| /* |
| * Copyright (C) 2015 The Android Open Source Project |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
| * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
| * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
| * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
| * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| */ |
| |
| #if !defined(__LP64__) && __mips_isa_rev >= 5 |
| #include <sys/prctl.h> |
| #endif |
| |
| #include "linker.h" |
| #include "linker_debug.h" |
| #include "linker_globals.h" |
| #include "linker_phdr.h" |
| #include "linker_relocs.h" |
| #include "linker_reloc_iterators.h" |
| #include "linker_sleb128.h" |
| #include "linker_soinfo.h" |
| |
| template bool soinfo::relocate<plain_reloc_iterator>(const VersionTracker& version_tracker, |
| plain_reloc_iterator&& rel_iterator, |
| const soinfo_list_t& global_group, |
| const soinfo_list_t& local_group); |
| |
| template bool soinfo::relocate<packed_reloc_iterator<sleb128_decoder>>( |
| const VersionTracker& version_tracker, |
| packed_reloc_iterator<sleb128_decoder>&& rel_iterator, |
| const soinfo_list_t& global_group, |
| const soinfo_list_t& local_group); |
| |
| template <typename ElfRelIteratorT> |
| bool soinfo::relocate(const VersionTracker& version_tracker, |
| ElfRelIteratorT&& rel_iterator, |
| const soinfo_list_t& global_group, |
| const soinfo_list_t& local_group) { |
| for (size_t idx = 0; rel_iterator.has_next(); ++idx) { |
| const auto rel = rel_iterator.next(); |
| |
| if (rel == nullptr) { |
| return false; |
| } |
| |
| ElfW(Word) type = ELFW(R_TYPE)(rel->r_info); |
| ElfW(Word) sym = ELFW(R_SYM)(rel->r_info); |
| |
| ElfW(Addr) reloc = static_cast<ElfW(Addr)>(rel->r_offset + load_bias); |
| ElfW(Addr) sym_addr = 0; |
| const char* sym_name = nullptr; |
| |
| DEBUG("Processing \"%s\" relocation at index %zd", get_realpath(), idx); |
| if (type == R_GENERIC_NONE) { |
| continue; |
| } |
| |
| const ElfW(Sym)* s = nullptr; |
| soinfo* lsi = nullptr; |
| |
| if (sym != 0) { |
| sym_name = get_string(symtab_[sym].st_name); |
| const version_info* vi = nullptr; |
| |
| if (!lookup_version_info(version_tracker, sym, sym_name, &vi)) { |
| return false; |
| } |
| |
| if (!soinfo_do_lookup(this, sym_name, vi, &lsi, global_group, local_group, &s)) { |
| return false; |
| } |
| |
| if (s == nullptr) { |
| // mips does not support relocation with weak-undefined symbols |
| DL_ERR("cannot locate symbol \"%s\" referenced by \"%s\"...", |
| sym_name, get_realpath()); |
| return false; |
| } else { |
| // We got a definition. |
| sym_addr = lsi->resolve_symbol_address(s); |
| } |
| count_relocation(kRelocSymbol); |
| } |
| |
| switch (type) { |
| case R_MIPS_REL32: |
| #if defined(__LP64__) |
| // MIPS Elf64_Rel entries contain compound relocations |
| // We only handle the R_MIPS_NONE|R_MIPS_64|R_MIPS_REL32 case |
| if (ELF64_R_TYPE2(rel->r_info) != R_MIPS_64 || |
| ELF64_R_TYPE3(rel->r_info) != R_MIPS_NONE) { |
| DL_ERR("Unexpected compound relocation type:%d type2:%d type3:%d @ %p (%zu)", |
| type, static_cast<unsigned>(ELF64_R_TYPE2(rel->r_info)), |
| static_cast<unsigned>(ELF64_R_TYPE3(rel->r_info)), rel, idx); |
| return false; |
| } |
| #endif |
| count_relocation(s == nullptr ? kRelocAbsolute : kRelocRelative); |
| MARK(rel->r_offset); |
| TRACE_TYPE(RELO, "RELO REL32 %08zx <- %08zx %s", static_cast<size_t>(reloc), |
| static_cast<size_t>(sym_addr), sym_name ? sym_name : "*SECTIONHDR*"); |
| if (s != nullptr) { |
| *reinterpret_cast<ElfW(Addr)*>(reloc) += sym_addr; |
| } else { |
| *reinterpret_cast<ElfW(Addr)*>(reloc) += load_bias; |
| } |
| break; |
| default: |
| DL_ERR("unknown reloc type %d @ %p (%zu)", type, rel, idx); |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| bool soinfo::mips_relocate_got(const VersionTracker& version_tracker, |
| const soinfo_list_t& global_group, |
