glibc/sysdeps/powerpc/dl-machine.h
Ulrich Drepper af6f39063b Update.
1997-10-26 18:12  Ulrich Drepper  <drepper@cygnus.com>

	* libio/genops.c: Partial undo of last patch.
	* libio/stdfiles.c: Likewise.
	* libio/iofdopen.c: Use _IO_FILE_complete, not _IO_file_plus.
	* libio/iopopen.c: Likewise.
	* libio/iovdprintf.c: Likewise.
	* libio/libio.h: Remove duplicated `;'.
	* libio/stdio.c: Remove misleading comment.
	* libio/stdio.h: Declare standard streams as variables.

	* login/Makefile (distribute): Add README.utmpd.
	* login/README.utmpd: New file.
	Provided by Mark M. Kettenis <kettenis@phys.uva.nl>.

	* manual/job.texi: Document tcgetsid.
	* manual/pattern.texi: Document globfree.
	* manual/terminal.texi: Document B38400 ... B460800.

	* posix/confstr.c: Print "-D_FILE_OFFSET_SIZE=64" for _CS_LFS_CFLAGS.

	* posix/unistd.h: Add explanation of _POSIX_* constants.

	* posix/unists.h: Add prototypes for __pread, __pread64, __pwrite
	and __pwrite64.
	* sysdeps/generic/pread.c: Define as __pread and make pread weak alias.
	* sysdeps/generic/pread64.c: Likewise.
	* sysdeps/generic/pwrite.c: Likewise.
	* sysdeps/generic/pwrite64.c: Likewise.
	* sysdeps/posix/pread.c: Likewise.
	* sysdeps/posix/pwrite.c: Likewise.
	* sysdeps/posix/pread64.c: New file.
	* sysdeps/posix/pwrite64.c: Likewise.
	* sysdeps/unix/sysv/linux/Makefile [$(subdir)=posix] (sysdep_routines):
	Add s_pread64 and s_pwrite64.
	* sysdeps/unix/sysv/linux/pread.c: New file.
	* sysdeps/unix/sysv/linux/pread64.c: New file.
	* sysdeps/unix/sysv/linux/pwrite.c: New file.
	* sysdeps/unix/sysv/linux/pwrite64.c: New file.
	* sysdeps/unix/sysv/linux/s_pread64.c: New file.
	* sysdeps/unix/sysv/linux/s_pwrite64.c: New file.
	* sysdeps/unix/sysv/linux/syscalls.list: Add pread and pwrite.
	* sysdeps/unix/sysv/linux/alpha/pread64.c: New (empty) file.
	* sysdeps/unix/sysv/linux/alpha/pwrite64.c: New (empty) file.
	* sysdeps/unix/sysv/linux/sparc/sparc64/pread64.c: New (empty) file.
	* sysdeps/unix/sysv/linux/sparc/sparc64/pwrite64.c: New (empty) file.
	* sysdeps/unix/sysv/linux/alpha/syscalls.list: Add pread and pwrite
	with weak aliases for *64 functions.
	* sysdeps/unix/sysv/linux/sparc/sparc64/syscalls.list: Likewise.

	* string/bits/string2.h: Add casts to allow void * arguments.

	* sysdeps/i386/i486/bits/string.h: Define index and rindex only if
	__USE_BSD or __USE_XOPEN_EXTENDED.

	* sysdeps/unix/sysv/linux/bits/socket.h: Add SCM_RIGHTS and other
	SCM_* constants from kernel header.

	* termios/termios.h: Add prototype for tcgetsid.

1997-10-26 13:26  Thorsten Kukuk  <kukuk@vt.uni-paderborn.de>

	* sunrpc/clnt_perr.c: Add trailing '\0' to strings.

	* sunrpc/get_myaddr.c: Include rpc/clnt.h for prototypes.

	* sunrpc/pmap_clnt.c: Use get_myaddress from header file.

1997-10-26 05:26  Ulrich Drepper  <drepper@cygnus.com>

	* configure.in: Punt if any directory mentioned in the
	enable-add-on parameter does not exist.

