-x86.c
+++ b/bfd/elfxx-x86.c
@ -1730,6 +1730,52 @@ _bfd_x86_elf_fixup_symbol (struct bfd_link_info *info,
  return TRUE;
 }

+/* Change the STT_GNU_IFUNC symbol defined in position-dependent
+   executable into the normal function symbol and set its address
+   to its PLT entry, which should be resolved by R_*_IRELATIVE at
+   run-time.  */
+
+void
+_bfd_x86_elf_link_fixup_ifunc_symbol (struct bfd_link_info *info,
+				      struct elf_x86_link_hash_table *htab,
+				      struct elf_link_hash_entry *h,
+				      Elf_Internal_Sym *sym)
+{
+  if (bfd_link_pde (info)
+      && h->def_regular
+      && h->dynindx != -1
+      && h->plt.offset != (bfd_vma) -1
+      && h->type == STT_GNU_IFUNC
+      && h->pointer_equality_needed)
+    {
+      asection *plt_s;
+      bfd_vma plt_offset;
+      bfd *output_bfd = info->output_bfd;
+
+      if (htab->plt_second)
+	{
+	  struct elf_x86_link_hash_entry *eh
+	    = (struct elf_x86_link_hash_entry *) h;
+
+	  plt_s = htab->plt_second;
+	  plt_offset = eh->plt_second.offset;
+	}
+      else
+	{
+	  plt_s = htab->elf.splt;
+	  plt_offset = h->plt.offset;
+	}
+
+      sym->st_size = 0;
+      sym->st_info = ELF_ST_INFO (ELF_ST_BIND (sym->st_info), STT_FUNC);
+      sym->st_shndx
+	= _bfd_elf_section_from_bfd_section (output_bfd,
+					     plt_s->output_section);
+      sym->st_value = (plt_s->output_section->vma
+		       + plt_s->output_offset + plt_offset);
+    }
+}
+
 /* Return TRUE if symbol should be hashed in the `.gnu.hash' section.  */

 bfd_boolean
--- a/bfd/elfxx-x86.h
+++ b/bfd/elfxx-x86.h
@ -674,6 +674,10 @@ extern bfd_boolean _bfd_x86_elf_merge_gnu_properties
 extern bfd * _bfd_x86_elf_link_setup_gnu_properties
  (struct bfd_link_info *, struct elf_x86_init_table *);

+extern void _bfd_x86_elf_link_fixup_ifunc_symbol
+  (struct bfd_link_info *, struct elf_x86_link_hash_table *,
+   struct elf_link_hash_entry *, Elf_Internal_Sym *sym);
+
 #define bfd_elf64_mkobject \
  _bfd_x86_elf_mkobject
 #define bfd_elf32_mkobject \
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@ -1,3 +1,17 @@
+2018-05-14  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/23169
+	* testsuite/ld-ifunc/ifunc-9-i386.d: New file.
+	* testsuite/ld-ifunc/ifunc-9-x86-64.d: Likewise.
+	* testsuite/ld-ifunc/pr23169a.c: Likewise.
+	* testsuite/ld-ifunc/pr23169a.rd: Likewise.
+	* testsuite/ld-ifunc/pr23169b.c: Likewise.
+	* testsuite/ld-ifunc/pr23169b.c: Likewise.
+	* testsuite/ld-ifunc/pr23169c.rd: Likewise.
+	* testsuite/ld-ifunc/pr23169c.rd: Likewise.
+	* testsuite/ld-ifunc/ifunc-9-x86.d: Removed.
+	* testsuite/ld-ifunc/ifunc.exp: Run PR ld/23169 tests.
+
 2018-05-14  H.J. Lu  <hongjiu.lu@intel.com>

