X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=gold%2Fs390.cc;h=23a203223d702b330cea1147f8ca7511f00a2d68;hb=48189beca8aeb629deaf2d92268d6d234ce19aeb;hp=2671441a2ac7bb2ff06a4909b52edb25cc309774;hpb=4d625b70fc3fb7facc7159feb8d49b78ac6641f9;p=deliverable%2Fbinutils-gdb.git diff --git a/gold/s390.cc b/gold/s390.cc index 2671441a2a..23a203223d 100644 --- a/gold/s390.cc +++ b/gold/s390.cc @@ -1,6 +1,6 @@ // s390.cc -- s390 target support for gold. -// Copyright (C) 2015-2016 Free Software Foundation, Inc. +// Copyright (C) 2015-2020 Free Software Foundation, Inc. // Written by Marcin Kościelnicki . // This file is part of gold. @@ -417,6 +417,20 @@ class Target_s390 : public Sized_target do_can_check_for_function_pointers() const { return true; } + // Return whether SYM is call to a non-split function. + bool + do_is_call_to_non_split(const Symbol* sym, const unsigned char* preloc, + const unsigned char* view, + section_size_type view_size) const; + + // Adjust -fsplit-stack code which calls non-split-stack code. + void + do_calls_non_split(Relobj* object, unsigned int shndx, + section_offset_type fnoffset, section_size_type fnsize, + const unsigned char* prelocs, size_t reloc_count, + unsigned char* view, section_size_type view_size, + std::string* from, std::string* to) const; + // Return the size of the GOT section. section_size_type got_size() const @@ -693,6 +707,17 @@ class Target_s390 : public Sized_target this->rela_dyn_section(layout)); } + // A function for targets to call. Return whether BYTES/LEN matches + // VIEW/VIEW_SIZE at OFFSET. Like the one in Target, but takes + // an unsigned char * parameter. + bool + match_view_u(const unsigned char* view, section_size_type view_size, + section_offset_type offset, const unsigned char* bytes, size_t len) const + { + return this->match_view(view, view_size, offset, + reinterpret_cast(bytes), len); + } + // Information about this specific target which we pass to the // general Target structure. static Target::Target_info s390_info; @@ -730,6 +755,50 @@ class Target_s390 : public Sized_target bool tls_base_symbol_defined_; // For use in do_tls_offset_for_* Layout *layout_; + + // Code sequences for -fsplit-stack matching. + static const unsigned char ss_code_bras_8[]; + static const unsigned char ss_code_l_basr[]; + static const unsigned char ss_code_a_basr[]; + static const unsigned char ss_code_larl[]; + static const unsigned char ss_code_brasl[]; + static const unsigned char ss_code_jg[]; + static const unsigned char ss_code_jgl[]; + + // Variable code sequence matchers for -fsplit-stack. + bool ss_match_st_r14(unsigned char* view, + section_size_type view_size, + section_offset_type *offset) const; + bool ss_match_l_r14(unsigned char* view, + section_size_type view_size, + section_offset_type *offset) const; + bool ss_match_mcount(unsigned char* view, + section_size_type view_size, + section_offset_type *offset) const; + bool ss_match_ear(unsigned char* view, + section_size_type view_size, + section_offset_type *offset) const; + bool ss_match_c(unsigned char* view, + section_size_type view_size, + section_offset_type *offset) const; + bool ss_match_l(unsigned char* view, + section_size_type view_size, + section_offset_type *offset, + int *guard_reg) const; + bool ss_match_ahi(unsigned char* view, + section_size_type view_size, + section_offset_type *offset, + int guard_reg, + uint32_t *arg) const; + bool ss_match_alfi(unsigned char* view, + section_size_type view_size, + section_offset_type *offset, + int guard_reg, + uint32_t *arg) const; + bool ss_match_cr(unsigned char* view, + section_size_type