PLT / non-PIC executable support for MIPS

PLT / non-PIC executable support for MIPS

[Daniel Jacobowitz]

I have checked in this patch, which adds support for the new PLT
format recently added to binutils and gcc.

This patch also fixes a bug in dlsym on MIPS, even with current GCC
and binutils; dlsym would sometimes return lazy binding stubs.  That's
what the copy of dl-lookup.c and the trick in do-lookup.h are for.

-- 
Daniel Jacobowitz
CodeSourcery

2008-10-01  Mark Shinwell  <shinwell@codesourcery.com>
	    Daniel Jacobowitz  <dan@codesourcery.com>
	    Richard Sandiford  <rdsandiford@googlemail.com>

	* sysdeps/mips/dl-dtprocnum.h (DT_MIPS_NUM): Redefine.
	* sysdeps/mips/dl-lookup.c: New.
	* sysdeps/mips/do-lookup.h: New.
	* sysdeps/mips/dl-machine.h (ELF_MACHINE_NO_PLT): Remove
	definition.
	(STO_MIPS_PLT, R_MIPS_COPY, R_MIPS_JUMP_SLOT, DT_MIPS_PLTGOT): Define
	if needed.
	(ELF_MACHINE_JMP_SLOT): Alter definition and update comment.
	(elf_machine_type_class): Likewise.
	(ELF_MACHINE_PLT_REL): Define.
	(elf_machine_fixup_plt): New.
	(elf_machine_plt_value): New.
	(elf_machine_reloc): Handle jump slot and copy relocations.
	(elf_machine_lazy_rel): Point relocation place at PLT if
	required.
	(RESOLVE_GOTSYM): Take a relocation type argument.
	(elf_machine_got_rel): Bind lazy stubs directly to their target if
	!lazy.  Skip lazy binding for PLT symbols.
	(elf_machine_runtime_setup): Fill in .got.plt header.
	* sysdeps/mips/dl-trampoline.c (IFNEWABI): New macro.
	(ELF_DL_PLT_FRAME_SIZE, ELF_DL_PLT_SAVE_ARG_REGS,
	ELF_DL_PLT_RESTORE_ARG_REGS): Define.
	(_dl_runtime_pltresolve): New.
	* sysdeps/mips/bits/linkmap.h: New file.
	* sysdeps/mips/tls-macros.h: Load $gp as required.  Merge 32-bit and
	64-bit versions.

	* sysdeps/unix/sysv/linux/mips/mips32/sysdep.h (SYSCALL_ERROR_LABEL):
	Delete definition.
	* sysdeps/unix/sysv/linux/mips/nptl/sysdep-cancel.h (PSEUDO_CPLOAD,
	PSEUDO_ERRJMP, PSEUDO_SAVEGP, PSEUDO_LOADGP): Define.
	(PSEUDO): Use them.  Move outside __PIC__.
	(PSEUDO_JMP): New.
	(CENABLE, CDISABLE): Use it.

Index: sysdeps/unix/sysv/linux/mips/mips32/sysdep.h
===================================================================
--- sysdeps/unix/sysv/linux/mips/mips32/sysdep.h	(revision 219453)
+++ sysdeps/unix/sysv/linux/mips/mips32/sysdep.h	(working copy)
@@ -35,15 +35,7 @@
 # define SYS_ify(syscall_name)	__NR_/**/syscall_name
 #endif
 
-#ifdef __ASSEMBLER__
-
-/* We don't want the label for the error handler to be visible in the symbol
-   table when we define it here.  */
-#ifdef __PIC__
-# define SYSCALL_ERROR_LABEL 99b
-#endif
-
-#else   /* ! __ASSEMBLER__ */
+#ifndef __ASSEMBLER__
 
 /* Define a macro which expands into the inline wrapper code for a system
    call.  */
Index: sysdeps/unix/sysv/linux/mips/nptl/sysdep-cancel.h
===================================================================
--- sysdeps/unix/sysv/linux/mips/nptl/sysdep-cancel.h	(revision 219453)
+++ sysdeps/unix/sysv/linux/mips/nptl/sysdep-cancel.h	(working copy)
@@ -25,28 +25,38 @@
 
 #if !defined NOT_IN_libc || defined IS_IN_libpthread || defined IS_IN_librt
 
-#ifdef __PIC__
+# ifdef __PIC__
+#  define PSEUDO_CPLOAD .cpload t9;
+#  define PSEUDO_ERRJMP la t9, __syscall_error; jr t9;
+#  define PSEUDO_SAVEGP sw gp, 32(sp); cfi_rel_offset (gp, 32);
+#  define PSEUDO_LOADGP lw gp, 32(sp);
+# else
+#  define PSEUDO_CPLOAD
+#  define PSEUDO_ERRJMP j __syscall_error;
+#  define PSEUDO_SAVEGP
+#  define PSEUDO_LOADGP
+# endif
+
 # undef PSEUDO
 # define PSEUDO(name, syscall_name, args)				      \
       .align 2;								      \
   L(pseudo_start):							      \
       cfi_startproc;							      \
-  99: la t9,__syscall_error;						      \
-      jr t9;								      \
+  99: PSEUDO_ERRJMP							      \
   .type __##syscall_name##_nocancel, @function;				      \
   .globl __##syscall_name##_nocancel;					      \
   __##syscall_name##_nocancel:						      \
     .set noreorder;							      \
-    .cpload t9;								      \
+    PSEUDO_CPLOAD							      \
     li v0, SYS_ify(syscall_name);					      \
     syscall;								      \
     .set reorder;							      \
-    bne a3, zero, SYSCALL_ERROR_LABEL;			       		      \
+    bne a3, zero, 99b;					       		      \
     ret;								      \
   .size __##syscall_name##_nocancel,.-__##syscall_name##_nocancel;	      \
   ENTRY (name)								      \
     .set noreorder;							      \
-    .cpload t9;								      \
+    PSEUDO_CPLOAD							      \
     .set reorder;							      \
     SINGLE_THREAD_P(v1);						      \
     bne zero, v1, L(pseudo_cancel);					      \
@@ -54,17 +64,16 @@
     li v0, SYS_ify(syscall_name);					      \
     syscall;								      \
     .set reorder;							      \
-    bne a3, zero, SYSCALL_ERROR_LABEL;			       		      \
+    bne a3, zero, 99b;					       		      \
     ret;								      \
   L(pseudo_cancel):							      \
     SAVESTK_##args;						              \
     sw ra, 28(sp);							      \
     cfi_rel_offset (ra, 28);						      \
-    sw gp, 32(sp);							      \
-    cfi_rel_offset (gp, 32);						      \
+    PSEUDO_SAVEGP							      \
     PUSHARGS_##args;			/* save syscall args */	      	      \
     CENABLE;								      \
-    lw gp, 32(sp);							      \
+    PSEUDO_LOADGP							      \
     sw v0, 44(sp);			/* save mask */			      \
     POPARGS_##args;			/* restore syscall args */	      \
     .set noreorder;							      \
@@ -75,12 +84,12 @@
     sw a3, 40(sp);			/* save syscall error flag */	      \
     lw a0, 44(sp);			/* pass mask as arg1 */		      \
     CDISABLE;								      \
-    lw gp, 32(sp);							      \
+    PSEUDO_LOADGP							      \
     lw v0, 36(sp);			/* restore syscall result */          \
     lw a3, 40(sp);			/* restore syscall error flag */      \
     lw ra, 28(sp);			/* restore return address */	      \
     .set noreorder;							      \
-    bne a3, zero, SYSCALL_ERROR_LABEL;					      \
+    bne a3, zero, 99b;							      \
      RESTORESTK;						              \
   L(pseudo_end):							      \
     .set reorder;
@@ -88,8 +97,6 @@
 # undef PSEUDO_END
 # define PSEUDO_END(sym) cfi_endproc; .end sym; .size sym,.-sym
 
-#endif
-
 # define PUSHARGS_0	/* nothing to do */
 # define PUSHARGS_1	PUSHARGS_0 sw a0, 0(sp); cfi_rel_offset (a0, 0);
 # define PUSHARGS_2	PUSHARGS_1 sw a1, 4(sp); cfi_rel_offset (a1, 4);
@@ -136,19 +143,25 @@
 # define RESTORESTK 	addu sp, STKSPACE; cfi_adjust_cfa_offset(-STKSPACE)
 
 
+# ifdef __PIC__
 /* We use jalr rather than jal.  This means that the assembler will not
    automatically restore $gp (in case libc has multiple GOTs) so we must
    do it manually - which we have to do anyway since we don't use .cprestore.
    It also shuts up the assembler warning about not using .cprestore.  */
+#  define PSEUDO_JMP(sym) la t9, sym; jalr t9;
+# else
+#  define PSEUDO_JMP(sym) jal sym;
+# endif
+
 # ifdef IS_IN_libpthread
-#  define CENABLE	la t9, __pthread_enable_asynccancel; jalr t9;
-#  define CDISABLE	la t9, __pthread_disable_asynccancel; jalr t9;
+#  define CENABLE	PSEUDO_JMP (__pthread_enable_asynccancel)
+#  define CDISABLE	PSEUDO_JMP (__pthread_disable_asynccancel)
 # elif defined IS_IN_librt
-#  define CENABLE	la t9, __librt_enable_asynccancel; jalr t9;
-#  define CDISABLE	la t9, __librt_disable_asynccancel; jalr t9;
+#  define CENABLE	PSEUDO_JMP (__librt_enable_asynccancel)
+#  define CDISABLE	PSEUDO_JMP (__librt_disable_asynccancel)
 # else
-#  define CENABLE	la t9, __libc_enable_asynccancel; jalr t9;
-#  define CDISABLE	la t9, __libc_disable_asynccancel; jalr t9;
+#  define CENABLE	PSEUDO_JMP (__libc_enable_asynccancel)
+#  define CDISABLE	PSEUDO_JMP (__libc_disable_asynccancel)
 # endif
 