 	PR ld/23162
--- a/ld/testsuite/ld-ifunc/ifunc-9-i386.d
+++ b/ld/testsuite/ld-ifunc/ifunc-9-i386.d
@ -0,0 +1,9 @@
+#source: ifunc-9-x86.s
+#as: --32
+#ld: -m elf_i386 --export-dynamic
+#readelf: -r --wide
+#target: x86_64-*-* i?86-*-*
+
+Relocation section '.rel.plt' at .*
+[ ]+Offset[ ]+Info[ ]+Type[ ]+.*
+[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_386_IRELATIVE[ ]*
--- a/ld/testsuite/ld-ifunc/ifunc-9-x86-64.d
+++ b/ld/testsuite/ld-ifunc/ifunc-9-x86-64.d
@ -0,0 +1,9 @@
+#source: ifunc-9-x86.s
+#as: --64
+#ld: -melf_x86_64 --export-dynamic
+#readelf: -r --wide
+#target: x86_64-*-*
+
+Relocation section '.rela.plt' at .*
+[ ]+Offset[ ]+Info[ ]+Type[ ]+.*
+[0-9a-f]+[ ]+[0-9a-f]+[ ]+R_X86_64_IRELATIVE[ ]+[0-9a-f]*
--- a/ld/testsuite/ld-ifunc/ifunc-9-x86.d
+++ b/ld/testsuite/ld-ifunc/ifunc-9-x86.d
@ -1,3 +0,0 @@
-#ld: --export-dynamic
-#error: .*dynamic STT_GNU_IFUNC symbol `foo' with pointer equality in `.*.o' can not be used when making an executable; recompile with -fPIE and relink with -pie
-#target: x86_64-*-* i?86-*-*
--- a/ld/testsuite/ld-ifunc/ifunc.exp
+++ b/ld/testsuite/ld-ifunc/ifunc.exp
@ -581,6 +581,76 @@ run_cc_link_tests [list \
 	{} \
 	"libpr18841cn.so" \
    ] \
+    [list \
+	"Build libpr23169a.so" \
+	"-shared" \
+	"-fPIC -O2 -g" \
+	{ pr23169a.c } \
+	{} \
+	"libpr23169a.so" \
+    ] \
+    [list \
+	"Build libpr23169b.so" \
+	"-shared -Wl,-z,now" \
+	"-fPIC -O2 -g" \
+	{ pr23169a.c } \
+	{} \
+	"libpr23169b.so" \
+    ] \
+    [list \
+	"Build pr23169a" \
+	"$NOPIE_LDFLAGS -Wl,--no-as-needed tmpdir/libpr23169a.so" \
+	"$NOPIE_CFLAGS -O2 -g" \
+	{ pr23169b.c pr23169c.c } \
+	{{readelf {--dyn-syms} pr23169a.rd} \
+	 {readelf {-r -W} pr23169b.rd}} \
+	"pr23169a" \
+    ] \
+    [list \
+	"Build pr23169b" \
+	"-pie -Wl,--no-as-needed tmpdir/libpr23169a.so" \
+	"-fPIE -O2 -g" \
+	{ pr23169b.c pr23169c.c } \
+	{{readelf {--dyn-syms} pr23169c.rd} \
+	 {readelf {-r -W} pr23169b.rd}} \
+	"pr23169b" \
+    ] \
+    [list \
+	"Build pr23169c" \
+	"$NOPIE_LDFLAGS -Wl,--no-as-needed tmpdir/libpr23169a.so" \
+	"-fPIE -O2 -g" \
+	{ pr23169b.c pr23169c.c } \
+	{{readelf {--dyn-syms} pr23169c.rd} \
+	 {readelf {-r -W} pr23169b.rd}} \
+	"pr23169c" \
+    ] \
+    [list \
+	"Build pr23169d" \
+	"$NOPIE_LDFLAGS -Wl,--no-as-needed,-z,now tmpdir/libpr23169b.so" \
+	"$NOPIE_CFLAGS -O2 -g" \
+	{ pr23169b.c pr23169c.c } \
+	{{readelf {--dyn-syms} pr23169a.rd} \
+	 {readelf {-r -W} pr23169b.rd}} \
+	"pr23169d" \
+    ] \
+    [list \
+	"Build pr23169e" \
+	"-pie -Wl,--no-as-needed,-z,now tmpdir/libpr23169b.so" \
+	"-fPIE -O2 -g" \
+	{ pr23169b.c pr23169c.c } \
+	{{readelf {--dyn-syms} pr23169c.rd} \
+	 {readelf {-r -W} pr23169b.rd}} \
+	"pr23169e" \
+    ] \
+    [list \
+	"Build pr23169f" \
+	"$NOPIE_LDFLAGS -Wl,--no-as-needed,-z,now tmpdir/libpr23169b.so" \
+	"-fPIE -O2 -g" \
+	{ pr23169b.c pr23169c.c } \
+	{{readelf {--dyn-syms} pr23169c.rd} \
+	 {readelf {-r -W} pr23169b.rd}} \
+	"pr23169f" \
+    ] \
 ]

