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https://sourceware.org/git/glibc.git
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351 lines
11 KiB
C
351 lines
11 KiB
C
/* Machine-dependent ELF dynamic relocation inline functions. RISC-V version.
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Copyright (C) 2011-2023 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 Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the 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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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<https://www.gnu.org/licenses/>. */
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#ifndef dl_machine_h
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#define dl_machine_h
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#define ELF_MACHINE_NAME "RISC-V"
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#include <entry.h>
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#include <elf/elf.h>
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#include <sys/asm.h>
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#include <dl-tls.h>
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#include <dl-irel.h>
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#include <dl-static-tls.h>
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#include <dl-machine-rel.h>
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#ifndef _RTLD_PROLOGUE
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# define _RTLD_PROLOGUE(entry) \
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".globl\t" __STRING (entry) "\n\t" \
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".type\t" __STRING (entry) ", @function\n" \
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__STRING (entry) ":\n\t"
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#endif
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#ifndef _RTLD_EPILOGUE
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# define _RTLD_EPILOGUE(entry) \
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".size\t" __STRING (entry) ", . - " __STRING (entry) "\n\t"
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#endif
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#define ELF_MACHINE_JMP_SLOT R_RISCV_JUMP_SLOT
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#define elf_machine_type_class(type) \
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((ELF_RTYPE_CLASS_PLT * ((type) == ELF_MACHINE_JMP_SLOT \
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|| (__WORDSIZE == 32 && (type) == R_RISCV_TLS_DTPREL32) \
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|| (__WORDSIZE == 32 && (type) == R_RISCV_TLS_DTPMOD32) \
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|| (__WORDSIZE == 32 && (type) == R_RISCV_TLS_TPREL32) \
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|| (__WORDSIZE == 64 && (type) == R_RISCV_TLS_DTPREL64) \
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|| (__WORDSIZE == 64 && (type) == R_RISCV_TLS_DTPMOD64) \
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|| (__WORDSIZE == 64 && (type) == R_RISCV_TLS_TPREL64))) \
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| (ELF_RTYPE_CLASS_COPY * ((type) == R_RISCV_COPY)))
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/* Return nonzero iff ELF header is compatible with the running host. */
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static inline int __attribute_used__
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elf_machine_matches_host (const ElfW(Ehdr) *ehdr)
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{
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/* We can only run RISC-V binaries. */
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if (ehdr->e_machine != EM_RISCV)
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return 0;
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/* Ensure the library's floating-point ABI matches that of the running
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system. For now we don't support mixing XLEN, so there's no need (or way)
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to check it matches. */
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#ifdef __riscv_float_abi_double
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if ((ehdr->e_flags & EF_RISCV_FLOAT_ABI) != EF_RISCV_FLOAT_ABI_DOUBLE)
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return 0;
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#else
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if ((ehdr->e_flags & EF_RISCV_FLOAT_ABI) != EF_RISCV_FLOAT_ABI_SOFT)
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return 0;
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#endif
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return 1;
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}
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/* Return the run-time load address of the shared object. */
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static inline ElfW(Addr)
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elf_machine_load_address (void)
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{
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extern const ElfW(Ehdr) __ehdr_start attribute_hidden;
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return (ElfW(Addr)) &__ehdr_start;
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}
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/* Return the link-time address of _DYNAMIC. */
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static inline ElfW(Addr)
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elf_machine_dynamic (void)
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{
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extern ElfW(Dyn) _DYNAMIC[] attribute_hidden;
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return (ElfW(Addr)) _DYNAMIC - elf_machine_load_address ();
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}
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#define STRINGXP(X) __STRING (X)
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#define STRINGXV(X) STRINGV_ (X)
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#define STRINGV_(...) # __VA_ARGS__
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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\n\
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" _RTLD_PROLOGUE (ENTRY_POINT) "\
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mv a0, sp\n\
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jal _dl_start\n\
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" _RTLD_PROLOGUE (_dl_start_user) "\
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# Stash user entry point in s0.\n\
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mv s0, a0\n\
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# Load the adjusted argument count.\n\
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" STRINGXP (REG_L) " a1, 0(sp)\n\
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# Call _dl_init (struct link_map *main_map, int argc, char **argv, char **env) \n\
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" STRINGXP (REG_L) " a0, _rtld_local\n\
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add a2, sp, " STRINGXP (SZREG) "\n\
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sll a3, a1, " STRINGXP (PTRLOG) "\n\
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add a3, a3, a2\n\
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add a3, a3, " STRINGXP (SZREG) "\n\
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# Stash the stack pointer in s1.\n\
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mv s1, sp\n\
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# Align stack to 128 bits for the _dl_init call.\n\
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andi sp, sp,-16\n\
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# Call the function to run the initializers.\n\
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jal _dl_init\n\
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# Restore the stack pointer for _start.\n\
