466 lines
13 KiB
C
466 lines
13 KiB
C
/* Machine-dependent ELF dynamic relocation inline functions. SPARC version.
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Copyright (C) 1996,1997,1998,1999,2000,2001 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc.,
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59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
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#define ELF_MACHINE_NAME "sparc"
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#include <string.h>
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#include <sys/param.h>
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#include <ldsodefs.h>
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/* Some SPARC opcodes we need to use for self-modifying code. */
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#define OPCODE_NOP 0x01000000 /* nop */
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#define OPCODE_CALL 0x40000000 /* call ?; add PC-rel word address */
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#define OPCODE_SETHI_G1 0x03000000 /* sethi ?, %g1; add value>>10 */
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#define OPCODE_JMP_G1 0x81c06000 /* jmp %g1+?; add lo 10 bits of value */
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#define OPCODE_SAVE_SP 0x9de3bfa8 /* save %sp, -(16+6)*4, %sp */
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/* Protect some broken versions of gcc from misinterpreting weak addresses. */
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#define WEAKADDR(x) ({ __typeof(x) *_px = &x; \
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__asm ("" : "=r" (_px) : "0" (_px)); \
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_px; })
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/* Use a different preload file when running in 32-bit emulation mode
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on a 64-bit host. */
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#define LD_SO_PRELOAD ((_dl_hwcap & HWCAP_SPARC_V9) ? "/etc/ld.so.preload32" \
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: "/etc/ld.so.preload")
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/* Return nonzero iff ELF header is compatible with the running host. */
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static inline int
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elf_machine_matches_host (const Elf32_Ehdr *ehdr)
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{
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if (ehdr->e_machine == EM_SPARC)
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return 1;
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else if (ehdr->e_machine == EM_SPARC32PLUS)
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{
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unsigned long *hwcap;
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weak_extern (_dl_hwcap);
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weak_extern (_dl_hwcap_mask);
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hwcap = WEAKADDR(_dl_hwcap);
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/* XXX The following is wrong! Dave Miller rejected to implement it
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correctly. If this causes problems shoot *him*! */
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return hwcap == NULL || (*hwcap & _dl_hwcap_mask & HWCAP_SPARC_V9);
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}
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else
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return 0;
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}
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/* Return the link-time address of _DYNAMIC. Conveniently, this is the
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first element of the GOT. This must be inlined in a function which
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uses global data. */
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static inline Elf32_Addr
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elf_machine_dynamic (void)
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{
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register Elf32_Addr *got asm ("%l7");
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return *got;
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}
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/* Return the run-time load address of the shared object. */
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static inline Elf32_Addr
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elf_machine_load_address (void)
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{
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register Elf32_Addr pc __asm("%o7"), pic __asm("%l7"), got;
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/* Utilize the fact that a local .got entry will be partially
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initialized at startup awaiting its RELATIVE fixup. */
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__asm("sethi %%hi(.Load_address),%1\n"
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".Load_address:\n\t"
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"call 1f\n\t"
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"or %1,%%lo(.Load_address),%1\n"
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"1:\tld [%2+%1],%1"
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: "=r"(pc), "=r"(got) : "r"(pic));
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return pc - got;
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}
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/* Set up the loaded object described by L so its unrelocated PLT
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entries will jump to the on-demand fixup code in dl-runtime.c. */
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static inline int
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elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
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{
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Elf32_Addr *plt;
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extern void _dl_runtime_resolve (Elf32_Word);
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extern void _dl_runtime_profile (Elf32_Word);
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if (l->l_info[DT_JMPREL] && lazy)
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{
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Elf32_Addr rfunc;
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/* The entries for functions in the PLT have not yet been filled in.
