glibc/ports/sysdeps/ia64/dl-machine.h
Mike Frysinger c5abd7ce01 ia64: fix strict aliasing warnings with func descriptors
Function pointers on ia64 are like parisc -- they're plabels.  While
the parisc port enjoys a gcc builtin for extracting the address here,
ia64 has no such luck.

Casting & dereferencing in one go triggers a strict aliasing warning.
Use a union to fix that.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2013-03-12 06:00:05 -04:00

507 lines
16 KiB
C

/* Machine-dependent ELF dynamic relocation inline functions. IA-64 version.
Copyright (C) 1995-2013 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, see
<http://www.gnu.org/licenses/>. */
#ifndef dl_machine_h
#define dl_machine_h 1
#define ELF_MACHINE_NAME "ia64"
#include <assert.h>
#include <string.h>
#include <link.h>
#include <errno.h>
#include <dl-fptr.h>
#include <tls.h>
/* Translate a processor specific dynamic tag to the index
in l_info array. */
#define DT_IA_64(x) (DT_IA_64_##x - DT_LOPROC + DT_NUM)
static inline void __attribute__ ((always_inline))
__ia64_init_bootstrap_fdesc_table (struct link_map *map)
{
Elf64_Addr *boot_table;
/* careful: this will be called before got has been relocated... */
asm (";; addl %0 = @gprel (_dl_boot_fptr_table), gp" : "=r"(boot_table));
map->l_mach.fptr_table_len = ELF_MACHINE_BOOT_FPTR_TABLE_LEN;
map->l_mach.fptr_table = boot_table;
}
#define ELF_MACHINE_BEFORE_RTLD_RELOC(dynamic_info) \
__ia64_init_bootstrap_fdesc_table (&bootstrap_map);
/* Return nonzero iff ELF header is compatible with the running host. */
static inline int __attribute__ ((unused))
elf_machine_matches_host (const Elf64_Ehdr *ehdr)
{
return ehdr->e_machine == EM_IA_64;
}
/* Return the link-time address of _DYNAMIC. */
static inline Elf64_Addr __attribute__ ((unused, const))
elf_machine_dynamic (void)
{
Elf64_Addr *p;
__asm__ (
".section .sdata\n"
" .type __dynamic_ltv#, @object\n"
" .size __dynamic_ltv#, 8\n"
"__dynamic_ltv:\n"
" data8 @ltv(_DYNAMIC#)\n"
".previous\n"
" addl %0 = @gprel(__dynamic_ltv#), gp ;;"
: "=r" (p));
return *p;
}
/* Return the run-time load address of the shared object. */
static inline Elf64_Addr __attribute__ ((unused))
elf_machine_load_address (void)
{
Elf64_Addr ip;
int *p;
__asm__ (
"1: mov %0 = ip\n"
".section .sdata\n"
"2: data4 @ltv(1b)\n"
" .align 8\n"
".previous\n"
" addl %1 = @gprel(2b), gp ;;"
: "=r" (ip), "=r" (p));
return ip - (Elf64_Addr) *p;
}
/* 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. */
static inline int __attribute__ ((unused, always_inline))
elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
{
extern void _dl_runtime_resolve (void);
extern void _dl_runtime_profile (void);
if (lazy)
{
register Elf64_Addr gp __asm__ ("gp");
Elf64_Addr *reserve, doit;
/*
* Careful with the typecast here or it will try to add l-l_addr
* pointer elements
*/
reserve = ((Elf64_Addr *)
(l->l_info[DT_IA_64 (PLT_RESERVE)]->d_un.d_ptr + l->l_addr));
/* Identify this shared object. */
reserve[0] = (Elf64_Addr) l;
/* This function will be called to perform the relocation. */
if (!profile)
doit = (Elf64_Addr) ELF_PTR_TO_FDESC (&_dl_runtime_resolve)->ip;
else
{
if (GLRO(dl_profile) != NULL
&& _dl_name_match_p (GLRO(dl_profile), l))
{
/* This is the object we are looking for. Say that we really
want profiling and the timers are started. */
GL(dl_profile_map) = l;
}
doit = (Elf64_Addr) ELF_PTR_TO_FDESC (&_dl_runtime_profile)->ip;
}
reserve[1] = doit;