 # ifndef __ASSEMBLER__
Index: sysdeps/mips/dl-dtprocnum.h
===================================================================
--- sysdeps/mips/dl-dtprocnum.h	(revision 219453)
+++ sysdeps/mips/dl-dtprocnum.h	(working copy)
@@ -17,6 +17,12 @@
    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
    02111-1307 USA.  */
 
+/* Until elf/elf.h in glibc is updated.  */
+#ifndef STO_MIPS_PLT
+# undef DT_MIPS_NUM
+# define DT_MIPS_NUM 0x35
+#endif
+
 /* Number of extra dynamic section entries for this architecture.  By
    default there are none.  */
 #define DT_THISPROCNUM	DT_MIPS_NUM
Index: sysdeps/mips/do-lookup.h
===================================================================
--- sysdeps/mips/do-lookup.h	(revision 0)
+++ sysdeps/mips/do-lookup.h	(revision 0)
@@ -0,0 +1,37 @@
+/* MIPS-specific veneer to GLIBC's do-lookup.h.
+   Copyright (C) 2008 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+/* The semantics of zero/non-zero values of undefined symbols differs
+   depending on whether the non-PIC ABI is in use.  Under the non-PIC ABI,
+   a non-zero value indicates that there is an address reference to the
+   symbol and thus it must always be resolved (except when resolving a jump
+   slot relocation) to the PLT entry whose address is provided as the
+   symbol's value; a zero value indicates that this canonical-address
+   behaviour is not required.  Yet under the classic MIPS psABI, a zero value
+   indicates that there is an address reference to the function and the
+   dynamic linker must resolve the symbol immediately upon loading.  To
+   avoid conflict, symbols for which the dynamic linker must assume the
+   non-PIC ABI semantics are marked with the STO_MIPS_PLT flag.  The
+   following ugly hack causes the code in the platform-independent
+   do-lookup.h file to check this flag correctly.  */
+#define st_value st_shndx == SHN_UNDEF && !(sym->st_other & STO_MIPS_PLT)) \
+		 || (sym->st_value
+#include_next "do-lookup.h"
+#undef st_value
+
Index: sysdeps/mips/tls-macros.h
===================================================================
--- sysdeps/mips/tls-macros.h	(revision 219453)
+++ sysdeps/mips/tls-macros.h	(working copy)
@@ -1,44 +1,56 @@
 /* Macros to support TLS testing in times of missing compiler support.  */
 
-#if _MIPS_SIM != _ABI64
+#include <sys/cdefs.h>
+#include <sys/asm.h>
 
-/* These versions are for o32 and n32.  */
-
-# define TLS_GD(x)					\
-  ({ void *__result;					\
-     extern void *__tls_get_addr (void *);		\
-     asm ("addiu %0, $28, %%tlsgd(" #x ")"		\
-	  : "=r" (__result));				\
-     (int *)__tls_get_addr (__result); })
+#define __STRING2(X) __STRING(X)
+#define ADDU __STRING2(PTR_ADDU)
+#define ADDIU __STRING2(PTR_ADDIU)
+#define LW __STRING2(PTR_L)
+
+/* Load the GOT pointer, which may not be in $28 in a non-PIC
+   (abicalls pic0) function.  */
+#ifndef __PIC__
+# if _MIPS_SIM != _ABI64
+#  define LOAD_GP "move %[tmp], $28\n\tla $28, __gnu_local_gp\n\t"
+# else
+#  define LOAD_GP "move %[tmp], $28\n\tdla $28, __gnu_local_gp\n\t"
+# endif
+# define UNLOAD_GP "\n\tmove $28, %[tmp]"
 #else
+# define LOAD_GP
+# define UNLOAD_GP
+#endif
+
 # define TLS_GD(x)					\
-  ({ void *__result;					\
+  ({ void *__result, *__tmp;				\
      extern void *__tls_get_addr (void *);		\
-     asm ("daddiu %0, $28, %%tlsgd(" #x ")"		\
-	  : "=r" (__result));				\
+     asm (LOAD_GP ADDIU " %0, $28, %%tlsgd(" #x ")"	\
+	  UNLOAD_GP					\
+	  : "=r" (__result), [tmp] "=&r" (__tmp));	\
      (int *)__tls_get_addr (__result); })
-#endif
-
-#if _MIPS_SIM != _ABI64
 # define TLS_LD(x)					\
-  ({ void *__result;					\
+  ({ void *__result, *__tmp;				\
      extern void *__tls_get_addr (void *);		\
-     asm ("addiu %0, $28, %%tlsldm(" #x ")"		\
-	  : "=r" (__result));				\
+     asm (LOAD_GP ADDIU " %0, $28, %%tlsldm(" #x ")"	\
+	  UNLOAD_GP					\
+	  : "=r" (__result), [tmp] "=&r" (__tmp));	\
      __result = __tls_get_addr (__result);		\
      asm ("lui $3,%%dtprel_hi(" #x ")\n\t"		\
 	  "addiu $3,$3,%%dtprel_lo(" #x ")\n\t"		\
-	  "addu %0,%0,$3"				\
+	  ADDU " %0,%0,$3"				\
 	  : "+r" (__result) : : "$3");			\
      __result; })
 # define TLS_IE(x)					\
-  ({ void *__result;					\
+  ({ void *__result, *__tmp;				\
      asm (".set push\n\t.set mips32r2\n\t"		\
 	  "rdhwr\t%0,$29\n\t.set pop"			\
 	  : "=v" (__result));				\
-     asm ("lw $3,%%gottprel(" #x ")($28)\n\t"		\
-	  "addu %0,%0,$3"				\
-	  : "+r" (__result) : : "$3");			\
+     asm (LOAD_GP LW " $3,%%gottprel(" #x ")($28)\n\t"	\
+	  ADDU " %0,%0,$3"				\
+	  UNLOAD_GP					\
+	  : "+r" (__result), [tmp] "=&r" (__tmp)	\
+	  : : "$3");					\
      __result; })
 # define TLS_LE(x)					\
   ({ void *__result;					\
@@ -47,42 +59,6 @@
 	  : "=v" (__result));				\
      asm ("lui $3,%%tprel_hi(" #x ")\n\t"		\
 	  "addiu $3,$3,%%tprel_lo(" #x ")\n\t"		\
-	  "addu %0,%0,$3"				\
-	  : "+r" (__result) : : "$3");			\
-     __result; })
-
-#else
-
-/* These versions are for n64.  */
-
-# define TLS_LD(x)					\
-  ({ void *__result;					\
-     extern void *__tls_get_addr (void *);		\
-     asm ("daddiu %0, $28, %%tlsldm(" #x ")"		\
-	  : "=r" (__result));				\
-     __result = __tls_get_addr (__result);		\
-     asm ("lui $3,%%dtprel_hi(" #x ")\n\t"		\
-	  "daddiu $3,$3,%%dtprel_lo(" #x ")\n\t"	\
-	  "daddu %0,%0,$3"				\
-	  : "+r" (__result) : : "$3");			\
-     __result; })
-# define TLS_IE(x)					\
-  ({ void *__result;					\
-     asm (".set push\n\t.set mips32r2\n\t"		\
-	  "rdhwr\t%0,$29\n\t.set pop"			\
-	  : "=v" (__result));				\
-     asm ("ld $3,%%gottprel(" #x ")($28)\n\t"		\
-	  "daddu %0,%0,$3"				\
-	  : "+r" (__result) : : "$3");			\
-     __result; })
-# define TLS_LE(x)					\
-  ({ void *__result;					\
-     asm (".set push\n\t.set mips32r2\n\t"		\
-	  "rdhwr\t%0,$29\n\t.set pop"			\
-	  : "=v" (__result));				\
-     asm ("lui $3,%%tprel_hi(" #x ")\n\t"		\
-	  "daddiu $3,$3,%%tprel_lo(" #x ")\n\t"		\
-	  "daddu %0,%0,$3"				\
+	  ADDU " %0,%0,$3"				\
 	  : "+r" (__result) : : "$3");			\
      __result; })
-#endif
Index: sysdeps/mips/dl-machine.h
===================================================================
--- sysdeps/mips/dl-machine.h	(revision 219453)
+++ sysdeps/mips/dl-machine.h	(working copy)
@@ -25,8 +25,6 @@
 
 #define ELF_MACHINE_NAME "MIPS"
 
-#define ELF_MACHINE_NO_PLT
-
 #include <entry.h>
 
 #ifndef ENTRY_POINT
@@ -55,11 +53,23 @@
 	".size\t" __STRING(entry) ", . - " __STRING(entry) "\n\t"
 #endif
 