1997-10-25 19:25  Ulrich Drepper  <drepper@cygnus.com>

	* termios/Makefile (routines): Add tcgetsid.
	* termios/tcgetsid.c: New file.
	Provided by Mark M. Kettenis <kettenis@phys.uva.nl>.

1997-10-25 18:56  Ulrich Drepper  <drepper@cygnus.com>

	* stdlib/stdlib.h: Remove mblen optimization.
	* stdlib/mblen.c: Rewrite to make sure global state is not changed.
	Reported by anderson@metrolink.com.

1997-10-19 21:51  Wolfram Gloger  <wg@wolfram.dent.med.uni-muenchen.de>

	* malloc/thread-m.h [_LIBC]:  Use new __libc_internal_tsd_{set,get}
	interface for thread-specific data.

1997-10-25 06:51  Ulrich Drepper  <drepper@cygnus.com>

	* elf/dl-addr.c: Use braces for correct logical grouping.
	Patch by Wolfram Gloger <wmglo@dent.med.uni-muenchen.de>.

1997-10-18 09:15  Geoff Keating  <geoffk@ozemail.com.au>

	* io/ftwtest-sh: Sometimes /tmp is a symlink to somewhere more
	convenient; that caused this test to break.

	* sysdeps/powerpc/dl-machine.h: Fix typo.

	* sysdeps/powerpc/bits/fenv.h: Don't use floating-point registers
	when -msoft-float is in effect, because this causes compilation to
	stop.
	* sysdeps/powerpc/bits/mathinlines.h: Likewise.

	* rpm/template: Add description, use RPM flags rather than the ones
	used to build the spec.  Build in a temporary directory, not /.

	* elf/dl-lookup.c: Don't include _itoa.h, it's not used.
	* elf/dl-minimal.c: Use _itoa_word rather than _itoa.  It seems that
	_itoa is the only routine that ld.so uses that requires something
	from libgcc.a on powerpc, so it would be best to avoid it in ld.so.
	* elf/rtld.c: Likewise.
	* sysdeps/generic/_strerror.c: Likewise.
	* stdio-common/_itoa.c: Split out digits strings.
	* stdio-common/itoa-digits.c: New file.
	* stdio-common/Makefile: Add itoa-digits.

1997-10-21  Andreas Jaeger  <aj@arthur.rhein-neckar.de>

	* manual/filesys.texi (Scanning Directory Content): Document error
	case more.

	* dirent/scandir.c (scandir): Ignore errors from select function.
	Suggested by urbanw@cs.umu.se (closes PR libc/316).

1997-10-25 06:18  Ulrich Drepper  <drepper@cygnus.com>

	* sysdeps/unix/sysv/linux/sparc/sparc32/socket.S: Corrections.
	Patch by Erik Troan <ewt@redhat.com>.

1997-10-25 04:00  Ulrich Drepper  <drepper@cygnus.com>

	* sysdeps/generic/dl-cache.c (_dl_load_cache_lookup): Favour exact
	matching of version function if both the general (1) and
	glibc-specific (3) entry are present.

1997-10-22 18:47  Thorsten Kukuk  <kukuk@vt.uni-paderborn.de>

	* sunrpc/rpc/clnt.h: Add get_myaddress prototype.

	* nis/libnsl.map: Fix typo.

	* nis/nis_call.c: Fix memory leak.

1997-10-22 19:29  Ulrich Drepper  <drepper@cygnus.com>

	* sysdeps/generic/memcmp.c: Define __P if not defined before.
	Patch by Jim Meyering <meyering@eng.ascend.com>.

1997-10-21 22:09  Ulrich Drepper  <drepper@cygnus.com>

	* sysdeps/unix/sysv/linux/sys/prctl.h: New file by Richard Gooch
	<rgooch@atnf.csiro.au>.

1997-10-21 21:50  Ulrich Drepper  <drepper@cygnus.com>

	* misc/syslog.c (vsyslog): Open console with O_NOCTTY.
	Patch by Zack Weinberg <zack@rabi.phys.columbia.edu>.

