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or1k: startup and dynamic linking code 

Code for C runtime startup and dynamic loading including PLT layout.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
This commit is contained in:
Stafford Horne 2021-10-20 06:48:11 +09:00
parent 6e5964311d
commit de5c0edc80
7 changed files with 666 additions and 0 deletions
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54
sysdeps/or1k/bits/link.h Normal file
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/* Declarations for dynamic linker interface. OpenRISC version.
Copyright (C) 2022 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU 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
<https://www.gnu.org/licenses/>. */
#ifndef _LINK_H
# error "Never include <bits/link.h> directly; use <link.h> instead."
#endif
/* Registers for entry into PLT. */
typedef struct La_or1k_regs
{
uint32_t lr_reg[6]; /* Args passed in r3-r8. */
uint32_t lr_sp; /* Register r1. */
uint32_t lr_lr; /* Register r9. */
} La_or1k_regs;
/* Return values for calls from PLT. */
typedef struct La_or1k_retval
{
/* Up to two 32-bit registers used for a return value. */
uint32_t lrv_reg[2];
} La_or1k_retval;
__BEGIN_DECLS
extern Elf32_Addr la_or1k_gnu_pltenter (Elf32_Sym *__sym, unsigned int __ndx,
uintptr_t *__refcook,
uintptr_t *__defcook,
La_or1k_regs *__regs,
unsigned int *__flags,
const char *__symname,
long int *__framesizep);
extern unsigned int la_or1k_gnu_pltexit (Elf32_Sym *__sym, unsigned int __ndx,
uintptr_t *__refcook,
uintptr_t *__defcook,
const La_or1k_regs *__inregs,
La_or1k_retval *__outregs,
const char *__symname);
__END_DECLS