+/* Until elf/elf.h in glibc is updated.  */
+#ifndef STO_MIPS_PLT
+#define STO_MIPS_PLT			0x8
+#define R_MIPS_COPY		126
+#define R_MIPS_JUMP_SLOT        127
+#define DT_MIPS_PLTGOT	     0x70000032
+#endif
+
 /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries.
-   This makes no sense on MIPS but we have to define this to R_MIPS_REL32
-   to avoid the asserts in dl-lookup.c from blowing.  */
-#define ELF_MACHINE_JMP_SLOT			R_MIPS_REL32
-#define elf_machine_type_class(type)		ELF_RTYPE_CLASS_PLT
+   This only makes sense on MIPS when using PLTs, so choose the
+   PLT relocation (not encountered when not using PLTs).  */
+#define ELF_MACHINE_JMP_SLOT			R_MIPS_JUMP_SLOT
+#define elf_machine_type_class(type) \
+  ((((type) == ELF_MACHINE_JMP_SLOT) * ELF_RTYPE_CLASS_PLT)	\
+   | (((type) == R_MIPS_COPY) * ELF_RTYPE_CLASS_COPY))
+
+#define ELF_MACHINE_PLT_REL 1
 
 /* Translate a processor specific dynamic tag to the index
    in l_info array.  */
@@ -73,6 +83,15 @@ do { if ((l)->l_info[DT_MIPS (RLD_MAP)])
        (ElfW(Addr)) (r); \
    } while (0)
 
+/* Allow ABIVERSION == 1, meaning PLTs and copy relocations are
+   required.  */
+#define VALID_ELF_ABIVERSION(ver)	(ver == 0 || ver == 2)
+#define VALID_ELF_OSABI(osabi)		(osabi == ELFOSABI_SYSV)
+#define VALID_ELF_HEADER(hdr,exp,size) \
+  memcmp (hdr,exp,size-2) == 0 \
+  && VALID_ELF_OSABI (hdr[EI_OSABI]) \
+  && VALID_ELF_ABIVERSION (hdr[EI_ABIVERSION])
+
 /* Return nonzero iff ELF header is compatible with the running host.  */
 static inline int __attribute_used__
 elf_machine_matches_host (const ElfW(Ehdr) *ehdr)
@@ -294,6 +313,24 @@ do {									\
 #  define ARCH_LA_PLTEXIT mips_n64_gnu_pltexit
 # endif
 
+/* For a non-writable PLT, rewrite the .got.plt entry at RELOC_ADDR to
+   point at the symbol with address VALUE.  For a writable PLT, rewrite
+   the corresponding PLT entry instead.  */
+static inline ElfW(Addr)
+elf_machine_fixup_plt (struct link_map *map, lookup_t t,
+		       const ElfW(Rel) *reloc,
+		       ElfW(Addr) *reloc_addr, ElfW(Addr) value)
+{
+  return *reloc_addr = value;
+}
+
+static inline ElfW(Addr)
+elf_machine_plt_value (struct link_map *map, const ElfW(Rel) *reloc,
+		       ElfW(Addr) value)
+{
+  return value;
+}
+
 #endif /* !dl_machine_h */
 
 #ifdef RESOLVE_MAP
@@ -461,6 +498,57 @@ elf_machine_reloc (struct link_map *map,
 #endif
     case R_MIPS_NONE:		/* Alright, Wilbur.  */
       break;
+
+    case R_MIPS_JUMP_SLOT:
+      {
+	struct link_map *sym_map;
+	ElfW(Addr) value;
+
+	/* The addend for a jump slot relocation must always be zero:
+	   calls via the PLT always branch to the symbol's address and
+	   not to the address plus a non-zero offset.  */
+	if (r_addend != 0)
+	  _dl_signal_error (0, map->l_name, NULL,
+			    "found jump slot relocation with non-zero addend");
+
+	sym_map = RESOLVE_MAP (&sym, version, r_type);
+	value = sym_map == NULL ? 0 : sym_map->l_addr + sym->st_value;
+	*addr_field = value;
+
+	break;
+      }
+
+    case R_MIPS_COPY:
+      {
+	const ElfW(Sym) *const refsym = sym;
+	struct link_map *sym_map;
+	ElfW(Addr) value;
+
+	/* Calculate the address of the symbol.  */
+	sym_map = RESOLVE_MAP (&sym, version, r_type);
+	value = sym_map == NULL ? 0 : sym_map->l_addr + sym->st_value;
+
+	if (__builtin_expect (sym == NULL, 0))
+	  /* This can happen in trace mode if an object could not be
+	     found.  */
+	  break;
+	if (__builtin_expect (sym->st_size > refsym->st_size, 0)
+	    || (__builtin_expect (sym->st_size < refsym->st_size, 0)
+		&& GLRO(dl_verbose)))
+	  {
+	    const char *strtab;
+
+	    strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
+	    _dl_error_printf ("\
+  %s: Symbol `%s' has different size in shared object, consider re-linking\n",
+			      rtld_progname ?: "<program name unknown>",
+			      strtab + refsym->st_name);
+	  }
+	memcpy (reloc_addr, (void *) value,
+	        MIN (sym->st_size, refsym->st_size));
+	break;
+      }
+
 #if _MIPS_SIM == _ABI64
     case R_MIPS_64:
       /* For full compliance with the ELF64 ABI, one must precede the
@@ -505,9 +593,23 @@ elf_machine_rel_relative (ElfW(Addr) l_a
 auto inline void
 __attribute__((always_inline))
 elf_machine_lazy_rel (struct link_map *map,
-		      ElfW(Addr) l_addr, const ElfW(Rela) *reloc)
+		      ElfW(Addr) l_addr, const ElfW(Rel) *reloc)
 {
-  /* Do nothing.  */
+  ElfW(Addr) *const reloc_addr = (void *) (l_addr + reloc->r_offset);
+  const unsigned int r_type = ELFW(R_TYPE) (reloc->r_info);
+  /* Check for unexpected PLT reloc type.  */
+  if (__builtin_expect (r_type == R_MIPS_JUMP_SLOT, 1))
+    {
+      if (__builtin_expect (map->l_mach.plt, 0) == 0)
+	{
+	  /* Nothing is required here since we only support lazy
+	     relocation in executables.  */
+	}
+      else
+	*reloc_addr = map->l_mach.plt;
+    }
+  else
+    _dl_reloc_bad_type (map, r_type, 1);
 }
 
 auto inline void
@@ -538,13 +640,13 @@ elf_machine_got_rel (struct link_map *ma
   const ElfW(Half) *vernum;
   int i, n, symidx;
 
-#define RESOLVE_GOTSYM(sym,vernum,sym_index)				  \
+#define RESOLVE_GOTSYM(sym,vernum,sym_index,reloc)			  \
     ({									  \
       const ElfW(Sym) *ref = sym;					  \
       const struct r_found_version *version				  \
         = vernum ? &map->l_versions[vernum[sym_index] & 0x7fff] : NULL;	  \
       struct link_map *sym_map;						  \
-      sym_map = RESOLVE_MAP (&ref, version, R_MIPS_REL32);		  \
+      sym_map = RESOLVE_MAP (&ref, version, reloc);			  \
       ref ? sym_map->l_addr + ref->st_value : 0;			  \
     })
 
@@ -585,25 +687,38 @@ elf_machine_got_rel (struct link_map *ma
     {
       if (sym->st_shndx == SHN_UNDEF)
 	{
-	  if (ELFW(ST_TYPE) (sym->st_info) == STT_FUNC
-	      && sym->st_value && lazy)
-	    *got = sym->st_value + map->l_addr;
+	  if (ELFW(ST_TYPE) (sym->st_info) == STT_FUNC && sym->st_value
+	      && !(sym->st_other & STO_MIPS_PLT))
+	    {
+	      if (lazy)
+		*got = sym->st_value + map->l_addr;
+	      else
+		/* This is a lazy-binding stub, so we don't need the
+		   canonical address.  */
+		*got = RESOLVE_GOTSYM (sym, vernum, symidx, R_MIPS_JUMP_SLOT);
+	    }
 	  else
-	    *got = RESOLVE_GOTSYM (sym, vernum, symidx);
+	    *got = RESOLVE_GOTSYM (sym, vernum, symidx, R_MIPS_32);
 	}
       else if (sym->st_shndx == SHN_COMMON)
-	*got = RESOLVE_GOTSYM (sym, vernum, symidx);
+	*got = RESOLVE_GOTSYM (sym, vernum, symidx, R_MIPS_32);
       else if (ELFW(ST_TYPE) (sym->st_info) == STT_FUNC
-	       && *got != sym->st_value
-	       && lazy)
-	*got += map->l_addr;
+	       && *got != sym->st_value)
+	{
+	  if (lazy)
+	    *got += map->l_addr;
+	  else
+	    /* This is a lazy-binding stub, so we don't need the
+	       canonical address.  */
+	    *got = RESOLVE_GOTSYM (sym, vernum, symidx, R_MIPS_JUMP_SLOT);
+	}
       else if (ELFW(ST_TYPE) (sym->st_info) == STT_SECTION)
 	{
 	  if (sym->st_other == 0)
 	    *got += map->l_addr;
 	}
       else
-	*got = RESOLVE_GOTSYM (sym, vernum, symidx);
+	*got = RESOLVE_GOTSYM (sym, vernum, symidx, R_MIPS_32);
 
       ++got;
       ++sym;
@@ -624,6 +739,7 @@ elf_machine_runtime_setup (struct link_m
 # ifndef RTLD_BOOTSTRAP
   ElfW(Addr) *got;
   extern void _dl_runtime_resolve (ElfW(Word));
+  extern void _dl_runtime_pltresolve (void);
   extern int _dl_mips_gnu_objects;
 
   if (lazy)
@@ -650,6 +766,20 @@ elf_machine_runtime_setup (struct link_m
   /* Relocate global offset table.  */
   elf_machine_got_rel (l, lazy);
 