1997-10-21 18:07  Ulrich Drepper  <drepper@cygnus.com>

	* posix/wordexp.c: Improve handling of $... expressions.
	Patch by Tim Waugh <tim@cyberelk.demon.co.uk>.

1997-10-21 16:12  Ulrich Drepper  <drepper@cygnus.com>

	* manual/string.texi: Correct return values of bcopy and bzero.
	Patch by Matthew Wilcox <willy@odie.barnet.ac.uk>.

1997-10-18 15:03  Philip Blundell  <Philip.Blundell@pobox.com>

	* sysdeps/unix/sysv/linux/bits/socket.h: Correct types of some
	elements in struct msghdr and struct cmsghdr, to keep in step with
	the kernel.

1997-10-17 22:29  Ulrich Drepper  <drepper@cygnus.com>

	* sysdeps/unix/sysv/linux/sparc/sparc32/init-first.h: Fix another
	bug in startup code.
	Patch by Eric Delaunay <delaunay@lix.polytechnique.fr>.

1997-10-16 20:17  Richard Henderson  <rth@cygnus.com>

	* sysdeps/unix/sysv/linux/sparc/sparc32/socket.S: Dump args to the
	stack and give the kernel a pointer.  Use the sysdep.h macros.

1997-10-17 04:07  Ulrich Drepper  <drepper@cygnus.com>

	* sysdeps/sparc/sparc32/elf/start.S: Calculate argv correctly.
	Patch by Eric Delaunay <delaunay@lix.polytechnique.fr>.

1997-10-16  Andreas Jaeger  <aj@arthur.rhein-neckar.de>

	* sysdeps/libm-ieee754/s_nextafterxf.c [!__STDC__]: Correct typo.

1997-10-16 14:50  Ulrich Drepper  <drepper@cygnus.com>

	* manual/pattern.texi: Document globfree.

1997-10-15 21:11  Philip Blundell  <Philip.Blundell@pobox.com>

	* sysdeps/unix/sysv/linux/net/if_packet.h: New file.
	* sysdeps/unix/sysv/linux/Makefile (sysdep_headers): Add
	net/if_packet.h.

	* sysdeps/unix/sysv/linux/net/if_arp.h (ARPHRD_ASH): New type, for
	64Mbps ASH.
	(ARPHRD_ETHER): This is used for 100Mbps networks too.

1997-10-15  Andreas Jaeger  <aj@arthur.rhein-neckar.de>

	* Makerules (install): Use full pathnames for linker script.
	This is to work around a limitation in `ld' while no better solution
	is possible.

1997-10-15  Andreas Jaeger  <aj@arthur.rhein-neckar.de>

	* malloc/malloc.c (mmap_chunk): Put inline before static in
	function definition to avoid compiler warning.
	(malloc_extend): Likewise.

	* sysdeps/generic/des_impl.c: Include "des.h" to avoid warning.

1997-10-15  Andreas Jaeger  <aj@arthur.rhein-neckar.de>

	* NEWS: Fix @gnu.ai.mit.edu -> @gnu.org.
	* README.template: Likewise.
	* db/makedb.c: Likewise.
	* elf/ldd.bash.in: Likewise.
	* elf/ldd.sh.in: Likewise.
	* intl/locale.alias: Likewise.
	* login/programs/utmpd.c: Likewise.
	* libio/stdfiles.c [!_IO_MTSAFE] (DEF_STDFILE): Fix parameter list.

1997-10-14  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* Rules: Remove all empty.* files.
	(shared-only-routines): Correct implementation.

1997-10-14  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* sysdeps/libm-ieee754/s_lrintl.c: Make compilable.
	* sysdeps/libm-ieee754/s_llrintl.c: Likewise.  Optimized.

1997-10-14  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* elf/ldd.bash.in: Only prepend ./ if the file contains no slash
	at all.
	* elf/ldd.sh.in: Likewise.

1997-10-14  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* sysdeps/m68k/sys/ucontext.h: New file.

