#!/usr/bin/env perl # SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause # # Copyright (C) 2017-2018 Samuel Neves . All Rights Reserved. # Copyright (C) 2006-2017 CRYPTOGAMS by . All Rights Reserved. # # This code is taken from the OpenSSL project but the author, Andy Polyakov, # has relicensed it under the licenses specified in the SPDX header above. # The original headers, including the original license headers, are # included below for completeness. # # ==================================================================== # Written by Andy Polyakov for the OpenSSL # project. The module is, however, dual licensed under OpenSSL and # CRYPTOGAMS licenses depending on where you obtain it. For further # details see http://www.openssl.org/~appro/cryptogams/. # ==================================================================== # # Ascetic x86_64 AT&T to MASM/NASM assembler translator by . # # Why AT&T to MASM and not vice versa? Several reasons. Because AT&T # format is way easier to parse. Because it's simpler to "gear" from # Unix ABI to Windows one [see cross-reference "card" at the end of # file]. Because Linux targets were available first... # # In addition the script also "distills" code suitable for GNU # assembler, so that it can be compiled with more rigid assemblers, # such as Solaris /usr/ccs/bin/as. # # This translator is not designed to convert *arbitrary* assembler # code from AT&T format to MASM one. It's designed to convert just # enough to provide for dual-ABI OpenSSL modules development... # There *are* limitations and you might have to modify your assembler # code or this script to achieve the desired result... # # Currently recognized limitations: # # - can't use multiple ops per line; # # Dual-ABI styling rules. # # 1. Adhere to Unix register and stack layout [see cross-reference # ABI "card" at the end for explanation]. # 2. Forget about "red zone," stick to more traditional blended # stack frame allocation. If volatile storage is actually required # that is. If not, just leave the stack as is. # 3. Functions tagged with ".type name,@function" get crafted with # unified Win64 prologue and epilogue automatically. If you want # to take care of ABI differences yourself, tag functions as # ".type name,@abi-omnipotent" instead. # 4. To optimize the Win64 prologue you can specify number of input # arguments as ".type name,@function,N." Keep in mind that if N is # larger than 6, then you *have to* write "abi-omnipotent" code, # because >6 cases can't be addressed with unified prologue. # 5. Name local labels as .L*, do *not* use dynamic labels such as 1: # (sorry about latter). # 6. Don't use [or hand-code with .byte] "rep ret." "ret" mnemonic is # required to identify the spots, where to inject Win64 epilogue! # But on the pros, it's then prefixed with rep automatically:-) # 7. Stick to explicit ip-relative addressing. If you have to use # GOTPCREL addressing, stick to mov symbol@GOTPCREL(%rip),%r??. # Both are recognized and translated to proper Win64 addressing # modes. # # 8. In order to provide for structured exception handling unified # Win64 prologue copies %rsp value to %rax. For further details # see SEH paragraph at the end. # 9. .init segment is allowed to contain calls to functions only. # a. If function accepts more than 4 arguments *and* >4th argument # is declared as non 64-bit value, do clear its upper part. use strict; my $flavour = shift; my $output = shift; if ($flavour =~ /\./) { $output = $flavour; undef $flavour; } open STDOUT,">$output" || die "can't open $output: $!" if (defined($output)); my $kernel=0; $kernel=1 if ($flavour =~ /linux/); my $gas=1; $gas=0 if ($output =~ /\.asm$/); my $elf=1; $elf=0 if (!