dl-machine.h

Glibc 2.3.2源代码(解压后有100多M)

/* Machine-dependent ELF dynamic relocation inline functions.
   PowerPC64 version.
   Copyright 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 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 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.  */

#ifndef dl_machine_h
#define dl_machine_h

#define ELF_MACHINE_NAME "powerpc64"

#include <assert.h>
#include <sys/param.h>

/* Translate a processor specific dynamic tag to the index
   in l_info array.  */
#define DT_PPC64(x) (DT_PPC64_##x - DT_LOPROC + DT_NUM)

/* A PowerPC64 function descriptor.  The .plt (procedure linkage
   table) and .opd (official procedure descriptor) sections are
   arrays of these.  */
typedef struct
{
  Elf64_Addr fd_func;
  Elf64_Addr fd_toc;
  Elf64_Addr fd_aux;
} Elf64_FuncDesc;

#define ELF_MULT_MACHINES_SUPPORTED

/* Return nonzero iff ELF header is compatible with the running host.  */
static inline int
elf_machine_matches_host (const Elf64_Ehdr *ehdr)
{
  return ehdr->e_machine == EM_PPC64;
}

/* Return nonzero iff ELF header is compatible with the running host,
   but not this loader.  */
static inline int
elf_host_tolerates_machine (const Elf64_Ehdr *ehdr)
{
  return ehdr->e_machine == EM_PPC;
}

/* Return nonzero iff ELF header is compatible with the running host,
   but not this loader.  */
static inline int
elf_host_tolerates_class (const Elf64_Ehdr *ehdr)
{
  return ehdr->e_ident[EI_CLASS] == ELFCLASS32;
}


/* Return the run-time load address of the shared object, assuming it
   was originally linked at zero.  */
static inline Elf64_Addr
elf_machine_load_address (void) __attribute__ ((const));

static inline Elf64_Addr
elf_machine_load_address (void)
{
  Elf64_Addr ret;

  /* The first entry in .got (and thus the first entry in .toc) is the
     link-time TOC_base, ie. r2.  So the difference between that and
     the current r2 set by the kernel is how far the shared lib has
     moved.  */
  asm (	"	ld	%0,-32768(2)\n"
	"	subf	%0,%0,2\n"
	: "=r"	(ret));
  return ret;
}

/* Return the link-time address of _DYNAMIC.  */
static inline Elf64_Addr
elf_machine_dynamic (void)
{
  Elf64_Addr runtime_dynamic;
  /* It's easier to get the run-time address.  */
  asm (	"	addis	%0,2,_DYNAMIC@toc@ha\n"
	"	addi	%0,%0,_DYNAMIC@toc@l\n"
	: "=b"	(runtime_dynamic));
  /* Then subtract off the load address offset.  */
  return runtime_dynamic - elf_machine_load_address() ;
}

#define ELF_MACHINE_BEFORE_RTLD_RELOC(dynamic_info) /* nothing */

/* The PLT uses Elf64_Rela relocs.  */
#define elf_machine_relplt elf_machine_rela

/* This code gets called via a .glink stub which loads PLT0.  It is
   used in dl-runtime.c to call the `fixup' function and then redirect
   to the address `fixup' returns.

   Enter with r0 = plt reloc index,
   r2 = ld.so tocbase,
   r11 = ld.so link map.  */