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mv sp, s1\n\
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# Pass our finalizer function to _start.\n\
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lla a0, _dl_fini\n\
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# Jump to the user entry point.\n\
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jr s0\n\
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" _RTLD_EPILOGUE (ENTRY_POINT) \
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_RTLD_EPILOGUE (_dl_start_user) "\
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.previous" \
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);
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/* Names of the architecture-specific auditing callback functions. */
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#define ARCH_LA_PLTENTER riscv_gnu_pltenter
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#define ARCH_LA_PLTEXIT riscv_gnu_pltexit
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/* Bias .got.plt entry by the offset requested by the PLT header. */
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#define elf_machine_plt_value(map, reloc, value) (value)
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static inline ElfW(Addr)
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elf_machine_fixup_plt (struct link_map *map, lookup_t t,
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const ElfW(Sym) *refsym, const ElfW(Sym) *sym,
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const ElfW(Rela) *reloc,
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ElfW(Addr) *reloc_addr, ElfW(Addr) value)
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{
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return *reloc_addr = value;
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}
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#endif /* !dl_machine_h */
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#ifdef RESOLVE_MAP
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static inline void
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__attribute__ ((always_inline))
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elf_machine_rela_relative (ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
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void *const reloc_addr)
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{
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/* R_RISCV_RELATIVE might located in debug info section which might not
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aligned to XLEN bytes. Also support relocations on unaligned offsets. */
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ElfW(Addr) value = l_addr + reloc->r_addend;
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memcpy (reloc_addr, &value, sizeof value);
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}
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/* Perform a relocation described by R_INFO at the location pointed to
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by RELOC_ADDR. SYM is the relocation symbol specified by R_INFO and
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MAP is the object containing the reloc. */
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static inline void
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__attribute__ ((always_inline))
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elf_machine_rela (struct link_map *map, struct r_scope_elem *scope[],
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const ElfW(Rela) *reloc, const ElfW(Sym) *sym,
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const struct r_found_version *version,
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void *const reloc_addr, int skip_ifunc)
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{
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ElfW(Addr) r_info = reloc->r_info;
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const unsigned long int r_type = ELFW (R_TYPE) (r_info);
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ElfW(Addr) *addr_field = (ElfW(Addr) *) reloc_addr;
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const ElfW(Sym) *const __attribute__ ((unused)) refsym = sym;
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struct link_map *sym_map = RESOLVE_MAP (map, scope, &sym, version, r_type);
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ElfW(Addr) value = 0;
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if (sym_map != NULL)
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value = SYMBOL_ADDRESS (sym_map, sym, true) + reloc->r_addend;
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if (sym != NULL
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&& __glibc_unlikely (ELFW(ST_TYPE) (sym->st_info) == STT_GNU_IFUNC)
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&& __glibc_likely (sym->st_shndx != SHN_UNDEF)
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&& __glibc_likely (!skip_ifunc))
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value = elf_ifunc_invoke (value);
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switch (r_type)
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{
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case R_RISCV_RELATIVE:
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elf_machine_rela_relative (map->l_addr, reloc, addr_field);
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break;
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case R_RISCV_JUMP_SLOT:
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case __WORDSIZE == 64 ? R_RISCV_64 : R_RISCV_32:
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*addr_field = value;
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break;
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# ifndef RTLD_BOOTSTRAP
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case __WORDSIZE == 64 ? R_RISCV_TLS_DTPMOD64 : R_RISCV_TLS_DTPMOD32:
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if (sym_map)
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*addr_field = sym_map->l_tls_modid;
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break;
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case __WORDSIZE == 64 ? R_RISCV_TLS_DTPREL64 : R_RISCV_TLS_DTPREL32:
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if (sym != NULL)
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*addr_field = TLS_DTPREL_VALUE (sym) + reloc->r_addend;
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break;
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case __WORDSIZE == 64 ? R_RISCV_TLS_TPREL64 : R_RISCV_TLS_TPREL32:
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if (sym != NULL)
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{
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CHECK_STATIC_TLS (map, sym_map);
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*addr_field = TLS_TPREL_VALUE (sym_map, sym) + reloc->r_addend;
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}
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break;
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case R_RISCV_COPY:
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{
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if (__glibc_unlikely (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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/* Handle TLS copy relocations. */
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if (__glibc_unlikely (ELFW (ST_TYPE) (sym->st_info) == STT_TLS))
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{
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/* There's nothing to do if the symbol is in .tbss. */
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if (__glibc_likely (sym->st_value >= sym_map->l_tls_initimage_size))
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break;
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value += (ElfW(Addr)) sym_map->l_tls_initimage - sym_map->l_addr;
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}
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size_t size = sym->st_size;
