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Diffstat (limited to 'sysdeps/riscv/dl-machine.h')
| -rw-r--r-- | sysdeps/riscv/dl-machine.h | 323 |
1 files changed, 323 insertions, 0 deletions
diff --git a/sysdeps/riscv/dl-machine.h b/sysdeps/riscv/dl-machine.h new file mode 100644 index 0000000000..9e3c2925f0 --- /dev/null +++ b/sysdeps/riscv/dl-machine.h @@ -0,0 +1,323 @@ +/* Machine-dependent ELF dynamic relocation inline functions. RISC-V version. + Copyright (C) 2011-2018 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 + <http://www.gnu.org/licenses/>. */ + +#ifndef dl_machine_h +#define dl_machine_h + +#define ELF_MACHINE_NAME "RISC-V" + +#include <entry.h> +#include <elf/elf.h> +#include <sys/asm.h> +#include <dl-tls.h> + +#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))) + +#define ELF_MACHINE_NO_REL 1 +#define ELF_MACHINE_NO_RELA 0 + +/* 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 link-time address of _DYNAMIC. */ +static inline ElfW(Addr) +elf_machine_dynamic (void) +{ + extern ElfW(Addr) _GLOBAL_OFFSET_TABLE_ __attribute__ ((visibility ("hidden"))); + return _GLOBAL_OFFSET_TABLE_; +} + +#define STRINGXP(X) __STRING (X) +#define STRINGXV(X) STRINGV_ (X) +#define STRINGV_(...) # __VA_ARGS__ + +/* Return the run-time load address of the shared object. */ +static inline ElfW(Addr) +elf_machine_load_address (void) +{ + ElfW(Addr) load_addr; + asm ("lla %0, _DYNAMIC" : "=r" (load_addr)); + return load_addr - elf_machine_dynamic (); +} + +/* 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\ + # 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\ + # Call the function to run the initializers.\n\ + jal _dl_init\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) "\ + .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. */ + +auto inline void +__attribute__ ((always_inline)) +elf_machine_rela (struct link_map *map, 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 (&sym, version, r_type); + ElfW(Addr) value = 0; + if (sym_map != NULL) + value = sym_map->l_addr + sym->st_value + reloc->r_addend; + + 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 ?: "<program name unknown>", + 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_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; + } +} + +auto 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; +} + +auto inline void +__attribute__ ((always_inline)) +elf_machine_lazy_rel (struct link_map *map, 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 + _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. */ + +auto inline int +__attribute__ ((always_inline)) +elf_machine_runtime_setup (struct link_map *l, 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; + } +#endif + + return lazy; +} + +#endif /* RESOLVE_MAP */ |