459 lines
14 KiB
C
459 lines
14 KiB
C
/* Machine-dependent ELF dynamic relocation inline functions. S390 Version.
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Copyright (C) 2000 Free Software Foundation, Inc.
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Contributed by Carl Pederson & Martin Schwidefsky.
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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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#ifndef dl_machine_h
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#define dl_machine_h
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#define ELF_MACHINE_NAME "s390"
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#include <sys/param.h>
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#include <string.h>
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#include <link.h>
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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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return ehdr->e_machine == EM_S390;
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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;
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asm( " bras %0,2f\n"
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"1: .long _GLOBAL_OFFSET_TABLE_-1b\n"
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"2: al %0,0(%0)"
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: "=&a" (got) : : "0" );
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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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Elf32_Addr addr;
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asm( " bras 1,2f\n"
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"1: .long _GLOBAL_OFFSET_TABLE_ - 1b\n"
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" .long _dl_start - 1b - 0x80000000\n"
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"2: l %0,4(1)\n"
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" ar %0,1\n"
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" al 1,0(1)\n"
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" sl %0,_dl_start@GOT12(1)"
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: "=&d" (addr) : : "1" );
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return addr;
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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 __attribute__ ((unused))
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elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
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{
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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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/* The GOT entries for functions in the PLT have not yet been filled
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in. Their initial contents will arrange when called to push an
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offset into the .rel.plt section, push _GLOBAL_OFFSET_TABLE_[1],
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and then jump to _GLOBAL_OFFSET_TABLE[2]. */
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Elf32_Addr *got;
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got = (Elf32_Addr *) D_PTR (l, l_info[DT_PLTGOT]);
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got[1] = (Elf32_Addr) l; /* Identify this shared object. */
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/* The got[2] entry contains the address of a function which gets
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called to get the address of a so far unresolved function and
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jump to it. The profiling extension of the dynamic linker allows
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to intercept the calls to collect information. In this case we
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don't store the address in the GOT so that all future calls also
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end in this function. */
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if (__builtin_expect (profile, 0))
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{
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got[2] = (Elf32_Addr) &_dl_runtime_profile;
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if (_dl_name_match_p (_dl_profile, l))
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/* This is the object we are looking for. Say that we really
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want profiling and the timers are started. */
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_dl_profile_map = l;
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}
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else
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/* This function will get called to fix up the GOT entry indicated by
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the offset on the stack, and then jump to the resolved address. */
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got[2] = (Elf32_Addr) &_dl_runtime_resolve;
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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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/* s390:
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Arguments are in register.
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r2 - r7 holds the original parameters for the function call, fixup
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and trampoline code use r0-r5 and r14-15. For the correct function
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call r2-r5 and r14-15 must be restored.
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Arguments from the PLT are stored at 24(r15) and 28(r15)
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and must be moved to r2 and r3 for the fixup call (see elf32-s390.c
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in the binutils for the PLT code).
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Fixup function address in r2.
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*/
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#ifndef PROF
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#define ELF_MACHINE_RUNTIME_TRAMPOLINE \
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asm ( "\
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.text\n\
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.globl _dl_runtime_resolve\n\
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.type _dl_runtime_resolve, @function\n\
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.align 16\n\
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_dl_runtime_resolve:\n\
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# save registers\n\
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stm 2,5,32(15)\n\
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st 14,48(15)\n\
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lr 0,15\n\
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ahi 15,-96\n\
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st 0,0(15)\n\
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# load args saved by PLT\n\
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lm 2,3,120(15)\n\
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basr 1,0\n\
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0: ahi 1,1f-0b\n\
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l 14,0(1)\n\
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bas 14,0(14,1) # call fixup\n\
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lr 1,2 # function addr returned in r2\n\
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# restore registers\n\
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ahi 15,96\n\
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l 14,48(15)\n\
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lm 2,5,32(15)\n\
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br 1\n\
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1: .long fixup-1b\n\
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.size _dl_runtime_resolve, .-_dl_runtime_resolve\n\
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\n\
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.globl _dl_runtime_profile\n\
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.type _dl_runtime_profile, @function\n\
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.align 16\n\
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_dl_runtime_profile:\n\
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# save registers\n\
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stm 2,5,32(15)\n\
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st 14,48(15)\n\