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Their initial contents will arrange when called to set the high 22
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bits of %g1 with an offset into the .rela.plt section and jump to
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the beginning of the PLT. */
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plt = (Elf32_Addr *) D_PTR (l, l_info[DT_PLTGOT]);
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if (! profile)
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rfunc = (Elf32_Addr) &_dl_runtime_resolve;
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else
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{
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rfunc = (Elf32_Addr) &_dl_runtime_profile;
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if (_dl_name_match_p (_dl_profile, l))
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_dl_profile_map = l;
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}
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/* The beginning of the PLT does:
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save %sp, -64, %sp
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pltpc: call _dl_runtime_resolve
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nop
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.word MAP
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This saves the register window containing the arguments, and the
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PC value (pltpc) implicitly saved in %o7 by the call points near the
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location where we store the link_map pointer for this object. */
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plt[0] = OPCODE_SAVE_SP;
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/* Construct PC-relative word address. */
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plt[1] = OPCODE_CALL | ((rfunc - (Elf32_Addr) &plt[1]) >> 2);
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plt[2] = OPCODE_NOP; /* Fill call delay slot. */
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plt[3] = (Elf32_Addr) l;
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}
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return lazy;
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}
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/* This code is used in dl-runtime.c to call the `fixup' function
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and then redirect to the address it returns. */
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#define TRAMPOLINE_TEMPLATE(tramp_name, fixup_name) \
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asm ( "\
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.text
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.globl " #tramp_name "
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.type " #tramp_name ", @function
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.align 32
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" #tramp_name ":
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/* Set up the arguments to fixup --
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%o0 = link_map out of plt0
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%o1 = offset of reloc entry
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%o2 = return address */
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ld [%o7 + 8], %o0
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srl %g1, 10, %o1
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mov %i7, %o2
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call " #fixup_name "
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sub %o1, 4*12, %o1
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jmp %o0
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restore
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.size " #tramp_name ", . - " #tramp_name "
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.previous")
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#ifndef PROF
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#define ELF_MACHINE_RUNTIME_TRAMPOLINE \
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TRAMPOLINE_TEMPLATE (_dl_runtime_resolve, fixup); \
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TRAMPOLINE_TEMPLATE (_dl_runtime_profile, profile_fixup);
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#else
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#define ELF_MACHINE_RUNTIME_TRAMPOLINE \
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TRAMPOLINE_TEMPLATE (_dl_runtime_resolve, fixup); \
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TRAMPOLINE_TEMPLATE (_dl_runtime_profile, fixup);
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#endif
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/* Nonzero iff TYPE should not be allowed to resolve to one of
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the main executable's symbols, as for a COPY reloc. */
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#define elf_machine_lookup_noexec_p(type) ((type) == R_SPARC_COPY)
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/* Nonzero iff TYPE describes relocation of a PLT entry, so
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PLT entries should not be allowed to define the value. */
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#define elf_machine_lookup_noplt_p(type) ((type) == R_SPARC_JMP_SLOT)
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/* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
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#define ELF_MACHINE_JMP_SLOT R_SPARC_JMP_SLOT
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/* The SPARC never uses Elf32_Rel relocations. */
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#define ELF_MACHINE_NO_REL 1
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/* The SPARC overlaps DT_RELA and DT_PLTREL. */
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#define ELF_MACHINE_PLTREL_OVERLAP 1
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/* Initial entry point code for the dynamic linker.
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The C function `_dl_start' is the real entry point;
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its return value is the user program's entry point. */
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#define RTLD_START __asm__ ("\
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.text
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.globl _start
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.type _start, @function
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.align 32
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_start:
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/* Allocate space for functions to drop their arguments. */
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sub %sp, 6*4, %sp
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/* Pass pointer to argument block to _dl_start. */
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call _dl_start
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add %sp, 22*4, %o0
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/* FALTHRU */
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.globl _dl_start_user
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.type _dl_start_user, @function
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_dl_start_user:
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/* Load the PIC register. */
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1: call 2f
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sethi %hi(_GLOBAL_OFFSET_TABLE_-(1b-.)), %l7
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2: or %l7, %lo(_GLOBAL_OFFSET_TABLE_-(1b-.)), %l7
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add %l7, %o7, %l7
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/* Save the user entry point address in %l0 */
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mov %o0, %l0
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/* Store the highest stack address. */
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sethi %hi(__libc_stack_end), %g2
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or %g2, %lo(__libc_stack_end), %g2