| const soinfo_list_t& local_group) { |
| ElfW(Addr)** got = plt_got_; |
| if (got == nullptr) { |
| return true; |
| } |
| |
| // got[0] is the address of the lazy resolver function. |
| // got[1] may be used for a GNU extension. |
| // FIXME: maybe this should be in a separate routine? |
| if ((flags_ & FLAG_LINKER) == 0) { |
| size_t g = 1; |
| // Check for the high bit to determine whether to skip got[1] |
| if (reinterpret_cast<intptr_t>(got[g]) < 0) { |
| g++; |
| } |
| // Relocate the local GOT entries. |
| for (; g < mips_local_gotno_; g++) { |
| got[g] = reinterpret_cast<ElfW(Addr)*>(reinterpret_cast<uintptr_t>(got[g]) + load_bias); |
| } |
| } |
| |
| // Now for the global GOT entries... |
| got = plt_got_ + mips_local_gotno_; |
| for (ElfW(Word) sym = mips_gotsym_; sym < mips_symtabno_; sym++, got++) { |
| // This is an undefined reference... try to locate it. |
| const ElfW(Sym)* local_sym = symtab_ + sym; |
| const char* sym_name = get_string(local_sym->st_name); |
| soinfo* lsi = nullptr; |
| const ElfW(Sym)* s = nullptr; |
| |
| ElfW(Word) st_visibility = (local_sym->st_other & 0x3); |
| |
| if (st_visibility == STV_DEFAULT) { |
| const version_info* vi = nullptr; |
| |
| if (!lookup_version_info(version_tracker, sym, sym_name, &vi)) { |
| return false; |
| } |
| |
| if (!soinfo_do_lookup(this, sym_name, vi, &lsi, global_group, local_group, &s)) { |
| return false; |
| } |
| } else if (st_visibility == STV_PROTECTED) { |
| if (local_sym->st_value == 0) { |
| DL_ERR("%s: invalid symbol \"%s\" (PROTECTED/UNDEFINED) ", |
| get_realpath(), sym_name); |
| return false; |
| } |
| s = local_sym; |
| lsi = this; |
| } else { |
| DL_ERR("%s: invalid symbol \"%s\" visibility: 0x%x", |
| get_realpath(), sym_name, st_visibility); |
| return false; |
| } |
| |
| if (s == nullptr) { |
| // We only allow an undefined symbol if this is a weak reference. |
| if (ELF_ST_BIND(local_sym->st_info) != STB_WEAK) { |
| DL_ERR("%s: cannot locate \"%s\"...", get_realpath(), sym_name); |
| return false; |
| } |
| *got = 0; |
| } else { |
| // FIXME: is this sufficient? |
| // For reference see NetBSD link loader |
| // http://cvsweb.netbsd.org/bsdweb.cgi/src/libexec/ld.elf_so/arch/mips/mips_reloc.c?rev=1.53&content-type=text/x-cvsweb-markup |
| *got = reinterpret_cast<ElfW(Addr)*>(lsi->resolve_symbol_address(s)); |
| } |
| } |
| return true; |
| } |
| |
| #if !defined(__LP64__) |
| |
| // Checks for mips32's various floating point abis. |
| // (Mips64 Android has a single floating point abi and doesn't need any checks) |
| |
| // Linux kernel has declarations similar to the following |
| // in <linux>/arch/mips/include/asm/elf.h, |
| // but that non-uapi internal header file will never be imported |
| // into bionic's kernel headers. |
| |
| #define PT_MIPS_ABIFLAGS 0x70000003 // is .MIPS.abiflags segment |
| |
| struct mips_elf_abiflags_v0 { |
| uint16_t version; // version of this structure |
| uint8_t isa_level, isa_rev, gpr_size, cpr1_size, cpr2_size; |
| uint8_t fp_abi; // mips32 ABI variants for floating point |
| uint32_t isa_ext, ases, flags1, flags2; |
| }; |
| |
| // Bits of flags1: |
| #define MIPS_AFL_FLAGS1_ODDSPREG 1 // Uses odd-numbered single-prec fp regs |
| |
| // Some values of fp_abi: via compiler flag: |
| #define MIPS_ABI_FP_ANY 0 // Not tagged or not using any ABIs affected by the differences. |
| #define MIPS_ABI_FP_DOUBLE 1 // -mdouble-float |
| #define MIPS_ABI_FP_XX 5 // -mfpxx |
| #define MIPS_ABI_FP_64A 7 // -mips32r* -mfp64 -mno-odd-spreg |
| |
| #if __mips_isa_rev >= 5 |
| static bool mips_fre_mode_on = false; // have set FRE=1 mode for process |
| #endif |
| |
| bool soinfo::mips_check_and_adjust_fp_modes() { |
| mips_elf_abiflags_v0* abiflags = nullptr; |
| int mips_fpabi; |
| |
| // Find soinfo's optional .MIPS.abiflags segment |
