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Diffstat (limited to 'ports/sysdeps/aarch64/dl-machine.h')
| -rw-r--r-- | ports/sysdeps/aarch64/dl-machine.h | 388 |
1 files changed, 388 insertions, 0 deletions
diff --git a/ports/sysdeps/aarch64/dl-machine.h b/ports/sysdeps/aarch64/dl-machine.h new file mode 100644 index 0000000000..324115d272 --- /dev/null +++ b/ports/sysdeps/aarch64/dl-machine.h @@ -0,0 +1,388 @@ +/* Copyright (C) 1995-2012 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 "aarch64" + +#include <tls.h> +#include <dl-tlsdesc.h> + +/* Return nonzero iff ELF header is compatible with the running host. */ +static inline int __attribute__ ((unused)) +elf_machine_matches_host (const ElfW(Ehdr) *ehdr) +{ + return ehdr->e_machine == EM_AARCH64; +} + +/* Return the link-time address of _DYNAMIC. Conveniently, this is the + first element of the GOT. */ +static inline ElfW(Addr) __attribute__ ((unused)) +elf_machine_dynamic (void) +{ + ElfW(Addr) addr = (ElfW(Addr)) &_DYNAMIC; + return addr; +} + +/* Return the run-time load address of the shared object. */ + +static inline ElfW(Addr) __attribute__ ((unused)) +elf_machine_load_address (void) +{ + /* To figure out the load address we use the definition that for any symbol: + dynamic_addr(symbol) = static_addr(symbol) + load_addr + + The choice of symbol is arbitrary. The static address we obtain + by constructing a non GOT reference to the symbol, the dynamic + address of the symbol we compute using adrp/add to compute the + symbol's address relative to the PC. */ + + ElfW(Addr) static_addr; + ElfW(Addr) dynamic_addr; + + asm (" \n\ + adrp %1, _dl_start; \n\ + add %1, %1, #:lo12:_dl_start \n\ + ldr %w0, 1f \n\ + b 2f \n\ +1: .word _dl_start \n\ +2: \n\ + " : "=r" (static_addr), "=r" (dynamic_addr)); + return dynamic_addr - static_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__ ((unused)) +elf_machine_runtime_setup (struct link_map *l, int lazy, int profile) +{ + if (l->l_info[DT_JMPREL] && lazy) + { + ElfW(Addr) *got; + extern void _dl_runtime_resolve (ElfW(Word)); + extern void _dl_runtime_profile (ElfW(Word)); + + got = (ElfW(Addr) *) D_PTR (l, l_info[DT_PLTGOT]); + if (got[1]) + { + l->l_mach.plt = got[1] + l->l_addr; + } + got[1] = (ElfW(Addr)) l; + + /* The got[2] entry contains the address of a function which gets + called to get the address of a so far unresolved function and + jump to it. The profiling extension of the dynamic linker allows + to intercept the calls to collect information. In this case we + don't store the address in the GOT so that all future calls also + end in this function. */ + if ( profile) + { + got[2] = (ElfW(Addr)) &_dl_runtime_profile; + + if (GLRO(dl_profile) != NULL + && _dl_name_match_p (GLRO(dl_profile), l)) + /* Say that we really want profiling and the timers are + started. */ + GL(dl_profile_map) = l; + } + else + { + /* 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; + } + } + + if (l->l_info[ADDRIDX (DT_TLSDESC_GOT)] && lazy) + *(Elf64_Addr*)(D_PTR (l, l_info[ADDRIDX (DT_TLSDESC_GOT)]) + l->l_addr) + = (Elf64_Addr) &_dl_tlsdesc_resolve_rela; + + return lazy; +} + +/* Initial entry point 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\ +.globl _start \n\ +.type _start, %function \n\ +.globl _dl_start_user \n\ +.type _dl_start_user, %function \n\ +_start: \n\ + mov x0, sp \n\ + bl _dl_start \n\ + // returns user entry point in x0 \n\ + mov x21, x0 \n\ +_dl_start_user: \n\ + // get the original arg count \n\ + ldr x1, [sp] \n\ + // get the argv address \n\ + add x2, sp, #8 \n\ + // get _dl_skip_args to see if we were \n\ + // invoked as an executable \n\ + adrp x4, _dl_skip_args \n\ + ldr w4, [x4, #:lo12:_dl_skip_args] \n\ + // do we need to adjust argc/argv \n\ + cmp w4, 0 \n\ + beq .L_done_stack_adjust \n\ + // subtract _dl_skip_args from original arg count \n\ + sub x1, x1, x4 \n\ + // store adjusted argc back to stack \n\ + str x1, [sp] \n\ + // find the first unskipped argument \n\ + mov x3, x2 \n\ + add x4, x2, x4, lsl #3 \n\ + // shuffle argv down \n\ +1: ldr x5, [x4], #8 \n\ + str x5, [x3], #8 \n\ + cmp x5, #0 \n\ + bne 1b \n\ + // shuffle envp down \n\ +1: ldr x5, [x4], #8 \n\ + str x5, [x3], #8 \n\ + cmp x5, #0 \n\ + bne 1b \n\ + // shuffle auxv down \n\ +1: ldp x0, x5, [x4, #16]! \n\ + stp x0, x5, [x3], #16 \n\ + cmp x0, #0 \n\ + bne 