300
sysdeps/or1k/dl-machine.h Normal file
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/* Machine-dependent ELF dynamic relocation inline functions. OpenRISC version.
Copyright (C) 2022 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU 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
<https://www.gnu.org/licenses/>. */
#ifndef dl_machine_h
#define dl_machine_h
#define ELF_MACHINE_NAME "or1k"
#include <sys/cdefs.h>
#include <sys/param.h>
#include <tls.h>
#include <dl-irel.h>
#include <dl-static-tls.h>
#include <dl-machine-rel.h>
/* Return nonzero iff ELF header is compatible with the running host. */
static inline int __attribute__ ((unused))
elf_machine_matches_host (const Elf32_Ehdr *ehdr)
{
return ehdr->e_machine == EM_OPENRISC;
}
static inline Elf32_Addr *
or1k_get_got (void)
{
Elf32_Addr *got;
asm ("l.jal 0x8\n"
" l.movhi %0, gotpchi(_GLOBAL_OFFSET_TABLE_-4)\n"
"l.ori %0, %0, gotpclo(_GLOBAL_OFFSET_TABLE_+0)\n"
"l.add %0, %0, r9\n"
: "=r" (got) : : "r9");
return got;
}
/* Return the link-time address of _DYNAMIC. Conveniently, this is the
first element of the GOT. */
static inline Elf32_Addr
elf_machine_dynamic (void)
{
Elf32_Addr *got = or1k_get_got ();
return *got;
}
/* Return the run-time load address of the shared object. */
static inline Elf32_Addr
elf_machine_load_address (void)
{
/* Compute the difference between the runtime address of _DYNAMIC as seen
by a GOTOFF reference, and the link-time address found in the special
unrelocated first GOT entry. */
Elf32_Addr dyn;
Elf32_Addr *got = or1k_get_got ();
asm ("l.movhi %0, gotoffhi(_DYNAMIC);"
"l.ori %0, %0, gotofflo(_DYNAMIC);"
"l.add %0, %0, %1;"
: "=&r"(dyn) : "r"(got));
return dyn - *got;
}
/* Initial entry point code for the dynamic linker. The function _dl_start
is the real entry point; it's return value is the user program's entry
point.
Code is really located in dl-start.S, just tell the linker that it
exists. */
#define RTLD_START asm (".globl _dl_start");
/* 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_NOCOPY 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_OR1K_JMP_SLOT \
|| (type) == R_OR1K_TLS_DTPMOD \
|| (type) == R_OR1K_TLS_DTPOFF \
|| (type) == R_OR1K_TLS_TPOFF) * ELF_RTYPE_CLASS_PLT \
| ((type) == R_OR1K_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_OR1K_JMP_SLOT
#define ARCH_LA_PLTENTER or1k_gnu_pltenter
#define ARCH_LA_PLTEXIT or1k_gnu_pltexit
/* 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, always_inline))
elf_machine_runtime_setup (struct link_map *l, struct r_scope_elem *scope[],
int lazy, int profile)
{
ElfW(Addr) *pltgot;
extern void _dl_runtime_resolve (ElfW(Word));
extern void _dl_runtime_profile (ElfW(Word));
if (l->l_info[DT_JMPREL] && lazy)
{
pltgot = (ElfW(Addr) *) D_PTR (l, l_info[DT_PLTGOT]);
/* Fill in initial entrys of the plt */
/* Register the link_map address in the plt at pltgot[1].
This will also be used in the resolver for accessing the
link_map structure. */
pltgot[1] = (ElfW(Addr)) l;
/* This function will get called to fix up the GOT entry and
then jump to the resolved address. */
pltgot[2] = (ElfW(Addr)) &_dl_runtime_resolve;
}
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
/* 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 ElfW(Addr)
elf_machine_fixup_plt (struct link_map *map, lookup_t t,
const ElfW(Sym) *refsym, const ElfW(Sym) *sym,
const ElfW(Rela) *reloc,
ElfW(Addr) *reloc_addr, ElfW(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 + reloc->r_addend;
}
#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. */
static inline void
__attribute ((always_inline))
elf_machine_rela (struct link_map *map, struct r_scope_elem *scope[],
const ElfW(Rela) *reloc, const ElfW(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 (__glibc_unlikely (r_type == R_OR1K_NONE))
return;
else
{
# ifndef RESOLVE_CONFLICT_FIND_MAP
const Elf32_Sym *const refsym = sym;
# endif
struct link_map *sym_map = RESOLVE_MAP (map, scope, &sym, version,
r_type);
Elf32_Addr value = SYMBOL_ADDRESS (sym_map, sym, true);
if (sym != NULL
&& __glibc_unlikely (ELFW(ST_TYPE) (sym->st_info) == STT_GNU_IFUNC)
&& __glibc_likely (sym->st_shndx != SHN_UNDEF)
&& __glibc_likely (!skip_ifunc))
value = elf_ifunc_invoke (value);
switch (r_type)
{
# ifndef RESOLVE_CONFLICT_FIND_MAP
case R_OR1K_COPY:
if (sym == NULL)
/* This can happen in trace mode if an object could not be
found. */
break;
if (__glibc_unlikely (sym->st_size > refsym->st_size)
|| (__glibc_unlikely (sym->st_size < refsym->st_size)
&& GLRO(dl_verbose)))
{
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 ?: "<program name unknown>",
strtab + refsym->st_name);
}
memcpy (reloc_addr_arg, (void *) value,
MIN (sym->st_size, refsym->st_size));
break;
# endif /* !RESOLVE_CONFLICT_FIND_MAP */
case R_OR1K_32:
/* Support relocations on mis-aligned offsets. */
value += reloc->r_addend;
memcpy (reloc_addr_arg, &value, 4);
break;
case R_OR1K_GLOB_DAT:
case R_OR1K_JMP_SLOT:
*reloc_addr = value + reloc->r_addend;
break;
case R_OR1K_TLS_DTPMOD:
# ifdef RTLD_BOOTSTRAP
/* During startup the dynamic linker is always the module
with index 1. */
*reloc_addr = 1;
# else
if (sym_map != NULL)
*reloc_addr = sym_map->l_tls_modid;
# endif
break;
case R_OR1K_TLS_DTPOFF:
# ifndef RTLD_BOOTSTRAP
*reloc_addr = (sym == NULL ? 0 : sym->st_value) + reloc->r_addend;
# endif
break;
case R_OR1K_TLS_TPOFF:
# ifdef RTLD_BOOTSTRAP
*reloc_addr = sym->st_value + reloc->r_addend +
map->l_tls_offset - TLS_TCB_SIZE;
# else
if (sym_map != NULL)
{
CHECK_STATIC_TLS (map, sym_map);
*reloc_addr = sym->st_value + reloc->r_addend +
sym_map->l_tls_offset - TLS_TCB_SIZE;
}
# endif
break;
default:
_dl_reloc_bad_type (map, r_type, 0);
break;
}
}
}
static 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;
}
static inline void
__attribute__ ((always_inline))
elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
ElfW(Addr) l_addr, const ElfW(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);
if (__glibc_likely (r_type == R_OR1K_JMP_SLOT))
*reloc_addr += l_addr;
else if (__glibc_unlikely (r_type == R_OR1K_NONE))
return;
else
_dl_reloc_bad_type (map, r_type, 1);
}
#endif /* RESOLVE_MAP */