$gas); my $win64=0; my $prefix=""; my $decor=".L"; my $masmref=8 + 50727*2**-32; # 8.00.50727 shipped with VS2005 my $masm=0; my $PTR=" PTR"; my $nasmref=2.03; my $nasm=0; if ($flavour eq "mingw64") { $gas=1; $elf=0; $win64=1; $prefix=`echo __USER_LABEL_PREFIX__ | $ENV{CC} -E -P -`; $prefix =~ s|\R$||; # Better chomp } elsif ($flavour eq "macosx") { $gas=1; $elf=0; $prefix="_"; $decor="L\$"; } elsif ($flavour eq "masm") { $gas=0; $elf=0; $masm=$masmref; $win64=1; $decor="\$L\$"; } elsif ($flavour eq "nasm") { $gas=0; $elf=0; $nasm=$nasmref; $win64=1; $decor="\$L\$"; $PTR=""; } elsif (!$gas) { if ($ENV{ASM} =~ m/nasm/ && `nasm -v` =~ m/version ([0-9]+)\.([0-9]+)/i) { $nasm = $1 + $2*0.01; $PTR=""; } elsif (`ml64 2>&1` =~ m/Version ([0-9]+)\.([0-9]+)(\.([0-9]+))?/) { $masm = $1 + $2*2**-16 + $4*2**-32; } die "no assembler found on %PATH%" if (!($nasm || $masm)); $win64=1; $elf=0; $decor="\$L\$"; } my $current_segment; my $current_function; my %globals; { package opcode; # pick up opcodes sub re { my ($class, $line) = @_; my $self = {}; my $ret; if ($$line =~ /^([a-z][a-z0-9]*)/i) { bless $self,$class; $self->{op} = $1; $ret = $self; $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; undef $self->{sz}; if ($self->{op} =~ /^(movz)x?([bw]).*/) { # movz is pain... $self->{op} = $1; $self->{sz} = $2; } elsif ($self->{op} =~ /call|jmp/) { $self->{sz} = ""; } elsif ($self->{op} =~ /^p/ && $' !~ /^(ush|op|insrw)/) { # SSEn $self->{sz} = ""; } elsif ($self->{op} =~ /^[vk]/) { # VEX or k* such as kmov $self->{sz} = ""; } elsif ($self->{op} =~ /mov[dq]/ && $$line =~ /%xmm/) { $self->{sz} = ""; } elsif ($self->{op} =~ /([a-z]{3,})([qlwb])$/) { $self->{op} = $1; $self->{sz} = $2; } } $ret; } sub size { my ($self, $sz) = @_; $self->{sz} = $sz if (defined($sz) && !defined($self->{sz})); $self->{sz}; } sub out { my $self = shift; if ($gas) { if ($self->{op} eq "movz") { # movz is pain... sprintf "%s%s%s",$self->{op},$self->{sz},shift; } elsif ($self->{op} =~ /^set/) { "$self->{op}"; } elsif ($self->{op} eq "ret") { my $epilogue = ""; if ($win64 && $current_function->{abi} eq "svr4") { $epilogue = "movq 8(%rsp),%rdi\n\t" . "movq 16(%rsp),%rsi\n\t"; } $epilogue . ".byte 0xf3,0xc3"; } elsif ($self->{op} eq "call" && !$elf && $current_segment eq ".init") { ".p2align\t3\n\t.quad"; } else { "$self->{op}$self->{sz}"; } } else { $self->{op} =~ s/^movz/movzx/; if ($self->{op} eq "ret") { $self->{op} = ""; if ($win64 && $current_function->{abi} eq "svr4") { $self->{op} = "mov rdi,QWORD$PTR\[8+rsp\]\t;WIN64 epilogue\n\t". "mov rsi,QWORD$PTR\[16+rsp\]\n\t"; } $self->{op} .= "DB\t0F3h,0C3h\t\t;repret"; } elsif ($self->{op} =~ /^(pop|push)f/) { $self->{op} .= $self->{sz}; } elsif ($self->{op} eq "call" && $current_segment eq ".CRT\$XCU") { $self->{op} = "\tDQ"; } $self->{op}; } } sub mnemonic { my ($self, $op) = @_; $self->{op}=$op if (defined($op)); $self->{op}; } } { package const; # pick up constants, which start with $ sub re { my ($class, $line) = @_; my $self = {}; my $ret; if ($$line =~ /^\$([^,]+)/) { bless $self, $class; $self->{value} = $1; $ret = $self; $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; } $ret; } sub out { my $self = shift; $self->{value} =~ s/\b(0b[0-1]+)/oct($1)/eig; if ($gas) { # Solaris /usr/ccs/bin/as can't handle multiplications # in $self->{value} my $value = $self->{value}; no warnings; # oct might complain about overflow, ignore here... $value =~ s/(?