diff options
Diffstat (limited to 'ports/sysdeps/mips/dl-trampoline.c')
| -rw-r--r-- | ports/sysdeps/mips/dl-trampoline.c | 386 |
1 files changed, 386 insertions, 0 deletions
diff --git a/ports/sysdeps/mips/dl-trampoline.c b/ports/sysdeps/mips/dl-trampoline.c new file mode 100644 index 0000000000..3454eb306f --- /dev/null +++ b/ports/sysdeps/mips/dl-trampoline.c @@ -0,0 +1,386 @@ +/* PLT trampoline. MIPS version. + Copyright (C) 1996-2001, 2002, 2003, 2004, 2005 + Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Kazumoto Kojima <kkojima@info.kanagawa-u.ac.jp>. + + 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/>. */ + +/* FIXME: Profiling of shared libraries is not implemented yet. */ + +#include <sysdep.h> +#include <link.h> +#include <elf.h> +#include <ldsodefs.h> +#include <dl-machine.h> +#include <sysdep-cancel.h> + +/* Get link map for callers object containing STUB_PC. */ +static inline struct link_map * +elf_machine_runtime_link_map (ElfW(Addr) gpreg, ElfW(Addr) stub_pc) +{ + extern int _dl_mips_gnu_objects; + + /* got[1] is reserved to keep its link map address for the shared + object generated by the gnu linker. If all are such objects, we + can find the link map from current GPREG simply. If not so, get + the link map for caller's object containing STUB_PC. */ + + if (_dl_mips_gnu_objects) + { + ElfW(Addr) *got = elf_mips_got_from_gpreg (gpreg); + ElfW(Word) g1; + + g1 = ((ElfW(Word) *) got)[1]; + + if ((g1 & ELF_MIPS_GNU_GOT1_MASK) != 0) + { + struct link_map *l = + (struct link_map *) (g1 & ~ELF_MIPS_GNU_GOT1_MASK); + ElfW(Addr) base, limit; + const ElfW(Phdr) *p = l->l_phdr; + ElfW(Half) this, nent = l->l_phnum; + + /* For the common case of a stub being called from the containing + object, STUB_PC will point to somewhere within the object that + is described by the link map fetched via got[1]. Otherwise we + have to scan all maps. */ + for (this = 0; this < nent; this++) + { + if (p[this].p_type == PT_LOAD) + { + base = p[this].p_vaddr + l->l_addr; + limit = base + p[this].p_memsz; + if (stub_pc >= base && stub_pc < limit) + return l; + } + } + } + } + + struct link_map *l; + Lmid_t nsid; + + for (nsid = 0; nsid < DL_NNS; ++nsid) + for (l = GL(dl_ns)[nsid]._ns_loaded; l != NULL; l = l->l_next) + { + ElfW(Addr) base, limit; + const ElfW(Phdr) *p = l->l_phdr; + ElfW(Half) this, nent = l->l_phnum; + + for (this = 0; this < nent; ++this) + { + if (p[this].p_type == PT_LOAD) + { + base = p[this].p_vaddr + l->l_addr; + limit = base + p[this].p_memsz; + if (stub_pc >= base && stub_pc < limit) + return l; + } + } + } + + _dl_signal_error (0, NULL, NULL, "cannot find runtime link map"); + return NULL; +} + +/* Define mips specific runtime resolver. The function __dl_runtime_resolve + is called from assembler function _dl_runtime_resolve which converts + special argument registers t7 ($15) and t8 ($24): + t7 address to return to the caller of the function + t8 index for this function symbol in .dynsym + to usual c arguments. + + Other architectures call fixup from dl-runtime.c in + _dl_runtime_resolve. MIPS instead calls __dl_runtime_resolve. We + have to use our own version because of the way the got section is + treated on MIPS (we've also got ELF_MACHINE_PLT defined). */ + +/* The flag _dl_mips_gnu_objects is set if all dynamic objects are + generated by the gnu linker. */ +int _dl_mips_gnu_objects = 1; + +#define VERSYMIDX(sym) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (sym)) + +/* This is called from assembly stubs below which the compiler can't see. */ +static ElfW(Addr) +__dl_runtime_resolve (ElfW(Word), ElfW(Word), ElfW(Addr), ElfW(Addr)) + __attribute_used__; + +static ElfW(Addr) +__dl_runtime_resolve (ElfW(Word) sym_index, + ElfW(Word) return_address, + ElfW(Addr) old_gpreg, + ElfW(Addr) stub_pc) +{ + struct link_map *l = elf_machine_runtime_link_map (old_gpreg, stub_pc); + const ElfW(Sym) *const symtab + = (const ElfW(Sym) *) D_PTR (l, l_info[DT_SYMTAB]); + const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]); + ElfW(Addr) *got + = (ElfW(Addr) *) D_PTR (l, l_info[DT_PLTGOT]); + const ElfW(Word) local_gotno + = (const ElfW(Word)) l->l_info[DT_MIPS (LOCAL_GOTNO)]->d_un.d_val; + const ElfW(Word) gotsym + = (const ElfW(Word)) l->l_info[DT_MIPS (GOTSYM)]->d_un.d_val; + const ElfW(Sym) *sym = &symtab[sym_index]; + struct link_map *sym_map; + ElfW(Addr) value; + + /* FIXME: The symbol versioning stuff is not tested yet. */ + if (__builtin_expect (ELFW(ST_VISIBILITY) (sym->st_other), 0) == 0) + { + switch (l->l_info[VERSYMIDX (DT_VERSYM)] != NULL) + { + default: + { + const ElfW(Half) *vernum = + (const void *) D_PTR (l, l_info[VERSYMIDX (DT_VERSYM)]); + ElfW(Half) ndx = vernum[sym_index] & 0x7fff; + const struct r_found_version *version = &l->l_versions[ndx]; + + if (version->hash != 0) + { + /* We need to keep the scope around so do some locking. This is + not necessary for objects which cannot be unloaded or when + we are not using any threads (yet). */ + if (!RTLD_SINGLE_THREAD_P) + THREAD_GSCOPE_SET_FLAG (); + + sym_map = _dl_lookup_symbol_x (strtab + sym->st_name, l, + &sym, l->l_scope, version, + ELF_RTYPE_CLASS_PLT, 0, 0); + + /* We are done with the global scope. */ + if (!RTLD_SINGLE_THREAD_P) + THREAD_GSCOPE_RESET_FLAG (); + + break; + } + /* Fall through. */ + } + case 0: + { + /* We need to keep the scope around so do some locking. This is + not necessary for objects which cannot be unloaded or when + we are not using any threads (yet). */ + int flags = DL_LOOKUP_ADD_DEPENDENCY; + if (!RTLD_SINGLE_THREAD_P) + { + THREAD_GSCOPE_SET_FLAG (); + flags |= DL_LOOKUP_GSCOPE_LOCK; + } + + sym_map = _dl_lookup_symbol_x (strtab + sym->st_name, l, &sym, + l->l_scope, 0, ELF_RTYPE_CLASS_PLT, + flags, 0); + + /* We are done with the global scope. */ + if (!RTLD_SINGLE_THREAD_P) + THREAD_GSCOPE_RESET_FLAG (); + } + } + + /* Currently value contains the base load address of the object + that defines sym. Now add in the symbol offset. */ + value = (sym ? sym_map->l_addr + sym->st_value : 0); + } + else + /* We already found the symbol. The module (and therefore its load + address) is also known. */ + value = l->l_addr + sym->st_value; + + /* Apply the relocation with that value. */ + *(got + local_gotno + sym_index - gotsym) = value; + + return value; +} + +#if _MIPS_SIM == _ABIO32 +#define ELF_DL_FRAME_SIZE 40 + +#define ELF_DL_SAVE_ARG_REGS "\ + sw $15, 36($29)\n \ + sw $4, 16($29)\n \ + sw $5, 20($29)\n \ + sw $6, 24($29)\n \ + sw $7, 28($29)\n \ +" + +#define ELF_DL_RESTORE_ARG_REGS "\ + lw $31, 36($29)\n \ + lw $4, 16($29)\n \ + lw $5, 20($29)\n \ + lw $6, 24($29)\n \ + lw $7, 28($29)\n \ +" + +/* The PLT resolver should also save and restore $2 and $3, which are used + as arguments to MIPS16 stub functions. */ +#define ELF_DL_PLT_FRAME_SIZE 48 + +#define ELF_DL_PLT_SAVE_ARG_REGS \ + ELF_DL_SAVE_ARG_REGS "\ + sw $2, 40($29)\n \ + sw $3, 44($29)\n \ +" + +#define ELF_DL_PLT_RESTORE_ARG_REGS \ + ELF_DL_RESTORE_ARG_REGS "\ + lw $2, 40($29)\n \ + lw $3, 44($29)\n \ +" + +#define IFABIO32(X) X +#define IFNEWABI(X) + +#else /* _MIPS_SIM == _ABIN32 || _MIPS_SIM == _ABI64 */ + +#define ELF_DL_FRAME_SIZE 80 + +#define ELF_DL_SAVE_ARG_REGS "\ + sd $15, 72($29)\n \ + sd $4, 8($29)\n \ + sd $5, 16($29)\n \ + sd $6, 24($29)\n \ + sd $7, 32($29)\n \ + sd $8, 40($29)\n \ + sd $9, 48($29)\n \ + sd $10, 56($29)\n \ + sd $11, 64($29)\n \ +" + +#define ELF_DL_RESTORE_ARG_REGS "\ + ld $31, 72($29)\n \ + ld $4, 8($29)\n \ + ld $5, 16($29)\n \ + ld $6, 24($29)\n \ + ld $7, 32($29)\n \ + ld $8, 40($29)\n \ + ld $9, 48($29)\n \ + ld $10, 56($29)\n \ + ld $11, 64($29)\n \ +" + +/* The PLT resolver should also save and restore $2 and $3, which are used + as arguments to MIPS16 stub functions. */ +#define ELF_DL_PLT_FRAME_SIZE 96 + +#define ELF_DL_PLT_SAVE_ARG_REGS \ + ELF_DL_SAVE_ARG_REGS "\ + sd $2, 80($29)\n \ + sd $3, 88($29)\n \ +" + +#define ELF_DL_PLT_RESTORE_ARG_REGS \ + ELF_DL_RESTORE_ARG_REGS "\ + ld $2, 80($29)\n \ + ld $3, 88($29)\n \ +" + +#define IFABIO32(X) +#define IFNEWABI(X) X + +#endif + +asm ("\n\ + .text\n\ + .align 2\n\ + .globl _dl_runtime_resolve\n\ + .type _dl_runtime_resolve,@function\n\ + .ent _dl_runtime_resolve\n\ +_dl_runtime_resolve:\n\ + .frame $29, " STRINGXP(ELF_DL_FRAME_SIZE) ", $31\n\ + .set noreorder\n\ + # Save GP.\n\ +1: move $3, $28\n\ + # Save arguments and sp value in stack.\n\ + " STRINGXP(PTR_SUBIU) " $29, " STRINGXP(ELF_DL_FRAME_SIZE) "\n\ + # Modify t9 ($25) so as to point .cpload instruction.\n\ + " IFABIO32(STRINGXP(PTR_ADDIU) " $25, (2f-1b)\n") "\ + # Compute GP.\n\ +2: " STRINGXP(SETUP_GP) "\n\ + " STRINGXV(SETUP_GP64 (0, _dl_runtime_resolve)) "\n\ + .set reorder\n\ + # Save slot call pc.\n\ + move $2, $31\n\ + " IFABIO32(STRINGXP(CPRESTORE(32))) "\n\ + " ELF_DL_SAVE_ARG_REGS "\ + move $4, $24\n\ + move $5, $15\n\ + move $6, $3\n\ + move $7, $2\n\ + jal __dl_runtime_resolve\n\ + " ELF_DL_RESTORE_ARG_REGS "\ + " STRINGXP(RESTORE_GP64) "\n\ + " STRINGXP(PTR_ADDIU) " $29, " STRINGXP(ELF_DL_FRAME_SIZE) "\n\ + move $25, $2\n\ + jr $25\n\ + .end _dl_runtime_resolve\n\ + .previous\n\ +"); + +/* Assembler veneer called from the PLT header code when using PLTs. + + Code in each PLT entry and the PLT header fills in the arguments to + this function: + + - $15 (o32 t7, n32/n64 t3) - caller's return address + - $24 (t8) - PLT entry index + - $25 (t9) - address of _dl_runtime_pltresolve + - o32 $28 (gp), n32/n64 $14 (t2) - address of .got.plt + + Different registers are used for .got.plt because the ABI was + originally designed for o32, where gp was available (call + clobbered). On n32/n64 gp is call saved. + + _dl_fixup needs: + + - $4 (a0) - link map address + - $5 (a1) - .rel.plt offset (== PLT entry index * 8) */ + +asm ("\n\ + .text\n\ + .align 2\n\ + .globl _dl_runtime_pltresolve\n\ + .type _dl_runtime_pltresolve,@function\n\ + .ent _dl_runtime_pltresolve\n\ +_dl_runtime_pltresolve:\n\ + .frame $29, " STRINGXP(ELF_DL_PLT_FRAME_SIZE) ", $31\n\ + .set noreorder\n\ + # Save arguments and sp value in stack.\n\ +1: " STRINGXP(PTR_SUBIU) " $29, " STRINGXP(ELF_DL_PLT_FRAME_SIZE) "\n\ + " IFABIO32(STRINGXP(PTR_L) " $13, " STRINGXP(PTRSIZE) "($28)") "\n\ + " IFNEWABI(STRINGXP(PTR_L) " $13, " STRINGXP(PTRSIZE) "($14)") "\n\ + # Modify t9 ($25) so as to point .cpload instruction.\n\ + " IFABIO32(STRINGXP(PTR_ADDIU) " $25, (2f-1b)\n") "\ + # Compute GP.\n\ +2: " STRINGXP(SETUP_GP) "\n\ + " STRINGXV(SETUP_GP64 (0, _dl_runtime_pltresolve)) "\n\ + .set reorder\n\ + " IFABIO32(STRINGXP(CPRESTORE(32))) "\n\ + " ELF_DL_PLT_SAVE_ARG_REGS "\ + move $4, $13\n\ + sll $5, $24, " STRINGXP(PTRLOG) " + 1\n\ + jal _dl_fixup\n\ + move $25, $2\n\ + " ELF_DL_PLT_RESTORE_ARG_REGS "\ + " STRINGXP(RESTORE_GP64) "\n\ + " STRINGXP(PTR_ADDIU) " $29, " STRINGXP(ELF_DL_PLT_FRAME_SIZE) "\n\ + jr $25\n\ + .end _dl_runtime_pltresolve\n\ + .previous\n\ +"); + |