OpenBSD-4.6/libexec/ld.so/sparc/rtld_machine.c
/* $OpenBSD: rtld_machine.c,v 1.31 2008/04/09 21:45:26 kurt Exp $ */
/*
* Copyright (c) 1999 Dale Rahn
* Copyright (c) 2001 Niklas Hallqvist
* Copyright (c) 2001 Artur Grabowski
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#define _DYN_LOADER
#include <sys/types.h>
#include <sys/cdefs.h>
#include <sys/mman.h>
#include <sys/param.h>
#include <sys/sysctl.h>
#include <machine/cpu.h>
#include <nlist.h>
#include <link.h>
#include <signal.h>
#include "syscall.h"
#include "archdep.h"
#include "resolve.h"
/*
* The following table holds for each relocation type:
* - the width in bits of the memory location the relocation
* applies to (not currently used)
* - the number of bits the relocation value must be shifted to the
* right (i.e. discard least significant bits) to fit into
* the appropriate field in the instruction word.
* - flags indicating whether
* * the relocation involves a symbol
* * the relocation is relative to the current position
* * the relocation is for a GOT entry
* * the relocation is relative to the load address
*
*/
#define _RF_S 0x80000000 /* Resolve symbol */
#define _RF_A 0x40000000 /* Use addend */
#define _RF_P 0x20000000 /* Location relative */
#define _RF_G 0x10000000 /* GOT offset */
#define _RF_B 0x08000000 /* Load address relative */
#define _RF_SZ(s) (((s) & 0xff) << 8) /* memory target size */
#define _RF_RS(s) ((s) & 0xff) /* right shift */
static int reloc_target_flags[] = {
0, /* NONE */
_RF_S|_RF_A| _RF_SZ(8) | _RF_RS(0), /* RELOC_8 */
_RF_S|_RF_A| _RF_SZ(16) | _RF_RS(0), /* RELOC_16 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* RELOC_32 */
_RF_S|_RF_A|_RF_P| _RF_SZ(8) | _RF_RS(0), /* DISP_8 */
_RF_S|_RF_A|_RF_P| _RF_SZ(16) | _RF_RS(0), /* DISP_16 */
_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* DISP_32 */
_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_30 */
_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_22 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* HI22 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 22 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 13 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* LO10 */
_RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT10 */
_RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT13 */
_RF_G| _RF_SZ(32) | _RF_RS(10), /* GOT22 */
_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PC10 */
_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PC22 */
_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WPLT30 */
_RF_S| _RF_SZ(32) | _RF_RS(0), /* COPY */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* GLOB_DAT */
_RF_S| _RF_SZ(32) | _RF_RS(0), /* JMP_SLOT */
_RF_A| _RF_B| _RF_SZ(32) | _RF_RS(0), /* RELATIVE */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* UA_32 */
/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* PLT32 */
/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* HIPLT22 */
/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* LOPLT10 */
/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* LOPLT10 */
/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* PCPLT22 */
/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* PCPLT32 */
_RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 10 */
_RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 11 */
_RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 64 */
_RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* OLO10 */
_RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* HH22 */
_RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* HM10 */
_RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* LM22 */
_RF_S|_RF_A|_RF_P|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* WDISP16 */
_RF_S|_RF_A|_RF_P|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* WDISP19 */
/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* GLOB_JMP */