+  /* If using PLTs, fill in the first two entries of .got.plt.  */
+  if (l->l_info[DT_JMPREL] && lazy)
+    {
+      ElfW(Addr) *gotplt;
+      gotplt = (ElfW(Addr) *) D_PTR (l, l_info[DT_MIPS (PLTGOT)]);
+      /* If a library is prelinked but we have to relocate anyway,
+	 we have to be able to undo the prelinking of .got.plt.
+	 The prelinker saved the address of .plt for us here.  */
+      if (gotplt[1])
+	l->l_mach.plt = gotplt[1] + l->l_addr;
+      gotplt[0] = (ElfW(Addr)) &_dl_runtime_pltresolve;
+      gotplt[1] = (ElfW(Addr)) l;
+    }
+
 # endif
   return lazy;
 }
Index: sysdeps/mips/dl-lookup.c
===================================================================
--- sysdeps/mips/dl-lookup.c	(revision 0)
+++ sysdeps/mips/dl-lookup.c	(revision 0)
@@ -0,0 +1,581 @@
+/* Look up a symbol in the loaded objects.
+   MIPS/Linux version - this is identical to the common version, but
+   because it is in sysdeps/mips, it gets sysdeps/mips/do-lookup.h.
+   Using <do-lookup.h> instead of "do-lookup.h" would work too.
+
+   Copyright (C) 1995-2005, 2006, 2007 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <alloca.h>
+#include <libintl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <ldsodefs.h>
+#include <dl-hash.h>
+#include <dl-machine.h>
+#include <sysdep-cancel.h>
+#include <bits/libc-lock.h>
+#include <tls.h>
+
+#include <assert.h>
+
+#define VERSTAG(tag)	(DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (tag))
+
+/* We need this string more than once.  */
+static const char undefined_msg[] = "undefined symbol: ";
+
+
+struct sym_val
+  {
+    const ElfW(Sym) *s;
+    struct link_map *m;
+  };
+
+
+#define make_string(string, rest...) \
+  ({									      \
+    const char *all[] = { string, ## rest };				      \
+    size_t len, cnt;							      \
+    char *result, *cp;							      \
+									      \
+    len = 1;								      \
+    for (cnt = 0; cnt < sizeof (all) / sizeof (all[0]); ++cnt)		      \
+      len += strlen (all[cnt]);						      \
+									      \
+    cp = result = alloca (len);						      \
+    for (cnt = 0; cnt < sizeof (all) / sizeof (all[0]); ++cnt)		      \
+      cp = __stpcpy (cp, all[cnt]);					      \
+									      \
+    result;								      \
+  })
+
+/* Statistics function.  */
+#ifdef SHARED
+# define bump_num_relocations() ++GL(dl_num_relocations)
+#else
+# define bump_num_relocations() ((void) 0)
+#endif
+
+
+/* The actual lookup code.  */
+#include "do-lookup.h"
+
+
+static uint_fast32_t
+dl_new_hash (const char *s)
+{
+  uint_fast32_t h = 5381;
+  for (unsigned char c = *s; c != '\0'; c = *++s)
+    h = h * 33 + c;
+  return h & 0xffffffff;
+}
+
+
+/* Add extra dependency on MAP to UNDEF_MAP.  */
+static int
+internal_function
+add_dependency (struct link_map *undef_map, struct link_map *map, int flags)
+{
+  struct link_map *runp;
+  unsigned int i;
+  int result = 0;
+
+  /* Avoid self-references and references to objects which cannot be
+     unloaded anyway.  */
+  if (undef_map == map)
+    return 0;
+
+  /* Avoid references to objects which cannot be unloaded anyway.  */
+  assert (map->l_type == lt_loaded);
+  if ((map->l_flags_1 & DF_1_NODELETE) != 0)
+    return 0;
+
+  struct link_map_reldeps *l_reldeps
+    = atomic_forced_read (undef_map->l_reldeps);
+
+  /* Make sure l_reldeps is read before l_initfini.  */
+  atomic_read_barrier ();
+
+  /* Determine whether UNDEF_MAP already has a reference to MAP.  First
+     look in the normal dependencies.  */
+  struct link_map **l_initfini = atomic_forced_read (undef_map->l_initfini);
+  if (l_initfini != NULL)
+    {
+      for (i = 0; l_initfini[i] != NULL; ++i)
+	if (l_initfini[i] == map)
+	  return 0;
+    }
+
+  /* No normal dependency.  See whether we already had to add it
+     to the special list of dynamic dependencies.  */
+  unsigned int l_reldepsact = 0;
+  if (l_reldeps != NULL)
+    {
+      struct link_map **list = &l_reldeps->list[0];
+      l_reldepsact = l_reldeps->act;
+      for (i = 0; i < l_reldepsact; ++i)
+	if (list[i] == map)
+	  return 0;
+    }
+
+  /* Save serial number of the target MAP.  */
+  unsigned long long serial = map->l_serial;
+
+  /* Make sure nobody can unload the object while we are at it.  */
+  if (__builtin_expect (flags & DL_LOOKUP_GSCOPE_LOCK, 0))
+    {
+      /* We can't just call __rtld_lock_lock_recursive (GL(dl_load_lock))
+	 here, that can result in ABBA deadlock.  */
+      THREAD_GSCOPE_RESET_FLAG ();
+      __rtld_lock_lock_recursive (GL(dl_load_lock));
+      /* While MAP value won't change, after THREAD_GSCOPE_RESET_FLAG ()
+	 it can e.g. point to unallocated memory.  So avoid the optimizer
+	 treating the above read from MAP->l_serial as ensurance it
+	 can safely dereference it.  */
+      map = atomic_forced_read (map);
+
+      /* From this point on it is unsafe to dereference MAP, until it
+	 has been found in one of the lists.  */
+
+      /* Redo the l_initfini check in case undef_map's l_initfini
+	 changed in the mean time.  */
+      if (undef_map->l_initfini != l_initfini
+	  && undef_map->l_initfini != NULL)
+	{
+	  l_initfini = undef_map->l_initfini;
+	  for (i = 0; l_initfini[i] != NULL; ++i)
+	    if (l_initfini[i] == map)
+	      goto out_check;
+	}
+
+      /* Redo the l_reldeps check if undef_map's l_reldeps changed in
+	 the mean time.  */
+      if (undef_map->l_reldeps != NULL)
+	{
+	  if (undef_map->l_reldeps != l_reldeps)
+	    {
+	      struct link_map **list = &undef_map->l_reldeps->list[0];
+	      l_reldepsact = undef_map->l_reldeps->act;
+	      for (i = 0; i < l_reldepsact; ++i)
+		if (list[i] == map)
+		  goto out_check;
+	    }
+	  else if (undef_map->l_reldeps->act > l_reldepsact)
+	    {
+	      struct link_map **list
+		= &undef_map->l_reldeps->list[0];
+	      i = l_reldepsact;
+	      l_reldepsact = undef_map->l_reldeps->act;
+	      for (; i < l_reldepsact; ++i)
+		if (list[i] == map)
+		  goto out_check;
+	    }
+	}
+    }
+  else
+    __rtld_lock_lock_recursive (GL(dl_load_lock));
+
+  /* The object is not yet in the dependency list.  Before we add
+     it make sure just one more time the object we are about to
+     reference is still available.  There is a brief period in
+     which the object could have been removed since we found the
+     definition.  */
+  runp = GL(dl_ns)[undef_map->l_ns]._ns_loaded;
+  while (runp != NULL && runp != map)
+    runp = runp->l_next;
+
+  if (runp != NULL)
+    {
+      /* The object is still available.  */
+
+      /* MAP could have been dlclosed, freed and then some other dlopened
+	 library could have the same link_map pointer.  */
+      if (map->l_serial != serial)
+	goto out_check;
+
+      /* Redo the NODELETE check, as when dl_load_lock wasn't held
+	 yet this could have changed.  */
+      if ((map->l_flags_1 & DF_1_NODELETE) != 0)
+	goto out;
+
+      /* If the object with the undefined reference cannot be removed ever
+	 just make sure the same is true for the object which contains the
+	 definition.  */
+      if (undef_map->l_type != lt_loaded
+	  || (undef_map->l_flags_1 & DF_1_NODELETE) != 0)
+	{
+	  map->l_flags_1 |= DF_1_NODELETE;
+	  goto out;
+	}
+
+      /* Add the reference now.  */
+      if (__builtin_expect (l_reldepsact >= undef_map->l_reldepsmax, 0))
+	{
+	  /* Allocate more memory for the dependency list.  Since this
+	     can never happen during the startup phase we can use
+	     `realloc'.  */
+	  struct link_map_reldeps *newp;
+	  unsigned int max
+	    = undef_map->l_reldepsmax ? undef_map->l_reldepsmax * 2 : 10;
+
+	  newp = malloc (sizeof (*newp) + max * sizeof (struct link_map *));
+	  if (newp == NULL)
+	    {
+	      /* If we didn't manage to allocate memory for the list this is
+		 no fatal problem.  We simply make sure the referenced object
+		 cannot be unloaded.  This is semantically the correct
+		 behavior.  */
+	      map->l_flags_1 |= DF_1_NODELETE;
+	      goto out;
+	    }
+	  else
+	    {
+	      if (l_reldepsact)
+		memcpy (&newp->list[0], &undef_map->l_reldeps->list[0],
+			l_reldepsact * sizeof (struct link_map *));
+	      newp->list[l_reldepsact] = map;
+	      newp->act = l_reldepsact + 1;
+	      atomic_write_barrier ();
+	      void *old = undef_map->l_reldeps;
+	      undef_map->l_reldeps = newp;
+	      undef_map->l_reldepsmax = max;
+	      if (old)
+		_dl_scope_free (old);
+	    }
+	}
+      else
+	{
+	  undef_map->l_reldeps->list[l_reldepsact] = map;
+	  atomic_write_barrier ();
+	  undef_map->l_reldeps->act = l_reldepsact + 1;
+	}
+
+      /* Display information if we are debugging.  */
+      if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_FILES, 0))
+	_dl_debug_printf ("\
+\nfile=%s [%lu];  needed by %s [%lu] (relocation dependency)\n\n",
+			  map->l_name[0] ? map->l_name : rtld_progname,
+			  map->l_ns,
+			  undef_map->l_name[0]
+			  ? undef_map->l_name : rtld_progname,
+			  undef_map->l_ns);
+    }
+  else
+    /* Whoa, that was bad luck.  We have to search again.  */
+    result = -1;
+
+ out:
+  /* Release the lock.  */
+  __rtld_lock_unlock_recursive (GL(dl_load_lock));
+
+  if (__builtin_expect (flags & DL_LOOKUP_GSCOPE_LOCK, 0))
+    THREAD_GSCOPE_SET_FLAG ();
+
+  return result;
+
+ out_check:
+  if (map->l_serial != serial)
+    result = -1;
+  goto out;
+}
+
+static void
+internal_function
+_dl_debug_bindings (const char *undef_name, struct link_map *undef_map,
+		    const ElfW(Sym) **ref, struct sym_val *value,
+		    const struct r_found_version *version, int type_class,
+		    int protected);
