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Diffstat (limited to 'sysdeps/arc/dl-machine.h')
| -rw-r--r-- | sysdeps/arc/dl-machine.h | 344 |
1 files changed, 344 insertions, 0 deletions
diff --git a/sysdeps/arc/dl-machine.h b/sysdeps/arc/dl-machine.h new file mode 100644 index 0000000000..e47f19905f --- /dev/null +++ b/sysdeps/arc/dl-machine.h @@ -0,0 +1,344 @@ +/* Machine-dependent ELF dynamic relocation inline functions. ARC version. + Copyright (C) 2020 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 "arc" + +#include <entry.h> + +#ifndef ENTRY_POINT +# error ENTRY_POINT needs to be defined for ARC +#endif + +#include <string.h> +#include <link.h> +#include <dl-tls.h> + +/* Dynamic Linking ABI for ARCv2 ISA. + + PLT + -------------------------------- <---- DT_PLTGOT + | ld r11, [pcl, off-to-GOT[1] | 0 + | | 4 + plt0 | ld r10, [pcl, off-to-GOT[2] | 8 + | | 12 + | j [r10] | 16 + -------------------------------- + | Base address of GOT | 20 + -------------------------------- + | ld r12, [pcl, off-to-GOT[3] | 24 + plt1 | | + | j.d [r12] | 32 + | mov r12, pcl | 36 + -------------------------------- + | | 40 + ~ ~ + ~ ~ + | | + -------------------------------- + + .got + -------------- + | [0] | + | ... | Runtime address for data symbols + | [n] | + -------------- + + .got.plt + -------------- + | [0] | Build address of .dynamic + -------------- + | [1] | Module info - setup by ld.so + -------------- + | [2] | resolver entry point + -------------- + | [3] | + | ... | Runtime address for function symbols + | [f] | + -------------- + + For ARCompact, the PLT is 12 bytes due to short instructions + + -------------------------------- + | ld r12, [pcl, off-to-GOT[3] | 24 (12 bytes each) + plt1 | | + | j_s.d [r12] | 32 + | mov_s r12, pcl | 34 + -------------------------------- + | | 36 */ + +/* Return nonzero iff ELF header is compatible with the running host. */ +static inline int +elf_machine_matches_host (const Elf32_Ehdr *ehdr) +{ + return (ehdr->e_machine == EM_ARCV2 /* ARC HS. */ + || ehdr->e_machine == EM_ARC_COMPACT); /* ARC 700. */ +} + +/* Get build time address of .dynamic as setup in GOT[0] + This is called very early in _dl_start so it has not been relocated to + runtime value. */ +static inline ElfW(Addr) +elf_machine_dynamic (void) +{ + extern const ElfW(Addr) _GLOBAL_OFFSET_TABLE_[] attribute_hidden; + return _GLOBAL_OFFSET_TABLE_[0]; +} + + +/* Return the run-time load address of the shared object. */ +static inline ElfW(Addr) +elf_machine_load_address (void) +{ + ElfW(Addr) build_addr, run_addr; + + /* For build address, below generates + ld r0, [pcl, _GLOBAL_OFFSET_TABLE_@pcl]. */ + build_addr = elf_machine_dynamic (); + __asm__ ("add %0, pcl, _DYNAMIC@pcl \n" : "=r" (run_addr)); + + return run_addr - build_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__ ((always_inline)) +elf_machine_runtime_setup (struct link_map *l, int lazy, int profile) +{ + extern void _dl_runtime_resolve (Elf32_Word); + + if (l->l_info[DT_JMPREL] && lazy) + { + /* On ARC DT_PLTGOT point to .plt whose 5th word (after the PLT header) + contains the address of .got. */ + ElfW(Addr) *plt_base = (ElfW(Addr) *) D_PTR (l, l_info[DT_PLTGOT]); + ElfW(Addr) *got = (ElfW(Addr) *) (plt_base[5] + l->l_addr); + + got[1] = (ElfW(Addr)) l; /* Identify this shared object. */ + + /* 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. */ + got[2] = (ElfW(Addr)) &_dl_runtime_resolve; + } + + return lazy; +} + +/* What this code does: + -ldso starts execution here when kernel returns from execve + -calls into generic ldso entry point _dl_start + -optionally adjusts argc for executable if exec passed as cmd + -calls into app main with address of finaliser. */ + +#define RTLD_START asm ("\ +.text \n\ +.globl __start \n\ +.type __start, @function \n\ +__start: \n\ + /* (1). bootstrap ld.so. */ \n\ + bl.d _dl_start \n\ + mov_s r0, sp /* pass ptr to aux vector tbl. */ \n\ + mov r13, r0 /* safekeep app elf entry point. */ \n\ + \n\ + /* (2). If ldso ran with executable as arg. */ \n\ + /* skip the