glibc/sysdeps/arm/dl-machine.h

524 lines
14 KiB
C

/* Machine-dependent ELF dynamic relocation inline functions. ARM version.
Copyright (C) 1995,96,97,98,99,2000,2001 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 "ARM"
#include <sys/param.h>
#define VALID_ELF_ABIVERSION(ver) (ver == 0)
#define VALID_ELF_OSABI(osabi) \
(osabi == ELFOSABI_SYSV || osabi == ELFOSABI_ARM)
#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])
#define CLEAR_CACHE(BEG,END) \
{ \
register unsigned long _beg __asm ("a1") = (unsigned long)(BEG); \
register unsigned long _end __asm ("a2") = (unsigned long)(END); \
register unsigned long _flg __asm ("a3") = 0; \
__asm __volatile ("swi 0x9f0002 @ sys_cacheflush" \
: /* no outputs */ \
: /* no inputs */ \
: "a1"); \
}
/* Return nonzero iff ELF header is compatible with the running host. */
static inline int __attribute__ ((unused))
elf_machine_matches_host (const Elf32_Ehdr *ehdr)
{
return ehdr->e_machine == EM_ARM;
}
/* Return the link-time address of _DYNAMIC. Conveniently, this is the
first element of the GOT. This must be inlined in a function which
uses global data. */
static inline Elf32_Addr __attribute__ ((unused))
elf_machine_dynamic (void)
{
register Elf32_Addr *got asm ("r10");
return *got;
}
/* Return the run-time load address of the shared object. */
static inline Elf32_Addr __attribute__ ((unused))
elf_machine_load_address (void)
{
extern void __dl_start asm ("_dl_start");
Elf32_Addr got_addr = (Elf32_Addr) &__dl_start;
Elf32_Addr pcrel_addr;
asm ("adr %0, _dl_start" : "=r" (pcrel_addr));
return pcrel_addr - got_addr;
}
/* 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))
elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
{
Elf32_Addr *got;
extern void _dl_runtime_resolve (Elf32_Word);
extern void _dl_runtime_profile (Elf32_Word);
if (l->l_info[DT_JMPREL] && lazy)
{
/* patb: this is different than i386 */
/* The GOT entries for functions in the PLT have not yet been filled
in. Their initial contents will arrange when called to push an
index into the .got section, load ip with &_GLOBAL_OFFSET_TABLE_[3],
and then jump to _GLOBAL_OFFSET_TABLE[2]. */
got = (Elf32_Addr *) D_PTR (l, l_info[DT_PLTGOT]);
got[1] = (Elf32_Addr) l; /* Identify this shared object. */
/* The got[2] entry contains the address of a function which gets
called to get the address of a so far unresolved function and
jump to it. The profiling extension of the dynamic linker allows
to intercept the calls to collect information. In this case we
don't store the address in the GOT so that all future calls also
end in this function. */
if (profile)
{
got[2] = (Elf32_Addr) &_dl_runtime_profile;
/* Say that we really want profiling and the timers are started. */
_dl_profile_map = l;
}
else
/* This function will get called to fix up the GOT entry indicated by
the offset on the stack, and then jump to the resolved address. */
got[2] = (Elf32_Addr) &_dl_runtime_resolve;
}
return lazy;
}
/* This code is used in dl-runtime.c to call the `fixup' function
and then redirect to the address it returns. */
// macro for handling PIC situation....
#ifdef PIC
#define CALL_ROUTINE(x) " ldr sl,0f
add sl, pc, sl
1: ldr r2, 2f
mov lr, pc
add pc, sl, r2
b 3f
0: .word _GLOBAL_OFFSET_TABLE_ - 1b - 4
2: .word " #x "(GOTOFF)
3: "
#else
#define CALL_ROUTINE(x) " bl " #x
#endif
#ifndef PROF
# define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\
.text
.globl _dl_runtime_resolve
.type _dl_runtime_resolve, #function
.align 2
_dl_runtime_resolve:
@ we get called with
@ stack[0] contains the return address from this call
@ ip contains &GOT[n+3] (pointer to function)
@ lr points to &GOT[2]
@ save almost everything; lr is already on the stack
stmdb sp!,{r0-r3,sl,fp}
@ prepare to call fixup()
@ change &GOT[n+3] into 8*n NOTE: reloc are 8 bytes each
sub r1, ip, lr
sub r1, r1, #4
add r1, r1, r1
@ get pointer to linker struct
ldr r0, [lr, #-4]
@ call fixup routine
" CALL_ROUTINE(fixup) "
@ save the return
mov ip, r0
@ restore the stack
ldmia sp!,{r0-r3,sl,fp,lr}
@ jump to the newly found address
mov pc, ip
.size _dl_runtime_resolve, .-_dl_runtime_resolve
.globl _dl_runtime_profile
.type _dl_runtime_profile, #function
.align 2
_dl_runtime_profile:
@ save almost everything; lr is already on the stack
stmdb sp!,{r0-r3,sl,fp}
@ prepare to call fixup()
@ change &GOT[n+3] into 8*n NOTE: reloc are 8 bytes each
sub r1, ip, lr
sub r1, r1, #4
add r1, r1, r1
@ get pointer to linker struct
ldr r0, [lr, #-4]
@ call profiling fixup routine
" CALL_ROUTINE(profile_fixup) "
@ save the return