/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 7 */
/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 5 */
/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 6 */
};
#define RELOC_RESOLVE_SYMBOL(t) ((reloc_target_flags[t] & _RF_S) != 0)
#define RELOC_PC_RELATIVE(t) ((reloc_target_flags[t] & _RF_P) != 0)
#define RELOC_USE_ADDEND(t) ((reloc_target_flags[t] & _RF_A) != 0)
#define RELOC_TARGET_SIZE(t) ((reloc_target_flags[t] >> 8) & 0xff)
#define RELOC_VALUE_RIGHTSHIFT(t) (reloc_target_flags[t] & 0xff)
static int reloc_target_bitmask[] = {
#define _BM(x) (~(-(1ULL << (x))))
0, /* NONE */
_BM(8), _BM(16), _BM(32), /* RELOC_8, _16, _32 */
_BM(8), _BM(16), _BM(32), /* DISP8, DISP16, DISP32 */
_BM(30), _BM(22), /* WDISP30, WDISP22 */
_BM(22), _BM(22), /* HI22, _22 */
_BM(13), _BM(10), /* RELOC_13, _LO10 */
_BM(10), _BM(13), _BM(22), /* GOT10, GOT13, GOT22 */
_BM(10), _BM(22), /* _PC10, _PC22 */
_BM(30), 0, /* _WPLT30, _COPY */
-1, -1, -1, /* _GLOB_DAT, JMP_SLOT, _RELATIVE */
_BM(32), _BM(32), /* _UA32, PLT32 */
_BM(22), _BM(10), /* _HIPLT22, LOPLT10 */
_BM(32), _BM(22), _BM(10), /* _PCPLT32, _PCPLT22, _PCPLT10 */
_BM(10), _BM(11), -1, /* _10, _11, _64 */
_BM(10), _BM(22), /* _OLO10, _HH22 */
_BM(10), _BM(22), /* _HM10, _LM22 */
_BM(16), _BM(19), /* _WDISP16, _WDISP19 */
-1, /* GLOB_JMP */
_BM(7), _BM(5), _BM(6) /* _7, _5, _6 */
#undef _BM
};
#define RELOC_VALUE_BITMASK(t) (reloc_target_bitmask[t])
static inline void
_dl_reloc_plt(Elf_Addr *where, Elf_Addr value)
{
/*
* At the PLT entry pointed at by `where', we now construct
* a direct transfer to the now fully resolved function
* address. The resulting code in the jump slot is:
*
* sethi %hi(roffset), %g1
* sethi %hi(addr), %g1
* jmp %g1+%lo(addr)
*
* We write the third instruction first, since that leaves the
* previous `b,a' at the second word in place. Hence the whole
* PLT slot can be atomically change to the new sequence by
* writing the `sethi' instruction at word 2.
*/
#define SETHI 0x03000000
#define JMP 0x81c06000
#define NOP 0x01000000
where[2] = JMP | (value & 0x000003ff);
where[1] = SETHI | ((value >> 10) & 0x003fffff);
__asm __volatile("iflush %0+8" : : "r" (where));
__asm __volatile("iflush %0+4" : : "r" (where));
/*
* iflush requires 5 subsequent cycles to be sure all copies
* are flushed from the CPU and the icache.
*/
__asm __volatile("nop;nop;nop;nop;nop");
}
int
_dl_md_reloc(elf_object_t *object, int rel, int relasz)
{
long i;
long numrela;
int fails = 0;
Elf_Addr loff;
Elf_RelA *relas;
struct load_list *llist;
loff = object->obj_base;
numrela = object->Dyn.info[relasz] / sizeof(Elf_RelA);
relas = (Elf_RelA *)(object->Dyn.info[rel]);
if (relas == NULL)
return(0);
/*
* unprotect some segments if we need it.
*/
if ((object->dyn.textrel == 1) && (rel == DT_REL || rel == DT_RELA)) {
for (llist = object->load_list; llist != NULL; llist = llist->next) {
if (!(llist->prot & PROT_WRITE))
_dl_mprotect(llist->start, llist->size,
llist->prot|PROT_WRITE);
}
}
for (i = 0; i < numrela; i++, relas++) {
Elf_Addr *where, ooff;
Elf_Word type, value, mask;
const Elf_Sym *sym, *this;
const char *symn;
type = ELF_R_TYPE(relas->r_info);
if (type == R_TYPE(NONE))
continue;
if (type == R_TYPE(JMP_SLOT) && rel != DT_JMPREL)
continue;
where = (Elf_Addr *)(relas->r_offset + loff);
if (type == R_TYPE(RELATIVE)) {
*where += (Elf_Addr)(loff + relas->r_addend);
continue;
}
if (RELOC_USE_ADDEND(type))
value = relas->r_addend;
else
value = 0;
sym = NULL;
symn = NULL;
if (RELOC_RESOLVE_SYMBOL(type)) {
sym = object->dyn.symtab;
sym += ELF_R_SYM(relas->r_info);
symn = object->dyn.strtab + sym->st_name;
if (sym->st_shndx != SHN_UNDEF &&
ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
value += loff;
} else {
this = NULL;
ooff = _dl_find_symbol_bysym(object,
ELF_R_SYM(relas->r_info), &this,
SYM_SEARCH_ALL|SYM_WARNNOTFOUND|
((type == R_TYPE(JMP_SLOT)) ?