{value} = $value; } sprintf "\$%s",$self->{value}; } else { my $value = $self->{value}; $value =~ s/0x([0-9a-f]+)/0$1h/ig if ($masm); sprintf "%s",$value; } } } { package ea; # pick up effective addresses: expr(%reg,%reg,scale) my %szmap = ( b=>"BYTE$PTR", w=>"WORD$PTR", l=>"DWORD$PTR", d=>"DWORD$PTR", q=>"QWORD$PTR", o=>"OWORD$PTR", x=>"XMMWORD$PTR", y=>"YMMWORD$PTR", z=>"ZMMWORD$PTR" ) if (!$gas); sub re { my ($class, $line, $opcode) = @_; my $self = {}; my $ret; # optional * ----vvv--- appears in indirect jmp/call if ($$line =~ /^(\*?)([^\(,]*)\(([%\w,]+)\)((?:{[^}]+})*)/) { bless $self, $class; $self->{asterisk} = $1; $self->{label} = $2; ($self->{base},$self->{index},$self->{scale})=split(/,/,$3); $self->{scale} = 1 if (!defined($self->{scale})); $self->{opmask} = $4; $ret = $self; $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; if ($win64 && $self->{label} =~ s/\@GOTPCREL//) { die if ($opcode->mnemonic() ne "mov"); $opcode->mnemonic("lea"); } $self->{base} =~ s/^%//; $self->{index} =~ s/^%// if (defined($self->{index})); $self->{opcode} = $opcode; } $ret; } sub size {} sub out { my ($self, $sz) = @_; $self->{label} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei; $self->{label} =~ s/\.L/$decor/g; # Silently convert all EAs to 64-bit. This is required for # elder GNU assembler and results in more compact code, # *but* most importantly AES module depends on this feature! $self->{index} =~ s/^[er](.?[0-9xpi])[d]?$/r\1/; $self->{base} =~ s/^[er](.?[0-9xpi])[d]?$/r\1/; # Solaris /usr/ccs/bin/as can't handle multiplications # in $self->{label}... use integer; $self->{label} =~ s/(?{label} =~ s/\b([0-9]+\s*[\*\/\%]\s*[0-9]+)\b/eval($1)/eg; # Some assemblers insist on signed presentation of 32-bit # offsets, but sign extension is a tricky business in perl... if ((1<<31)<<1) { $self->{label} =~ s/\b([0-9]+)\b/$1<<32>>32/eg; } else { $self->{label} =~ s/\b([0-9]+)\b/$1>>0/eg; } # if base register is %rbp or %r13, see if it's possible to # flip base and index registers [for better performance] if (!$self->{label} && $self->{index} && $self->{scale}==1 && $self->{base} =~ /(rbp|r13)/) { $self->{base} = $self->{index}; $self->{index} = $1; } if ($gas) { $self->{label} =~ s/^___imp_/__imp__/ if ($flavour eq "mingw64"); if (defined($self->{index})) { sprintf "%s%s(%s,%%%s,%d)%s", $self->{asterisk},$self->{label}, $self->{base}?"%$self->{base}":"", $self->{index},$self->{scale}, $self->{opmask}; } else { sprintf "%s%s(%%%s)%s", $self->{asterisk},$self->{label}, $self->{base},$self->{opmask}; } } else { $self->{label} =~ s/\./\$/g; $self->{label} =~ s/(?{label} = "($self->{label})" if ($self->{label} =~ /[\*\+\-\/]/); my $mnemonic = $self->{opcode}->mnemonic(); ($self->{asterisk}) && ($sz="q") || ($mnemonic =~ /^v?mov([qd])$/) && ($sz=$1) || ($mnemonic =~ /^v?pinsr([qdwb])$/) && ($sz=$1) || ($mnemonic =~ /^vpbroadcast([qdwb])$/) && ($sz=$1) || ($mnemonic =~ /^v(?!perm)[a-z]+[fi]128$/) && ($sz="x"); $self->{opmask} =~ s/%(k[0-7])/$1/; if (defined($self->{index})) { sprintf "%s[%s%s*%d%s]%s",$szmap{$sz}, $self->{label}?"