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glibc/sysdeps/s390/s390-32/dl-machine.h
Stefan Liebler 4603c51ef7 S390: Save and restore fprs/vrs while resolving symbols. 
On s390, no fpr/vrs were saved while resolving a symbol
via _dl_runtime_resolve/_dl_runtime_profile.

According to the abi, the fpr-arguments are defined as call clobbered.
In leaf-functions, gcc 4.9 and newer can use fprs for saving/restoring gprs
instead of saving them to the stack.
If gcc do this in one of the resolver-functions, then the floating point
arguments of a library-function are invalid for the first library-function-call.
Thus, this patch saves/restores the fprs around the resolving code.

The same could occur for vector registers. Furthermore an ifunc-resolver
could also clobber the vector/floating point argument registers.
Thus this patch provides the further variants _dl_runtime_resolve_vx/
_dl_runtime_profile_vx, which are used if the kernel claims, that
we run on a machine with vector registers.

Furthermore, if _dl_runtime_profile calls _dl_call_pltexit,
the pointers to inregs-/outregs-structs were setup invalid.
Now they point to the correct location in the stack-frame.
Before branching back to the caller, the return values are now
restored instead of containing the return values of the
_dl_call_pltexit() call.
On s390-32, an endless loop occurs if _dl_call_pltexit() should be called.
Now, this code-path branches to this function instead of just after the
preceding basr-instruction.

ChangeLog:

	* sysdeps/s390/s390-32/dl-trampoline.S: Include dl-trampoline.h twice
	to create a non-vector/vector version for _dl_runtime_resolve and
	_dl_runtime_profile. Move implementation to ...
	* sysdeps/s390/s390-32/dl-trampoline.h: ... here.
	(_dl_runtime_resolve) Save and restore fpr/vrs.
	(_dl_runtime_profile) Save and restore vrs and fix some issues
	if _dl_call_pltexit is called.
	* sysdeps/s390/s390-32/dl-machine.h (elf_machine_runtime_setup):
	Choose the correct resolver function if running on a machine with vx.
	* sysdeps/s390/s390-64/dl-trampoline.S: Include dl-trampoline.h twice
	to create a non-vector/vector version for _dl_runtime_resolve and
	_dl_runtime_profile. Move implementation to ...
	* sysdeps/s390/s390-64/dl-trampoline.h: ... here.
	(_dl_runtime_resolve) Save and restore fpr/vrs.
	(_dl_runtime_profile) Save and restore vrs and fix some issues
	* sysdeps/s390/s390-64/dl-machine.h: (elf_machine_runtime_setup):
	Choose the correct resolver function if running on a machine with vx.
2016-03-31 17:37:16 +02:00

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/* Machine-dependent ELF dynamic relocation inline functions. S390 Version.
Copyright (C) 2000-2016 Free Software Foundation, Inc.
Contributed by Carl Pederson & Martin Schwidefsky.
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 Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#ifndef dl_machine_h
#define dl_machine_h
#define ELF_MACHINE_NAME "s390"
#include <sys/param.h>
#include <string.h>
#include <link.h>
#include <sysdeps/s390/dl-procinfo.h>
#include <dl-irel.h>
/* This is an older, now obsolete value. */
#define EM_S390_OLD 0xA390
/* Return nonzero iff ELF header is compatible with the running host. */
static inline int
elf_machine_matches_host (const Elf32_Ehdr *ehdr)
{
/* Check if the kernel provides the high gpr facility if needed by
the binary. */
if ((ehdr->e_flags & EF_S390_HIGH_GPRS)
&& !(GLRO (dl_hwcap) & HWCAP_S390_HIGH_GPRS))
return 0;
return (ehdr->e_machine == EM_S390 || ehdr->e_machine == EM_S390_OLD)
&& ehdr->e_ident[EI_CLASS] == ELFCLASS32;
}
/* 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__( " bras %0,2f\n"
"1: .long _GLOBAL_OFFSET_TABLE_-1b\n"
"2: al %0,0(%0)"
: "=&a" (got) : : "0" );
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__( " bras 1,2f\n"
"1: .long _GLOBAL_OFFSET_TABLE_ - 1b\n"
" .long (_dl_start - 1b - 0x80000000) & 0x00000000ffffffff\n"
"2: l %0,4(1)\n"
" ar %0,1\n"
" al 1,0(1)\n"
" sl %0,_dl_start@GOT(1)"
: "=&d" (addr) : : "1" );
return addr;
}
/* Set up the loaded object described by L so its unrelocated PLT
entries will jump to the on-demand fixup code in dl-runtime.c. */
static inline int __attribute__ ((unused))
elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
{
extern void _dl_runtime_resolve (Elf32_Word);
extern void _dl_runtime_profile (Elf32_Word);
#if defined HAVE_S390_VX_ASM_SUPPORT
extern void _dl_runtime_resolve_vx (Elf32_Word);
extern void _dl_runtime_profile_vx (Elf32_Word);
#endif
if (l->l_info[DT_JMPREL] && lazy)
{
/* The GOT entries for functions in the PLT have not yet been filled
in. Their initial contents will arrange when called to push an
offset into the .rel.plt section, push _GLOBAL_OFFSET_TABLE_[1],
and then jump to _GLOBAL_OFFSET_TABLE[2]. */
Elf32_Addr *got;
got = (Elf32_Addr *) D_PTR (l, l_info[DT_PLTGOT]);
/* If a library is prelinked but we have to relocate anyway,
we have to be able to undo the prelinking of .got.plt.