view_size, + section_offset_type *offset, + int guard_reg) const; }; template<> @@ -758,6 +827,7 @@ Target::Target_info Target_s390<32>::s390_info = NULL, // attributes_vendor "_start", // entry_symbol_name 32, // hash_entry_size + elfcpp::SHT_PROGBITS, // unwind_section_type }; template<> @@ -786,6 +856,7 @@ Target::Target_info Target_s390<64>::s390_info = NULL, // attributes_vendor "_start", // entry_symbol_name 64, // hash_entry_size + elfcpp::SHT_PROGBITS, // unwind_section_type }; template @@ -2486,7 +2557,7 @@ Target_s390::Scan::local(Symbol_table* symtab, unsupported_reloc_local(object, r_type); } } - // fall through + // Fall through. case elfcpp::R_390_TLS_IEENT: case elfcpp::R_390_TLS_GOTIE12: case elfcpp::R_390_TLS_GOTIE20: @@ -2924,7 +2995,7 @@ Target_s390::Scan::global(Symbol_table* symtab, unsupported_reloc_global(object, r_type, gsym); } } - // fall through + // Fall through. case elfcpp::R_390_TLS_IEENT: case elfcpp::R_390_TLS_GOTIE12: case elfcpp::R_390_TLS_GOTIE20: @@ -3172,7 +3243,7 @@ Target_s390::Relocate::relocate( || (gsym->is_defined() && !gsym->is_from_dynobj() && !gsym->is_preemptible())); - // fallthru + // Fall through. case elfcpp::R_390_8: case elfcpp::R_390_12: case elfcpp::R_390_16: @@ -3201,7 +3272,7 @@ Target_s390::Relocate::relocate( gold_assert(gsym == NULL || gsym->has_plt_offset() || gsym->final_value_is_known()); - // fallthru + // Fall through. case elfcpp::R_390_GOTOFF64: case elfcpp::R_390_GOTOFF32: case elfcpp::R_390_GOTOFF16: @@ -4192,6 +4263,622 @@ Target_s390::do_code_fill(section_size_type length) const return std::string(length, static_cast(0x07)); } +// Return whether SYM should be treated as a call to a non-split +// function. We don't want that to be true of a larl instruction +// that merely loads its address. + +template +bool +Target_s390::do_is_call_to_non_split(const Symbol* sym, + const unsigned char* preloc, + const unsigned char* view, + section_size_type view_size) const +{ + if (sym->type() != elfcpp::STT_FUNC) + return false; + typename Reloc_types::Reloc reloc(preloc); + typename elfcpp::Elf_types::Elf_WXword r_info + = reloc.get_r_info(); + unsigned int r_type = elfcpp::elf_r_type(r_info); + section_offset_type offset = reloc.get_r_offset(); + switch (r_type) + { + // PLT refs always involve calling the function. + case elfcpp::R_390_PLT12DBL: + case elfcpp::R_390_PLT16DBL: + case elfcpp::R_390_PLT24DBL: + case elfcpp::R_390_PLT32: + case elfcpp::R_390_PLT32DBL: + case elfcpp::R_390_PLT64: + case elfcpp::R_390_PLTOFF16: + case elfcpp::R_390_PLTOFF32: + case elfcpp::R_390_PLTOFF64: + // Could be used for calls for -msmall-exec. + case elfcpp::R_390_PC16DBL: + return true; + + // Tricky case. When used in a brasl, jg, and other branch instructions, + // it's a call or a sibcall. However, when used in larl, it only loads + // the function's address - not a call. + case elfcpp::R_390_PC32DBL: + { + if (offset < 2 + || offset + 4 > static_cast(view_size)) + { + // Should not happen. + gold_error(_("instruction with PC32DBL not wholly within section")); + return false; + } + + uint8_t op0 = view[offset-2]; + uint8_t op1 = view[offset-1] & 0xf; + + // LARL + if (op0 == 0xc0 && op1 == 0) + return false; + + // Otherwise, it's either a call instruction, a branch instruction + // (used as a sibcall), or a data manipulation instruction (which + // has no business being used on a function, and can be ignored). + return true; + } + + // Otherwise, it's probably not a call. + default: + return false; + } +} + +// Code sequences to match below. + +template +const unsigned char +Target_s390::ss_code_bras_8[] = { + 0xa7, 0x15, 0x00, 0x06, // bras %r1, .