extra args calc by dl_start. */ \n\ + ld_s r1, [sp] /* orig argc. */ \n\ + ld r12, [pcl, _dl_skip_args@pcl] \n\ + breq r12, 0, 1f \n\ + \n\ + add2 sp, sp, r12 /* discard argv entries from stack. */ \n\ + sub_s r1, r1, r12 /* adjusted argc on stack. */ \n\ + st_s r1, [sp] \n\ + add r2, sp, 4 \n\ + /* intermediate LD for ST emcoding limitations. */ \n\ + ld r3, [pcl, _dl_argv@gotpc] \n\ + st r2, [r3] \n\ +1: \n\ + /* (3). call preinit stuff. */ \n\ + ld r0, [pcl, _rtld_local@pcl] \n\ + add r2, sp, 4 ; argv \n\ + add2 r3, r2, r1 \n\ + add r3, r3, 4 ; env \n\ + bl _dl_init@plt \n\ + \n\ + /* (4) call app elf entry point. */ \n\ + add r0, pcl, _dl_fini@pcl \n\ + j [r13] \n\ + \n\ + .size __start,.-__start \n\ + .previous \n\ +"); + +/* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry, so + PLT entries 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_ARC_JUMP_SLOT \ + || (type) == R_ARC_TLS_DTPMOD \ + || (type) == R_ARC_TLS_DTPOFF \ + || (type) == R_ARC_TLS_TPOFF) * ELF_RTYPE_CLASS_PLT) \ + | (((type) == R_ARC_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_ARC_JUMP_SLOT + +/* ARC uses Elf32_Rela relocations. */ +#define ELF_MACHINE_NO_REL 1 +#define ELF_MACHINE_NO_RELA 0 + +/* Fixup a PLT entry to bounce directly to the function at 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 Elf32_Rela *reloc, + ElfW(Addr) *reloc_addr, ElfW(Addr) value) +{ + return *reloc_addr = value; +} + +/* Return the final value of a plt relocation. */ +static inline ElfW(Addr) +elf_machine_plt_value (struct link_map *map, const Elf32_Rela *reloc, + ElfW(Addr) value) +{ + return value; +} + +/* Names of the architecture-specific auditing callback functions. */ +#define ARCH_LA_PLTENTER arc_gnu_pltenter +#define ARCH_LA_PLTEXIT arc_gnu_pltexit + +#endif /* dl_machine_h */ + +#ifdef RESOLVE_MAP + +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_arg, int skip_ifunc) +{ + ElfW(Addr) *const reloc_addr = reloc_addr_arg; + const unsigned int r_type = ELF32_R_TYPE (reloc->r_info); + + if (__glibc_unlikely (r_type == R_ARC_RELATIVE)) + *reloc_addr += map->l_addr; + else if (__glibc_unlikely (r_type == R_ARC_NONE)) + return; + else + { + const ElfW(Sym) *const refsym = sym; + struct link_map *sym_map = RESOLVE_MAP (&sym, version, r_type); + ElfW(Addr) value = SYMBOL_ADDRESS (sym_map, sym, true); + + switch (r_type) + { + case R_ARC_COPY: + if (__glibc_unlikely (sym == NULL)) + /* This can happen in trace mode if an object could not be + found. */ + break; + + size_t size = sym->st_size; + if (__glibc_unlikely (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_arg, (void *) value, size); + break; + + case R_ARC_GLOB_DAT: + case R_ARC_JUMP_SLOT: + *reloc_addr = value; + break; + + case R_ARC_TLS_DTPMOD: + if (sym_map != NULL) + /* Get the information from the link map returned by the + resolv function. */ + *reloc_addr = sym_map->l_tls_modid; + break; + + case R_ARC_TLS_DTPOFF: + if (sym != NULL) + /* Offset set by the linker in the GOT entry would be overwritten + by dynamic loader instead of added to the symbol location. + Other target have the same approach on DTPOFF relocs. */ + *reloc_addr += sym->st_value; + break; + + case R_ARC_TLS_TPOFF: + if (sym != NULL) + { + CHECK_STATIC_TLS (map, sym_map); + *reloc_addr = sym_map->l_tls_offset + sym->st_value + reloc->r_addend; + } + break; + + case R_ARC_32: + *reloc_addr += value + reloc->r_addend; + break; + + case R_ARC_PC32: + *reloc_addr += value + reloc->r_addend - (unsigned long int) reloc_addr; + break; + + default: + _dl_reloc_bad_type (map, r_type, 0); + break; + } + } +} + +inline void +__attribute__ ((always_inline)) +elf_machine_rela_relative (ElfW(Addr) l_addr, const ElfW(Rela) *reloc, + void *const reloc_addr_arg) +{ + ElfW(Addr) *const reloc_addr = reloc_addr_arg; + *reloc_addr += l_addr; +} + +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); + + if (ELF32_R_TYPE (reloc->r_info) == R_ARC_JUMP_SLOT) + *reloc_addr += l_addr; + else + _dl_reloc_bad_type (map, ELF32_R_TYPE (reloc->r_info), 1); +} + +#endif /* RESOLVE_MAP */ |