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ld [%l7 + %g2], %l1
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sethi %hi(_dl_skip_args), %g2
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add %sp, 6*4, %l2
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or %g2, %lo(_dl_skip_args), %g2
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st %l2, [%l1]
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/* See if we were run as a command with the executable file name as an
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extra leading argument. If so, adjust the contents of the stack. */
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ld [%l7+%g2], %i0
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ld [%i0], %i0
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tst %i0
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beq 3f
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ld [%sp+22*4], %i5 /* load argc */
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/* Find out how far to shift. */
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sethi %hi(_dl_argv), %l3
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or %l3, %lo(_dl_argv), %l3
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ld [%l7+%l3], %l3
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sub %i5, %i0, %i5
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ld [%l3], %l4
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sll %i0, 2, %i2
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st %i5, [%sp+22*4]
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sub %l4, %i2, %l4
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add %sp, 23*4, %i1
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add %i1, %i2, %i2
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st %l4, [%l3]
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/* Copy down argv */
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21: ld [%i2], %i3
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add %i2, 4, %i2
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tst %i3
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st %i3, [%i1]
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bne 21b
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add %i1, 4, %i1
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/* Copy down env */
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22: ld [%i2], %i3
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add %i2, 4, %i2
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tst %i3
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st %i3, [%i1]
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bne 22b
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add %i1, 4, %i1
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/* Copy down auxiliary table. */
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23: ld [%i2], %i3
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ld [%i2+4], %i4
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add %i2, 8, %i2
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tst %i3
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st %i3, [%i1]
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st %i4, [%i1+4]
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bne 23b
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add %i1, 8, %i1
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/* %o0 = _dl_loaded, %o1 = argc, %o2 = argv, %o3 = envp. */
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3: sethi %hi(_dl_loaded), %o0
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add %sp, 23*4, %o2
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orcc %o0, %lo(_dl_loaded), %o0
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sll %i5, 2, %o3
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ld [%l7+%o0], %o0
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add %o3, 4, %o3
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mov %i5, %o1
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add %o2, %o3, %o3
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call _dl_init
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ld [%o0], %o0
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/* Pass our finalizer function to the user in %g1. */
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sethi %hi(_dl_fini), %g1
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or %g1, %lo(_dl_fini), %g1
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ld [%l7+%g1], %g1
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/* Jump to the user's entry point and deallocate the extra stack we got. */
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jmp %l0
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add %sp, 6*4, %sp
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.size _dl_start_user, . - _dl_start_user
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.previous");
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static inline Elf32_Addr
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elf_machine_fixup_plt (struct link_map *map, lookup_t t,
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const Elf32_Rela *reloc,
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Elf32_Addr *reloc_addr, Elf32_Addr value)
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{
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#ifndef RTLD_BOOTSTRAP
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/* Note that we don't mask the hwcap here, as the flush is essential to
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functionality on those cpu's that implement it. */
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unsigned long *hwcap;
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int do_flush;
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weak_extern (_dl_hwcap);
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hwcap = WEAKADDR(_dl_hwcap);
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do_flush = (!hwcap || (*hwcap & HWCAP_SPARC_FLUSH));
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#else
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/* Unfortunately, this is necessary, so that we can ensure
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ld.so will not execute corrupt PLT entry instructions. */
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const int do_flush = 1;
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#endif
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/* For thread safety, write the instructions from the bottom and
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flush before we overwrite the critical "b,a". This of course
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need not be done during bootstrapping, since there are no threads.
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But we also can't tell if we _can_ use flush, so don't. */
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reloc_addr[2] = OPCODE_JMP_G1 | (value & 0x3ff);
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if (do_flush)
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__asm __volatile ("flush %0+8" : : "r"(reloc_addr));
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reloc_addr[1] = OPCODE_SETHI_G1 | (value >> 10);
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if (do_flush)
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__asm __volatile ("flush %0+4" : : "r"(reloc_addr));
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return value;
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}
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/* Return the final value of a plt relocation. */
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static inline Elf32_Addr
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elf_machine_plt_value (struct link_map *map, const Elf32_Rela *reloc,
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Elf32_Addr value)
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{
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return value + reloc->r_addend;
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}
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#ifdef RESOLVE
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/* Perform the relocation specified by RELOC and SYM (which is fully resolved).