1997-10-13  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* sysdeps/m68k/fpu/s_scalbln.c: New (empty) file.
	* sysdeps/m68k/fpu/s_scalblnf.c: New (empty) file.
	* sysdeps/m68k/fpu/s_scalblnl.c: New (empty) file.

	* sysdeps/m68k/fpu/s_scalbn.c: Add scalbln alias.
	* sysdeps/m68k/fpu/s_scalbnf.c: Adapted.
	* sysdeps/m68k/fpu/s_scalbnl.c: Adapted.

	* sysdeps/m68k/fpu/s_lrint.c: Add standard skeleton stuff.
	* sysdeps/m68k/fpu/s_lrintf.c: New file.
	* sysdeps/m68k/fpu/s_lrintl.c: New file.

	* sysdeps/m68k/fpu/bits/mathinline.h: Add fma and scalbln.  Update
	lrint and scalbn.
	(__m81_inline) [__cplusplus]: Define to __inline.

	* math/bits/mathcalls.h: Remove whitespace before second argument
	of __MATHDECL.  Add note explaining this.

1997-10-13  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* manual/arith.texi (Absolute Value): Spelling fix.

1997-10-13  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* malloc/obstack.h (obstack_empty_p) [!__GNUC__]: Properly
	parenthesize the macro parameter.

	* Rules: Remove rules to magically install <subdir>.h headers.
1997-10-26 20:13:00 +00:00