reserve[2] = gp;
}
return lazy;
}
/* Names of the architecture-specific auditing callback functions. */
#define ARCH_LA_PLTENTER ia64_gnu_pltenter
#define ARCH_LA_PLTEXIT ia64_gnu_pltexit
/* Undo the adds out0 = 16, sp below to get at the value we want in
__libc_stack_end. */
#define DL_STACK_END(cookie) \
((void *) (((long) (cookie)) - 16))
/* 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 ( \
".text\n" \
" .global _start#\n" \
" .proc _start#\n" \
"_start:\n" \
"0: { .mii\n" \
" .prologue\n" \
" .save rp, r0\n" \
" .body\n" \
" .prologue\n" \
" .save ar.pfs, r32\n" \
" alloc loc0 = ar.pfs, 0, 3, 4, 0\n" \
" .body\n" \
" mov r2 = ip\n" \
" addl r3 = @gprel(0b), r0\n" \
" ;;\n" \
" }\n" \
" { .mlx\n" \
" /* Calculate the GP, and save a copy in loc1. */\n" \
" sub gp = r2, r3\n" \
" movl r8 = 0x9804c0270033f\n" \
" ;;\n" \
" }\n" \
" { .mii\n" \
" mov ar.fpsr = r8\n" \
" sub loc1 = r2, r3\n" \
" /* _dl_start wants a pointer to the pointer to the arg block and\n" \
" the arg block starts with an integer, thus the magic 16. */\n" \
" adds out0 = 16, sp\n" \
" }\n" \
" { .bbb\n" \
" br.call.sptk.many b0 = _dl_start#\n" \
" ;;\n" \
" }\n" \
" .endp _start#\n" \
" /* FALLTHRU */\n" \
" .global _dl_start_user#\n" \
" .proc _dl_start_user#\n" \
"_dl_start_user:\n" \
" .prologue\n" \
" .save rp, r0\n" \
" .body\n" \
" .prologue\n" \
" .save ar.pfs, r32\n" \
" .body\n" \
" { .mii\n" \
" addl r3 = @gprel(_dl_skip_args), gp\n" \
" adds r11 = 24, sp /* Load the address of argv. */\n" \
" /* Save the pointer to the user entry point fptr in loc2. */\n" \
" mov loc2 = ret0\n" \
" ;;\n" \
" }\n" \
" { .mii\n" \
" ld4 r3 = [r3]\n" \
" adds r10 = 16, sp /* Load the address of argc. */\n" \
" mov out2 = r11\n" \
" ;;\n" \
" /* See if we were run as a command with the executable file\n" \
" name as an extra leading argument. If so, adjust the argv\n" \
" pointer to skip _dl_skip_args words.\n" \
" Note that _dl_skip_args is an integer, not a long - Jes\n" \
"\n" \
" The stack pointer has to be 16 byte aligned. We cannot simply\n" \
" addjust the stack pointer. We have to move the whole argv and\n" \
" envp and adjust _dl_argv by _dl_skip_args. H.J. */\n" \
" }\n" \
" { .mib\n" \
" ld8 out1 = [r10] /* is argc actually stored as a long\n" \
" or as an int? */\n" \
" addl r2 = @ltoff(_dl_argv), gp\n" \
" ;;\n" \
" }\n" \
" { .mmi\n" \
" ld8 r2 = [r2] /* Get the address of _dl_argv. */\n" \
" sub out1 = out1, r3 /* Get the new argc. */\n" \
" shladd r3 = r3, 3, r0\n" \
" ;;\n" \
" }\n" \
" {\n" \
" .mib\n" \
" ld8 r17 = [r2] /* Get _dl_argv. */\n" \
" add r15 = r11, r3 /* The address of the argv we move */\n" \
" ;;\n" \
" }\n" \
" /* ??? Could probably merge these two loops into 3 bundles.\n" \
" using predication to control which set of copies we're on. */\n" \
"1: /* Copy argv. */\n" \
" { .mfi\n" \
" ld8 r16 = [r15], 8 /* Load the value in the old argv. */\n" \
" ;;\n" \
" }\n" \
" { .mib\n" \
" st8 [r11] = r16, 8 /* Store it in the new argv. */\n" \
" cmp.ne p6, p7 = 0, r16\n" \
"(p6) br.cond.dptk.few 1b\n" \
" ;;\n" \
" }\n" \
" { .mmi\n" \
" mov out3 = r11\n" \
" sub r17 = r17, r3 /* Substract _dl_skip_args. */\n" \
" addl out0 = @gprel(_rtld_local), gp\n" \
" }\n" \
"1: /* Copy env. */\n" \
" { .mfi\n" \
" ld8 r16 = [r15], 8 /* Load the value in the old env. */\n" \
" ;;\n" \
" }\n" \
" { .mib\n" \
" st8 [r11] = r16, 8 /* Store it in the new env. */\n" \
" cmp.ne p6, p7 = 0, r16\n" \
