/* Machine-dependent ELF dynamic relocation inline functions. RISC-V version.
Copyright (C) 2011-2021 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
. */
#ifndef dl_machine_h
#define dl_machine_h
#define ELF_MACHINE_NAME "RISC-V"
#include
#include
#include
#include
#include
#include
#include
#ifndef _RTLD_PROLOGUE
# define _RTLD_PROLOGUE(entry) \
".globl\t" __STRING (entry) "\n\t" \
".type\t" __STRING (entry) ", @function\n" \
__STRING (entry) ":\n\t"
#endif
#ifndef _RTLD_EPILOGUE
# define _RTLD_EPILOGUE(entry) \
".size\t" __STRING (entry) ", . - " __STRING (entry) "\n\t"
#endif
#define ELF_MACHINE_JMP_SLOT R_RISCV_JUMP_SLOT
#define elf_machine_type_class(type) \
((ELF_RTYPE_CLASS_PLT * ((type) == ELF_MACHINE_JMP_SLOT \
|| (__WORDSIZE == 32 && (type) == R_RISCV_TLS_DTPREL32) \
|| (__WORDSIZE == 32 && (type) == R_RISCV_TLS_DTPMOD32) \
|| (__WORDSIZE == 32 && (type) == R_RISCV_TLS_TPREL32) \
|| (__WORDSIZE == 64 && (type) == R_RISCV_TLS_DTPREL64) \
|| (__WORDSIZE == 64 && (type) == R_RISCV_TLS_DTPMOD64) \
|| (__WORDSIZE == 64 && (type) == R_RISCV_TLS_TPREL64))) \
| (ELF_RTYPE_CLASS_COPY * ((type) == R_RISCV_COPY)))
/* Return nonzero iff ELF header is compatible with the running host. */
static inline int __attribute_used__
elf_machine_matches_host (const ElfW(Ehdr) *ehdr)
{
/* We can only run RISC-V binaries. */
if (ehdr->e_machine != EM_RISCV)
return 0;
/* Ensure the library's floating-point ABI matches that of the running
system. For now we don't support mixing XLEN, so there's no need (or way)
to check it matches. */
#ifdef __riscv_float_abi_double
if ((ehdr->e_flags & EF_RISCV_FLOAT_ABI) != EF_RISCV_FLOAT_ABI_DOUBLE)
return 0;
#else
if ((ehdr->e_flags & EF_RISCV_FLOAT_ABI) != EF_RISCV_FLOAT_ABI_SOFT)
return 0;
#endif
return 1;
}
/* Return the run-time load address of the shared object. */
static inline ElfW(Addr)
elf_machine_load_address (void)
{
extern const ElfW(Ehdr) __ehdr_start attribute_hidden;
return (ElfW(Addr)) &__ehdr_start;
}
/* Return the link-time address of _DYNAMIC. */
static inline ElfW(Addr)
elf_machine_dynamic (void)
{
extern ElfW(Dyn) _DYNAMIC[] attribute_hidden;
return (ElfW(Addr)) _DYNAMIC - elf_machine_load_address ();
}
#define STRINGXP(X) __STRING (X)
#define STRINGXV(X) STRINGV_ (X)
#define STRINGV_(...) # __VA_ARGS__
/* 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 (\
".text\n\
" _RTLD_PROLOGUE (ENTRY_POINT) "\
mv a0, sp\n\
jal _dl_start\n\
" _RTLD_PROLOGUE (_dl_start_user) "\
# Stash user entry point in s0.\n\
mv s0, a0\n\
# See if we were run as a command with the executable file\n\
# name as an extra leading argument.\n\
lw a0, _dl_skip_args\n\
# Load the original argument count.\n\
" STRINGXP (REG_L) " a1, 0(sp)\n\
# Subtract _dl_skip_args from it.\n\
sub a1, a1, a0\n\
# Adjust the stack pointer to skip _dl_skip_args words.\n\
sll a0, a0, " STRINGXP (PTRLOG) "\n\
add sp, sp, a0\n\
# Save back the modified argument count.\n\
" STRINGXP (REG_S) " a1, 0(sp)\n\
# Call _dl_init (struct link_map *main_map, int argc, char **argv, char **env) \n\
" STRINGXP (REG_L) " a0, _rtld_local\n\
add a2, sp, " STRINGXP (SZREG) "\n\
sll a3, a1, " STRINGXP (PTRLOG) "\n\
add a3, a3, a2\n\
add a3, a3, " STRINGXP (SZREG) "\n\
# Stash the stack pointer in s1.\n\
mv s1, sp\n\
# Align stack to 128 bits for the _dl_init call.\n\
andi sp, sp,-16\n\
# Call the function to run the initializers.\n\
jal _dl_init\n\
# Restore the stack pointer for _start.\n\
mv sp, s1\n\
# Pass our finalizer function to _start.\n\
lla a0, _dl_fini\n\
# Jump to the user entry point.\n\
jr s0\n\
" _RTLD_EPILOGUE (ENTRY_POINT) \
_RTLD_EPILOGUE (_dl_start_user) "\
.previous" \
);
/* Names of the architecture-specific auditing callback functions. */
#define ARCH_LA_PLTENTER riscv_gnu_pltenter
#define ARCH_LA_PLTEXIT riscv_gnu_pltexit
/* Bias .got.plt entry by the offset requested by the PLT header. */
#define elf_machine_plt_value(map, reloc, value) (value)
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;
}
#endif /* !dl_machine_h */
#ifdef RESOLVE_MAP
/* Perform a relocation described by R_INFO at the location pointed to
by RELOC_ADDR. SYM is the relocation symbol specified by R_INFO and
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, int skip_ifunc)
{
ElfW(Addr) r_info = reloc->r_info;