+
+
+/* Search loaded objects' symbol tables for a definition of the symbol
+   UNDEF_NAME, perhaps with a requested version for the symbol.
+
+   We must never have calls to the audit functions inside this function
+   or in any function which gets called.  If this would happen the audit
+   code might create a thread which can throw off all the scope locking.  */
+lookup_t
+internal_function
+_dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map,
+		     const ElfW(Sym) **ref,
+		     struct r_scope_elem *symbol_scope[],
+		     const struct r_found_version *version,
+		     int type_class, int flags, struct link_map *skip_map)
+{
+  const uint_fast32_t new_hash = dl_new_hash (undef_name);
+  unsigned long int old_hash = 0xffffffff;
+  struct sym_val current_value = { NULL, NULL };
+  struct r_scope_elem **scope = symbol_scope;
+
+  bump_num_relocations ();
+
+  /* No other flag than DL_LOOKUP_ADD_DEPENDENCY or DL_LOOKUP_GSCOPE_LOCK
+     is allowed if we look up a versioned symbol.  */
+  assert (version == NULL
+	  || (flags & ~(DL_LOOKUP_ADD_DEPENDENCY | DL_LOOKUP_GSCOPE_LOCK))
+	     == 0);
+
+  size_t i = 0;
+  if (__builtin_expect (skip_map != NULL, 0))
+    /* Search the relevant loaded objects for a definition.  */
+    while ((*scope)->r_list[i] != skip_map)
+      ++i;
+
+  /* Search the relevant loaded objects for a definition.  */
+  for (size_t start = i; *scope != NULL; start = 0, ++scope)
+    {
+      int res = do_lookup_x (undef_name, new_hash, &old_hash, *ref,
+			     &current_value, *scope, start, version, flags,
+			     skip_map, type_class);
+      if (res > 0)
+	break;
+
+      if (__builtin_expect (res, 0) < 0 && skip_map == NULL)
+	{
+	  /* Oh, oh.  The file named in the relocation entry does not
+	     contain the needed symbol.  This code is never reached
+	     for unversioned lookups.  */
+	  assert (version != NULL);
+	  const char *reference_name = undef_map ? undef_map->l_name : NULL;
+
+	  /* XXX We cannot translate the message.  */
+	  _dl_signal_cerror (0, (reference_name[0]
+				 ? reference_name
+				 : (rtld_progname ?: "<main program>")),
+			     N_("relocation error"),
+			     make_string ("symbol ", undef_name, ", version ",
+					  version->name,
+					  " not defined in file ",
+					  version->filename,
+					  " with link time reference",
+					  res == -2
+					  ? " (no version symbols)" : ""));
+	  *ref = NULL;
+	  return 0;
+	}
+    }
+
+  if (__builtin_expect (current_value.s == NULL, 0))
+    {
+      if ((*ref == NULL || ELFW(ST_BIND) ((*ref)->st_info) != STB_WEAK)
+	  && skip_map == NULL)
+	{
+	  /* We could find no value for a strong reference.  */
+	  const char *reference_name = undef_map ? undef_map->l_name : "";
+	  const char *versionstr = version ? ", version " : "";
+	  const char *versionname = (version && version->name
+				     ? version->name : "");
+
+	  /* XXX We cannot translate the message.  */
+	  _dl_signal_cerror (0, (reference_name[0]
+				 ? reference_name
+				 : (rtld_progname ?: "<main program>")),
+			     N_("symbol lookup error"),
+			     make_string (undefined_msg, undef_name,
+					  versionstr, versionname));
+	}
+      *ref = NULL;
+      return 0;
+    }
+
+  int protected = (*ref
+		   && ELFW(ST_VISIBILITY) ((*ref)->st_other) == STV_PROTECTED);
+  if (__builtin_expect (protected != 0, 0))
+    {
+      /* It is very tricky.  We need to figure out what value to
+         return for the protected symbol.  */
+      if (type_class == ELF_RTYPE_CLASS_PLT)
+	{
+	  if (current_value.s != NULL && current_value.m != undef_map)
+	    {
+	      current_value.s = *ref;
+	      current_value.m = undef_map;
+	    }
+	}
+      else
+	{
+	  struct sym_val protected_value = { NULL, NULL };
+
+	  for (scope = symbol_scope; *scope != NULL; i = 0, ++scope)
+	    if (do_lookup_x (undef_name, new_hash, &old_hash, *ref,
+			     &protected_value, *scope, i, version, flags,
+			     skip_map, ELF_RTYPE_CLASS_PLT) != 0)
+	      break;
+
+	  if (protected_value.s != NULL && protected_value.m != undef_map)
+	    {
+	      current_value.s = *ref;
+	      current_value.m = undef_map;
+	    }
+	}
+    }
+
+  /* We have to check whether this would bind UNDEF_MAP to an object
+     in the global scope which was dynamically loaded.  In this case
+     we have to prevent the latter from being unloaded unless the
+     UNDEF_MAP object is also unloaded.  */
+  if (__builtin_expect (current_value.m->l_type == lt_loaded, 0)
+      /* Don't do this for explicit lookups as opposed to implicit
+	 runtime lookups.  */
+      && (flags & DL_LOOKUP_ADD_DEPENDENCY) != 0
+      /* Add UNDEF_MAP to the dependencies.  */
+      && add_dependency (undef_map, current_value.m, flags) < 0)
+      /* Something went wrong.  Perhaps the object we tried to reference
+	 was just removed.  Try finding another definition.  */
+      return _dl_lookup_symbol_x (undef_name, undef_map, ref,
+				  (flags & DL_LOOKUP_GSCOPE_LOCK)
+				  ? undef_map->l_scope : symbol_scope,
+				  version, type_class, flags, skip_map);
+
+  /* The object is used.  */
+  current_value.m->l_used = 1;
+
+  if (__builtin_expect (GLRO(dl_debug_mask)
+			& (DL_DEBUG_BINDINGS|DL_DEBUG_PRELINK), 0))
+    _dl_debug_bindings (undef_name, undef_map, ref,
+			&current_value, version, type_class, protected);
+
+  *ref = current_value.s;
+  return LOOKUP_VALUE (current_value.m);
+}
+
+
+/* Cache the location of MAP's hash table.  */
+
+void
+internal_function
+_dl_setup_hash (struct link_map *map)
+{
+  Elf_Symndx *hash;
+  Elf_Symndx nchain;
+
+  if (__builtin_expect (map->l_info[DT_ADDRTAGIDX (DT_GNU_HASH) + DT_NUM
+  				    + DT_THISPROCNUM + DT_VERSIONTAGNUM
+				    + DT_EXTRANUM + DT_VALNUM] != NULL, 1))
+    {
+      Elf32_Word *hash32
+	= (void *) D_PTR (map, l_info[DT_ADDRTAGIDX (DT_GNU_HASH) + DT_NUM
+				      + DT_THISPROCNUM + DT_VERSIONTAGNUM
+				      + DT_EXTRANUM + DT_VALNUM]);
+      map->l_nbuckets = *hash32++;
+      Elf32_Word symbias = *hash32++;
+      Elf32_Word bitmask_nwords = *hash32++;
+      /* Must be a power of two.  */
+      assert ((bitmask_nwords & (bitmask_nwords - 1)) == 0);
+      map->l_gnu_bitmask_idxbits = bitmask_nwords - 1;
+      map->l_gnu_shift = *hash32++;
+
+      map->l_gnu_bitmask = (ElfW(Addr) *) hash32;
+      hash32 += __ELF_NATIVE_CLASS / 32 * bitmask_nwords;
+
+      map->l_gnu_buckets = hash32;
+      hash32 += map->l_nbuckets;
+      map->l_gnu_chain_zero = hash32 - symbias;
+      return;
+    }
+
+  if (!map->l_info[DT_HASH])
+    return;
+  hash = (void *) D_PTR (map, l_info[DT_HASH]);
+
+  map->l_nbuckets = *hash++;
+  nchain = *hash++;
+  map->l_buckets = hash;
+  hash += map->l_nbuckets;
+  map->l_chain = hash;
+}
+
+
+static void
+internal_function
+_dl_debug_bindings (const char *undef_name, struct link_map *undef_map,
+		    const ElfW(Sym) **ref, struct sym_val *value,
+		    const struct r_found_version *version, int type_class,
+		    int protected)
+{
+  const char *reference_name = undef_map->l_name;
+
+  if (GLRO(dl_debug_mask) & DL_DEBUG_BINDINGS)
+    {
+      _dl_debug_printf ("binding file %s [%lu] to %s [%lu]: %s symbol `%s'",
+			(reference_name[0]
+			 ? reference_name
+			 : (rtld_progname ?: "<main program>")),
+			undef_map->l_ns,
+			value->m->l_name[0] ? value->m->l_name : rtld_progname,
+			value->m->l_ns,
+			protected ? "protected" : "normal", undef_name);
+      if (version)
+	_dl_debug_printf_c (" [%s]\n", version->name);
+      else
+	_dl_debug_printf_c ("\n");
+    }
+#ifdef SHARED
+  if (GLRO(dl_debug_mask) & DL_DEBUG_PRELINK)
+    {
+      int conflict = 0;
+      struct sym_val val = { NULL, NULL };
+
+      if ((GLRO(dl_trace_prelink_map) == NULL
+	   || GLRO(dl_trace_prelink_map) == GL(dl_ns)[LM_ID_BASE]._ns_loaded)
+	  && undef_map != GL(dl_ns)[LM_ID_BASE]._ns_loaded)
+	{
+	  const uint_fast32_t new_hash = dl_new_hash (undef_name);
+	  unsigned long int old_hash = 0xffffffff;
+
+	  do_lookup_x (undef_name, new_hash, &old_hash, *ref, &val,
+		       undef_map->l_local_scope[0], 0, version, 0, NULL,
+		       type_class);
+
+	  if (val.s != value->s || val.m != value->m)
+	    conflict = 1;
+	}
+
+      if (value->s
+	  && (__builtin_expect (ELFW(ST_TYPE) (value->s->st_info)
+				== STT_TLS, 0)))
+	type_class = 4;
+
+      if (conflict
+	  || GLRO(dl_trace_prelink_map) == undef_map
+	  || GLRO(dl_trace_prelink_map) == NULL
+	  || type_class == 4)
+	{
+	  _dl_printf ("%s 0x%0*Zx 0x%0*Zx -> 0x%0*Zx 0x%0*Zx ",
+		      conflict ? "conflict" : "lookup",
+		      (int) sizeof (ElfW(Addr)) * 2,
+		      (size_t) undef_map->l_map_start,
+		      (int) sizeof (ElfW(Addr)) * 2,
+		      (size_t) (((ElfW(Addr)) *ref) - undef_map->l_map_start),
+		      (int) sizeof (ElfW(Addr)) * 2,
+		      (size_t) (value->s ? value->m->l_map_start : 0),
+		      (int) sizeof (ElfW(Addr)) * 2,
+		      (size_t) (value->s ? value->s->st_value : 0));
+
+	  if (conflict)
+	    _dl_printf ("x 0x%0*Zx 0x%0*Zx ",
+			(int) sizeof (ElfW(Addr)) * 2,
+			(size_t) (val.s ? val.m->l_map_start : 0),
+			(int) sizeof (ElfW(Addr)) * 2,
+			(size_t) (val.s ? val.s->st_value : 0));
+
+	  _dl_printf ("/%x %s\n", type_class, undef_name);
+	}
+    }
+#endif
+}
Index: sysdeps/mips/dl-trampoline.c
===================================================================
--- sysdeps/mips/dl-trampoline.c	(revision 219453)
+++ sysdeps/mips/dl-trampoline.c	(working copy)
@@ -200,7 +200,24 @@ __dl_runtime_resolve (ElfW(Word) sym_ind
 	lw	$7, 28($29)\n						      \
 "
 
