Update.

1998-08-09  Geoff Keating  <geoffk@ozemail.com.au>

	* sysdeps/powerpc/Makefile [subdir=elf]: Add new files split out of
	dl-machine.h.
	* sysdeps/powerpc/dl-machine.c: New file.
	* sysdeps/powerpc/dl-machine.h: Move much stuff into separate
	files.  Revise ELF_PREFERRED_ADDRESS to take account of
	the new mapping information (fixes bug involving huge bloated
	web browser).  Set ELF_MACHINE_PLTREL_OVERLAP.
	* sysdeps/powerpc/dl-start.S: New file.

	* elf/dl-load.c (_dl_map_object_from_fd): Initialise l_map_start,
	l_map_end.
	* elf/do-rel.h: Call elf_machine_rel only once (to save space).
	* elf/dynamic-link.h: Allow PLT relocs to be in the middle of the
	others.  Call elf_dynamic_do_##reloc only once (to save even more
	space).
	* elf/link.h: Add new members l_map_start and l_map_end to keep
	track of the memory map.
	* elf/rtld.c (_dl_start): Initialise l_map_start for ld.so and
	the executable.

1998-09-01 11:53  Ulrich Drepper  <drepper@cygnus.com>

	* debug/Makefile (catchsegv): We need not rewrite SOVER anymore.
	Reported by Andreas Jaeger.

	* posix/glob.h: Use __size_t instead of size_t in definitions and
	make sure this is defined.