+0xc +}; + +template +const unsigned char +Target_s390::ss_code_l_basr[] = { + 0x58, 0xe0, 0x10, 0x00, // l %r14, 0(%r1) + 0x58, 0x10, 0x10, 0x04, // l %r1, 4(%r1) + 0x0d, 0xee, // basr %r14, %r14 +}; + +template +const unsigned char +Target_s390::ss_code_a_basr[] = { + 0x18, 0xe1, // lr %r14, %r1 + 0x5a, 0xe0, 0x10, 0x00, // a %r14, 0(%r1) + 0x5a, 0x10, 0x10, 0x04, // a %r1, 4(%r1) + 0x0d, 0xee, // basr %r14, %r14 +}; + +template +const unsigned char +Target_s390::ss_code_larl[] = { + 0xc0, 0x10, // larl %r1, ... +}; + +template +const unsigned char +Target_s390::ss_code_brasl[] = { + 0xc0, 0xe5, // brasl %r14, ... +}; + +template +const unsigned char +Target_s390::ss_code_jg[] = { + 0xc0, 0xf4, // jg ... +}; + +template +const unsigned char +Target_s390::ss_code_jgl[] = { + 0xc0, 0x44, // jgl ... +}; + +template<> +bool +Target_s390<32>::ss_match_st_r14(unsigned char* view, + section_size_type view_size, + section_offset_type *offset) const +{ + static const unsigned char ss_code_st_r14[] = { + 0x50, 0xe0, 0xf0, 0x04, // st %r14, 4(%r15) + }; + if (!this->match_view_u(view, view_size, *offset, ss_code_st_r14, + sizeof ss_code_st_r14)) + return false; + *offset += sizeof ss_code_st_r14; + return true; +} + +template<> +bool +Target_s390<64>::ss_match_st_r14(unsigned char* view, + section_size_type view_size, + section_offset_type *offset) const +{ + static const unsigned char ss_code_st_r14[] = { + 0xe3, 0xe0, 0xf0, 0x08, 0x00, 0x24 // stg %r14, 8(%r15) + }; + if (!this->match_view_u(view, view_size, *offset, ss_code_st_r14, + sizeof ss_code_st_r14)) + return false; + *offset += sizeof ss_code_st_r14; + return true; +} + +template<> +bool +Target_s390<32>::ss_match_l_r14(unsigned char* view, + section_size_type view_size, + section_offset_type *offset) const +{ + static const unsigned char ss_code_l_r14[] = { + 0x58, 0xe0, 0xf0, 0x04, // l %r14, 4(%r15) + }; + if (!this->match_view_u(view, view_size, *offset, ss_code_l_r14, + sizeof ss_code_l_r14)) + return false; + *offset += sizeof ss_code_l_r14; + return true; +} + +template<> +bool +Target_s390<64>::ss_match_l_r14(unsigned char* view, + section_size_type view_size, + section_offset_type *offset) const +{ + static const unsigned char ss_code_l_r14[] = { + 0xe3, 0xe0, 0xf0, 0x08, 0x00, 0x04 // lg %r14, 8(%r15) + }; + if (!this->match_view_u(view, view_size, *offset, ss_code_l_r14, + sizeof ss_code_l_r14)) + return false; + *offset += sizeof ss_code_l_r14; + return true; +} + +template +bool +Target_s390::ss_match_mcount(unsigned char* view, + section_size_type view_size, + section_offset_type *offset) const +{ + // Match the mcount call sequence. + section_offset_type myoff = *offset; + + // First, look for the store instruction saving %r14. + if (!this->ss_match_st_r14(view, view_size, &myoff)) + return false; + + // Now, param load and the actual call. + if (this->match_view_u(view, view_size, myoff, ss_code_larl, + sizeof ss_code_larl)) + { + myoff += sizeof ss_code_larl + 4; + + // After larl, expect a brasl. + if (!this->match_view_u(view, view_size, myoff, ss_code_brasl, + sizeof ss_code_brasl)) + return false; + myoff += sizeof ss_code_brasl + 4; + } + else if (size == 32 && + this->match_view_u(view, view_size, myoff, ss_code_bras_8, + sizeof ss_code_bras_8)) + { + // The bras skips over a block of 8 bytes, loading its address + // to %r1. + myoff += sizeof ss_code_bras_8 + 8; + + // Now, there are two sequences used for actual load and call, + // absolute and PIC. + if (this->match_view_u(view, view_size, myoff, ss_code_l_basr, + sizeof