The prelinker saved us here address of .plt + 0x2c. */
if (got[1])
{
l->l_mach.plt = got[1] + l->l_addr;
l->l_mach.gotplt = (Elf32_Addr) &got[3];
}
got[1] = (Elf32_Addr) l; /* Identify this shared object. */
/* The got[2] entry contains the address of a function which gets
called to get the address of a so far unresolved function and
jump to it. The profiling extension of the dynamic linker allows
to intercept the calls to collect information. In this case we
don't store the address in the GOT so that all future calls also
end in this function. */
if (__glibc_unlikely (profile))
{
#if defined HAVE_S390_VX_ASM_SUPPORT
if (GLRO(dl_hwcap) & HWCAP_S390_VX)
got[2] = (Elf32_Addr) &_dl_runtime_profile_vx;
else
got[2] = (Elf32_Addr) &_dl_runtime_profile;
#else
got[2] = (Elf32_Addr) &_dl_runtime_profile;
#endif
if (GLRO(dl_profile) != NULL
&& _dl_name_match_p (GLRO(dl_profile), l))
/* This is the object we are looking for. Say that we really
want profiling and the timers are started. */
GL(dl_profile_map) = l;
}
else
{
/* This function will get called to fix up the GOT entry indicated by
the offset on the stack, and then jump to the resolved address. */
#if defined HAVE_S390_VX_ASM_SUPPORT
if (GLRO(dl_hwcap) & HWCAP_S390_VX)
got[2] = (Elf32_Addr) &_dl_runtime_resolve_vx;
else
got[2] = (Elf32_Addr) &_dl_runtime_resolve;
#else
got[2] = (Elf32_Addr) &_dl_runtime_resolve;
#endif
}
}
return lazy;
}
/* Mask identifying addresses reserved for the user program,
where the dynamic linker should not map anything. */
#define ELF_MACHINE_USER_ADDRESS_MASK 0xf8000000UL
/* Initial entry point code for the dynamic linker.