98
sysdeps/or1k/dl-start.S Normal file
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/* Machine-dependent ELF startup code. OpenRISC version.
Copyright (C) 2022 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU 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
<https://www.gnu.org/licenses/>. */
#include <sysdep.h>
/* Initial entry point code for the dynamic linker.
The function _dl_start is the real entry point;
it's return value is the user program's entry point. */
ENTRY (_start)
/* Count arguments in r11 */
l.ori r3, r1, 0
l.movhi r11, 0
1:
l.addi r3, r3, 4
l.lwz r12, 0(r3)
l.sfnei r12, 0
l.addi r11, r11, 1
l.bf 1b
l.nop
l.addi r11, r11, -1
/* store argument counter to stack. */
l.sw 0(r1), r11
/* Load the PIC register. */
l.jal 0x8
l.movhi r16, gotpchi(_GLOBAL_OFFSET_TABLE_-4)
l.ori r16, r16, gotpclo(_GLOBAL_OFFSET_TABLE_+0)
l.add r16, r16, r9
l.ori r3, r1, 0
l.jal _dl_start
l.nop
/* Save user entry in a call saved reg. */
l.ori r22, r11, 0
/* Fall through to _dl_start_user. */
_dl_start_user:
/* Set up for _dl_init. */
/* Load _rtld_local (a.k.a _dl_loaded). */
l.lwz r12, got(_rtld_local)(r16)
l.lwz r3, 0(r12)
/* Load argc */
l.lwz r18, got(_dl_argc)(r16)
l.lwz r4, 0(r18)
/* Load argv */
l.lwz r20, got(_dl_argv)(r16)
l.lwz r5, 0(r20)
/* Load envp = &argv[argc + 1]. */
l.slli r6, r4, 2
l.addi r6, r6, 4
l.add r6, r6, r5
l.jal plt(_dl_init)
l.nop
/* Now set up for user entry.
The already defined ABI loads argc and argv from the stack.
argc = 0(r1)
argv = r1 + 4
*/
/* Load SP as argv - 4. */
l.lwz r3, 0(r20)
l.addi r1, r3, -4
/* Save argc. */
l.lwz r3, 0(r18)
l.sw 0(r1), r3
/* Pass _dl_fini function address to _start.
Next start.S will then pass this as rtld_fini to __libc_start_main. */
l.lwz r3, got(_dl_fini)(r16)
l.jr r22
l.nop
END (_start)

40
sysdeps/or1k/ldsodefs.h Normal file
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/* Run-time dynamic linker data structures for loaded ELF shared objects.
Copyright (C) 2022 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU 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
<https://www.gnu.org/licenses/>. */
#ifndef _OR1K_LDSODEFS_H
#define _OR1K_LDSODEFS_H 1
#include <elf.h>
struct La_or1k_regs;
struct La_or1k_retval;
#define ARCH_PLTENTER_MEMBERS \
uintptr_t (*or1k_gnu_pltenter) (Elf32_Sym *, unsigned int, uintptr_t *, \
uintptr_t *, struct La_or1k_regs *, \
unsigned int *, const char *name, \
long int *framesizep)
#define ARCH_PLTEXIT_MEMBERS \
unsigned int (*or1k_gnu_pltexit) (Elf32_Sym *, unsigned int, uintptr_t *, \
uintptr_t *, const struct La_or1k_regs *, \
struct La_or1k_retval *, const char *)
#include_next <ldsodefs.h>
#endif