| for (size_t i = 0; i<phnum; ++i) { |
| const ElfW(Phdr)& ph = phdr[i]; |
| if (ph.p_type == PT_MIPS_ABIFLAGS) { |
| if (ph.p_filesz < sizeof (mips_elf_abiflags_v0)) { |
| DL_ERR("Corrupt PT_MIPS_ABIFLAGS header found \"%s\"", get_realpath()); |
| return false; |
| } |
| abiflags = reinterpret_cast<mips_elf_abiflags_v0*>(ph.p_vaddr + load_bias); |
| break; |
| } |
| } |
| |
| // FP ABI-variant compatibility checks for MIPS o32 ABI |
| if (abiflags == nullptr) { |
| // Old compilers lack the new abiflags section. |
| // These compilers used -mfp32 -mdouble-float -modd-spreg defaults, |
| // ie FP32 aka DOUBLE, using odd-numbered single-prec regs |
| mips_fpabi = MIPS_ABI_FP_DOUBLE; |
| } else { |
| mips_fpabi = abiflags->fp_abi; |
| if ( (abiflags->flags1 & MIPS_AFL_FLAGS1_ODDSPREG) |
| && (mips_fpabi == MIPS_ABI_FP_XX || |
| mips_fpabi == MIPS_ABI_FP_64A ) ) { |
| // Android supports fewer cases than Linux |
| DL_ERR("Unsupported odd-single-prec FloatPt reg uses in \"%s\"", |
| get_realpath()); |
| return false; |
| } |
| } |
| if (!(mips_fpabi == MIPS_ABI_FP_DOUBLE || |
| #if __mips_isa_rev >= 5 |
| mips_fpabi == MIPS_ABI_FP_64A || |
| #endif |
| mips_fpabi == MIPS_ABI_FP_ANY || |
| mips_fpabi == MIPS_ABI_FP_XX )) { |
| DL_ERR("Unsupported MIPS32 FloatPt ABI %d found in \"%s\"", |
| mips_fpabi, get_realpath()); |
| return false; |
| } |
| |
| #if __mips_isa_rev >= 5 |
| // Adjust process's FR Emulation mode, if needed |
| // |
| // On Mips R5 & R6, Android runs continuously in FR=1 64bit-fpreg mode. |
| // NDK mips32 apps compiled with old compilers generate FP32 code |
| // which expects FR=0 32-bit fp registers. |
| // NDK mips32 apps compiled with newer compilers generate modeless |
| // FPXX code which runs on both FR=0 and FR=1 modes. |
| // Android itself is compiled in FP64A which requires FR=1 mode. |
| // FP32, FPXX, and FP64A all interlink okay, without dynamic FR mode |
| // changes during calls. For details, see |
| // http://dmz-portal.mips.com/wiki/MIPS_O32_ABI_-_FR0_and_FR1_Interlinking |
| // Processes containing FR32 FR=0 code are run via kernel software assist, |
| // which maps all odd-numbered single-precision reg refs onto the |
| // upper half of the paired even-numbered double-precision reg. |
| // FRE=1 triggers traps to the kernel's emulator on every single-precision |
| // fp op (for both odd and even-numbered registers). |
| // Turning on FRE=1 traps is done at most once per process, simultanously |
| // for all threads of that process, when dlopen discovers FP32 code. |
| // The kernel repacks threads' registers when FRE mode is turn on or off. |
| // These asynchronous adjustments are wrong if any thread was executing |
| // FPXX code using odd-numbered single-precision regs. |
| // Current Android compilers default to the -mno-oddspreg option, |
| // and this requirement is checked by Android's dlopen. |
| // So FRE can always be safely turned on for FP32, anytime. |
| // Deferred enhancement: Allow loading of odd-spreg FPXX modules. |
| |
| if (mips_fpabi == MIPS_ABI_FP_DOUBLE && !mips_fre_mode_on) { |
| // Turn on FRE mode, which emulates mode-sensitive FR=0 code on FR=1 |
| // register files, by trapping to kernel on refs to single-precision regs |
| if (prctl(PR_SET_FP_MODE, PR_FP_MODE_FR|PR_FP_MODE_FRE)) { |
| DL_ERR("Kernel or cpu failed to set FRE mode required for running \"%s\"", |
| get_realpath()); |
| return false; |
| } |
| DL_WARN("Using FRE=1 mode to run \"%s\"", get_realpath()); |
| mips_fre_mode_on = true; // Avoid future redundant mode-switch calls |
| // FRE mode is never turned back off. |
| // Deferred enhancement: |
| // Reset FRE mode when dlclose() removes all FP32 modules |
| } |
| #else |
| // Android runs continuously in FR=0 32bit-fpreg mode. |
| #endif // __mips_isa_rev |
| return true; |
| } |
| |
| #endif // __LP64___ |