The C function `_dl_start' is the real entry point;
its return value is the user program's entry point. */
#define RTLD_START __asm__ ("\n\
.text\n\
.align 4\n\
.globl _start\n\
.globl _dl_start_user\n\
_start:\n\
basr %r13,0\n\
0: ahi %r13,.Llit-0b\n\
lr %r2,%r15\n\
# Alloc stack frame\n\
ahi %r15,-96\n\
# Set the back chain to zero\n\
xc 0(4,%r15),0(%r15)\n\
# Call _dl_start with %r2 pointing to arg on stack\n\
l %r14,.Ladr1-.Llit(%r13)\n\
bas %r14,0(%r14,%r13) # call _dl_start\n\
_dl_start_user:\n\
# Save the user entry point address in %r8.\n\
lr %r8,%r2\n\
# Point %r12 at the GOT.\n\
l %r12,.Ladr0-.Llit(%r13)\n\
ar %r12,%r13\n\
# See if we were run as a command with the executable file\n\
# name as an extra leading argument.\n\
l %r1,_dl_skip_args@GOT(%r12)\n\
l %r1,0(%r1) # load _dl_skip_args\n\
ltr %r1,%r1\n\
je 4f # Skip the arg adjustment if there were none.\n\
# Get the original argument count.\n\
l %r0,96(%r15)\n\
# Subtract _dl_skip_args from it.\n\
sr %r0,%r1\n\
# Store back the modified argument count.\n\
st %r0,96(%r15)\n\
# Copy argv and envp forward to account for skipped argv entries.\n\
# We skipped at least one argument or we would not get here.\n\
la %r6,100(%r15) # Destination pointer i.e. &argv[0]\n\
lr %r5,%r6\n\
lr %r0,%r1\n\
sll %r0,2\n # Number of skipped bytes.\n\
ar %r5,%r0 # Source pointer = Dest + Skipped args.\n\
# argv copy loop:\n\
1: l %r7,0(%r5) # Load a word from the source.\n\
st %r7,0(%r6) # Store the word in the destination.\n\
ahi %r5,4\n\
ahi %r6,4\n\
ltr %r7,%r7\n\
jne 1b # Stop after copying the NULL.\n\
# envp copy loop:\n\
2: l %r7,0(%r5) # Load a word from the source.\n\
st %r7,0(%r6) # Store the word in the destination.\n\
ahi %r5,4\n\
ahi %r6,4\n\
ltr %r7,%r7\n\
jne 2b # Stop after copying the NULL.\n\
# Now we have to zero out the envp entries after NULL to allow\n\
# start.S to properly find auxv by skipping zeroes.\n\
# zero out loop:\n\
lhi %r7,0\n\
3: st %r7,0(%r6) # Store zero.\n\
ahi %r6,4 # Advance dest pointer.\n\
ahi %r1,-1 # Subtract one from the word count.\n\
ltr %r1,%r1\n\
jne 3b # Keep copying if the word count is non-zero.\n\
# Adjust _dl_argv\n\
la %r6,100(%r15)\n\
l %r1,_dl_argv@GOT(%r12)\n\
st %r6,0(%r1)\n\
# The special initializer gets called with the stack just\n\
# as the application's entry point will see it; it can\n\
# switch stacks if it moves these contents over.\n\
" RTLD_START_SPECIAL_INIT "\n\
# Call the function to run the initializers.\n\
# Load the parameters:\n\
# (%r2, %r3, %r4, %r5) = (_dl_loaded, argc, argv, envp)\n\
4: l %r2,_rtld_local@GOT(%r12)\n\
l %r2,0(%r2)\n\
l %r3,96(%r15)\n\
la %r4,100(%r15)\n\
lr %r5,%r3\n\
sll %r5,2\n\
la %r5,104(%r5,%r15)\n\
l %r1,.Ladr4-.Llit(%r13)\n\
bas %r14,0(%r1,%r13)\n\
# Pass our finalizer function to the user in %r14, as per ELF ABI.\n\
l %r14,_dl_fini@GOT(%r12)\n\
# Free stack frame\n\
ahi %r15,96\n\
# Jump to the user's entry point (saved in %r8).\n\
br %r8\n\
.Llit:\n\
.Ladr0: .long _GLOBAL_OFFSET_TABLE_-.Llit\n\
.Ladr1: .long _dl_start-.Llit\n\
.Ladr4: .long _dl_init@PLT-.Llit\n\
");
#ifndef RTLD_START_SPECIAL_INIT
#define RTLD_START_SPECIAL_INIT /* nothing */
#endif
/* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry or
TLS variable, so undefined references should not be allowed to
define the value.