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sysdeps/or1k/sotruss-lib.c Normal file
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/* Override generic sotruss-lib.c to define actual functions for OpenRISC.
Copyright (C) 2022 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU 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
<https://www.gnu.org/licenses/>. */
#define HAVE_ARCH_PLTENTER
#define HAVE_ARCH_PLTEXIT
#include <elf/sotruss-lib.c>
Elf32_Addr
la_or1k_gnu_pltenter (Elf32_Sym *sym __attribute__ ((unused)),
unsigned int ndx __attribute__ ((unused)),
uintptr_t *refcook, uintptr_t *defcook,
La_or1k_regs *regs, unsigned int *flags,
const char *symname, long int *framesizep)
{
print_enter (refcook, defcook, symname,
regs->lr_reg[0], regs->lr_reg[1], regs->lr_reg[2],
*flags);
/* No need to copy anything, we will not need the parameters in any case. */
*framesizep = 0;
return sym->st_value;
}
unsigned int
la_or1k_gnu_pltexit (Elf32_Sym *sym, unsigned int ndx, uintptr_t *refcook,
uintptr_t *defcook,
const struct La_or1k_regs *inregs,
struct La_or1k_retval *outregs,
const char *symname)
{
print_exit (refcook, defcook, symname, outregs->lrv_reg[0]);
return 0;
}

99
sysdeps/or1k/start.S Normal file
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/* start, OpenRISC version.
Copyright (C) 2022 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
/* This is the canonical entry point, usually the first thing in the text
segment.
sp The stack contains the arguments and environment:
0(sp) argc
4(sp) argv[0]
...
(4*argc)(sp) NULL
(4*(argc+1))(sp) envp[0]
...
NULL
*/
#define __ASSEMBLY__
#include <sysdep.h>
#include <entry.h>
ENTRY (ENTRY_POINT)
/* Setup Arguments to the __libc_start_main function. */
/* Take values for argc and argv off the stack.
These will be passed as arguments two and three to main
and thus go in registers r4 and r5, respectively. */
l.lwz r4, 0(r1)
l.addi r5, r1, 4
/* Pass in rtld_fini from dl-start.S. */
l.or r8, r3, r3
#ifdef PIC
/* Obtain a pointer to .got in r16 */
l.jal 0x8
l.movhi r16, gotpchi(_GLOBAL_OFFSET_TABLE_-4)
l.ori r16, r16, gotpclo(_GLOBAL_OFFSET_TABLE_+0)
l.add r16, r16, r9
/* Pass in the the main symbol. */
l.lwz r3, got(main)(r16)
#else
/* Pass in the the main symbol. */
l.movhi r3, hi(main)
l.ori r3, r3, lo(main)
#endif
/* Used to be init and fini. */
l.movhi r6, 0x0
l.movhi r7, 0x0
/* Push stack limit onto the stack.
This provides the highest stack address to user code (as stack grows
downwards.
This is the seventh argument to __libc_start_main and thus needs to
be passed on the stack. */
l.sw -4(r1), r1
/* Adjust stack to account for a total of 7 args (i.e. the last one is
on the stack. */
l.addi r1, r1, -4
/* Clear the frame pointer and link register since this is the
outermost frame. */
l.movhi r2, 0x0
l.movhi r9, 0x0
/* Let the libc call main and exit with its return code. */
#ifdef PIC
l.j plt(__libc_start_main)
#else
l.j __libc_start_main
#endif
l.nop
END (ENTRY_POINT)
/* Define a symbol for the first piece of initialized data. */
.data
.globl __data_start
__data_start:
.long 0
.weak data_start
data_start = __data_start

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sysdeps/or1k/tst-audit.h Normal file
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/* Definitions for testing PLT entry/exit auditing. OpenRISC version.
Copyright (C) 2022 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU 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
<https://www.gnu.org/licenses/>. */
#define pltenter la_or1k_gnu_pltenter
#define pltexit la_or1k_gnu_pltexit
#define La_regs La_or1k_regs
#define La_retval La_or1k_retval
#define int_retval lrv_reg[0]