ss_code_l_basr)) + myoff += sizeof ss_code_l_basr; + else if (this->match_view_u(view, view_size, myoff, ss_code_a_basr, + sizeof ss_code_a_basr)) + myoff += sizeof ss_code_a_basr; + else + return false; + } + else + return false; + + // Finally, a load bringing %r14 back. + if (!this->ss_match_l_r14(view, view_size, &myoff)) + return false; + + // Found it. + *offset = myoff; + return true; +} + +template<> +bool +Target_s390<32>::ss_match_ear(unsigned char* view, + section_size_type view_size, + section_offset_type *offset) const +{ + static const unsigned char ss_code_ear[] = { + 0xb2, 0x4f, 0x00, 0x10, // ear %r1, %a0 + }; + if (!this->match_view_u(view, view_size, *offset, ss_code_ear, + sizeof ss_code_ear)) + return false; + *offset += sizeof ss_code_ear; + return true; +} + +template<> +bool +Target_s390<64>::ss_match_ear(unsigned char* view, + section_size_type view_size, + section_offset_type *offset) const +{ + static const unsigned char ss_code_ear[] = { + 0xb2, 0x4f, 0x00, 0x10, // ear %r1, %a0 + 0xeb, 0x11, 0x00, 0x20, 0x00, 0x0d, // sllg %r1,%r1,32 + 0xb2, 0x4f, 0x00, 0x11, // ear %r1, %a1 + }; + if (!this->match_view_u(view, view_size, *offset, ss_code_ear, + sizeof ss_code_ear)) + return false; + *offset += sizeof ss_code_ear; + return true; +} + +template<> +bool +Target_s390<32>::ss_match_c(unsigned char* view, + section_size_type view_size, + section_offset_type *offset) const +{ + static const unsigned char ss_code_c[] = { + 0x59, 0xf0, 0x10, 0x20, // c %r15, 0x20(%r1) + }; + if (!this->match_view_u(view, view_size, *offset, ss_code_c, + sizeof ss_code_c)) + return false; + *offset += sizeof ss_code_c; + return true; +} + +template<> +bool +Target_s390<64>::ss_match_c(unsigned char* view, + section_size_type view_size, + section_offset_type *offset) const +{ + static const unsigned char ss_code_c[] = { + 0xe3, 0xf0, 0x10, 0x38, 0x00, 0x20, // cg %r15, 0x38(%r1) + }; + if (!this->match_view_u(view, view_size, *offset, ss_code_c, + sizeof ss_code_c)) + return false; + *offset += sizeof ss_code_c; + return true; +} + +template<> +bool +Target_s390<32>::ss_match_l(unsigned char* view, + section_size_type view_size, + section_offset_type *offset, + int *guard_reg) const +{ + // l %guard_reg, 0x20(%r1) + if (convert_to_section_size_type(*offset + 4) > view_size + || view[*offset] != 0x58 + || (view[*offset + 1] & 0xf) != 0x0 + || view[*offset + 2] != 0x10 + || view[*offset + 3] != 0x20) + return false; + *offset += 4; + *guard_reg = view[*offset + 1] >> 4 & 0xf; + return true; +} + +template<> +bool +Target_s390<64>::ss_match_l(unsigned char* view, + section_size_type view_size, + section_offset_type *offset, + int *guard_reg) const +{ + // lg %guard_reg, 0x38(%r1) + if (convert_to_section_size_type(*offset + 6) > view_size + || view[*offset] != 0xe3 + || (view[*offset + 1] & 0xf) != 0x0 + || view[*offset + 2] != 0x10 + || view[*offset + 3] != 0x38 + || view[*offset + 4] != 0x00 + || view[*offset + 5] != 0x04) + return false; + *offset += 6; + *guard_reg = view[*offset + 1] >> 4 & 0xf; + return true; +} + +template +bool +Target_s390::ss_match_ahi(unsigned char* view, + section_size_type view_size, + section_offset_type *offset, + int guard_reg, + uint32_t *arg) const +{ + int op = size == 32 ? 0xa : 0xb; + // a[g]hi %guard_reg, + if (convert_to_section_size_type(*offset + 4) > view_size + || view[*offset] != 0xa7 + || view[*offset + 1] != (guard_reg << 4 | op) + // Disallow negative size. + || view[*offset + 2] & 0x80) + return false; + *arg = elfcpp::Swap<16, true>::readval(view + *offset + 2); + *offset += 4; + return true; +} + +template +bool +Target_s390::ss_match_alfi(unsigned char* view, + section_size_type view_size, + section_offset_type *offset, + int guard_reg, + uint32_t *arg) const +{ + int op = size == 32 ? 