#define TRAMPOLINE_TEMPLATE(tramp_name, fixup_name) \
  asm (".section \".text\"\n"						\
"	.align	2\n"							\
"	.globl	." #tramp_name "\n"					\
"	.type	." #tramp_name ",@function\n"				\
"	.section \".opd\",\"aw\"\n"					\
"	.align	3\n"							\
"	.globl	" #tramp_name "\n"					\
"	.size	" #tramp_name ",24\n"					\
#tramp_name ":\n"							\
"	.quad	." #tramp_name ",.TOC.@tocbase,0\n"			\
"	.previous\n"							\
"." #tramp_name ":\n"							\
/* We need to save the registers used to pass parameters, ie. r3 thru	\
   r10; the registers are saved in a stack frame.  */			\
"	stdu	1,-128(1)\n"						\
"	std	3,48(1)\n"						\
"	mr	3,11\n"							\
"	std	4,56(1)\n"						\
"	sldi	4,0,1\n"						\
"	std	5,64(1)\n"						\
"	add	4,4,0\n"						\
"	std	6,72(1)\n"						\
"	sldi	4,4,3\n"						\
"	std	7,80(1)\n"						\
"	mflr	0\n"							\
"	std	8,88(1)\n"						\
/* Store the LR in the LR Save area of the previous frame.  */    \
"	std	0,128+16(1)\n"						\
"	mfcr	0\n"							\
"	std	9,96(1)\n"						\
"	std	10,104(1)\n"						\
/* I'm almost certain we don't have to save cr...  be safe.  */    \
"	std	0,8(1)\n"						\
"	bl	." #fixup_name "\n"					\
/* Put the registers back.  */						\
"	ld	0,128+16(1)\n"						\
"	ld	10,104(1)\n"						\
"	ld	9,96(1)\n"						\
"	ld	8,88(1)\n"						\
"	ld	7,80(1)\n"						\
"	mtlr	0\n"							\
"	ld	0,8(1)\n"						\
"	ld	6,72(1)\n"						\
"	ld	5,64(1)\n"						\
"	ld	4,56(1)\n"						\
"	mtcrf	0xFF,0\n"						\
/* Load the target address, toc and static chain reg from the function  \
   descriptor returned by fixup.  */					\
"	ld	0,0(3)\n"						\
"	ld	2,8(3)\n"						\
"	mtctr	0\n"							\
"	ld	11,16(3)\n"						\
"	ld	3,48(1)\n"						\
/* Unwind the stack frame, and jump.  */				\
"	addi	1,1,128\n"						\
"	bctr\n"								\
".LT_" #tramp_name ":\n"						\
"	.long 0\n"							\
"	.byte 0x00,0x0c,0x24,0x40,0x00,0x00,0x00,0x00\n"		\
"	.long .LT_" #tramp_name "-."#tramp_name "\n"			\
"	.short .LT_" #tramp_name "_name_end-.LT_" #tramp_name "_name_start\n" \
".LT_" #tramp_name "_name_start:\n"					\
"	.ascii \"" #tramp_name "\"\n"					\
".LT_" #tramp_name "_name_end:\n"					\
"	.align 2\n"							\
"	.size	." #tramp_name ",. - ." #tramp_name "\n"		\
"	.previous");

#ifndef PROF
#define ELF_MACHINE_RUNTIME_TRAMPOLINE			\
  TRAMPOLINE_TEMPLATE (_dl_runtime_resolve, fixup);	\
  TRAMPOLINE_TEMPLATE (_dl_profile_resolve, profile_fixup);
#else
#define ELF_MACHINE_RUNTIME_TRAMPOLINE			\
  TRAMPOLINE_TEMPLATE (_dl_runtime_resolve, fixup);	\
  void _dl_runtime_resolve (void);			\
  strong_alias (_dl_runtime_resolve, _dl_profile_resolve);
#endif