ELF_RTYPE_CLASS_COPY iff TYPE should not be allowed to resolve to one
of the main executable's symbols, as for a COPY reloc. */
#define elf_machine_type_class(type) \
((((type) == R_390_JMP_SLOT || (type) == R_390_TLS_DTPMOD \
|| (type) == R_390_TLS_DTPOFF || (type) == R_390_TLS_TPOFF) \
* ELF_RTYPE_CLASS_PLT) \
| (((type) == R_390_COPY) * ELF_RTYPE_CLASS_COPY))
/* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
#define ELF_MACHINE_JMP_SLOT R_390_JMP_SLOT
/* The S390 never uses Elf32_Rel relocations. */
#define ELF_MACHINE_NO_REL 1
#define ELF_MACHINE_NO_RELA 0
/* We define an initialization functions. This is called very early in
_dl_sysdep_start. */
#define DL_PLATFORM_INIT dl_platform_init ()
static inline void __attribute__ ((unused))
dl_platform_init (void)
{
if (GLRO(dl_platform) != NULL && *GLRO(dl_platform) == '\0')
/* Avoid an empty string which would disturb us. */
GLRO(dl_platform) = NULL;
}
static inline Elf32_Addr
elf_machine_fixup_plt (struct link_map *map, lookup_t t,
const Elf32_Rela *reloc,
Elf32_Addr *reloc_addr, Elf32_Addr value)
{
return *reloc_addr = value;
}
/* Return the final value of a plt relocation. */
static inline Elf32_Addr
elf_machine_plt_value (struct link_map *map, const Elf32_Rela *reloc,
Elf32_Addr value)
{
return value;
}
/* Names of the architecture-specific auditing callback functions. */
#define ARCH_LA_PLTENTER s390_32_gnu_pltenter
#define ARCH_LA_PLTEXIT s390_32_gnu_pltexit
#endif /* !dl_machine_h */
#ifdef RESOLVE_MAP
/* Perform the relocation specified by RELOC and SYM (which is fully resolved).
MAP is the object containing the reloc. */
auto inline void
__attribute__ ((always_inline))
elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc,
const Elf32_Sym *sym, const struct r_found_version *version,
void *const reloc_addr_arg, int skip_ifunc)
{
Elf32_Addr *const reloc_addr = reloc_addr_arg;
const unsigned int r_type = ELF32_R_TYPE (reloc->r_info);
#if !defined RTLD_BOOTSTRAP || !defined HAVE_Z_COMBRELOC
if (__glibc_unlikely (r_type == R_390_RELATIVE))
{
# if !defined RTLD_BOOTSTRAP && !defined HAVE_Z_COMBRELOC
/* This is defined in rtld.c, but nowhere in the static libc.a;
make the reference weak so static programs can still link.
This declaration cannot be done when compiling rtld.c
(i.e. #ifdef RTLD_BOOTSTRAP) because rtld.c contains the
common defn for _dl_rtld_map, which is incompatible with a
weak decl in the same file. */
# ifndef SHARED
weak_extern (GL(dl_rtld_map));
# endif
if (map != &GL(dl_rtld_map)) /* Already done in rtld itself. */
# endif
*reloc_addr = map->l_addr + reloc->r_addend;
}
else
#endif
if (__glibc_unlikely (r_type == R_390_NONE))
return;
else
{
#if !defined RTLD_BOOTSTRAP && !defined RESOLVE_CONFLICT_FIND_MAP
/* Only needed for R_390_COPY below. */
const Elf32_Sym *const refsym = sym;
#endif
struct link_map *sym_map = RESOLVE_MAP (&sym, version, r_type);
Elf32_Addr value = sym == NULL ? 0 : sym_map->l_addr + sym->st_value;
if (sym != NULL
&& __builtin_expect (ELFW(ST_TYPE) (sym->st_info) == STT_GNU_IFUNC, 0)
&& __builtin_expect (sym->st_shndx != SHN_UNDEF, 1)
&& __builtin_expect (!skip_ifunc, 1))
value = elf_ifunc_invoke (value);
switch (r_type)
{
case R_390_IRELATIVE:
value = map->l_addr + reloc->r_addend;
if (__glibc_likely (!skip_ifunc))
value = elf_ifunc_invoke (value);
*reloc_addr = value;
break;
case R_390_GLOB_DAT:
case R_390_JMP_SLOT:
*reloc_addr = value + reloc->r_addend;
break;
#ifndef RESOLVE_CONFLICT_FIND_MAP
case R_390_TLS_DTPMOD:
# ifdef RTLD_BOOTSTRAP
/* During startup the dynamic linker is always the module
with index 1.
XXX If this relocation is necessary move before RESOLVE
call. */
*reloc_addr = 1;
# else
/* Get the information from the link map returned by the
resolv function. */
if (sym_map != NULL)
*reloc_addr = sym_map->l_tls_modid;
# endif
break;
case R_390_TLS_DTPOFF:
# ifndef RTLD_BOOTSTRAP
/* During relocation all TLS symbols are defined and used.