 run_ld_link_exec_tests [list \
@ -632,4 +702,58 @@ run_ld_link_exec_tests [list \
 	"pr18841cn" \
 	"pr18841.out" \
    ] \
+    [list \
+	"Run pr23169a" \
+	"$NOPIE_LDFLAGS -Wl,--no-as-needed tmpdir/libpr23169a.so" \
+	"" \
+	{ pr23169b.c pr23169c.c } \
+	"pr23169a" \
+	"pass.out" \
+	"$NOPIE_CFLAGS -O2 -g" \
+    ] \
+    [list \
+	"Run pr23169b" \
+	"-pie -Wl,--no-as-needed tmpdir/libpr23169a.so" \
+	"" \
+	{ pr23169b.c pr23169c.c } \
+	"pr23169b" \
+	"pass.out" \
+	"-fPIE -O2 -g" \
+    ] \
+    [list \
+	"Run pr23169c" \
+	"$NOPIE_LDFLAGS -Wl,--no-as-needed tmpdir/libpr23169a.so" \
+	"" \
+	{ pr23169b.c pr23169c.c } \
+	"pr23169c" \
+	"pass.out" \
+	"-fPIE -O2 -g" \
+    ] \
+    [list \
+	"Run pr23169d" \
+	"$NOPIE_LDFLAGS -Wl,--no-as-needed,-z,now tmpdir/libpr23169b.so" \
+	"" \
+	{ pr23169b.c pr23169c.c } \
+	"pr23169d" \
+	"pass.out" \
+	"$NOPIE_CFLAGS -O2 -g" \
+    ] \
+    [list \
+	"Run pr23169e" \
+	"-pie -Wl,--no-as-needed,-z,now tmpdir/libpr23169b.so" \
+	"" \
+	{ pr23169b.c pr23169c.c } \
+	"pr23169e" \
+	"pass.out" \
+	"-fPIE -O2 -g" \
+    ] \
+    [list \
+	"Run pr23169f" \
+	"$NOPIE_LDFLAGS -Wl,--no-as-needed,-z,now tmpdir/libpr23169b.so" \
+	"" \
+	{ pr23169b.c pr23169c.c } \
+	"pr23169f" \
+	"pass.out" \
+	"-fPIE -O2 -g" \
+    ] \
 ]
--- a/ld/testsuite/ld-ifunc/pr23169a.c
+++ b/ld/testsuite/ld-ifunc/pr23169a.c
@ -0,0 +1,9 @@
+int (*func_p) (void);
+extern int func (void);
+
+void
+foo (void)
+{
+  if (func_p != &func || func_p () != 0xbadbeef)
+    __builtin_abort ();
+}
--- a/ld/testsuite/ld-ifunc/pr23169a.rd
+++ b/ld/testsuite/ld-ifunc/pr23169a.rd
@ -0,0 +1,6 @@
+
+Symbol table '\.dynsym' contains [0-9]+ entries:
+ +Num: +Value +Size Type +Bind +Vis +Ndx Name
+#...
+ +[0-9]+: +[a-f0-9]+ +0 +FUNC +GLOBAL +DEFAULT +[0-9]+ +func
+#...
--- a/ld/testsuite/ld-ifunc/pr23169b.c
+++ b/ld/testsuite/ld-ifunc/pr23169b.c
@ -0,0 +1,23 @@
+#include <stdio.h>
+
+extern int (*func_p) (void);
+extern int func (void);
+extern void foo (void);
+
+
+void
+bar (void)
+{
+  if (func_p != &func || func_p () != 0xbadbeef)
+    __builtin_abort ();
+}
+
+int
+main ()
+{
+  func_p = &func;
+  foo ();
+  bar ();
+  printf ("PASS\n");
+  return 0;
+}
--- a/ld/testsuite/ld-ifunc/pr23169b.rd
+++ b/ld/testsuite/ld-ifunc/pr23169b.rd
@ -0,0 +1,3 @@
+#failif
+[a-f0-9]+ +[0-9a-f]+ +R_.*_* +[a-f0-9]+ +func(| \+ 0)
+...
--- a/ld/testsuite/ld-ifunc/pr23169c.c
+++ b/ld/testsuite/ld-ifunc/pr23169c.c
@ -0,0 +1,13 @@
+static int
+ifunc (void)
+{
+  return 0xbadbeef;
+}
+
+void func(void) __attribute__((ifunc("resolve_func")));
+
+static void *
+resolve_func (void)
+{
+  return ifunc;
+}
--- a/ld/testsuite/ld-ifunc/pr23169c.rd
+++ b/ld/testsuite/ld-ifunc/pr23169c.rd
@ -0,0 +1,6 @@
+
+Symbol table '\.dynsym' contains [0-9]+ entries:
+ +Num: +Value +Size Type +Bind +Vis +Ndx Name
+#...
+ +[0-9]+: +[a-f0-9]+ +[0-9]+ +IFUNC +GLOBAL +DEFAULT +[0-9]+ +func
+#...