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/* Machine-dependent ELF dynamic relocation inline functions. SPARC version.
Copyright (C) 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. */
#define ELF_MACHINE_NAME "sparc"
#include <assert.h>
#include <string.h>
#include <link.h>
#include <sys/param.h>
/* Some SPARC opcodes we need to use for self-modifying code. */
#define OPCODE_NOP 0x01000000 /* nop */
#define OPCODE_CALL 0x40000000 /* call ?; add PC-rel word address */
#define OPCODE_SETHI_G1 0x03000000 /* sethi ?, %g1; add value>>10 */
#define OPCODE_JMP_G1 0x81c06000 /* jmp %g1+?; add lo 10 bits of value */
#define OPCODE_SAVE_SP64 0x9de3bfc0 /* save %sp, -64, %sp */
/* 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_SPARC;
}
/* 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
elf_machine_dynamic (void)
{
register Elf32_Addr *got asm ("%l7");
return *got;
}
/* Return the run-time load address of the shared object. */
static inline Elf32_Addr
elf_machine_load_address (void)
{
Elf32_Addr addr;
asm (
"add %%fp,0x44,%%o2\n\t" /* o2 = point to argc */
"ld [%%o2 - 4],%%o0\n\t" /* o0 = load argc */
"sll %%o0, 2, %%o0\n\t" /* o0 = argc * sizeof (int) */
"add %%o2,%%o0,%%o2\n\t" /* o2 = skip over argv */
"add %%o2,4,%%o2\n\t" /* skip over null after argv */
/* Now %o2 is pointing to env, skip over that as well. */
"1:\n\t"
"ld [%%o2],%%o0\n\t"
"cmp %%o0,0\n\t"
"bnz 1b\n\t"
"add %%o2,4,%%o2\n\t"
/* Note that above, we want to advance the NULL after envp so
we always add 4. */
/* Now, search for the AT_BASE property. */
"2:\n\t"
"ld [%%o2],%%o0\n\t"
"cmp %%o0,0\n\t"
"be,a 3f\n\t"
"or %%g0,%%g0,%0\n\t"
"cmp %%o0,7\n\t" /* AT_BASE = 7 */
"be,a 3f\n\t"
"ld [%%o2+4],%0\n\t"
"b 2b\n\t"
"add %%o2,8,%%o2\n\t"
/* At this point %0 has the load address for the interpreter */
"3:\n\t"
: "=r" (addr)
: /* no inputs */
: "o0", "o2");
return addr;
}
#ifdef RESOLVE
/* Perform the relocation specified by RELOC and SYM (which is fully resolved).
MAP is the object containing the reloc. */
static inline 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)
{
Elf32_Addr loadbase;
if (ELF32_R_TYPE (reloc->r_info) == R_SPARC_RELATIVE)
{
#ifndef RTLD_BOOTSTRAP
if (map != &_dl_rtld_map) /* Already done in rtld itself. */
#endif
*reloc_addr += map->l_addr + reloc->r_addend;
}
else
{
const Elf32_Sym *const refsym = sym;
Elf32_Addr value;
if (sym->st_shndx != SHN_UNDEF &&
ELF32_ST_BIND (sym->st_info) == STB_LOCAL)
value = map->l_addr;
else
{
value = RESOLVE (&sym, version, ELF32_R_TYPE (reloc->r_info));
if (sym)
value += sym->st_value;
}
value += reloc->r_addend; /* Assume copy relocs have zero addend. */
switch (ELF32_R_TYPE (reloc->r_info))
{
case R_SPARC_COPY:
if (sym->st_size > refsym->st_size
|| (_dl_verbose && sym->st_size < refsym->st_size))
{
extern char **_dl_argv;
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, (void *) value, MIN (sym->st_size,
refsym->st_size));
break;
case R_SPARC_GLOB_DAT:
case R_SPARC_32:
*reloc_addr = value;
break;
case R_SPARC_JMP_SLOT:
reloc_addr[1] = OPCODE_SETHI_G1 | (value >> 10);
reloc_addr[2] = OPCODE_JMP_G1 | (value & 0x3ff);
break;
case R_SPARC_8:
*(char *) reloc_addr = value;
break;
case R_SPARC_16:
*(short *) reloc_addr = value;
break;
case R_SPARC_DISP8:
*(char *) reloc_addr = (value - (Elf32_Addr) reloc_addr);
break;
case R_SPARC_DISP16:
*(short *) reloc_addr = (value - (Elf32_Addr) reloc_addr);
break;
case R_SPARC_DISP32:
*reloc_addr = (value - (Elf32_Addr) reloc_addr);
break;
case R_SPARC_LO10:
*reloc_addr = (*reloc_addr & ~0x3ff) | (value & 0x3ff);
break;
case R_SPARC_WDISP30:
*reloc_addr = ((*reloc_addr & 0xc0000000)
| ((value - (unsigned int) reloc_addr) >> 2));
break;
case R_SPARC_HI22:
*reloc_addr = (*reloc_addr & 0xffc00000) | (value >> 10);
break;
case R_SPARC_NONE: /* Alright, Wilbur. */
break;
default:
assert (! "unexpected dynamic reloc type");
break;
}
}
}
static inline void
elf_machine_lazy_rel (struct link_map *map, const Elf32_Rela *reloc)
{
switch (ELF32_R_TYPE (reloc->r_info))
{
case R_SPARC_NONE:
break;
case R_SPARC_JMP_SLOT:
break;
default:
assert (! "unexpected PLT reloc type");
break;
}
}
#endif /* RESOLVE */
/* 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_SPARC_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_SPARC_JMP_SLOT)
/* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
#define ELF_MACHINE_RELOC_NOPLT R_SPARC_JMP_SLOT
/* The SPARC never uses Elf32_Rel relocations. */
#define ELF_MACHINE_NO_REL 1
/* 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
elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
{
Elf32_Addr *plt;
extern void _dl_runtime_resolve (Elf32_Word);
if (l->l_info[DT_JMPREL] && lazy)
{
/* The entries for functions in the PLT have not yet been filled in.