/* Initial entry point code for the dynamic linker.  The C function
   `_dl_start' is the real entry point; its return value is the user
   program's entry point.  */
#define RTLD_START \
  asm (".section \".text\"\n"						\
"	.align	2\n"							\
"	.globl	._start\n"						\
"	.type	._start,@function\n"					\
"	.section \".opd\",\"aw\"\n"					\
"	.align	3\n"							\
"	.globl	_start\n"						\
"	.size	_start,24\n"						\
"_start:\n"								\
"	.quad	._start,.TOC.@tocbase,0\n"				\
"	.previous\n"							\
"._start:\n"								\
/* We start with the following on the stack, from top:			\
   argc (4 bytes);							\
   arguments for program (terminated by NULL);				\
   environment variables (terminated by NULL);				\
   arguments for the program loader.  */				\
"	mr	3,1\n"							\
"	li	4,0\n"							\
"	stdu	4,-128(1)\n"						\
/* Call _dl_start with one parameter pointing at argc.  */		\
"	bl	._dl_start\n"						\
"	nop\n"								\
/* Transfer control to _dl_start_user!  */				\
"	b	._dl_start_user\n"					\
".LT__start:\n"  \
"	.long 0\n"      \
"	.byte 0x00,0x0c,0x24,0x40,0x00,0x00,0x00,0x00\n"		\
"	.long .LT__start-._start\n"					\
"	.short .LT__start_name_end-.LT__start_name_start\n"		\
".LT__start_name_start:\n"						\
"	.ascii \"_start\"\n"						\
".LT__start_name_end:\n"						\
"	.align 2\n"							\
"	.size	._start,.-._start\n"					\
"	.globl	_dl_start_user\n"					\
"	.section \".opd\",\"aw\"\n"					\
"_dl_start_user:\n"							\
"	.quad	._dl_start_user, .TOC.@tocbase, 0\n"			\
"	.previous\n"							\
"	.globl	._dl_start_user\n"					\
"	.type	._dl_start_user,@function\n"				\
/* Now, we do our main work of calling initialisation procedures.  \
   The ELF ABI doesn't say anything about parameters for these,  \
   so we just pass argc, argv, and the environment.  \
   Changing these is strongly discouraged (not least because argc is  \
   passed by value!).  */  \
"._dl_start_user:\n"  \
/* the address of _start in r30.  */					\
"	mr	30,3\n"							\
/* &_dl_argc in 29, &_dl_argv in 27, and _dl_loaded in 28.  */		\
"	ld	28,_rtld_global@got(2)\n"    \
"	ld	29,_dl_argc@got(2)\n"					\
"	ld	27,_dl_argv@got(2)\n"					\
/* _dl_init (_dl_loaded, _dl_argc, _dl_argv, _dl_argv+_dl_argc+1).  */	\
"	ld	3,0(28)\n"						\
"	lwa	4,0(29)\n"						\
"	ld	5,0(27)\n"						\
"	sldi	6,4,3\n"						\
"	add	6,5,6\n"						\
"	addi	6,6,8\n"						\
"	bl	._dl_init\n"						\
"	nop\n"								\
/* Now, to conform to the ELF ABI, we have to:				\
   Pass argc (actually _dl_argc) in r3;  */				\
"	lwa	3,0(29)\n"						\
/* Pass argv (actually _dl_argv) in r4;  */				\
"	ld	4,0(27)\n"						\
/* Pass argv+argc+1 in r5;  */						\
"	sldi	5,3,3\n"						\
"	add	6,4,5\n"						\
"	addi	5,6,8\n"						\
/* Pass the auxilary vector in r6. This is passed to us just after	\
   _envp.  */								\
"2:	ldu	0,8(6)\n"						\
"	cmpdi	0,0\n"							\
"	bne	2b\n"							\
"	addi	6,6,8\n"						\
/* Pass a termination function pointer (in this case _dl_fini) in	\
   r7.  */								\
"	ld	7,_dl_fini@got(2)\n"					\
"	ld 	26,_dl_starting_up@got(2)\n"				\
/* Pass the stack pointer in r1 (so far so good), pointing to a NULL	\
   value.  This lets our startup code distinguish between a program	\
   linked statically, which linux will call with argc on top of the	\
   stack which will hopefully never be zero, and a dynamically linked	\
   program which will always have a NULL on the top of the stack.	\
   Take the opportunity to clear LR, so anyone who accidentally  \
   returns from _start gets SEGV.  Also clear the next few words of	\
   the stack.  */							\
"	li	31,0\n"							\
"	std	31,0(1)\n"						\
"	mtlr	31\n"							\
"	std	31,8(1)\n"						\
"	std	31,16(1)\n"						\
"	std	31,24(1)\n"						\
/* Clear _dl_starting_up.  */						\
"	stw	31,0(26)\n"						\
/* Now, call the start function descriptor at r30...  */		\
"	.globl	._dl_main_dispatch\n"  \
"._dl_main_dispatch:\n"  \
"	ld	0,0(30)\n"						\
"	ld	2,8(30)\n"						\
"	mtctr	0\n"							\
"	ld	11,16(30)\n"						\
"	bctr\n"								\
".LT__dl_start_user:\n"	\
"	.long 0\n"							\
"	.byte 0x00,0x0c,0x24,0x40,0x00,0x00,0x00,0x00\n"		\
"	.long .LT__dl_start_user-._dl_start_user\n"			\
"	.short .LT__dl_start_user_name_end-.LT__dl_start_user_name_start\n" \
".LT__dl_start_user_name_start:\n"					\
"	.ascii \"_dl_start_user\"\n"					\
".LT__dl_start_user_name_end:\n"					\
"	.align 2\n"							\
"	.size	._dl_start_user,.-._dl_start_user\n"			\
"	.previous");

/* Nonzero iff TYPE should not be allowed to resolve to one of
   the main executable's symbols, as for a COPY reloc.  */
#define elf_machine_lookup_noexec_p(type) ((type) == R_PPC64_COPY)

/* Nonzero iff TYPE describes relocation of a PLT entry, so
   PLT entries should not be allowed to define the value.  */
#define elf_machine_lookup_noplt_p(type) ((type) == R_PPC64_JMP_SLOT)

/* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry, so
   PLT entries should not be allowed to define the value.
   ELF_RTYPE_CLASS_NOCOPY iff TYPE should not be allowed to resolve to one
   of the main executable's symbols, as for a COPY reloc.  */