	* manual/locale.texi: Almost complete rewrite.  Document more functions

1 files changed, 442 insertions, 0 deletions

diff --git a/sysdeps/powerpc/dl-machine.c b/sysdeps/powerpc/dl-machine.c
new file mode 100644
index 0000000000..095a3f21d8
--- /dev/null
+++ b/sysdeps/powerpc/dl-machine.c
@@ -0,0 +1,442 @@
+/* Machine-dependent ELF dynamic relocation functions.  PowerPC version.
+   Copyright (C) 1995, 1996, 1997, 1998 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 Library General Public License as
+   published by the Free Software Foundation; either version 2 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <unistd.h>
+#include <string.h>
+#include <sys/param.h>
+#include <link.h>
+#include <dl-machine.h>
+#include <elf/ldsodefs.h>
+#include <elf/dynamic-link.h>
+
+/* Because ld.so is now versioned, these functions can be in their own file;
+   no relocations need to be done to call them.
+   Of course, if ld.so is not versioned...  */
+#if !(DO_VERSIONING - 0)
+#error This will not work with versioning turned off, sorry.
+#endif
+
+
+/* stuff for the PLT */
+#define PLT_INITIAL_ENTRY_WORDS 18
+#define PLT_LONGBRANCH_ENTRY_WORDS 10
+#define PLT_DOUBLE_SIZE (1<<13)
+#define PLT_ENTRY_START_WORDS(entry_number) \
+  (PLT_INITIAL_ENTRY_WORDS + (entry_number)*2 + \
+   ((entry_number) > PLT_DOUBLE_SIZE ? \
+    ((entry_number) - PLT_DOUBLE_SIZE)*2 : \
+    0))
+#define PLT_DATA_START_WORDS(num_entries) PLT_ENTRY_START_WORDS(num_entries)
+
+#define OPCODE_ADDI(rd,ra,simm) \
+  (0x38000000 | (rd) << 21 | (ra) << 16 | (simm) & 0xffff)
+#define OPCODE_ADDIS(rd,ra,simm) \
+  (0x3c000000 | (rd) << 21 | (ra) << 16 | (simm) & 0xffff)
+#define OPCODE_ADD(rd,ra,rb) \
+  (0x7c000214 | (rd) << 21 | (ra) << 16 | (rb) << 11)
+#define OPCODE_B(target) (0x48000000 | (target) & 0x03fffffc)
+#define OPCODE_BA(target) (0x48000002 | (target) & 0x03fffffc)
+#define OPCODE_BCTR() 0x4e800420
+#define OPCODE_LWZ(rd,d,ra) \
+  (0x80000000 | (rd) << 21 | (ra) << 16 | (d) & 0xffff)
+#define OPCODE_MTCTR(rd) (0x7C0903A6 | (rd) << 21)
+#define OPCODE_RLWINM(ra,rs,sh,mb,me) \
+  (0x54000000 | (rs) << 21 | (ra) << 16 | (sh) << 11 | (mb) << 6 | (me) << 1)
+
+#define OPCODE_LI(rd,simm)    OPCODE_ADDI(rd,0,simm)
+#define OPCODE_SLWI(ra,rs,sh) OPCODE_RLWINM(ra,rs,sh,0,31-sh)
+
+
+#define PPC_DCBST(where) asm volatile ("dcbst 0,%0" : : "r"(where))
+#define PPC_SYNC asm volatile ("sync")
+#define PPC_ISYNC asm volatile ("sync; isync")
+#define PPC_ICBI(where) asm volatile ("icbi 0,%0" : : "r"(where))
+#define PPC_DIE asm volatile ("tweq 0,0")
+
+/* Use this when you've modified some code, but it won't be in the
+   instruction fetch queue (or when it doesn't matter if it is). */
+#define MODIFIED_CODE_NOQUEUE(where) \
+     do { PPC_DCBST(where); PPC_SYNC; PPC_ICBI(where); } while (0)
+/* Use this when it might be in the instruction queue. */
+#define MODIFIED_CODE(where) \
+     do { PPC_DCBST(where); PPC_SYNC; PPC_ICBI(where); PPC_ISYNC; } while (0)
+
+
+/* The idea here is that to conform to the ABI, we are supposed to try
+   to load dynamic objects between 0x10000 (we actually use 0x40000 as
+   the lower bound, to increase the chance of a memory reference from
+   a null pointer giving a segfault) and the program's load address;
+   this may allow us to use a branch instruction in the PLT rather
+   than a computed jump.  The address is only used as a preference for
+   mmap, so if we get it wrong the worst that happens is that it gets
+   mapped somewhere else.  */
+
+ElfW(Addr)
+__elf_preferred_address(struct link_map *loader, size_t maplength,
+			ElfW(Addr) mapstartpref)
+{
+  ElfW(Addr) low, high;
+  struct link_map *l;
+
+  /* If the object has a preference, load it there!  */
+  if (mapstartpref != 0)
+    return mapstartpref;
+