Their initial contents will arrange when called to set the high 22
bits of %g1 with an offset into the .rela.plt section and jump to
the beginning of the PLT. */
plt = (Elf32_Addr *) (l->l_addr + l->l_info[DT_PLTGOT]->d_un.d_ptr);
/* The beginning of the PLT does:
save %sp, -64, %sp
pltpc: call _dl_runtime_resolve
nop
.word MAP
This saves the register window containing the arguments, and the
PC value (pltpc) implicitly saved in %o7 by the call points near the
location where we store the link_map pointer for this object. */
plt[0] = OPCODE_SAVE_SP64; /* save %sp, -64, %sp */
/* Construct PC-relative word address. */
plt[1] = OPCODE_CALL | (((Elf32_Addr) &_dl_runtime_resolve -
(Elf32_Addr) &plt[1]) >> 2);
plt[2] = OPCODE_NOP; /* Fill call delay slot. */
plt[3] = (Elf32_Addr *) l;
}
return lazy;
}
/* This code is used in dl-runtime.c to call the `fixup' function
and then redirect to the address it returns. */
#define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\
# Trampoline for _dl_runtime_resolver
.globl _dl_runtime_resolve
.type _dl_runtime_resolve, @function
_dl_runtime_resolve:
t 1
#call %g0
# Pass two args to fixup: the PLT address computed from the PC saved
# in the PLT's call insn, and the reloc offset passed in %g1.
#ld [%o7 + 8], %o1 | Second arg, loaded from PLTPC[2].
#call fixup
#shrl %g1, 22, %o0 | First arg, set in delay slot of call.
# Jump to the real function.
#jmpl %o0, %g0
# In the delay slot of that jump, restore the register window
# saved by the first insn of the PLT.
#restore
.size _dl_runtime_resolve, . - _dl_runtime_resolve
");
/* The PLT uses Elf32_Rela relocs. */
#define elf_machine_relplt elf_machine_rela
/* Mask identifying addresses reserved for the user program,
where the dynamic linker should not map anything. */
#define ELF_MACHINE_USER_ADDRESS_MASK ???
/* 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\
.globl _start\n\
.type _start,@function\n\
_start:\n\
/* Pass pointer to argument block to _dl_start. */\n\
add %sp,64,%o0\n\
call _dl_start\n\
nop\n\
\n\
mov %o0,%l0\n\
\n\
2:\n\
call 1f\n\
nop\n\
1:\n\
sethi %hi(_GLOBAL_OFFSET_TABLE_-(2b-.)),%l2\n\
sethi %hi(_dl_default_scope),%l3\n\
or %l2,%lo(_GLOBAL_OFFSET_TABLE_-(2b-.)),%l2\n\
or %l3,%lo(_dl_default_scope),%l3\n\
add %o7,%l2,%l1\n\
# %l1 has the GOT. %l3 has _dl_default_scope GOT offset\n\
ld [%l1+%l3],%l4\n\
# %l4 has pointer to _dl_default_scope. Now, load _dl_default_scope [2]\n\
ld [%l4+8],%l4\n\
# %l4 has _dl_default_scope [2]\n\
# call _dl_init_next until it returns 0, pass _dl_default_scope [2]\n\
3:\n\
call _dl_init_next\n\
mov %l4,%o0\n\
cmp %o0,%g0\n\
bz,a 4f\n\
nop\n\
call %o0\n\
/* Pass pointer to argument block to this init function */\n\
add %sp,64,%o0\n\
b,a 3b\n\
4:\n\
# Clear the _dl_starting_up variable and pass _dl_fini in %g1 as per ELF ABI.\n\
sethi %hi(_dl_starting_up),%l4\n\
sethi %hi(_dl_fini),%l3\n\
or %l4,%lo(_dl_starting_up),%l4\n\
or %l3,%lo(_dl_fini),%l3\n\
# clear _dl_starting_up\n\
ld [%l1+%l4],%l5\n\
st %g0,[%l5]\n\
# load out fini function for atexit in %g1\n\
ld [%l3+%l1],%g1\n\
# jump to the user program entry point.\n\
jmpl %l0,%g0\n\
nop\n\
");
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