1b \n\ + // Update _dl_argv \n\ + adrp x3, _dl_argv \n\ + str x2, [x3, #:lo12:_dl_argv] \n\ +.L_done_stack_adjust: \n\ + // compute envp \n\ + add x3, x2, x1, lsl #3 \n\ + add x3, x3, #8 \n\ + adrp x16, _rtld_local \n\ + add x16, x16, #:lo12:_rtld_local \n\ + ldr x0, [x16] \n\ + bl _dl_init_internal \n\ + // load the finalizer function \n\ + adrp x0, _dl_fini \n\ + add x0, x0, #:lo12:_dl_fini \n\ + // jump to the user_s entry point \n\ + br x21 \n\ +"); + +#define elf_machine_type_class(type) \ + ((((type) == R_AARCH64_JUMP_SLOT || \ + (type) == R_AARCH64_TLS_DTPMOD64 || \ + (type) == R_AARCH64_TLS_DTPREL64 || \ + (type) == R_AARCH64_TLS_TPREL64 || \ + (type) == R_AARCH64_TLSDESC) * ELF_RTYPE_CLASS_PLT) \ + | (((type) == R_AARCH64_COPY) * ELF_RTYPE_CLASS_COPY)) + +#define ELF_MACHINE_JMP_SLOT R_AARCH64_JUMP_SLOT + +/* AArch64 uses RELA not REL */ +#define ELF_MACHINE_NO_REL 1 + +static inline ElfW(Addr) +elf_machine_fixup_plt (struct link_map *map, lookup_t t, + 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 ElfW(Addr) +elf_machine_plt_value (struct link_map *map, + const ElfW(Rela) *reloc, + ElfW(Addr) value) +{ + return value; +} + +#endif + +/* Names of the architecture-specific auditing callback functions. */ +#define ARCH_LA_PLTENTER aarch64_gnu_pltenter +#define ARCH_LA_PLTEXIT aarch64_gnu_pltexit + +#ifdef RESOLVE_MAP + +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_arg, int skip_ifunc) +{ + ElfW(Addr) *const reloc_addr = reloc_addr_arg; + const unsigned int r_type = ELF64_R_TYPE (reloc->r_info); + + if (__builtin_expect (r_type == R_AARCH64_RELATIVE, 0)) + *reloc_addr = map->l_addr + reloc->r_addend; + else if (__builtin_expect (r_type == R_AARCH64_NONE, 0)) + return; + else + { + const ElfW(Sym) *const refsym = sym; + struct link_map *sym_map = RESOLVE_MAP (&sym, version, r_type); + ElfW(Addr) value = sym_map == NULL ? 0 : sym_map->l_addr + sym->st_value; + + switch (r_type) + { + case R_AARCH64_COPY: + if (sym == NULL) + break; + + if (sym->st_size > refsym->st_size + || (GLRO(dl_verbose) && sym->st_size < refsym->st_size)) + { + const char *strtab; + + strtab = (const void *) 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; + + case R_AARCH64_RELATIVE: + case R_AARCH64_GLOB_DAT: + case R_AARCH64_JUMP_SLOT: + case R_AARCH64_ABS32: + case R_AARCH64_ABS64: + *reloc_addr = value + reloc->r_addend; + break; + + case R_AARCH64_TLSDESC: + { + struct tlsdesc volatile *td = + (struct tlsdesc volatile *)reloc_addr; +#ifndef RTLD_BOOTSTRAP + if (! sym) + { + td->arg = (void*)reloc->r_addend; + td->entry = _dl_tlsdesc_undefweak; + } + else +#endif + { +#ifndef RTLD_BOOTSTRAP +# ifndef SHARED + CHECK_STATIC_TLS (map, sym_map); +# else + if (!TRY_STATIC_TLS (map, sym_map)) + { + td->arg = _dl_make_tlsdesc_dynamic + (sym_map, sym->st_value + reloc->r_addend); + td->entry = _dl_tlsdesc_dynamic; + } + else +# endif +#endif + { + td->arg = (void*)(sym->st_value + sym_map->l_tls_offset + + reloc->r_addend); + td->entry = _dl_tlsdesc_return; + } + } + break; + } + + case R_AARCH64_TLS_DTPMOD64: +#ifdef RTLD_BOOTSTRAP + *reloc_addr = 1; +#else + if (sym_map != NULL) + { + *reloc_addr = sym_map->l_tls_modid; + } +#endif + break; + + case R_AARCH64_TLS_DTPREL64: + if (sym) + { + const char *strtab; + strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]); + *reloc_addr = sym->st_value + reloc->r_addend; + } + break; + + case R_AARCH64_TLS_TPREL64: + if (sym) + { + const char *strtab; + strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]); + CHECK_STATIC_TLS (map, sym_map); + *reloc_addr = + sym->st_value + reloc->r_addend + sym_map->l_tls_offset; + } + 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 + reloc->r_addend; +} + +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 = ELF64_R_TYPE (reloc->r_info); + /* Check for unexpected PLT reloc type. */ + if (__builtin_expect (r_type == R_AARCH64_JUMP_SLOT, 1)) + { + if (__builtin_expect (map->l_mach.plt, 0) == 0) + *reloc_addr += l_addr; + else + *reloc_addr = map->l_mach.plt; + } + else if (__builtin_expect (r_type == R_AARCH64_TLSDESC, 1)) + { + struct tlsdesc volatile *td = + (struct tlsdesc volatile *)reloc_addr; + + td->arg = (void*)reloc; + td->entry = (void*)(D_PTR (map, l_info[ADDRIDX (DT_TLSDESC_PLT)]) + + map->l_addr); + } + else + _dl_reloc_bad_type (map, r_type, 1); +} + +#endif |