769 lines
24 KiB
C

/* Machine-dependent ELF dynamic relocation inline functions. PowerPC version.
Copyright (C) 1995, 1996, 1997 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 "powerpc"
#include <assert.h>
#include <string.h>
#include <link.h>
#include <sys/param.h>
/* 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)
/* Return nonzero iff E_MACHINE is compatible with the running host. */
static inline int
elf_machine_matches_host (Elf32_Half e_machine)
{
return e_machine == EM_PPC;
}
/* Return the link-time address of _DYNAMIC, stored as
the first value in the GOT. */
static inline Elf32_Addr
elf_machine_dynamic (void)
{
Elf32_Addr *got;
asm (" bl _GLOBAL_OFFSET_TABLE_-4@local"
: "=l"(got));
return *got;
}
/* Return the run-time load address of the shared object. */
static inline Elf32_Addr
elf_machine_load_address (void)
{
unsigned *got;
unsigned *branchaddr;
/* This is much harder than you'd expect. Possibly I'm missing something.
The 'obvious' way:
Apparently, "bcl 20,31,$+4" is what should be used to load LR
with the address of the next instruction.
I think this is so that machines that do bl/blr pairing don't
get confused.
asm ("bcl 20,31,0f ;"
"0: mflr 0 ;"
"lis %0,0b@ha;"
"addi %0,%0,0b@l;"
"subf %0,%0,0"
: "=b" (addr) : : "r0", "lr");
doesn't work, because the linker doesn't have to (and in fact doesn't)
update the @ha and @l references; the loader (which runs after this
code) will do that.
Instead, we use the following trick:
The linker puts the _link-time_ address of _DYNAMIC at the first
word in the GOT. We could branch to that address, if we wanted,
by using an @local reloc; the linker works this out, so it's safe
to use now. We can't, of course, actually branch there, because
we'd cause an illegal instruction exception; so we need to compute
the address ourselves. That gives us the following code: */
/* Get address of the 'b _DYNAMIC@local'... */
asm ("bl 0f ;"
"b _DYNAMIC@local;"
"0:"
: "=l"(branchaddr));
/* ... and the address of the GOT. */
asm (" bl _GLOBAL_OFFSET_TABLE_-4@local"
: "=l"(got));
/* So now work out the difference between where the branch actually points,
and the offset of that location in memory from the start of the file. */
return ((Elf32_Addr)branchaddr - *got
+ (*branchaddr & 0x3fffffc
| (int)(*branchaddr << 6 & 0x80000000) >> 6));
}
#define ELF_MACHINE_BEFORE_RTLD_RELOC(dynamic_info) /* nothing */
/* The PLT uses Elf32_Rela relocs. */
#define elf_machine_relplt elf_machine_rela
/* This code is used in dl-runtime.c to call the `fixup' function
and then redirect to the address it returns. It is called
from code built in the PLT by elf_machine_runtime_setup. */
#define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\
.section \".text\"
.align 2
.globl _dl_runtime_resolve
.type _dl_runtime_resolve,@function
_dl_runtime_resolve:
# We need to save the registers used to pass parameters, and register 0,
# which is used by _mcount; the registers are saved in a stack frame.
stwu 1,-48(1)
stw 0,12(1)
stw 3,16(1)
stw 4,20(1)
# The code that calls this has put parameters for `fixup' in r12 and r11.
mr 3,12
stw 5,24(1)
mr 4,11
stw 6,28(1)
mflr 0
# We also need to save some of the condition register fields.
stw 7,32(1)
stw 0,52(1)
stw 8,36(1)
mfcr 0
stw 9,40(1)
stw 10,44(1)
stw 0,8(1)
bl fixup@local
# 'fixup' returns the address we want to branch to.
mtctr 3
# Put the registers back...
lwz 0,52(1)
lwz 10,44(1)
lwz 9,40(1)
mtlr 0
lwz 8,36(1)
lwz 0,8(1)
lwz 7,32(1)
lwz 6,28(1)
mtcrf 0xFF,0
lwz 5,24(1)
lwz 4,20(1)
lwz 3,16(1)
lwz 0,12(1)
# ...unwind the stack frame, and jump to the PLT entry we updated.
addi 1,1,48
bctr
.size _dl_runtime_resolve,.-_dl_runtime_resolve
.align 2
.globl _dl_prof_resolve
.type _dl_prof_resolve,@function
_dl_prof_resolve:
# We need to save the registers used to pass parameters, and register 0,
# which is used by _mcount; the registers are saved in a stack frame.
stwu 1,-48(1)
stw 0,12(1)
stw 3,16(1)
stw 4,20(1)
# The code that calls this has put parameters for `fixup' in r12 and r11.
mr 3,12
stw 5,24(1)
mr 4,11