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lr 0,15\n\
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ahi 15,-96\n\
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st 0,0(15)\n\
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# load args saved by PLT\n\
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lm 2,3,120(15)\n\
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# load return address as third parameter\n\
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lr 4,14\n\
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basr 1,0\n\
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0: ahi 1,1f-0b\n\
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l 14,0(1)\n\
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bas 14,0(14,1) # call fixup\n\
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lr 1,2 # function addr returned in r2\n\
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# restore registers\n\
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ahi 15,96\n\
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l 14,48(15)\n\
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lm 2,5,32(15)\n\
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br 1\n\
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1: .long profile_fixup-1b\n\
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.size _dl_runtime_profile, .-_dl_runtime_profile\n\
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");
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#else
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#define ELF_MACHINE_RUNTIME_TRAMPOLINE \
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asm ( "\
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.text\n\
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.globl _dl_runtime_resolve\n\
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.globl _dl_runtime_profile\n\
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.type _dl_runtime_resolve, @function\n\
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.type _dl_runtime_profile, @function\n\
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.align 16\n\
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_dl_runtime_resolve:\n\
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_dl_runtime_profile:\n\
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# save registers\n\
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stm 2,5,32(15)\n\
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st 14,48(15)\n\
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lr 0,15\n\
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ahi 15,-96\n\
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st 0,0(15)\n\
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# load args saved by PLT\n\
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lm 2,3,120(15)\n\
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# load return address as third parameter\n\
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lr 4,14\n\
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basr 1,0\n\
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0: ahi 1,1f-0b\n\
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l 14,0(1)\n\
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bas 14,0(14,1) # call fixup\n\
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lr 1,2 # function addr returned in r2\n\
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# restore registers\n\
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ahi 15,96\n\
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l 14,48(15)\n\
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lm 2,5,32(15)\n\
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br 1\n\
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1: .long fixup-1b\n\
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.size _dl_runtime_resolve, .-_dl_runtime_resolve\n\
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.size _dl_runtime_profile, .-_dl_runtime_profile\n\
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");
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#endif
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/* The PLT uses Elf32_Rela relocs. */
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#define elf_machine_relplt elf_machine_rela
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/* Mask identifying addresses reserved for the user program,
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where the dynamic linker should not map anything. */
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#define ELF_MACHINE_USER_ADDRESS_MASK 0xf8000000UL
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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 ("\n\
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.text\n\
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.align 4\n\
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.globl _start\n\
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.globl _dl_start_user\n\
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_start:\n\
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basr %r13,0\n\
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.L0: ahi %r13,.Llit-.L0\n\
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lr %r2,%r15\n\
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# Alloc stack frame\n\
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ahi %r15,-96\n\
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# Set the back chain to zero\n\
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xc 0(4,%r15),0(%r15)\n\
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# Call _dl_start with %r2 pointing to arg on stack\n\
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l %r14,.Ladr1-.Llit(%r13)\n\
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bas %r14,0(%r14,%r13) # call _dl_start\n\
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_dl_start_user:\n\
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# Save the user entry point address in %r8.\n\
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lr %r8,%r2\n\
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# Point %r12 at the GOT.\n\
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l %r12,.Ladr0-.Llit(%r13)\n\
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ar %r12,%r13\n\
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# Store the highest stack address\n\
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l %r1,__libc_stack_end@GOT(%r12)\n\
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st %r15, 0(%r1)\n\
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# See if we were run as a command with the executable file\n\
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# name as an extra leading argument.\n\
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l %r1,_dl_skip_args@GOT12(0,%r12)\n\
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l %r1,0(%r1) # load _dl_skip_args\n\
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# Get the original argument count.\n\
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l %r0,96(%r15)\n\
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# Subtract _dl_skip_args from it.\n\
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sr %r0,%r1\n\
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# Adjust the stack pointer to skip _dl_skip_args words.\n\
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sll %r1,2\n\
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ar %r15,%r1\n\
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# Set the back chain to zero again\n\
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xc 0(4,%r15),0(%r15)\n\
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# Store back the modified argument count.\n\
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st %r0,96(%r15)\n\
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# The special initializer gets called with the stack just\n\
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# as the application's entry point will see it; it can\n\
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# switch stacks if it moves these contents over.\n\
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" RTLD_START_SPECIAL_INIT "\n\
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# Call the function to run the initializers.\n\
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# Load the parameters:\n\
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# (%r2, %r3, %r4, %r5) = (_dl_loaded, argc, argv, envp)\n\
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l %r2,_dl_loaded@GOT(%r12)\n\
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l %r2,0(%r2)\n\
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l %r3,96(%r15)\n\
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la %r4,100(%r15)\n\