SYM_PLT : SYM_NOTPLT),
sym, NULL);
if (this == NULL) {
resolve_failed:
if (ELF_ST_BIND(sym->st_info) !=
STB_WEAK)
fails++;
continue;
}
value += (Elf_Addr)(ooff + this->st_value);
}
}
if (type == R_TYPE(COPY)) {
void *dstaddr = where;
const void *srcaddr;
const Elf_Sym *dstsym = sym, *srcsym = NULL;
size_t size = dstsym->st_size;
Elf_Addr soff;
soff = _dl_find_symbol(symn, &srcsym,
SYM_SEARCH_OTHER|SYM_WARNNOTFOUND|
((type == R_TYPE(JMP_SLOT)) ? SYM_PLT : SYM_NOTPLT),
dstsym, object, NULL);
if (srcsym == NULL)
goto resolve_failed;
srcaddr = (void *)(soff + srcsym->st_value);
_dl_bcopy(srcaddr, dstaddr, size);
continue;
}
if (type == R_TYPE(JMP_SLOT)) {
_dl_reloc_plt(where, value);
continue;
}
if (RELOC_PC_RELATIVE(type))
value -= (Elf_Addr)where;
mask = RELOC_VALUE_BITMASK(type);
value >>= RELOC_VALUE_RIGHTSHIFT(type);
value &= mask;
/* We ignore alignment restrictions here */
*where &= ~mask;
*where |= value;
}
/* reprotect the unprotected segments */
if ((object->dyn.textrel == 1) && (rel == DT_REL || rel == DT_RELA)) {
for (llist = object->load_list; llist != NULL; llist = llist->next) {
if (!(llist->prot & PROT_WRITE))
_dl_mprotect(llist->start, llist->size,
llist->prot);
}
}
return (fails);
}
/*
* Resolve a symbol at run-time.
*/
Elf_Addr
_dl_bind(elf_object_t *object, int reloff)
{
const Elf_Sym *sym, *this;
Elf_Addr *addr, ooff;
const char *symn;
Elf_Addr value;
Elf_RelA *rela;
sigset_t omask, nmask;
rela = (Elf_RelA *)(object->Dyn.info[DT_JMPREL] + reloff);
sym = object->dyn.symtab;
sym += ELF_R_SYM(rela->r_info);
symn = object->dyn.strtab + sym->st_name;
addr = (Elf_Addr *)(object->obj_base + rela->r_offset);
this = NULL;
ooff = _dl_find_symbol(symn, &this,
SYM_SEARCH_ALL|SYM_WARNNOTFOUND|SYM_PLT, sym,
object, NULL);
if (this == NULL) {
_dl_printf("lazy binding failed!\n");
*((int *)0) = 0; /* XXX */
}
value = ooff + this->st_value;
/* if PLT is protected, allow the write */
if (object->plt_size != 0) {
sigfillset(&nmask);
_dl_sigprocmask(SIG_BLOCK, &nmask, &omask);
_dl_thread_bind_lock(0);
/* mprotect the actual modified region, not the whole plt */
_dl_mprotect((void*)addr, sizeof (Elf_Addr) * 3,
PROT_READ|PROT_WRITE|PROT_EXEC);
}
_dl_reloc_plt(addr, value);
/* if PLT is (to be protected, change back to RO/X */
if (object->plt_size != 0) {
/* mprotect the actual modified region, not the whole plt */
_dl_mprotect((void*)addr, sizeof (Elf_Addr) * 3,
PROT_READ|PROT_EXEC);
_dl_thread_bind_lock(1);
_dl_sigprocmask(SIG_SETMASK, &omask, NULL);
}
return (value);
}
int
_dl_md_reloc_got(elf_object_t *object, int lazy)
{
int fails = 0;
Elf_Addr *pltgot;
extern void _dl_bind_start(void); /* XXX */
Elf_Addr ooff;
const Elf_Sym *this;
Elf_Addr plt_addr;
pltgot = (Elf_Addr *)object->Dyn.info[DT_PLTGOT];
if (pltgot != NULL) {
/*
* PLTGOT is the PLT on the sparc.
* The first entry holds the call the dynamic linker.
* We construct a `call' sequence that transfers
* to `_dl_bind_start()'.
* The second entry holds the object identification.
* Note: each PLT entry is three words long.
*/
#define SAVE 0x9de3bfc0 /* i.e. `save %sp,-64,%sp' */
#define CALL 0x40000000
#define NOP 0x01000000
pltgot[0] = SAVE;
pltgot[1] = CALL |
((Elf_Addr)&_dl_bind_start - (Elf_Addr)&pltgot[1]) >> 2;
pltgot[2] = NOP;
pltgot[3] = (Elf_Addr) object;
__asm __volatile("iflush %0+8" : : "r" (pltgot));
__asm __volatile("iflush %0+4" : : "r" (pltgot));
__asm __volatile("iflush %0+0" : : "r" (pltgot));
/*
* iflush requires 5 subsequent cycles to be sure all copies
* are flushed from the CPU and the icache.