+/* The PLT resolver should also save and restore $2 and $3, which are used
+   as arguments to MIPS16 stub functions.  */
+#define ELF_DL_PLT_FRAME_SIZE 48
+
+#define ELF_DL_PLT_SAVE_ARG_REGS \
+	ELF_DL_SAVE_ARG_REGS "\
+	sw	$2, 40($29)\n						      \
+	sw	$3, 44($29)\n						      \
+"
+
+#define ELF_DL_PLT_RESTORE_ARG_REGS \
+	ELF_DL_RESTORE_ARG_REGS "\
+	lw	$2, 40($29)\n						      \
+	lw	$3, 44($29)\n						      \
+"
+
 #define IFABIO32(X) X
+#define IFNEWABI(X)
 
 #else /* _MIPS_SIM == _ABIN32 || _MIPS_SIM == _ABI64 */
 
@@ -230,7 +247,24 @@ __dl_runtime_resolve (ElfW(Word) sym_ind
 	ld	$11, 64($29)\n						      \
 "
 
+/* The PLT resolver should also save and restore $2 and $3, which are used
+   as arguments to MIPS16 stub functions.  */
+#define ELF_DL_PLT_FRAME_SIZE 96
+
+#define ELF_DL_PLT_SAVE_ARG_REGS \
+	ELF_DL_SAVE_ARG_REGS "\
+	sd	$2, 80($29)\n						      \
+	sd	$3, 88($29)\n						      \
+"
+
+#define ELF_DL_PLT_RESTORE_ARG_REGS \
+	ELF_DL_RESTORE_ARG_REGS "\
+	ld	$2, 80($29)\n						      \
+	ld	$3, 88($29)\n						      \
+"
+
 #define IFABIO32(X)
+#define IFNEWABI(X) X
 
 #endif
 
@@ -270,3 +304,56 @@ _dl_runtime_resolve:\n\
 	.end	_dl_runtime_resolve\n\
 	.previous\n\
 ");
+
+/* Assembler veneer called from the PLT header code when using PLTs.
+
+   Code in each PLT entry and the PLT header fills in the arguments to
+   this function:
+
+   - $15 (o32 t7, n32/n64 t3) - caller's return address
+   - $24 (t8) - PLT entry index
+   - $25 (t9) - address of _dl_runtime_pltresolve
+   - o32 $28 (gp), n32/n64 $14 (t2) - address of .got.plt
+
+   Different registers are used for .got.plt because the ABI was
+   originally designed for o32, where gp was available (call
+   clobbered).  On n32/n64 gp is call saved.
+
+   _dl_fixup needs:
+
+   - $4 (a0) - link map address
+   - $5 (a1) - .rel.plt offset (== PLT entry index * 8)  */
+
+asm ("\n\
+	.text\n\
+	.align	2\n\
+	.globl	_dl_runtime_pltresolve\n\
+	.type	_dl_runtime_pltresolve,@function\n\
+	.ent	_dl_runtime_pltresolve\n\
+_dl_runtime_pltresolve:\n\
+	.frame	$29, " STRINGXP(ELF_DL_PLT_FRAME_SIZE) ", $31\n\
+	.set noreorder\n\
+	# Save arguments and sp value in stack.\n\
+	" STRINGXP(PTR_SUBIU) "	$29, " STRINGXP(ELF_DL_PLT_FRAME_SIZE) "\n\
+	" IFABIO32(STRINGXP(PTR_L) "	$13, " STRINGXP(PTRSIZE) "($28)") "\n\
+	" IFNEWABI(STRINGXP(PTR_L) "	$13, " STRINGXP(PTRSIZE) "($14)") "\n\
+	# Modify t9 ($25) so as to point .cpload instruction.\n\
+	" IFABIO32(STRINGXP(PTR_ADDIU) "	$25, 12\n") "\
+	# Compute GP.\n\
+	" STRINGXP(SETUP_GP) "\n\
+	" STRINGXV(SETUP_GP64 (0, _dl_runtime_pltresolve)) "\n\
+	.set reorder\n\
+	" IFABIO32(STRINGXP(CPRESTORE(32))) "\n\
+	" ELF_DL_PLT_SAVE_ARG_REGS "\
+	move	$4, $13\n\
+	sll	$5, $24, " STRINGXP(PTRLOG) " + 1\n\
+	jal	_dl_fixup\n\
+	move	$25, $2\n\
+	" ELF_DL_PLT_RESTORE_ARG_REGS "\
+	" STRINGXP(RESTORE_GP64) "\n\
+	" STRINGXP(PTR_ADDIU) "	$29, " STRINGXP(ELF_DL_PLT_FRAME_SIZE) "\n\
+	jr	$25\n\
+	.end	_dl_runtime_pltresolve\n\
+	.previous\n\
+");
+
Index: sysdeps/mips/bits/linkmap.h
===================================================================
--- sysdeps/mips/bits/linkmap.h	(revision 0)
+++ sysdeps/mips/bits/linkmap.h	(revision 0)
@@ -0,0 +1,4 @@
+struct link_map_machine
+  {
+    ElfW(Addr) plt; /* Address of .plt */
+  };

static link on MIPS

[Atsushi Nemoto]

As glibc bugzilla #1048 show, static linking on MIPS is somewhat
broken for years.  For example,

$ cat foo.c
#include <netdb.h>
int main(int argc, char **argv)
{
        gethostbyname("localhost");
        return 0;
}
$ gcc -o foo foo.c -static
/tmp/ccSCPyxW.o: In function `main':
foo.c:(.text+0x2c): warning: Using 'gethostbyname' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
$ ./foo
foo: ../sysdeps/unix/sysv/linux/ia64/getpagesize.c:35: __getpagesize: Assertion `_rtld_global_ro._dl_pagesize != 0' failed.
Floating point exception

(Note that mips getpagesize.c includes ia64/getpagesize.c)


Up to glibc 2.8, glibc-2.3.90-20050704-mips-dl-static.patch by Maciej
could be used to fix the problem.  But with glibc 2.9, it causes
segfaults.