mov ip, r0
@ restore the stack
ldmia sp!,{r0-r3,sl,fp,lr}
@ jump to the newly found address
mov pc, ip
.size _dl_runtime_resolve, .-_dl_runtime_resolve
.previous
");
#else // PROF
# define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\
.text
.globl _dl_runtime_resolve
.globl _dl_runtime_profile
.type _dl_runtime_resolve, #function
.type _dl_runtime_profile, #function
.align 2
_dl_runtime_resolve:
_dl_runtime_profile:
@ we get called with
@ stack[0] contains the return address from this call
@ ip contains &GOT[n+3] (pointer to function)
@ lr points to &GOT[2]
@ save almost everything; return add is already on the stack
stmdb sp!,{r0-r3,sl,fp}
@ prepare to call fixup()
@ change &GOT[n+3] into 8*n NOTE: reloc are 8 bytes each
sub r1, ip, lr
sub r1, r1, #4
add r1, r1, r1
@ get pointer to linker struct
ldr r0, [lr, #-4]
@ call profiling fixup routine
" CALL_ROUTINE(fixup) "
@ save the return
mov ip, r0
@ restore the stack
ldmia sp!,{r0-r3,sl,fp,lr}
@ jump to the newly found address
mov pc, ip
.size _dl_runtime_profile, .-_dl_runtime_profile
.previous
");
#endif //PROF
/* Mask identifying addresses reserved for the user program,
where the dynamic linker should not map anything. */
#define ELF_MACHINE_USER_ADDRESS_MASK 0xf8000000UL
/* 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
.globl _start
.globl _dl_start_user
_start:
@ at start time, all the args are on the stack
mov r0, sp
bl _dl_start
@ returns user entry point in r0
_dl_start_user:
mov r6, r0
@ we are PIC code, so get global offset table
ldr sl, .L_GET_GOT
add sl, pc, sl
.L_GOT_GOT:
@ Store the highest stack address
ldr r1, .L_STACK_END
ldr r1, [sl, r1]
str sp, [r1]
@ See if we were run as a command with the executable file
@ name as an extra leading argument.
ldr r4, .L_SKIP_ARGS
ldr r4, [sl, r4]
@ get the original arg count
ldr r1, [sp]
@ subtract _dl_skip_args from it
sub r1, r1, r4
@ adjust the stack pointer to skip them
add sp, sp, r4, lsl #2
@ get the argv address
add r2, sp, #4
@ store the new argc in the new stack location
str r1, [sp]
@ compute envp
add r3, r2, r1, lsl #2
add r3, r3, #4
@ now we call _dl_init
ldr r0, .L_LOADED
ldr r0, [sl, r0]
ldr r0, [r0]
@ call _dl_init
bl _dl_init(PLT)
@ clear the startup flag
ldr r2, .L_STARTUP_FLAG
ldr r1, [sl, r2]
mov r0, #0
str r0, [r1]
@ load the finalizer function
ldr r0, .L_FINI_PROC
ldr r0, [sl, r0]
@ jump to the user_s entry point
mov pc, r6
.L_GET_GOT:
.word _GLOBAL_OFFSET_TABLE_ - .L_GOT_GOT - 4 \n\
.L_SKIP_ARGS: \n\
.word _dl_skip_args(GOTOFF) \n\
.L_STARTUP_FLAG:
.word _dl_starting_up(GOT)
.L_FINI_PROC:
.word _dl_fini(GOT)
.L_STACK_END:
.word __libc_stack_end(GOT)
.L_LOADED:
.word _dl_loaded(GOT)
.previous\n\
");
/* 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_ARM_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_ARM_JUMP_SLOT)
/* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
#define ELF_MACHINE_JMP_SLOT R_ARM_JUMP_SLOT
/* The ARM never uses Elf32_Rela relocations. */
#define ELF_MACHINE_NO_RELA 1
/* We define an initialization functions. This is called very early in
_dl_sysdep_start. */
#define DL_PLATFORM_INIT dl_platform_init ()
extern const char *_dl_platform;
static inline void __attribute__ ((unused))
dl_platform_init (void)
{
if (_dl_platform != NULL && *_dl_platform == '\0')
/* Avoid an empty string which would disturb us. */
_dl_platform = NULL;
}
static inline Elf32_Addr
elf_machine_fixup_plt (struct link_map *map, lookup_t t,
const Elf32_Rel *reloc,
Elf32_Addr *reloc_addr, Elf32_Addr value)
{
return *reloc_addr = value;
}
/* Return the final value of a plt relocation. */
static inline Elf32_Addr
elf_machine_plt_value (struct link_map *map, const Elf32_Rel *reloc,
Elf32_Addr value)
{
return value;
}
#endif /* !dl_machine_h */
#ifdef RESOLVE
extern char **_dl_argv;
/* Deal with an out-of-range PC24 reloc. */
static Elf32_Addr
fix_bad_pc24 (Elf32_Addr *const reloc_addr, Elf32_Addr value)
{
static void *fix_page;
static unsigned int fix_offset;
static size_t pagesize;
Elf32_Word *fix_address;
if (! fix_page)
{
if (! pagesize)
pagesize = getpagesize ();
fix_page = mmap (NULL, pagesize, PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (! fix_page)
assert (! "could not map page for fixup");
fix_offset = 0;
}
fix_address = (Elf32_Word *)(fix_page + fix_offset);
fix_address[0] = 0xe51ff004; /* ldr pc, [pc, #-4] */
fix_address[1] = value;
fix_offset += 8;
if (fix_offset >= pagesize)
fix_page = NULL;
return (Elf32_Addr)fix_address;
}
/* Perform the relocation specified by RELOC and SYM (which is fully resolved).