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if (__glibc_unlikely (sym->st_size != refsym->st_size))
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{
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const char *strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
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if (sym->st_size > refsym->st_size)
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size = refsym->st_size;
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if (sym->st_size > refsym->st_size || GLRO(dl_verbose))
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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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rtld_progname ?: "<program name unknown>",
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strtab + refsym->st_name);
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}
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memcpy (reloc_addr, (void *)value, size);
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break;
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}
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case R_RISCV_IRELATIVE:
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value = map->l_addr + reloc->r_addend;
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if (__glibc_likely (!skip_ifunc))
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value = elf_ifunc_invoke (value);
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*addr_field = value;
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break;
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case R_RISCV_NONE:
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break;
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# endif /* !RTLD_BOOTSTRAP */
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default:
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_dl_reloc_bad_type (map, r_type, 0);
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break;
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}
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}
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static inline void
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__attribute__ ((always_inline))
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elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
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ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
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int skip_ifunc)
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{
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ElfW(Addr) *const reloc_addr = (void *) (l_addr + reloc->r_offset);
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const unsigned int r_type = ELFW (R_TYPE) (reloc->r_info);
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/* Check for unexpected PLT reloc type. */
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if (__glibc_likely (r_type == R_RISCV_JUMP_SLOT))
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{
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if (__glibc_unlikely (map->l_mach.plt == 0))
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{
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if (l_addr)
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*reloc_addr += l_addr;
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}
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else
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*reloc_addr = map->l_mach.plt;
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}
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else if (__glibc_unlikely (r_type == R_RISCV_IRELATIVE))
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{
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ElfW(Addr) value = map->l_addr + reloc->r_addend;
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if (__glibc_likely (!skip_ifunc))
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value = elf_ifunc_invoke (value);
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*reloc_addr = value;
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}
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else
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_dl_reloc_bad_type (map, r_type, 1);
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}
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/* Set up the loaded object described by L so its stub function
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will jump to the on-demand fixup code __dl_runtime_resolve. */
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static inline int
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__attribute__ ((always_inline))
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elf_machine_runtime_setup (struct link_map *l, struct r_scope_elem *scope[],
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int lazy, int profile)
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{
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#ifndef RTLD_BOOTSTRAP
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/* If using PLTs, fill in the first two entries of .got.plt. */
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if (l->l_info[DT_JMPREL])
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{
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extern void _dl_runtime_resolve (void) __attribute__ ((visibility ("hidden")));
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ElfW(Addr) *gotplt = (ElfW(Addr) *) D_PTR (l, l_info[DT_PLTGOT]);
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/* If a library is prelinked but we have to relocate anyway,
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we have to be able to undo the prelinking of .got.plt.
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The prelinker saved the address of .plt for us here. */
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if (gotplt[1])
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l->l_mach.plt = gotplt[1] + l->l_addr;
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gotplt[0] = (ElfW(Addr)) &_dl_runtime_resolve;
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gotplt[1] = (ElfW(Addr)) l;
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}
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if (l->l_type == lt_executable)
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{
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/* The __global_pointer$ may not be defined by the linker if the
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$gp register does not be used to access the global variable
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in the executable program. Therefore, the search symbol is
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set to a weak symbol to avoid we error out if the
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__global_pointer$ is not found. */
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ElfW(Sym) gp_sym = { 0 };
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gp_sym.st_info = (unsigned char) ELFW (ST_INFO (STB_WEAK, STT_NOTYPE));
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const ElfW(Sym) *ref = &gp_sym;
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_dl_lookup_symbol_x ("__global_pointer$", l, &ref,
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l->l_scope, NULL, 0, 0, NULL);
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if (ref)
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asm (
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"mv gp, %0\n"
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:
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: "r" (ref->st_value)
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);
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}
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#endif
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return lazy;
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}
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#endif /* RESOLVE_MAP */
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