Did someone already fixed this for recent glibc?

If no, I want to forward-port the patch.  Can anybody suggests where
to fix?  I suppose the patch was broken since this commit
(http://sourceware.org/ml/libc-ports/2008-10/msg00000.html), but not
sure yet.

On Wed, 1 Oct 2008 09:30:40 -0400, Daniel Jacobowitz <drow@false.org> wrote:
> I have checked in this patch, which adds support for the new PLT
> format recently added to binutils and gcc.
> 
> This patch also fixes a bug in dlsym on MIPS, even with current GCC
> and binutils; dlsym would sometimes return lazy binding stubs.  That's
> what the copy of dl-lookup.c and the trick in do-lookup.h are for.
> 
> -- 
> Daniel Jacobowitz
> CodeSourcery
> 
> 2008-10-01  Mark Shinwell  <shinwell@codesourcery.com>
> 	    Daniel Jacobowitz  <dan@codesourcery.com>
> 	    Richard Sandiford  <rdsandiford@googlemail.com>

Any suggestions are welcome.  Thanks.

---
Atsushi Nemoto

Re: static link on MIPS

[Atsushi Nemoto]

On Wed, 24 Dec 2008 02:28:10 +0900 (JST), Atsushi Nemoto <anemo@mba.ocn.ne.jp> wrote:
> Up to glibc 2.8, glibc-2.3.90-20050704-mips-dl-static.patch by Maciej
> could be used to fix the problem.  But with glibc 2.9, it causes
> segfaults.
> 
> Did someone already fixed this for recent glibc?
> 
> If no, I want to forward-port the patch.  Can anybody suggests where
> to fix?  I suppose the patch was broken since this commit
> (http://sourceware.org/ml/libc-ports/2008-10/msg00000.html), but not
> sure yet.

Sorry, this commit is irrelevant.  The mips-dl-static.patch was just
too old.

This code in _dl_static_init() should be updated to post glibc 2.4 (!)
while type of loadbase (lookup_t) is a poingter to struct link_map
rather than ElfW(Addr).

  for (scope = l->l_local_scope; *scope != NULL; scope++)
    for (i = 0; i < (*scope)->r_nlist; i++)
      if ((*scope)->r_list[i]->l_addr == loadbase)
        rtld_map = (*scope)->r_list[i];

This should be:

  for (scope = l->l_local_scope; *scope != NULL; scope++)
    for (i = 0; i < (*scope)->r_nlist; i++)
      if ((*scope)->r_list[i] == loadbase)
        rtld_map = (*scope)->r_list[i];

I'll post a replacement of the libc-port part of the patch in bugzilla.

---
Atsushi Nemoto

Re: PLT / non-PIC executable support for MIPS

[Atsushi Nemoto]

On Wed, 1 Oct 2008 09:30:40 -0400, Daniel Jacobowitz <drow@false.org> wrote:
> This patch also fixes a bug in dlsym on MIPS, even with current GCC
> and binutils; dlsym would sometimes return lazy binding stubs.  That's
> what the copy of dl-lookup.c and the trick in do-lookup.h are for.

Is this a same "bug" reported on Debian BTS #265678 ?

It looks local-lazy-eval.diff contains similar (but slightly different
place) fix.
---
Atsushi Nemoto

Re: PLT / non-PIC executable support for MIPS

[Daniel Jacobowitz]

On Mon, Jan 05, 2009 at 10:10:48PM +0900, Atsushi Nemoto wrote:
> On Wed, 1 Oct 2008 09:30:40 -0400, Daniel Jacobowitz <drow@false.org> wrote:
> > This patch also fixes a bug in dlsym on MIPS, even with current GCC
> > and binutils; dlsym would sometimes return lazy binding stubs.  That's
> > what the copy of dl-lookup.c and the trick in do-lookup.h are for.
> 
> Is this a same "bug" reported on Debian BTS #265678 ?
> 
> It looks local-lazy-eval.diff contains similar (but slightly different
> place) fix.

Thanks - I wasn't aware of that patch.  Yes, it is the same issue.

-- 
Daniel Jacobowitz
CodeSourcery

Re: static link on MIPS

[Daniel Jacobowitz]

On Mon, Jan 05, 2009 at 09:43:16PM +0900, Atsushi Nemoto wrote:
> I'll post a replacement of the libc-port part of the patch in bugzilla.

I've committed your latest patch, as below.  Thanks!

-- 
Daniel Jacobowitz
CodeSourcery

Index: ChangeLog.mips
===================================================================
RCS file: /cvs/glibc/ports/ChangeLog.mips,v
retrieving revision 1.69
diff -u -p -r1.69 ChangeLog.mips
--- ChangeLog.mips	12 Jan 2009 16:45:43 -0000	1.69
+++ ChangeLog.mips	27 Jan 2009 15:32:29 -0000
@@ -1,3 +1,13 @@
+2009-01-27  Maciej W. Rozycki  <macro@linux-mips.org>
+	    Atsushi Nemoto  <anemo@mba.ocn.ne.jp>
+
+	PR glibc/1048
+	* sysdeps/unix/sysv/linux/mips/dl-static.c: New file to support
+	variable page size for MIPS.
+	* sysdeps/unix/sysv/linux/mips/ldsodefs.h: Likewise.
+	* sysdeps/unix/sysv/linux/mips/Makefile: Build dl-static in elf.
+	* sysdeps/unix/sysv/linux/mips/Versions: Add _dl_var_init.
+
 2009-01-12  Joseph Myers  <joseph@codesourcery.com>
 
 	* sysdeps/unix/sysv/linux/mips/bits/resource.h (enum
Index: sysdeps/unix/sysv/linux/mips/Makefile
===================================================================
RCS file: /cvs/glibc/ports/sysdeps/unix/sysv/linux/mips/Makefile,v
retrieving revision 1.15
diff -u -p -r1.15 Makefile
--- sysdeps/unix/sysv/linux/mips/Makefile	25 Feb 2005 15:18:06 -0000	1.15
+++ sysdeps/unix/sysv/linux/mips/Makefile	27 Jan 2009 15:32:29 -0000
@@ -126,3 +126,12 @@ else
 	mv -f $(@:.h=.d)-t $(@:.h=.d)
 endif
 endif
+
+ifeq ($(subdir),elf)
+ifeq ($(build-shared),yes)
+# This is needed for DSO loading from static binaries.
+sysdep-dl-routines += dl-static
+sysdep_routines += dl-static
+sysdep-rtld-routines += dl-static
+endif
+endif
Index: sysdeps/unix/sysv/linux/mips/Versions
===================================================================
RCS file: /cvs/glibc/ports/sysdeps/unix/sysv/linux/mips/Versions,v
retrieving revision 1.9
diff -u -p -r1.9 Versions
--- sysdeps/unix/sysv/linux/mips/Versions	6 Nov 2002 02:53:24 -0000	1.9
+++ sysdeps/unix/sysv/linux/mips/Versions	27 Jan 2009 15:32:29 -0000
@@ -1,3 +1,9 @@
+ld {
+  GLIBC_PRIVATE {
+    # used for loading by static libraries
+    _dl_var_init;
+  }
+}
 libc {
   # The comment lines with "#errlist-compat" are magic; see errlist-compat.awk.
   # When you get an error from errlist-compat.awk, you need to add a new
Index: sysdeps/unix/sysv/linux/mips/dl-static.c
===================================================================
RCS file: sysdeps/unix/sysv/linux/mips/dl-static.c
diff -N sysdeps/unix/sysv/linux/mips/dl-static.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ sysdeps/unix/sysv/linux/mips/dl-static.c	27 Jan 2009 15:32:29 -0000
@@ -0,0 +1,92 @@
+/* Variable initialization.  MIPS version.
+   Copyright (C) 2001, 2002, 2003, 2005 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <ldsodefs.h>
+
+#ifdef SHARED
+
+void
+_dl_var_init (void *array[])
+{
+  /* It has to match "variables" below. */
+  enum
+    {
+      DL_PAGESIZE = 0
+    };
+
+  GLRO(dl_pagesize) = *((size_t *) array[DL_PAGESIZE]);
+}
+
+#else
+#include <bits/libc-lock.h>
+
+__libc_lock_define_initialized_recursive (static, _dl_static_lock)
+
+static void *variables[] =
+{
+  &GLRO(dl_pagesize)
+};
+
+static void
+_dl_unprotect_relro (struct link_map *l)
+{
+  ElfW(Addr) start = ((l->l_addr + l->l_relro_addr)
+		      & ~(GLRO(dl_pagesize) - 1));
+  ElfW(Addr) end = ((l->l_addr + l->l_relro_addr + l->l_relro_size)
+		    & ~(GLRO(dl_pagesize) - 1));
+
+  if (start != end)
+    __mprotect ((void *) start, end - start, PROT_READ | PROT_WRITE);
+}
+
+void
+_dl_static_init (struct link_map *l)
+{
+  struct link_map *rtld_map = l;
+  struct r_scope_elem **scope;
+  const ElfW(Sym) *ref = NULL;
+  lookup_t loadbase;
+  void (*f) (void *[]);
+  size_t i;
+
+  __libc_lock_lock_recursive (_dl_static_lock);
+
+  loadbase = _dl_lookup_symbol_x ("_dl_var_init", l, &ref, l->l_local_scope,
+				  NULL, 0, 1, NULL);
+  
+  for (scope = l->l_local_scope; *scope != NULL; scope++)
+    for (i = 0; i < (*scope)->r_nlist; i++)
+      if ((*scope)->r_list[i] == loadbase)
+	{
+	  rtld_map = (*scope)->r_list[i];
+	  break;
+	}
+
+  if (ref != NULL)
+    {
+      f = (void (*) (void *[])) DL_SYMBOL_ADDRESS (loadbase, ref);
+      _dl_unprotect_relro (rtld_map);
+      f (variables);
+      _dl_protect_relro (rtld_map);
+    }
+
+  __libc_lock_unlock_recursive (_dl_static_lock);
+}
+
+#endif
Index: sysdeps/unix/sysv/linux/mips/ldsodefs.h
===================================================================
RCS file: sysdeps/unix/sysv/linux/mips/ldsodefs.h
diff -N sysdeps/unix/sysv/linux/mips/ldsodefs.h
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ sysdeps/unix/sysv/linux/mips/ldsodefs.h	27 Jan 2009 15:32:29 -0000
@@ -0,0 +1,33 @@
+/* Run-time dynamic linker data structures for loaded ELF shared objects. MIPS.
+   Copyright (C) 2001, 2003 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#ifndef	_LDSODEFS_H
+
+/* Get the real definitions.  */
+#include_next <ldsodefs.h>
+
+/* Now define our stuff.  */
+
+/* We need special support to initialize DSO loaded for statically linked
+   binaries.  */
+extern void _dl_static_init (struct link_map *map);
+#undef DL_STATIC_INIT
+#define DL_STATIC_INIT(map) _dl_static_init (map)
+
+#endif /* ldsodefs.h */