#if defined USE_TLS && (!defined RTLD_BOOTSTRAP || USE___THREAD)
#define elf_machine_type_class(type) \
  (   (((type) == R_PPC64_DTPMOD64	\
    ||  (type) == R_PPC64_DTPREL64	\
    ||  (type) == R_PPC64_TPREL64 \
    ||  (type) == R_PPC64_ADDR24) * ELF_RTYPE_CLASS_PLT)	\
    | (((type) == R_PPC64_COPY) * ELF_RTYPE_CLASS_COPY))
#else
#define elf_machine_type_class(type) \
  ((((type) == R_PPC64_ADDR24) * ELF_RTYPE_CLASS_PLT)	\
   | (((type) == R_PPC64_COPY) * ELF_RTYPE_CLASS_COPY))
#endif

/* A reloc type used for ld.so cmdline arg lookups to reject PLT entries.  */
#define ELF_MACHINE_JMP_SLOT	R_PPC64_JMP_SLOT

/* The PowerPC never uses REL relocations.  */
#define ELF_MACHINE_NO_REL 1

/* Stuff for the PLT.  */
#define PLT_INITIAL_ENTRY_WORDS 3
#define GLINK_INITIAL_ENTRY_WORDS 8

#define PPC_DCBST(where) asm volatile ("dcbst 0,%0" : : "r"(where) : "memory")
#define PPC_SYNC asm volatile ("sync" : : : "memory")
#define PPC_ISYNC asm volatile ("sync; isync" : : : "memory")
#define PPC_ICBI(where) asm volatile ("icbi 0,%0" : : "r"(where) : "memory")
#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)

/* Set up the loaded object described by MAP so its unrelocated PLT
   entries will jump to the on-demand fixup code in dl-runtime.c.  */
static inline int
elf_machine_runtime_setup (struct link_map *map, int lazy, int profile)
{
  if (map->l_info[DT_JMPREL])
    {
      Elf64_Word i;
      Elf64_Word *glink = NULL;
      Elf64_Xword *plt = (Elf64_Xword *) D_PTR (map, l_info[DT_PLTGOT]);
      Elf64_Word num_plt_entries = (map->l_info[DT_PLTRELSZ]->d_un.d_val
				    / sizeof (Elf64_Rela));
      Elf64_Addr l_addr = map->l_addr;
      Elf64_Dyn **info = map->l_info;
      char *p;

      extern void _dl_runtime_resolve (void);
      extern void _dl_profile_resolve (void);

      /* Relocate the DT_PPC64_GLINK entry in the _DYNAMIC section.
	 elf_get_dynamic_info takes care of the standard entries but
	 doesn't know exactly what to do with processor specific
	 entires.  */
      if (info[DT_PPC64(GLINK)] != NULL)
	info[DT_PPC64(GLINK)]->d_un.d_ptr += l_addr;

      if (lazy)
	{
	  /* The function descriptor of the appropriate trampline
	     routine is used to set the 1st and 2nd doubleword of the
	     plt_reserve.  */
	  Elf64_FuncDesc *resolve_fd;
	  Elf64_Word glink_offset;
	  /* the plt_reserve area is the 1st 3 doublewords of the PLT */
	  Elf64_FuncDesc *plt_reserve = (Elf64_FuncDesc *) plt;
	  Elf64_Word offset;

	  resolve_fd = (Elf64_FuncDesc *) (profile ? _dl_profile_resolve
					   : _dl_runtime_resolve);
	  if (profile && _dl_name_match_p (GL(dl_profile), map))
	    /* This is the object we are looking for.  Say that we really
	       want profiling and the timers are started.  */
	    GL(dl_profile_map) = map;


	  /* We need to stuff the address/TOC of _dl_runtime_resolve
	     into doublewords 0 and 1 of plt_reserve.  Then we need to
	     stuff the map address into doubleword 2 of plt_reserve.
	     This allows the GLINK0 code to transfer control to the
	     correct trampoline which will transfer control to fixup
	     in dl-machine.c.  */
	  plt_reserve->fd_func = resolve_fd->fd_func;
	  plt_reserve->fd_toc  = resolve_fd->fd_toc;
	  plt_reserve->fd_aux  = (Elf64_Addr) map;
#ifdef RTLD_BOOTSTRAP
	  /* When we're bootstrapping, the opd entry will not have
	     been relocated yet.  */
	  plt_reserve->fd_func += l_addr;
	  plt_reserve->fd_toc  += l_addr;
#endif

	  /* Set up the lazy PLT entries.  */
	  glink = (Elf64_Word *) D_PTR (map, l_info[DT_PPC64(GLINK)]);
	  offset = PLT_INITIAL_ENTRY_WORDS;
	  glink_offset = GLINK_INITIAL_ENTRY_WORDS;
	  for (i = 0; i < num_plt_entries; i++)
	    {

	      plt[offset] = (Elf64_Xword) &glink[glink_offset];
	      offset += 3;