$self->{label}+":"", $self->{index},$self->{scale}, $self->{base}?"+$self->{base}":"", $self->{opmask}; } elsif ($self->{base} eq "rip") { sprintf "%s[%s]",$szmap{$sz},$self->{label}; } else { sprintf "%s[%s%s]%s", $szmap{$sz}, $self->{label}?"$self->{label}+":"", $self->{base},$self->{opmask}; } } } } { package register; # pick up registers, which start with %. sub re { my ($class, $line, $opcode) = @_; my $self = {}; my $ret; # optional * ----vvv--- appears in indirect jmp/call if ($$line =~ /^(\*?)%(\w+)((?:{[^}]+})*)/) { bless $self,$class; $self->{asterisk} = $1; $self->{value} = $2; $self->{opmask} = $3; $opcode->size($self->size()); $ret = $self; $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; } $ret; } sub size { my $self = shift; my $ret; if ($self->{value} =~ /^r[\d]+b$/i) { $ret="b"; } elsif ($self->{value} =~ /^r[\d]+w$/i) { $ret="w"; } elsif ($self->{value} =~ /^r[\d]+d$/i) { $ret="l"; } elsif ($self->{value} =~ /^r[\w]+$/i) { $ret="q"; } elsif ($self->{value} =~ /^[a-d][hl]$/i){ $ret="b"; } elsif ($self->{value} =~ /^[\w]{2}l$/i) { $ret="b"; } elsif ($self->{value} =~ /^[\w]{2}$/i) { $ret="w"; } elsif ($self->{value} =~ /^e[a-z]{2}$/i){ $ret="l"; } $ret; } sub out { my $self = shift; if ($gas) { sprintf "%s%%%s%s", $self->{asterisk}, $self->{value}, $self->{opmask}; } else { $self->{opmask} =~ s/%(k[0-7])/$1/; $self->{value}.$self->{opmask}; } } } { package label; # pick up labels, which end with : sub re { my ($class, $line) = @_; my $self = {}; my $ret; if ($$line =~ /(^[\.\w]+)\:/) { bless $self,$class; $self->{value} = $1; $ret = $self; $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; $self->{value} =~ s/^\.L/$decor/; } $ret; } sub out { my $self = shift; if ($gas) { my $func = ($globals{$self->{value}} or $self->{value}) . ":"; if ($win64 && $current_function->{name} eq $self->{value} && $current_function->{abi} eq "svr4") { $func .= "\n"; $func .= " movq %rdi,8(%rsp)\n"; $func .= " movq %rsi,16(%rsp)\n"; $func .= " movq %rsp,%rax\n"; $func .= "${decor}SEH_begin_$current_function->{name}:\n"; my $narg = $current_function->{narg}; $narg=6 if (!defined($narg)); $func .= " movq %rcx,%rdi\n" if ($narg>0); $func .= " movq %rdx,%rsi\n" if ($narg>1); $func .= " movq %r8,%rdx\n" if ($narg>2); $func .= " movq %r9,%rcx\n" if ($narg>3); $func .= " movq 40(%rsp),%r8\n" if ($narg>4); $func .= " movq 48(%rsp),%r9\n" if ($narg>5); } $func; } elsif ($self->{value} ne "$current_function->{name}") { # Make all labels in masm global. $self->{value} .= ":" if ($masm); $self->{value} . ":"; } elsif ($win64 && $current_function->{abi} eq "svr4") { my $func = "$current_function->{name}" . ($nasm ? ":" : "\tPROC $current_function->{scope}") . "\n"; $func .= " mov QWORD$PTR\[8+rsp\],rdi\t;WIN64 prologue\n"; $func .= " mov QWORD$PTR\[16+rsp\],rsi\n"; $func .= " mov rax,rsp\n"; $func .= "${decor}SEH_begin_$current_function->{name}:"; $func .= ":" if ($masm); $func .= "\n"; my $narg = $current_function->{narg}; $narg=6 if (!defined($narg)); $func .= " mov rdi,rcx\n" if ($narg>0); $func .= " mov rsi,rdx\n" if ($narg>1); $func .= " mov rdx,r8\n" if ($narg>2); $func .= " mov rcx,r9\n" if ($narg>3); $func .= " mov r8,QWORD$PTR\[40+rsp\]\n" if ($narg>4); $func .= " mov r9,QWORD$PTR\[48+rsp\]\n" if ($narg>5); $func .