*/
__asm __volatile("nop;nop;nop;nop;nop");
}
object->got_addr = NULL;
object->got_size = 0;
this = NULL;
ooff = _dl_find_symbol("__got_start", &this,
SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL,
object, NULL);
if (this != NULL)
object->got_addr = ooff + this->st_value;
this = NULL;
ooff = _dl_find_symbol("__got_end", &this,
SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL,
object, NULL);
if (this != NULL)
object->got_size = ooff + this->st_value - object->got_addr;
plt_addr = 0;
object->plt_size = 0;
this = NULL;
ooff = _dl_find_symbol("__plt_start", &this,
SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL,
object, NULL);
if (this != NULL)
plt_addr = ooff + this->st_value;
this = NULL;
ooff = _dl_find_symbol("__plt_end", &this,
SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL,
object, NULL);
if (this != NULL)
object->plt_size = ooff + this->st_value - plt_addr;
if (object->got_addr == NULL)
object->got_start = NULL;
else {
object->got_start = ELF_TRUNC(object->got_addr, _dl_pagesz);
object->got_size += object->got_addr - object->got_start;
object->got_size = ELF_ROUND(object->got_size, _dl_pagesz);
}
if (plt_addr == NULL)
object->plt_start = NULL;
else {
object->plt_start = ELF_TRUNC(plt_addr, _dl_pagesz);
object->plt_size += plt_addr - object->plt_start;
object->plt_size = ELF_ROUND(object->plt_size, _dl_pagesz);
}
if (object->obj_type == OBJTYPE_LDR || !lazy || pltgot == NULL) {
fails = _dl_md_reloc(object, DT_JMPREL, DT_PLTRELSZ);
}
if (object->got_size != 0)
_dl_mprotect((void*)object->got_start, object->got_size,
PROT_READ);
if (object->plt_size != 0)
_dl_mprotect((void*)object->plt_start, object->plt_size,
PROT_READ|PROT_EXEC);
return (fails);
}
void __mul(void);
void _mulreplace_end(void);
void _mulreplace(void);
void __umul(void);
void _umulreplace_end(void);
void _umulreplace(void);
void __div(void);
void _divreplace_end(void);
void _divreplace(void);
void __udiv(void);
void _udivreplace_end(void);
void _udivreplace(void);
void __rem(void);
void _remreplace_end(void);
void _remreplace(void);
void __urem(void);
void _uremreplace_end(void);
void _uremreplace(void);
void
_dl_mul_fixup()
{
int mib[2], v8mul;
size_t len;
mib[0] = CTL_MACHDEP;
mib[1] = CPU_V8MUL;
len = sizeof(v8mul);
_dl_sysctl(mib, 2, &v8mul, &len, NULL, 0);
if (!v8mul)
return;
_dl_mprotect(&__mul, _mulreplace_end-_mulreplace,
PROT_READ|PROT_WRITE|PROT_EXEC);
_dl_bcopy(_mulreplace, __mul, _mulreplace_end-_mulreplace);
_dl_mprotect(&__mul, _mulreplace_end-_mulreplace,
PROT_READ|PROT_EXEC);
_dl_mprotect(&__umul, _umulreplace_end-_umulreplace,
PROT_READ|PROT_WRITE|PROT_EXEC);
_dl_bcopy(_umulreplace, __umul, _umulreplace_end-_umulreplace);
_dl_mprotect(&__umul, _umulreplace_end-_umulreplace,
PROT_READ|PROT_EXEC);
_dl_mprotect(&__div, _divreplace_end-_divreplace,
PROT_READ|PROT_WRITE|PROT_EXEC);
_dl_bcopy(_divreplace, __div, _divreplace_end-_divreplace);
_dl_mprotect(&__div, _divreplace_end-_divreplace,
PROT_READ|PROT_EXEC);
_dl_mprotect(&__udiv, _udivreplace_end-_udivreplace,
PROT_READ|PROT_WRITE|PROT_EXEC);
_dl_bcopy(_udivreplace, __udiv, _udivreplace_end-_udivreplace);
_dl_mprotect(&__udiv, _udivreplace_end-_udivreplace,
PROT_READ|PROT_EXEC);
_dl_mprotect(&__rem, _remreplace_end-_remreplace,
PROT_READ|PROT_WRITE|PROT_EXEC);
_dl_bcopy(_remreplace, __rem, _remreplace_end-_remreplace);
_dl_mprotect(&__rem, _remreplace_end-_remreplace,
PROT_READ|PROT_EXEC);
_dl_mprotect(&__urem, _uremreplace_end-_uremreplace,
PROT_READ|PROT_WRITE|PROT_EXEC);
_dl_bcopy(_uremreplace, __urem, _uremreplace_end-_uremreplace);
_dl_mprotect(&__urem, _uremreplace_end-_uremreplace,
PROT_READ|PROT_EXEC);
}