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MAP is the object containing the reloc. */
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static inline void
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elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc,
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const Elf32_Sym *sym, const struct r_found_version *version,
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Elf32_Addr *const reloc_addr)
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{
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#ifndef RTLD_BOOTSTRAP
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/* This is defined in rtld.c, but nowhere in the static libc.a; make the
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reference weak so static programs can still link. This declaration
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cannot be done when compiling rtld.c (i.e. #ifdef RTLD_BOOTSTRAP)
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because rtld.c contains the common defn for _dl_rtld_map, which is
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incompatible with a weak decl in the same file. */
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weak_extern (_dl_rtld_map);
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#endif
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if (ELF32_R_TYPE (reloc->r_info) == R_SPARC_RELATIVE)
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{
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#ifndef RTLD_BOOTSTRAP
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if (map != &_dl_rtld_map) /* Already done in rtld itself. */
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#endif
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*reloc_addr += map->l_addr + reloc->r_addend;
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}
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else
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{
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#ifndef RTLD_BOOTSTRAP
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const Elf32_Sym *const refsym = sym;
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#endif
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Elf32_Addr value;
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if (sym->st_shndx != SHN_UNDEF &&
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ELF32_ST_BIND (sym->st_info) == STB_LOCAL)
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value = map->l_addr;
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else
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{
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value = RESOLVE (&sym, version, ELF32_R_TYPE (reloc->r_info));
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if (sym)
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value += sym->st_value;
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}
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value += reloc->r_addend; /* Assume copy relocs have zero addend. */
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switch (ELF32_R_TYPE (reloc->r_info))
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{
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#ifndef RTLD_BOOTSTRAP
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case R_SPARC_COPY:
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if (sym == NULL)
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/* This can happen in trace mode if an object could not be
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found. */
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break;
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if (sym->st_size > refsym->st_size
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|| (_dl_verbose && sym->st_size < refsym->st_size))
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{
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extern char **_dl_argv;
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const char *strtab;
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strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
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_dl_error_printf ("\
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%s: Symbol `%s' has different size in shared object, consider re-linking\n",
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_dl_argv[0] ?: "<program name unknown>",
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strtab + refsym->st_name);
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}
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memcpy (reloc_addr, (void *) value, MIN (sym->st_size,
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refsym->st_size));
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break;
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#endif
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case R_SPARC_GLOB_DAT:
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case R_SPARC_32:
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*reloc_addr = value;
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break;
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case R_SPARC_JMP_SLOT:
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elf_machine_fixup_plt(map, 0, reloc, reloc_addr, value);
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break;
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#ifndef RTLD_BOOTSTRAP
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case R_SPARC_8:
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*(char *) reloc_addr = value;
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break;
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case R_SPARC_16:
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*(short *) reloc_addr = value;
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break;
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case R_SPARC_DISP8:
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*(char *) reloc_addr = (value - (Elf32_Addr) reloc_addr);
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break;
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case R_SPARC_DISP16:
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*(short *) reloc_addr = (value - (Elf32_Addr) reloc_addr);
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break;
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case R_SPARC_DISP32:
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*reloc_addr = (value - (Elf32_Addr) reloc_addr);
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break;
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case R_SPARC_LO10:
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*reloc_addr = (*reloc_addr & ~0x3ff) | (value & 0x3ff);
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break;
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case R_SPARC_WDISP30:
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*reloc_addr = ((*reloc_addr & 0xc0000000)
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| ((value - (unsigned int) reloc_addr) >> 2));
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break;
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case R_SPARC_HI22:
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*reloc_addr = (*reloc_addr & 0xffc00000) | (value >> 10);
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break;
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#endif
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case R_SPARC_NONE: /* Alright, Wilbur. */
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break;
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#if !defined RTLD_BOOTSTRAP || defined _NDEBUG
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default:
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_dl_reloc_bad_type (map, ELFW(R_TYPE) (reloc->r_info), 0);
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break;
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#endif
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}
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}
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}
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static inline void
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elf_machine_lazy_rel (struct link_map *map,
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Elf32_Addr l_addr, const Elf32_Rela *reloc)
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{
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switch (ELF32_R_TYPE (reloc->r_info))
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{
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case R_SPARC_NONE:
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break;
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case R_SPARC_JMP_SLOT:
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break;
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default:
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_dl_reloc_bad_type (map, ELFW(R_TYPE) (reloc->r_info), 1);
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break;
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}
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}
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#endif /* RESOLVE */
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