"(p6) br.cond.dptk.few 1b\n" \
" ;;\n" \
" }\n" \
" { .mmb\n" \
" st8 [r10] = out1 /* Record the new argc. */\n" \
" ld8 out0 = [out0] /* get the linkmap */\n" \
" }\n" \
" { .mmb\n" \
" st8 [r2] = r17 /* Load the new _dl_argv. */\n" \
" br.call.sptk.many b0 = _dl_init_internal#\n" \
" ;;\n" \
" }\n" \
" /* Pass our finalizer function to the user,\n" \
" and jump to the user's entry point. */\n" \
" { .mmi\n" \
" ld8 r3 = [loc2], 8\n" \
" mov b0 = r0\n" \
" }\n" \
" { .mmi\n" \
" addl ret0 = @ltoff(@fptr(_dl_fini#)), gp\n" \
" ;;\n" \
" mov b6 = r3\n" \
" }\n" \
" { .mmi\n" \
" ld8 ret0 = [ret0]\n" \
" ld8 gp = [loc2]\n" \
" mov ar.pfs = loc0\n" \
" ;;\n" \
" }\n" \
" { .mfb\n" \
" br.sptk.many b6\n" \
" ;;\n" \
" }\n" \
" .endp _dl_start_user#\n" \
".previous\n");
#ifndef RTLD_START_SPECIAL_INIT
#define RTLD_START_SPECIAL_INIT /* nothing */
#endif
/* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry or TLS
variable, so undefined references 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, which we don't
use. */
/* ??? Ignore *MSB for now. */
#define elf_machine_type_class(type) \
(((type) == R_IA64_IPLTLSB || (type) == R_IA64_DTPMOD64LSB \
|| (type) == R_IA64_DTPREL64LSB || (type) == R_IA64_TPREL64LSB) \
* ELF_RTYPE_CLASS_PLT)
/* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
#define ELF_MACHINE_JMP_SLOT R_IA64_IPLTLSB
/* According to the IA-64 specific documentation, Rela is always used. */
#define ELF_MACHINE_NO_REL 1
/* Return the address of the entry point. */
#define ELF_MACHINE_START_ADDRESS(map, start) \
DL_STATIC_FUNCTION_ADDRESS (map, start)
/* Fixup a PLT entry to bounce directly to the function at VALUE. */
static inline struct fdesc __attribute__ ((always_inline))
elf_machine_fixup_plt (struct link_map *l, lookup_t t,
const Elf64_Rela *reloc,
Elf64_Addr *reloc_addr, struct fdesc value)
{
/* l is the link_map for the caller, t is the link_map for the object
* being called */
/* got has already been relocated in elf_get_dynamic_info() */
reloc_addr[1] = value.gp;
/* we need a "release" here to ensure that the gp is visible before
the code entry point is updated: */
((volatile Elf64_Addr *) reloc_addr)[0] = value.ip;
return value;
}
/* Return the final value of a plt relocation. */
static inline struct fdesc
elf_machine_plt_value (struct link_map *map, const Elf64_Rela *reloc,
struct fdesc value)
{
/* No need to handle rel vs rela since IA64 is rela only */
return (struct fdesc) { value.ip + reloc->r_addend, value.gp };
}
#endif /* !dl_machine_h */
#ifdef RESOLVE_MAP
#define R_IA64_TYPE(R) ((R) & -8)
#define R_IA64_FORMAT(R) ((R) & 7)
#define R_IA64_FORMAT_32MSB 4
#define R_IA64_FORMAT_32LSB 5
#define R_IA64_FORMAT_64MSB 6
#define R_IA64_FORMAT_64LSB 7
/* Perform the relocation specified by RELOC and SYM (which is fully
resolved). MAP is the object containing the reloc. */
auto inline void
__attribute ((always_inline))
elf_machine_rela (struct link_map *map,
const Elf64_Rela *reloc,
const Elf64_Sym *sym,
const struct r_found_version *version,
void *const reloc_addr_arg,
int skip_ifunc)
{
Elf64_Addr *const reloc_addr = reloc_addr_arg;
const unsigned long int r_type = ELF64_R_TYPE (reloc->r_info);
Elf64_Addr value;
#if !defined RTLD_BOOTSTRAP && !defined HAVE_Z_COMBRELOC && !defined SHARED
/* This is defined in rtld.c, but nowhere in the static libc.a; make the
reference weak so static programs can still link. This declaration