stw 6,28(1)
mflr 5
# We also need to save some of the condition register fields.
stw 7,32(1)
stw 5,52(1)
stw 8,36(1)
mfcr 0
stw 9,40(1)
stw 10,44(1)
stw 0,8(1)
bl profile_fixup@local
# 'fixup' returns the address we want to branch to.
mtctr 3
# Put the registers back...
lwz 0,52(1)
lwz 10,44(1)
lwz 9,40(1)
mtlr 0
lwz 8,36(1)
lwz 0,8(1)
lwz 7,32(1)
lwz 6,28(1)
mtcrf 0xFF,0
lwz 5,24(1)
lwz 4,20(1)
lwz 3,16(1)
lwz 0,12(1)
# ...unwind the stack frame, and jump to the PLT entry we updated.
addi 1,1,48
bctr
.size _dl_prof_resolve,.-_dl_prof_resolve
# Undo '.section text'.
.previous
");
/* 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 \
static ElfW(Addr) _dl_start (void *arg) __attribute__((unused)); \
asm ("\
.section \".text\"
.align 2
.globl _start
.type _start,@function
_start:
# 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.
# FIXME: perhaps this should do the same trick as elf/start.c?
# Call _dl_start with one parameter pointing at argc
mr 3,1
# (we have to frob the stack pointer a bit to allow room for
# _dl_start to save the link register)
li 4,0
addi 1,1,-16
stw 4,0(1)
bl _dl_start@local
# 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!).
# Put our GOT pointer in r31,
bl _GLOBAL_OFFSET_TABLE_-4@local
mflr 31
# the address of _start in r30,
mr 30,3
# &_dl_argc in 29, &_dl_argv in 27, and _dl_default_scope in 28.
lwz 28,_dl_default_scope@got(31)
lwz 29,_dl_argc@got(31)
lwz 27,_dl_argv@got(31)
0:
# Set initfunc = _dl_init_next(_dl_default_scope[2])
lwz 3,8(28)
bl _dl_init_next@plt
# If initfunc is NULL, we exit the loop; otherwise,
cmpwi 3,0
beq 1f
# call initfunc(_dl_argc, _dl_argv, _dl_argv+_dl_argc+1)
mtlr 3
lwz 3,0(29)
lwz 4,0(27)
slwi 5,3,2
add 5,4,5
addi 5,5,4
blrl
# and loop.
b 0b
1:
# Now, to conform to the ELF ABI, we have to:
# Pass argc (actually _dl_argc) in r3;
lwz 3,0(29)
# pass argv (actually _dl_argv) in r4;
lwz 4,0(27)
# pass envp (actually _dl_argv+_dl_argc+1) in r5;
slwi 5,3,2
add 6,4,5
addi 5,6,4
# pass the auxilary vector in r6. This is passed to us just after _envp.
2: lwzu 0,4(6)
cmpwi 0,0,0
bne 2b
addi 6,6,4
# Pass a termination function pointer (in this case _dl_fini) in r7.
lwz 7,_dl_fini@got(31)
# Now, call the start function in r30...
mtctr 30
lwz 26,_dl_starting_up@got(31)
# 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
stw 31,0(1)
mtlr 31
stw 31,4(1)
stw 31,8(1)
stw 31,12(1)
# Clear _dl_starting_up.
stw 31,0(26)
# Go do it!
bctr
0:
.size _start,0b-_start
# Undo '.section text'.
.previous
");
/* 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.
Regrettably, in this code we can't find the program's load address,
so we punt and choose 0x01800000, which is below the ABI's
recommended default, and what GNU ld currently chooses. We only use
the address as a preference for mmap, so if we get it wrong the
worst that happens is that it gets mapped somewhere else.
FIXME: Unfortunately, 'somewhere else' is probably right after the
program's break, which causes malloc to fail. We really need more
information here about the way memory is mapped. */
#define ELF_PREFERRED_ADDRESS_DATA \
static ElfW(Addr) _dl_preferred_address = 1
#define ELF_PREFERRED_ADDRESS(loader, maplength, mapstartpref) \
( { \
ElfW(Addr) prefd; \
if (mapstartpref != 0 && _dl_preferred_address == 1) \
_dl_preferred_address = mapstartpref; \
if (mapstartpref != 0) \
prefd = mapstartpref; \
else if (_dl_preferred_address == 1) \
prefd = _dl_preferred_address = \
(0x01800000 - maplength - 0x10000) & \
~(_dl_pagesize - 1); \
else if (_dl_preferred_address < maplength + 0x50000) \
prefd = 0; \
else \
prefd = _dl_preferred_address = \
((_dl_preferred_address - maplength - 0x10000) \
& ~(_dl_pagesize - 1)); \
prefd; \
} )
#define ELF_FIXED_ADDRESS(loader, mapstart) \
( { \
if (mapstart != 0 && _dl_preferred_address == 1) \
_dl_preferred_address = mapstart; \
} )
/* 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_PPC_COPY)
/* Nonzero iff TYPE describes relocation of a PLT entry, so
PLT entries should not be allowed to define the value. */