Therefore the offset is already correct. */
if (sym != NULL)
*reloc_addr = sym->st_value + reloc->r_addend;
# endif
break;
case R_390_TLS_TPOFF:
/* The offset is negative, forward from the thread pointer. */
# ifdef RTLD_BOOTSTRAP
*reloc_addr = sym->st_value + reloc->r_addend - map->l_tls_offset;
# else
/* We know the offset of the object the symbol is contained in.
It is a negative value which will be added to the
thread pointer. */
if (sym != NULL)
{
CHECK_STATIC_TLS (map, sym_map);
*reloc_addr = (sym->st_value + reloc->r_addend
- sym_map->l_tls_offset);
}
#endif
break;
#endif /* use TLS */
#ifndef RTLD_BOOTSTRAP
# ifndef RESOLVE_CONFLICT_FIND_MAP
/* Not needed in dl-conflict.c. */
case R_390_COPY:
if (sym == NULL)
/* This can happen in trace mode if an object could not be
found. */
break;
if (__builtin_expect (sym->st_size > refsym->st_size, 0)
|| (__builtin_expect (sym->st_size < refsym->st_size, 0)
&& __builtin_expect (GLRO(dl_verbose), 0)))
{
const char *strtab;
strtab = (const char *) D_PTR(map,l_info[DT_STRTAB]);
_dl_error_printf ("\
%s: Symbol `%s' has different size in shared object, consider re-linking\n",
RTLD_PROGNAME, strtab + refsym->st_name);
}
memcpy (reloc_addr_arg, (void *) value,
MIN (sym->st_size, refsym->st_size));
break;
# endif
case R_390_32:
*reloc_addr = value + reloc->r_addend;
break;
case R_390_16:
*(unsigned short *) reloc_addr = value + reloc->r_addend;
break;
case R_390_8:
*(char *) reloc_addr = value + reloc->r_addend;
break;
# ifndef RESOLVE_CONFLICT_FIND_MAP
case R_390_PC32:
*reloc_addr = value + reloc->r_addend - (Elf32_Addr) reloc_addr;
break;
case R_390_PC16DBL:
*(unsigned short *) reloc_addr = (unsigned short)
((short) (value + reloc->r_addend - (Elf32_Addr) reloc_addr) >> 1);
break;
case R_390_PC32DBL:
*(unsigned int *) reloc_addr = (unsigned int)
((int) (value + reloc->r_addend - (Elf32_Addr) reloc_addr) >> 1);
break;
case R_390_PC16:
*(unsigned short *) reloc_addr =
value + reloc->r_addend - (Elf32_Addr) reloc_addr;
break;
case R_390_NONE:
break;
# endif
#endif
#if !defined(RTLD_BOOTSTRAP) || defined(_NDEBUG)
default:
/* We add these checks in the version to relocate ld.so only
if we are still debugging. */
_dl_reloc_bad_type (map, r_type, 0);
break;
#endif
}
}
}
auto inline void
__attribute__ ((always_inline))
elf_machine_rela_relative (Elf32_Addr l_addr, const Elf32_Rela *reloc,
void *const reloc_addr_arg)
{
Elf32_Addr *const reloc_addr = reloc_addr_arg;
*reloc_addr = l_addr + reloc->r_addend;
}
auto inline void
__attribute__ ((always_inline))
elf_machine_lazy_rel (struct link_map *map,
Elf32_Addr l_addr, const Elf32_Rela *reloc,
int skip_ifunc)
{
Elf32_Addr *const reloc_addr = (void *) (l_addr + reloc->r_offset);
const unsigned int r_type = ELF32_R_TYPE (reloc->r_info);
/* Check for unexpected PLT reloc type. */
if (__glibc_likely (r_type == R_390_JMP_SLOT))
{
if (__builtin_expect (map->l_mach.plt, 0) == 0)
*reloc_addr += l_addr;
else
*reloc_addr =
map->l_mach.plt
+ (((Elf32_Addr) reloc_addr) - map->l_mach.gotplt) * 8;
}
else if (__glibc_likely (r_type == R_390_IRELATIVE))
{
Elf32_Addr value = map->l_addr + reloc->r_addend;
if (__glibc_likely (!skip_ifunc))
value = elf_ifunc_invoke (value);
*reloc_addr = value;
}
else
_dl_reloc_bad_type (map, r_type, 1);
}
#endif /* RESOLVE_MAP */
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