cannot be done when compiling rtld.c (i.e. #ifdef RTLD_BOOTSTRAP)
because rtld.c contains the common defn for _dl_rtld_map, which is
incompatible with a weak decl in the same file. */
weak_extern (_dl_rtld_map);
#endif
/* We cannot use a switch here because we cannot locate the switch
jump table until we've self-relocated. */
#if !defined RTLD_BOOTSTRAP || !defined HAVE_Z_COMBRELOC
if (__builtin_expect (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_REL64LSB),
0))
{
assert (ELF64_R_TYPE (reloc->r_info) == R_IA64_REL64LSB);
value = *reloc_addr;
# if !defined RTLD_BOOTSTRAP && !defined HAVE_Z_COMBRELOC
/* Already done in dynamic linker. */
if (map != &GL(dl_rtld_map))
# endif
value += map->l_addr;
}
else
#endif
if (__builtin_expect (r_type == R_IA64_NONE, 0))
return;
else
{
struct link_map *sym_map;
/* RESOLVE_MAP() will return NULL if it fail to locate the symbol. */
if ((sym_map = RESOLVE_MAP (&sym, version, r_type)))
{
value = sym_map->l_addr + sym->st_value + reloc->r_addend;
if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_DIR64LSB))
;/* No adjustment. */
else if (r_type == R_IA64_IPLTLSB)
{
elf_machine_fixup_plt (NULL, NULL, reloc, reloc_addr,
DL_FIXUP_MAKE_VALUE (sym_map, value));
return;
}
else if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_FPTR64LSB))
value = _dl_make_fptr (sym_map, sym, value);
else if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_PCREL64LSB))
value -= (Elf64_Addr) reloc_addr & -16;
else if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_DTPMOD64LSB))
#ifdef RTLD_BOOTSTRAP
/* During startup the dynamic linker is always index 1. */
value = 1;
#else
/* Get the information from the link map returned by the
resolv function. */
value = sym_map->l_tls_modid;
else if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_DTPREL64LSB))
value -= sym_map->l_addr;
#endif
else if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_TPREL64LSB))
{
#ifndef RTLD_BOOTSTRAP
CHECK_STATIC_TLS (map, sym_map);
#endif
value += sym_map->l_tls_offset - sym_map->l_addr;
}
else
_dl_reloc_bad_type (map, r_type, 0);
}
else
value = 0;
}
/* ??? Ignore MSB and Instruction format for now. */
if (R_IA64_FORMAT (r_type) == R_IA64_FORMAT_64LSB)
*reloc_addr = value;
else if (R_IA64_FORMAT (r_type) == R_IA64_FORMAT_32LSB)
*(int *) reloc_addr = value;
else if (r_type == R_IA64_IPLTLSB)
{
reloc_addr[0] = 0;
reloc_addr[1] = 0;
}
else
_dl_reloc_bad_type (map, r_type, 0);
}
/* Let do-rel.h know that on IA-64 if l_addr is 0, all RELATIVE relocs
can be skipped. */
#define ELF_MACHINE_REL_RELATIVE 1
auto inline void
__attribute ((always_inline))
elf_machine_rela_relative (Elf64_Addr l_addr, const Elf64_Rela *reloc,
void *const reloc_addr_arg)
{
Elf64_Addr *const reloc_addr = reloc_addr_arg;
/* ??? Ignore MSB and Instruction format for now. */
assert (ELF64_R_TYPE (reloc->r_info) == R_IA64_REL64LSB);
*reloc_addr += l_addr;
}
/* Perform a RELATIVE reloc on the .got entry that transfers to the .plt. */
auto inline void
__attribute ((always_inline))
elf_machine_lazy_rel (struct link_map *map,
Elf64_Addr l_addr, const Elf64_Rela *reloc,
int skip_ifunc)
{
Elf64_Addr *const reloc_addr = (void *) (l_addr + reloc->r_offset);
const unsigned long int r_type = ELF64_R_TYPE (reloc->r_info);
if (r_type == R_IA64_IPLTLSB)
{
reloc_addr[0] += l_addr;
reloc_addr[1] += l_addr;
}
else if (r_type == R_IA64_NONE)
return;
else
_dl_reloc_bad_type (map, r_type, 1);
}
#endif /* RESOLVE_MAP */