const unsigned long int r_type = ELFW (R_TYPE) (r_info);
ElfW(Addr) *addr_field = (ElfW(Addr) *) reloc_addr;
const ElfW(Sym) *const __attribute__ ((unused)) refsym = sym;
struct link_map *sym_map = RESOLVE_MAP (map, scope, &sym, version, r_type);
ElfW(Addr) value = 0;
if (sym_map != NULL)
value = SYMBOL_ADDRESS (sym_map, sym, true) + reloc->r_addend;
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 RTLD_BOOTSTRAP
case __WORDSIZE == 64 ? R_RISCV_TLS_DTPMOD64 : R_RISCV_TLS_DTPMOD32:
if (sym_map)
*addr_field = sym_map->l_tls_modid;
break;
case __WORDSIZE == 64 ? R_RISCV_TLS_DTPREL64 : R_RISCV_TLS_DTPREL32:
if (sym != NULL)
*addr_field = TLS_DTPREL_VALUE (sym) + reloc->r_addend;
break;
case __WORDSIZE == 64 ? R_RISCV_TLS_TPREL64 : R_RISCV_TLS_TPREL32:
if (sym != NULL)
{
CHECK_STATIC_TLS (map, sym_map);
*addr_field = TLS_TPREL_VALUE (sym_map, sym) + reloc->r_addend;
}
break;
case R_RISCV_COPY:
{
if (__glibc_unlikely (sym == NULL))
/* This can happen in trace mode if an object could not be
found. */
break;
/* Handle TLS copy relocations. */
if (__glibc_unlikely (ELFW (ST_TYPE) (sym->st_info) == STT_TLS))
{
/* There's nothing to do if the symbol is in .tbss. */
if (__glibc_likely (sym->st_value >= sym_map->l_tls_initimage_size))
break;
value += (ElfW(Addr)) sym_map->l_tls_initimage - sym_map->l_addr;
}
size_t size = sym->st_size;
if (__glibc_unlikely (sym->st_size != refsym->st_size))
{
const char *strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
if (sym->st_size > refsym->st_size)
size = refsym->st_size;
if (sym->st_size > refsym->st_size || GLRO(dl_verbose))
_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, (void *)value, size);
break;
}
#endif
#if !defined RTLD_BOOTSTRAP || !defined HAVE_Z_COMBRELOC
case R_RISCV_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
*addr_field = map->l_addr + reloc->r_addend;
break;
}
#endif
case R_RISCV_IRELATIVE:
value = map->l_addr + reloc->r_addend;
if (__glibc_likely (!skip_ifunc))
value = elf_ifunc_invoke (value);
*addr_field = value;
break;
case R_RISCV_JUMP_SLOT:
case __WORDSIZE == 64 ? R_RISCV_64 : R_RISCV_32:
*addr_field = value;
break;
case R_RISCV_NONE:
break;
default:
_dl_reloc_bad_type (map, r_type, 0);
break;
}
}
static inline void
__attribute__ ((always_inline))
elf_machine_rela_relative (ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
void *const reloc_addr)
{
*(ElfW(Addr) *) 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)
{
ElfW(Addr) *const reloc_addr = (void *) (l_addr + reloc->r_offset);
const unsigned int r_type = ELFW (R_TYPE) (reloc->r_info);
/* Check for unexpected PLT reloc type. */
if (__glibc_likely (r_type == R_RISCV_JUMP_SLOT))
{
if (__glibc_unlikely (map->l_mach.plt == 0))
{
if (l_addr)
*reloc_addr += l_addr;
}
else
*reloc_addr = map->l_mach.plt;
}
else if (__glibc_unlikely (r_type == R_RISCV_IRELATIVE))
{
ElfW(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);
}
/* Set up the loaded object described by L so its stub function
will jump to the on-demand fixup code __dl_runtime_resolve. */
static inline int
__attribute__ ((always_inline))
elf_machine_runtime_setup (struct link_map *l, struct r_scope_elem *scope[],
int lazy, int profile)
{
#ifndef RTLD_BOOTSTRAP
/* If using PLTs, fill in the first two entries of .got.plt. */
if (l->l_info[DT_JMPREL])
{
extern void _dl_runtime_resolve (void) __attribute__ ((visibility ("hidden")));
ElfW(Addr) *gotplt = (ElfW(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 the address of .plt for us here. */
if (gotplt[1])
l->l_mach.plt = gotplt[1] + l->l_addr;
gotplt[0] = (ElfW(Addr)) &_dl_runtime_resolve;
gotplt[1] = (ElfW(Addr)) l;
}
if (l->l_type == lt_executable)
{
/* The __global_pointer$ may not be defined by the linker if the
$gp register does not be used to access the global variable
in the executable program. Therefore, the search symbol is
set to a weak symbol to avoid we error out if the
__global_pointer$ is not found. */
ElfW(Sym) gp_sym = { 0 };
gp_sym.st_info = (unsigned char) ELFW (ST_INFO (STB_WEAK, STT_NOTYPE));
const ElfW(Sym) *ref = &gp_sym;
_dl_lookup_symbol_x ("__global_pointer$", l, &ref,
l->l_scope, NULL, 0, 0, NULL);
if (ref)
asm (
"mv gp, %0\n"
:
: "r" (ref->st_value)
);
}
#endif
return lazy;
}
#endif /* RESOLVE_MAP */