+  /* Otherwise, quickly look for a suitable gap between 0x3FFFF and
+     0x70000000.  0x3FFFF is so that references off NULL pointers will
+     cause a segfault, 0x70000000 is just paranoia (it should always
+     be superceded by the program's load address).  */
+  low =  0x0003FFFF;
+  high = 0x70000000;
+  for (l = _dl_loaded; l; l = l->l_next)
+    {
+      ElfW(Addr) mapstart, mapend;
+      mapstart = l->l_map_start & ~(_dl_pagesize - 1);
+      mapend = l->l_map_end | (_dl_pagesize - 1);
+      assert (mapend > mapstart);
+
+      if (mapend >= high && high >= mapstart)
+	high = mapstart;
+      else if (mapend >= low && low >= mapstart)
+	low = mapend;
+      else if (high >= mapend && mapstart >= low)
+	{
+	  if (high - mapend >= mapstart - low)
+	    low = mapend;
+	  else
+	    high = mapstart;
+	}
+    }
+
+  high -= 0x10000; /* Allow some room between objects.  */
+  maplength = (maplength | (_dl_pagesize-1)) + 1;
+  if (high <= low || high - low < maplength )
+    return 0;
+  return high - maplength;  /* Both high and maplength are page-aligned.  */
+}
+
+/* Set up the loaded object described by L so its unrelocated PLT
+   entries will jump to the on-demand fixup code in dl-runtime.c.
+   Also install a small trampoline to be used by entries that have
+   been relocated to an address too far away for a single branch.  */
+
+/* A PLT entry does one of three things:
+   (i)   Jumps to the actual routine. Such entries are set up above, in
+         elf_machine_rela.
+
+   (ii)  Jumps to the actual routine via glue at the start of the PLT.
+         We do this by putting the address of the routine in space
+         allocated at the end of the PLT, and when the PLT entry is
+         called we load the offset of that word (from the start of the
+         space) into r11, then call the glue, which loads the word and
+         branches to that address. These entries are set up in
+         elf_machine_rela, but the glue is set up here.
+
+   (iii) Loads the index of this PLT entry (we count the double-size
+	 entries as one entry for this purpose) into r11, then
+	 branches to code at the start of the PLT. This code then
+	 calls `fixup', in dl-runtime.c, via the glue in the macro
+	 ELF_MACHINE_RUNTIME_TRAMPOLINE, which resets the PLT entry to
+	 be one of the above two types. These entries are set up here.  */
+int
+__elf_machine_runtime_setup (struct link_map *map, int lazy, int profile)
+{
+  if (map->l_info[DT_JMPREL])
+    {
+      Elf32_Word i;
+      /* Fill in the PLT. Its initial contents are directed to a
+	 function earlier in the PLT which arranges for the dynamic
+	 linker to be called back.  */
+      Elf32_Word *plt = (Elf32_Word *) ((char *) map->l_addr
+					+ map->l_info[DT_PLTGOT]->d_un.d_val);
+      Elf32_Word num_plt_entries = (map->l_info[DT_PLTRELSZ]->d_un.d_val
+				    / sizeof (Elf32_Rela));
+      Elf32_Word rel_offset_words = PLT_DATA_START_WORDS (num_plt_entries);
+      Elf32_Word size_modified;
+      extern void _dl_runtime_resolve (void);
+      extern void _dl_prof_resolve (void);
+      Elf32_Word dlrr;
+
+      dlrr = (Elf32_Word)(char *)(profile
+				  ? _dl_prof_resolve
+				  : _dl_runtime_resolve);
+
+      if (lazy)
+	for (i = 0; i < num_plt_entries; i++)
+	{
+	  Elf32_Word offset = PLT_ENTRY_START_WORDS (i);
+
+	  if (i >= PLT_DOUBLE_SIZE)
+	    {
+	      plt[offset  ] = OPCODE_LI (11, i * 4);
+	      plt[offset+1] = OPCODE_ADDIS (11, 11, (i * 4 + 0x8000) >> 16);
+	      plt[offset+2] = OPCODE_B (-(4 * (offset + 2)));
+	    }
+	  else
+	    {
+	      plt[offset  ] = OPCODE_LI (11, i * 4);
+	      plt[offset+1] = OPCODE_B (-(4 * (offset + 1)));
+	    }
+	}
+
+      /* Multiply index of entry by 3 (in r11).  */
+      plt[0] = OPCODE_SLWI (12, 11, 1);