/* We never want to use a PLT entry as the destination of a
reloc, when what is being relocated is a branch. This is
partly for efficiency, but mostly so we avoid loops. */
#define elf_machine_lookup_noplt_p(type) ((type) == R_PPC_REL24 || \
(type) == R_PPC_ADDR24 || \
(type) == R_PPC_JMP_SLOT)
/* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
#define ELF_MACHINE_JMP_SLOT R_PPC_JMP_SLOT
/* Nonzero iff TYPE describes relocation of a PLT entry, so
PLT entries should not be allowed to define the value. */
#define elf_machine_pltrel_p(type) ((type) == R_PPC_JMP_SLOT)
/* 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. */
static inline 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;
}
static inline void
elf_machine_lazy_rel (struct link_map *map, const Elf32_Rela *reloc)
{
/* elf_machine_runtime_setup handles this. */
}
static inline 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);
}
/* Return the final value of a plt relocation. */
static inline Elf32_Addr
elf_machine_plt_value (struct link_map *map, const Elf32_Rela *reloc,
Elf32_Addr value)
{
return value + reloc->r_addend;
}
#endif /* dl_machine_h */
#ifdef RESOLVE
/* Perform the relocation specified by RELOC and SYM (which is fully resolved).
LOADADDR is the load address of the object; INFO is an array indexed
by DT_* of the .dynamic section info. */
static void
elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc,
const Elf32_Sym *sym, const struct r_found_version *version,
Elf32_Addr *const reloc_addr)
{
#ifndef RTLD_BOOTSTRAP
const Elf32_Sym *const refsym = sym;
extern char **_dl_argv;
#endif
Elf32_Word loadbase, finaladdr;
const int rinfo = ELF32_R_TYPE (reloc->r_info);
if (rinfo == R_PPC_NONE)
return;
assert (sym != NULL);
/* The condition on the next two lines is a hack around a bug in Solaris
tools on Sparc. It's not clear whether it should really be here at all,
but if not the binutils need to be changed. */
if ((sym->st_shndx != SHN_UNDEF
&& ELF32_ST_BIND (sym->st_info) == STB_LOCAL)
|| rinfo == R_PPC_RELATIVE)
{
/* Has already been relocated. */
loadbase = map->l_addr;
finaladdr = loadbase + reloc->r_addend;
}
else
{
loadbase = (Elf32_Word) (char *) (RESOLVE (&sym, version,
ELF32_R_TYPE(reloc->r_info)));
if (sym == NULL)
{
/* Weak symbol that wasn't actually defined anywhere. */
assert(loadbase == 0);
finaladdr = reloc->r_addend;
}
else
finaladdr = (loadbase + (Elf32_Word) (char *) sym->st_value
+ reloc->r_addend);
}
/* This is still an if/else if chain because GCC uses the GOT to find
the table for table-based switch statements, and we haven't set it
up yet. */
if (rinfo == R_PPC_UADDR32 ||
rinfo == R_PPC_GLOB_DAT ||
rinfo == R_PPC_ADDR32 ||
rinfo == R_PPC_RELATIVE)
{
*reloc_addr = finaladdr;
}
#ifndef RTLD_BOOTSTRAP
else if (rinfo == R_PPC_ADDR16_LO)
{
*(Elf32_Half*) reloc_addr = finaladdr;
}
else if (rinfo == R_PPC_ADDR16_HI)
{
*(Elf32_Half*) reloc_addr = finaladdr >> 16;
}
else if (rinfo == R_PPC_ADDR16_HA)
{
*(Elf32_Half*) reloc_addr = (finaladdr + 0x8000) >> 16;
}
else if (rinfo == 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;
}
else if (rinfo == R_PPC_ADDR24)
{
if (finaladdr << 6 >> 6 != finaladdr)
{
_dl_signal_error(0, map->l_name,
"R_PPC_ADDR24 relocation out of range");
}
*reloc_addr = *reloc_addr & 0xfc000003 | finaladdr & 0x3fffffc;
}
else if (rinfo == 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));
}
#endif
else if (rinfo == R_PPC_REL32)
{
*reloc_addr = finaladdr - (Elf32_Word) (char *) reloc_addr;
}
else if (rinfo == R_PPC_JMP_SLOT)
{
elf_machine_fixup_plt (map, reloc, reloc_addr, finaladdr);
}
else
{
#ifdef RTLD_BOOTSTRAP
PPC_DIE; /* There is no point calling _dl_sysdep_error, it
almost certainly hasn't been relocated properly. */
#else
_dl_sysdep_error (_dl_argv[0] ?: "<program name unknown>",
": Unknown relocation type\n", NULL);
#endif
}
#ifndef RTLD_BOOTSTRAP
if (rinfo == R_PPC_ADDR16_LO ||
rinfo == R_PPC_ADDR16_HI ||
rinfo == R_PPC_ADDR16_HA ||
rinfo == R_PPC_REL24 ||
rinfo == R_PPC_ADDR24)
MODIFIED_CODE_NOQUEUE (reloc_addr);
#endif
}
#define ELF_MACHINE_NO_REL 1
#endif /* RESOLVE */