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lr %r5,%r3\n\
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sll %r5,2\n\
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la %r5,104(%r5,%r15)\n\
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l %r1,.Ladr4-.Llit(%r13)\n\
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bas %r14,0(%r1,%r13)\n\
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# Pass our finalizer function to the user in %r14, as per ELF ABI.\n\
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l %r14,_dl_fini@GOT(%r12)\n\
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# Free stack frame\n\
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ahi %r15,96\n\
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# Jump to the user's entry point (saved in %r8).\n\
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br %r8\n\
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.Llit:\n\
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.Ladr0: .long _GLOBAL_OFFSET_TABLE_-.Llit\n\
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.Ladr1: .long _dl_start-.Llit\n\
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.Ladr4: .long _dl_init@PLT-.Llit\n\
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");
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#ifndef RTLD_START_SPECIAL_INIT
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#define RTLD_START_SPECIAL_INIT /* nothing */
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#endif
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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_pltrel_p(type) ((type) == R_390_JMP_SLOT)
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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_390_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_390_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_390_JMP_SLOT
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/* The S390 never uses Elf32_Rel relocations. */
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#define ELF_MACHINE_NO_REL 1
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/* The S390 overlaps DT_RELA and DT_PLTREL. */
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#define ELF_MACHINE_PLTREL_OVERLAP 1
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/* We define an initialization functions. This is called very early in
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_dl_sysdep_start. */
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#define DL_PLATFORM_INIT dl_platform_init ()
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extern const char *_dl_platform;
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static inline void __attribute__ ((unused))
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dl_platform_init (void)
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{
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if (_dl_platform != NULL && *_dl_platform == '\0')
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/* Avoid an empty string which would disturb us. */
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_dl_platform = NULL;
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}
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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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return *reloc_addr = 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;
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}
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#endif /* !dl_machine_h */
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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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if (ELF32_R_TYPE (reloc->r_info) == R_390_RELATIVE) {
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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 if (ELF32_R_TYPE (reloc->r_info) != R_390_NONE)
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{
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const Elf32_Sym *const refsym = sym;
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Elf32_Addr 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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switch (ELF32_R_TYPE (reloc->r_info))
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{
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case R_390_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 (__builtin_expect (sym->st_size > refsym->st_size, 0)
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|| (__builtin_expect (sym->st_size < refsym->st_size, 0)
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&& __builtin_expect (_dl_verbose, 0)))
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{
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const char *strtab;
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strtab = (const char *) D_PTR(map,l_info[DT_STRTAB]);
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_dl_sysdep_error (_dl_argv[0] ?: "<program name unknown>",
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": Symbol `", strtab + refsym->st_name,
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"' has different size in shared object, "
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"consider re-linking\n", NULL);
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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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case R_390_GLOB_DAT:
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case R_390_JMP_SLOT:
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*reloc_addr = value;
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break;
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case R_390_32:
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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
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libc.a; make the reference weak so static programs can
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still link. This declaration cannot be done when
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compiling rtld.c (i.e. #ifdef RTLD_BOOTSTRAP) because
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rtld.c contains the common defn for _dl_rtld_map, which
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is incompatible with a weak decl in the same file. */
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weak_extern (_dl_rtld_map);
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if (map == &_dl_rtld_map)
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/* Undo the relocation done here during bootstrapping.
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Now we will relocate it anew, possibly using a
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binding found in the user program or a loaded library
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rather than the dynamic linker's built-in definitions
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used while loading those libraries. */
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value -= map->l_addr + refsym->st_value;
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#endif
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*reloc_addr = value + reloc->r_addend;
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break;
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}
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case R_390_PC32:
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*reloc_addr = value +reloc->r_addend - (Elf32_Addr) reloc_addr;
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break;
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case R_390_NONE:
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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), 0);
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break;
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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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Elf32_Addr *const reloc_addr = (void *) (l_addr + reloc->r_offset);
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/* Check for unexpected PLT reloc type. */
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if (__builtin_expect (ELF32_R_TYPE (reloc->r_info), R_390_JMP_SLOT)
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== R_390_JMP_SLOT)
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*reloc_addr += l_addr;
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else
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_dl_reloc_bad_type (map, ELFW(R_TYPE) (reloc->r_info), 1);
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}
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#endif /* RESOLVE */
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