+      plt[1] = OPCODE_ADD (11, 12, 11);
+      if (dlrr <= 0x01fffffc || dlrr >= 0xfe000000)
+	{
+	  /* Load address of link map in r12.  */
+	  plt[2] = OPCODE_LI (12, (Elf32_Word) (char *) map);
+	  plt[3] = OPCODE_ADDIS (12, 12, (((Elf32_Word) (char *) map
+					   + 0x8000) >> 16));
+
+	  /* Call _dl_runtime_resolve.  */
+	  plt[4] = OPCODE_BA (dlrr);
+	}
+      else
+	{
+	  /* Get address of _dl_runtime_resolve in CTR.  */
+	  plt[2] = OPCODE_LI (12, dlrr);
+	  plt[3] = OPCODE_ADDIS (12, 12, (dlrr + 0x8000) >> 16);
+	  plt[4] = OPCODE_MTCTR (12);
+
+	  /* Load address of link map in r12.  */
+	  plt[5] = OPCODE_LI (12, (Elf32_Word) (char *) map);
+	  plt[6] = OPCODE_ADDIS (12, 12, (((Elf32_Word) (char *) map
+					   + 0x8000) >> 16));
+
+	  /* Call _dl_runtime_resolve.  */
+	  plt[7] = OPCODE_BCTR ();
+	}
+
+
+      /* Convert the index in r11 into an actual address, and get the
+	 word at that address.  */
+      plt[PLT_LONGBRANCH_ENTRY_WORDS] =
+	OPCODE_ADDIS (11, 11, (((Elf32_Word) (char*) (plt + rel_offset_words)
+				+ 0x8000) >> 16));
+      plt[PLT_LONGBRANCH_ENTRY_WORDS+1] =
+	OPCODE_LWZ (11, (Elf32_Word) (char*) (plt+rel_offset_words), 11);
+
+      /* Call the procedure at that address.  */
+      plt[PLT_LONGBRANCH_ENTRY_WORDS+2] = OPCODE_MTCTR (11);
+      plt[PLT_LONGBRANCH_ENTRY_WORDS+3] = OPCODE_BCTR ();
+
+
+      /* Now, we've modified code (quite a lot of code, possibly).  We
+	 need to write the changes from the data cache to a
+	 second-level unified cache, then make sure that stale data in
+	 the instruction cache is removed.  (In a multiprocessor
+	 system, the effect is more complex.)
+
+	 Assumes the cache line size is at least 32 bytes, or at least
+	 that dcbst and icbi apply to 32-byte lines. At present, all
+	 PowerPC processors have line sizes of exactly 32 bytes.  */
+
+      size_modified = lazy ? rel_offset_words : PLT_INITIAL_ENTRY_WORDS;
+      for (i = 0; i < size_modified; i+=8)
+	PPC_DCBST (plt + i);
+      PPC_SYNC;
+      for (i = 0; i < size_modified; i+=8)
+	PPC_ICBI (plt + i);
+      PPC_ISYNC;
+    }
+
+  return lazy;
+}
+
+void
+__elf_machine_fixup_plt(struct link_map *map, const Elf32_Rela *reloc,
+			Elf32_Addr *reloc_addr, Elf32_Addr finaladdr)
+{
+  Elf32_Sword delta = finaladdr - (Elf32_Word) (char *) reloc_addr;
+  if (delta << 6 >> 6 == delta)
+    *reloc_addr = OPCODE_B (delta);
+  else if (finaladdr <= 0x01fffffc || finaladdr >= 0xfe000000)
+    *reloc_addr = OPCODE_BA (finaladdr);
+  else
+    {
+      Elf32_Word *plt;
+      Elf32_Word index;
+
+      plt = (Elf32_Word *)((char *)map->l_addr
+			   + map->l_info[DT_PLTGOT]->d_un.d_val);
+      index = (reloc_addr - plt - PLT_INITIAL_ENTRY_WORDS)/2;
+      if (index >= PLT_DOUBLE_SIZE)
+	{
+	  /* Slots greater than or equal to 2^13 have 4 words available
+	     instead of two.  */
+	  /* FIXME: There are some possible race conditions in this code,
+	     when called from 'fixup'.
+
+	     1) Suppose that a lazy PLT entry is executing, a context switch
+	     between threads (or a signal) occurs, and the new thread or
+	     signal handler calls the same lazy PLT entry.  Then the PLT entry
+	     would be changed while it's being run, which will cause a segfault
+	     (almost always).
+
+	     2) Suppose the reverse: that a lazy PLT entry is being updated,
+	     a context switch occurs, and the new code calls the lazy PLT
+	     entry that is being updated.  Then the half-fixed PLT entry will
+	     be executed, which will also almost always cause a segfault.
+
+	     These problems don't happen with the 2-word entries, because
+	     only one of the two instructions are changed when a lazy entry
+	     is retargeted at the actual PLT entry; the li instruction stays
+	     the same (we have to update it anyway, because we might not be