0xb : 0xa; + // al[g]fi %guard_reg, + if (convert_to_section_size_type(*offset + 6) > view_size + || view[*offset] != 0xc2 + || view[*offset + 1] != (guard_reg << 4 | op)) + return false; + *arg = elfcpp::Swap<32, true>::readval(view + *offset + 2); + *offset += 6; + return true; +} + +template<> +bool +Target_s390<32>::ss_match_cr(unsigned char* view, + section_size_type view_size, + section_offset_type *offset, + int guard_reg) const +{ + // cr %r15, %guard_reg + if (convert_to_section_size_type(*offset + 2) > view_size + || view[*offset] != 0x19 + || view[*offset + 1] != (0xf0 | guard_reg)) + return false; + *offset += 2; + return true; +} + +template<> +bool +Target_s390<64>::ss_match_cr(unsigned char* view, + section_size_type view_size, + section_offset_type *offset, + int guard_reg) const +{ + // cgr %r15, %guard_reg + if (convert_to_section_size_type(*offset + 4) > view_size + || view[*offset] != 0xb9 + || view[*offset + 1] != 0x20 + || view[*offset + 2] != 0x00 + || view[*offset + 3] != (0xf0 | guard_reg)) + return false; + *offset += 4; + return true; +} + + +// FNOFFSET in section SHNDX in OBJECT is the start of a function +// compiled with -fsplit-stack. The function calls non-split-stack +// code. We have to change the function so that it always ensures +// that it has enough stack space to run some random function. + +template +void +Target_s390::do_calls_non_split(Relobj* object, unsigned int shndx, + section_offset_type fnoffset, + section_size_type, + const unsigned char *prelocs, + size_t reloc_count, + unsigned char* view, + section_size_type view_size, + std::string*, + std::string*) const +{ + // true if there's a conditional call to __morestack in the function, + // false if there's an unconditional one. + bool conditional = false; + // Offset of the byte after the compare insn, if conditional. + section_offset_type cmpend = 0; + // Type and immediate offset of the add instruction that adds frame size + // to guard. + enum { + SS_ADD_NONE, + SS_ADD_AHI, + SS_ADD_ALFI, + } fsadd_type = SS_ADD_NONE; + section_offset_type fsadd_offset = 0; + uint32_t fsadd_frame_size = 0; + // Register used for loading guard. Usually r1, but can also be r0 or r2-r5. + int guard_reg; + // Offset of the conditional jump. + section_offset_type jump_offset = 0; + // Section view and offset of param block. + section_offset_type param_offset = 0; + unsigned char *param_view = 0; + section_size_type param_view_size = 0; + // Current position in function. + section_offset_type curoffset = fnoffset; + // And the position of split-stack prologue. + section_offset_type ssoffset; + // Frame size. + typename elfcpp::Elf_types::Elf_Addr frame_size; + // Relocation parsing. + typedef typename Reloc_types::Reloc Reltype; + const int reloc_size = Reloc_types::reloc_size; + const unsigned char *pr = prelocs; + + // If the function was compiled with -pg, the profiling code may come before + // the split-stack prologue. Skip it. + + this->ss_match_mcount(view, view_size, &curoffset); + ssoffset = curoffset; + + // First, figure out if there's a conditional call by looking for the + // extract-tp, add, cmp sequence. + + if (this->ss_match_ear(view, view_size, &curoffset)) + { + // Found extract-tp, now look for an add and compare. + conditional = true; + if (this->ss_match_c(view, view_size, &curoffset)) + { + // Found a direct compare of stack pointer with the guard, + // we're