MAP is the object containing the reloc. */
static inline void
elf_machine_rel (struct link_map *map, const Elf32_Rel *reloc,
const Elf32_Sym *sym, const struct r_found_version *version,
Elf32_Addr *const reloc_addr)
{
if (ELF32_R_TYPE (reloc->r_info) == R_ARM_RELATIVE)
{
#ifndef RTLD_BOOTSTRAP
if (map != &_dl_rtld_map) /* Already done in rtld itself. */
#endif
*reloc_addr += map->l_addr;
}
else if (ELF32_R_TYPE (reloc->r_info) != R_ARM_NONE)
{
const Elf32_Sym *const refsym = sym;
Elf32_Addr value = RESOLVE (&sym, version, ELF32_R_TYPE (reloc->r_info));
if (sym)
value += sym->st_value;
switch (ELF32_R_TYPE (reloc->r_info))
{
case R_ARM_COPY:
if (sym == NULL)
/* This can happen in trace mode if an object could not be
found. */
break;
if (sym->st_size > refsym->st_size
|| (_dl_verbose && sym->st_size < refsym->st_size))
{
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",
_dl_argv[0] ?: "<program name unknown>",
strtab + refsym->st_name);
}
memcpy (reloc_addr, (void *) value, MIN (sym->st_size,
refsym->st_size));
break;
case R_ARM_GLOB_DAT:
case R_ARM_JUMP_SLOT:
#ifdef RTLD_BOOTSTRAP
/* Fix weak undefined references. */
if (sym != NULL && sym->st_value == 0)
*reloc_addr = 0;
else
#endif
*reloc_addr = value;
break;
case R_ARM_ABS32:
{
#ifndef RTLD_BOOTSTRAP
/* 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);
if (map == &_dl_rtld_map)
/* Undo the relocation done here during bootstrapping.
Now we will relocate it anew, possibly using a
binding found in the user program or a loaded library
rather than the dynamic linker's built-in definitions
used while loading those libraries. */
value -= map->l_addr + refsym->st_value;
#endif
*reloc_addr += value;
break;
}
case R_ARM_PC24:
{
Elf32_Sword addend;
Elf32_Addr newvalue, topbits;
addend = *reloc_addr & 0x00ffffff;
if (addend & 0x00800000) addend |= 0xff000000;
newvalue = value - (Elf32_Addr)reloc_addr + (addend << 2);
topbits = newvalue & 0xfe000000;
if (topbits != 0xfe000000 && topbits != 0x00000000)
{
newvalue = fix_bad_pc24(reloc_addr, value)
- (Elf32_Addr)reloc_addr + (addend << 2);
topbits = newvalue & 0xfe000000;
if (topbits != 0xfe000000 && topbits != 0x00000000)
{
_dl_signal_error (0, map->l_name,
"R_ARM_PC24 relocation out of range");
}
}
newvalue >>= 2;
value = (*reloc_addr & 0xff000000) | (newvalue & 0x00ffffff);
*reloc_addr = value;
}
break;
default:
_dl_reloc_bad_type (map, ELF32_R_TYPE (reloc->r_info), 0);
break;
}
}
}
static inline void
elf_machine_lazy_rel (struct link_map *map,
Elf32_Addr l_addr, const Elf32_Rel *reloc)
{
Elf32_Addr *const reloc_addr = (void *) (l_addr + reloc->r_offset);
/* Check for unexpected PLT reloc type. */
if (ELF32_R_TYPE (reloc->r_info) == R_ARM_JUMP_SLOT)
*reloc_addr += l_addr;
else
_dl_reloc_bad_type (map, ELF32_R_TYPE (reloc->r_info), 1);
}
#endif /* RESOLVE */