+	     updating a lazy PLT entry).  */
+
+	  reloc_addr[0] = OPCODE_LI (11, finaladdr);
+	  reloc_addr[1] = OPCODE_ADDIS (11, 11, finaladdr + 0x8000 >> 16);
+	  reloc_addr[2] = OPCODE_MTCTR (11);
+	  reloc_addr[3] = OPCODE_BCTR ();
+	}
+      else
+	{
+	  Elf32_Word num_plt_entries;
+
+	  num_plt_entries = (map->l_info[DT_PLTRELSZ]->d_un.d_val
+			     / sizeof(Elf32_Rela));
+
+	  plt[index+PLT_DATA_START_WORDS (num_plt_entries)] = finaladdr;
+	  reloc_addr[0] = OPCODE_LI (11, index*4);
+	  reloc_addr[1] = OPCODE_B (-(4*(index*2
+					 + 1
+					 - PLT_LONGBRANCH_ENTRY_WORDS
+					 + PLT_INITIAL_ENTRY_WORDS)));
+	}
+    }
+  MODIFIED_CODE (reloc_addr);
+}
+
+void
+__process_machine_rela (struct link_map *map,
+			const Elf32_Rela *reloc,
+			const Elf32_Sym *sym,
+			const Elf32_Sym *refsym,
+			Elf32_Addr *const reloc_addr,
+			Elf32_Addr const finaladdr,
+			int rinfo)
+{
+  switch (rinfo)
+    {
+    case R_PPC_NONE:
+      return;
+
+    case R_PPC_ADDR32:
+    case R_PPC_UADDR32:
+    case R_PPC_GLOB_DAT:
+    case R_PPC_RELATIVE:
+      *reloc_addr = finaladdr;
+      return;
+
+    case R_PPC_ADDR24:
+      if (finaladdr > 0x01fffffc && finaladdr < 0xfe000000)
+	{
+	  _dl_signal_error(0, map->l_name,
+			   "R_PPC_ADDR24 relocation out of range");
+	}
+      *reloc_addr = *reloc_addr & 0xfc000003 | finaladdr & 0x3fffffc;
+      break;
+
+    case R_PPC_ADDR16:
+    case R_PPC_UADDR16:
+      if (finaladdr > 0x7fff && finaladdr < 0x8000)
+	{
+	  _dl_signal_error(0, map->l_name,
+			   "R_PPC_ADDR16 relocation out of range");
+	}
+      *(Elf32_Half*) reloc_addr = finaladdr;
+      break;
+
+    case R_PPC_ADDR16_LO:
+      *(Elf32_Half*) reloc_addr = finaladdr;
+      break;
+
+    case R_PPC_ADDR16_HI:
+      *(Elf32_Half*) reloc_addr = finaladdr >> 16;
+      break;
+
+    case R_PPC_ADDR16_HA:
+      *(Elf32_Half*) reloc_addr = (finaladdr + 0x8000) >> 16;
+      break;
+
+    case R_PPC_ADDR14:
+    case R_PPC_ADDR14_BRTAKEN:
+    case R_PPC_ADDR14_BRNTAKEN:
+      if (finaladdr > 0x7fff && finaladdr < 0x8000)
+	{
+	  _dl_signal_error(0, map->l_name,
+			   "R_PPC_ADDR14 relocation out of range");
+	}
+      *reloc_addr = *reloc_addr & 0xffff0003 | finaladdr & 0xfffc;
+      if (rinfo != R_PPC_ADDR14)
+	*reloc_addr = (*reloc_addr & 0xffdfffff
+		       | (rinfo == R_PPC_ADDR14_BRTAKEN
+			  ^ finaladdr >> 31) << 21);
+      break;
+
+    case R_PPC_REL24:
+      {
+	Elf32_Sword delta = finaladdr - (Elf32_Word) (char *) reloc_addr;
+	if (delta << 6 >> 6 != delta)
+	  {
+	    _dl_signal_error(0, map->l_name,
+			     "R_PPC_REL24 relocation out of range");
+	  }
+	*reloc_addr = *reloc_addr & 0xfc000003 | delta & 0x3fffffc;
+      }
+      break;
+
+    case R_PPC_COPY:
+      if (sym == NULL)
+	/* This can happen in trace mode when an object could not be
+	   found.  */
+	return;
+      if (sym->st_size > refsym->st_size
+	  || (_dl_verbose && sym->st_size < refsym->st_size))
+	{
+	  const char *strtab;
+
+	  strtab = ((void *) map->l_addr
+		    + map->l_info[DT_STRTAB]->d_un.d_ptr);
+	  _dl_sysdep_error (_dl_argv[0] ?: "<program name unknown>",
+			    ": Symbol `", strtab + refsym->st_name,
+			    "' has different size in shared object, "
+			    "consider re-linking\n", NULL);
+	}
+      memcpy (reloc_addr, (char *) finaladdr, MIN (sym->st_size,
+						   refsym->st_size));
+      return;
+
+    case R_PPC_REL32:
+      *reloc_addr = finaladdr - (Elf32_Word) (char *) reloc_addr;
+      return;
+
+    case R_PPC_JMP_SLOT:
+      elf_machine_fixup_plt(map, reloc, reloc_addr, finaladdr);
+      return;
+
+    default:
+      _dl_sysdep_error (_dl_argv[0] ?: "<program name unknown>",
+			": Unknown relocation type\n", NULL);
+      return;
+    }
+
+  MODIFIED_CODE_NOQUEUE (reloc_addr);
+}