done here. + } + else if (this->ss_match_l(view, view_size, &curoffset, &guard_reg)) + { + // Found a load of guard to register, look for an add and compare. + if (this->ss_match_ahi(view, view_size, &curoffset, guard_reg, + &fsadd_frame_size)) + { + fsadd_type = SS_ADD_AHI; + fsadd_offset = curoffset - 2; + } + else if (this->ss_match_alfi(view, view_size, &curoffset, guard_reg, + &fsadd_frame_size)) + { + fsadd_type = SS_ADD_ALFI; + fsadd_offset = curoffset - 4; + } + else + { + goto bad; + } + // Now, there has to be a compare. + if (!this->ss_match_cr(view, view_size, &curoffset, guard_reg)) + goto bad; + } + else + { + goto bad; + } + cmpend = curoffset; + } + + // Second, look for the call. + if (!this->match_view_u(view, view_size, curoffset, ss_code_larl, + sizeof ss_code_larl)) + goto bad; + curoffset += sizeof ss_code_larl; + + // Find out larl's operand. It should be a local symbol in .rodata + // section. + for (size_t i = 0; i < reloc_count; ++i, pr += reloc_size) + { + Reltype reloc(pr); + if (static_cast(reloc.get_r_offset()) + == curoffset) + { + typename elfcpp::Elf_types::Elf_WXword r_info + = reloc.get_r_info(); + unsigned int r_sym = elfcpp::elf_r_sym(r_info); + unsigned int r_type = elfcpp::elf_r_type(r_info); + if (r_type != elfcpp::R_390_PC32DBL) + goto bad; + if (r_sym >= object->local_symbol_count()) + goto bad; + Sized_relobj_file *object_sized = + static_cast *>(object); + const Symbol_value* sym = object_sized->local_symbol(r_sym); + bool param_shndx_ordinary; + const unsigned int param_shndx = + sym->input_shndx(¶m_shndx_ordinary); + if (!param_shndx_ordinary) + goto bad; + param_offset = sym->input_value() + reloc.get_r_addend() - 2 + - object->output_section(param_shndx)->address() + - object->output_section_offset(param_shndx); + param_view = object->get_output_view(param_shndx, + ¶m_view_size); + break; + } + } + + if (!param_view) + goto bad; + + curoffset += 4; + + // Now, there has to be a jump to __morestack. + jump_offset = curoffset; + + if (this->match_view_u(view, view_size, curoffset, + conditional ? ss_code_jgl : ss_code_jg, + sizeof ss_code_jg)) + curoffset += sizeof ss_code_jg; + else + goto bad; + + curoffset += 4; + + // Read the frame size. + if (convert_to_section_size_type(param_offset + size / 8) > param_view_size) + goto bad; + frame_size = elfcpp::Swap::readval(param_view + param_offset); + + // Sanity check. + if (fsadd_type != SS_ADD_NONE && fsadd_frame_size != frame_size) + goto bad; + + // Bump the frame size. + frame_size += parameters->options().split_stack_adjust_size(); + + // Store it to the param block. + elfcpp::Swap::writeval(param_view + param_offset, frame_size); + + if (!conditional) + { + // If the call was already unconditional, we're done. + } + else if (frame_size <= 0xffffffff && fsadd_type == SS_ADD_ALFI) + { + // Using alfi to add the frame size, and it still fits. Adjust it. + elfcpp::Swap_unaligned<32, true>::writeval(view + fsadd_offset, + frame_size); + } + else + { + // We were either relying on the backoff area, or used ahi to load + // frame size. This won't fly, as our new frame size is too large. + // Convert the sequence to unconditional by nopping out the comparison, + // and rewiring the jump. + this->set_view_to_nop(view, view_size, ssoffset, cmpend - ssoffset); + + // The jump is jgl, we'll mutate it to jg. + view[jump_offset+1] = 0xf4; + } + + return; + +bad: + if (!object->has_no_split_stack()) + object->error(_("failed to match split-stack sequence at " + "section %u offset %0zx"), + shndx, static_cast(fnoffset)); +} + // Relocate section data. template