Re: static link on MIPS

[Maciej W. Rozycki]

On Tue, 27 Jan 2009, Daniel Jacobowitz wrote:

> I've committed your latest patch, as below.  Thanks!

 Thanks for pushing it through finally! :)

  Maciej

Re: PLT / non-PIC executable support for MIPS

[Joseph S. Myers]

On Wed, 1 Oct 2008, Daniel Jacobowitz wrote:

> +/* Allow ABIVERSION == 1, meaning PLTs and copy relocations are
> +   required.  */
> +#define VALID_ELF_ABIVERSION(ver)	(ver == 0 || ver == 2)
> +#define VALID_ELF_OSABI(osabi)		(osabi == ELFOSABI_SYSV)
> +#define VALID_ELF_HEADER(hdr,exp,size) \
> +  memcmp (hdr,exp,size-2) == 0 \
> +  && VALID_ELF_OSABI (hdr[EI_OSABI]) \
> +  && VALID_ELF_ABIVERSION (hdr[EI_ABIVERSION])

I am looking at updating this code and the corresponding ARM code for the 
recent libc-abis changes in libc.  I don't follow how the comparison ver 
== 2 works with allowing ABIVERSION == 1.

If there is indeed a target-specific ABIVERSION value for MIPS, then ports 
needs its own libc-abis file.  Is there something I don't follow about how 
the above matches, or is in fact the static linker never generating the 
value 1 (which it does seem to have code to generate) in any context for 
which the above code is active?

-- 
Joseph S. Myers
joseph@codesourcery.com

Re: PLT / non-PIC executable support for MIPS

[Daniel Jacobowitz]

On Sun, Mar 28, 2010 at 03:46:04PM +0000, Joseph S. Myers wrote:
> On Wed, 1 Oct 2008, Daniel Jacobowitz wrote:
> 
> > +/* Allow ABIVERSION == 1, meaning PLTs and copy relocations are
> > +   required.  */
> > +#define VALID_ELF_ABIVERSION(ver)	(ver == 0 || ver == 2)
> > +#define VALID_ELF_OSABI(osabi)		(osabi == ELFOSABI_SYSV)
> > +#define VALID_ELF_HEADER(hdr,exp,size) \
> > +  memcmp (hdr,exp,size-2) == 0 \
> > +  && VALID_ELF_OSABI (hdr[EI_OSABI]) \
> > +  && VALID_ELF_ABIVERSION (hdr[EI_ABIVERSION])
> 
> I am looking at updating this code and the corresponding ARM code for the 
> recent libc-abis changes in libc.  I don't follow how the comparison ver 
> == 2 works with allowing ABIVERSION == 1.

I don't either.  It may be that at some point, the abiversion value
was going to be 2, and I failed to update it.  This was wrong by the
very first public posting.

> If there is indeed a target-specific ABIVERSION value for MIPS, then ports 
> needs its own libc-abis file.  Is there something I don't follow about how 
> the above matches, or is in fact the static linker never generating the 
> value 1 (which it does seem to have code to generate) in any context for 
> which the above code is active?

I suspect that VALID_ELF_HEADER is not used for the executable.  The
linker only sets it for the executable, since shared libraries don't
use PLTs or copy relocs.  Either that, or it's only used for the
executable if ld.so was invoked directly (but if that were the case, I
think we'd have noticed a problem by now).

-- 
Daniel Jacobowitz
CodeSourcery

Re: PLT / non-PIC executable support for MIPS

[Joseph S. Myers]

On Sun, 28 Mar 2010, Daniel Jacobowitz wrote:

> > If there is indeed a target-specific ABIVERSION value for MIPS, then ports 
> > needs its own libc-abis file.  Is there something I don't follow about how 
> > the above matches, or is in fact the static linker never generating the 
> > value 1 (which it does seem to have code to generate) in any context for 
> > which the above code is active?
> 
> I suspect that VALID_ELF_HEADER is not used for the executable.  The
> linker only sets it for the executable, since shared libraries don't
> use PLTs or copy relocs.  Either that, or it's only used for the
> executable if ld.so was invoked directly (but if that were the case, I
> think we'd have noticed a problem by now).

Given that it's only set for the executable, should we still say that 
numbers higher than 1 are used for STB_GNU_UNIQUE (and STT_GNU_IFUNC if 
MIPS gets support for that in future) on MIPS to avoid confusion?  With 1 
being accepted with ELFOSABI_SYSV but higher values only for 
ELFOSABI_LINUX.

(I don't actually see any static linker support to set the ABI versions 
for STB_GNU_UNIQUE and STT_GNU_IFUNC that libc now checks for; I presume 
that will be forthcoming in due course.)

-- 
Joseph S. Myers
joseph@codesourcery.com

Re: PLT / non-PIC executable support for MIPS

[Daniel Jacobowitz]

On Sun, Mar 28, 2010 at 08:16:54PM +0000, Joseph S. Myers wrote:
> Given that it's only set for the executable, should we still say that 
> numbers higher than 1 are used for STB_GNU_UNIQUE (and STT_GNU_IFUNC if 
> MIPS gets support for that in future) on MIPS to avoid confusion?  With 1 
> being accepted with ELFOSABI_SYSV but higher values only for 
> ELFOSABI_LINUX.
> 
> (I don't actually see any static linker support to set the ABI versions 
> for STB_GNU_UNIQUE and STT_GNU_IFUNC that libc now checks for; I presume 
> that will be forthcoming in due course.)

I'm not sure.  I think this might be a good question to get Roland's
opinion on... I do not see how having one copy of the file in ports,
and another in glibc, should work.  It has to be append-only.

Historically, we've used abiversion 1 already.  So reusing it for
UNIQUE does not seem like a good idea.

If glibc is still not checking the abi version of the main executable,
then that seems a serious problem.  But that may not matter.

-- 
Daniel Jacobowitz
CodeSourcery

ABI versions and ports (was: Re: PLT / non-PIC executable support for MIPS)

[Joseph S. Myers]

On Sun, 28 Mar 2010, Daniel Jacobowitz wrote:

> On Sun, Mar 28, 2010 at 08:16:54PM +0000, Joseph S. Myers wrote:
> > Given that it's only set for the executable, should we still say that 
> > numbers higher than 1 are used for STB_GNU_UNIQUE (and STT_GNU_IFUNC if 
> > MIPS gets support for that in future) on MIPS to avoid confusion?  With 1 
> > being accepted with ELFOSABI_SYSV but higher values only for 
> > ELFOSABI_LINUX.
> > 
> > (I don't actually see any static linker support to set the ABI versions 
> > for STB_GNU_UNIQUE and STT_GNU_IFUNC that libc now checks for; I presume 
> > that will be forthcoming in due course.)
> 
> I'm not sure.  I think this might be a good question to get Roland's
> opinion on... I do not see how having one copy of the file in ports,
> and another in glibc, should work.  It has to be append-only.

As far as I can see:

* The file will be taken from an add-on if found there, else from libc; 
only one copy will be used.

* Thus, a ports copy needs to include all definitions from the libc copy 
that are relevant to ports targets.  At present, this means

UNIQUE
IFUNC		powerpc-*-linux*

because powerpc-* targets come from ports (soft-float) as well as libc.

* Although the patterns in libc-abis use wildcards such as i?86, they are 
actually matching against $(base-machine)-$(config-vendor)-$(config-os), 
and base-machine is a value that has been canonicalized by configure, 
meaning that it will always be i386 for the above, and that the powerpc64 
and sparc64 cases will never match.  It might make more sense to use 
$(abi-name) instead (in which case a new line would be needed in ports for 
powerpcsoft-linux-gnu).

> Historically, we've used abiversion 1 already.  So reusing it for
> UNIQUE does not seem like a good idea.
> 
> If glibc is still not checking the abi version of the main executable,
> then that seems a serious problem.  But that may not matter.

-- 
Joseph S. Myers
joseph@codesourcery.com