= "\n"; } else { "$current_function->{name}". ($nasm ? ":" : "\tPROC $current_function->{scope}"); } } } { package expr; # pick up expressions sub re { my ($class, $line, $opcode) = @_; my $self = {}; my $ret; if ($$line =~ /(^[^,]+)/) { bless $self,$class; $self->{value} = $1; $ret = $self; $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; $self->{value} =~ s/\@PLT// if (!$elf); $self->{value} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei; $self->{value} =~ s/\.L/$decor/g; $self->{opcode} = $opcode; } $ret; } sub out { my $self = shift; if ($nasm && $self->{opcode}->mnemonic()=~m/^j(?![re]cxz)/) { "NEAR ".$self->{value}; } else { $self->{value}; } } } { package cfi_directive; # CFI directives annotate instructions that are significant for # stack unwinding procedure compliant with DWARF specification, # see http://dwarfstd.org/. Besides naturally expected for this # script platform-specific filtering function, this module adds # three auxiliary synthetic directives not recognized by [GNU] # assembler: # # - .cfi_push to annotate push instructions in prologue, which # translates to .cfi_adjust_cfa_offset (if needed) and # .cfi_offset; # - .cfi_pop to annotate pop instructions in epilogue, which # translates to .cfi_adjust_cfa_offset (if needed) and # .cfi_restore; # - [and most notably] .cfi_cfa_expression which encodes # DW_CFA_def_cfa_expression and passes it to .cfi_escape as # byte vector; # # CFA expressions were introduced in DWARF specification version # 3 and describe how to deduce CFA, Canonical Frame Address. This # becomes handy if your stack frame is variable and you can't # spare register for [previous] frame pointer. Suggested directive # syntax is made-up mix of DWARF operator suffixes [subset of] # and references to registers with optional bias. Following example # describes offloaded *original* stack pointer at specific offset # from *current* stack pointer: # # .cfi_cfa_expression %rsp+40,deref,+8 # # Final +8 has everything to do with the fact that CFA is defined # as reference to top of caller's stack, and on x86_64 call to # subroutine pushes 8-byte return address. In other words original # stack pointer upon entry to a subroutine is 8 bytes off from CFA. # Below constants are taken from "DWARF Expressions" section of the # DWARF specification, section is numbered 7.7 in versions 3 and 4. my %DW_OP_simple = ( # no-arg operators, mapped directly deref => 0x06, dup => 0x12, drop => 0x13, over => 0x14, pick => 0x15, swap => 0x16, rot => 0x17, xderef => 0x18, abs => 0x19, and => 0x1a, div => 0x1b, minus => 0x1c, mod => 0x1d, mul => 0x1e, neg => 0x1f, not => 0x20, or => 0x21, plus => 0x22, shl => 0x24, shr => 0x25, shra => 0x26, xor => 0x27, ); my %DW_OP_complex = ( # used in specific subroutines constu => 0x10, # uleb128 consts => 0x11, # sleb128 plus_uconst => 0x23, # uleb128 lit0 => 0x30, # add 0-31 to opcode reg0 => 0x50, # add 0-31 to opcode breg0 => 0x70, # add 0-31 to opcole, sleb128 regx => 0x90, # uleb28 fbreg => 0x91, # sleb128 bregx => 0x92, # uleb128, sleb128 piece => 0x93, # uleb128 ); # Following constants are defined in x86_64 ABI supplement, for # example available at https://www.uclibc.org/docs/psABI-x86_64.pdf, # see section 3.7 "Stack Unwind Algorithm". my %DW_reg_idx = ( "%rax"=>0, "%rdx"=>1, "%rcx"=>2, "%rbx"=>3, "%rsi"=>4, "%rdi"=>5, "%rbp"=>6, "%rsp"=>7, "%r8" =>8, "%r9" =>9, "%r10"=>10, "%r11"=>11, "%r12"=>12, "%r13"=>13, "%r14"=>14, "%r15"=>15 ); my ($cfa_reg, $cfa_rsp); # [us]leb128 format is variable-length integer representation base # 2^128, with most significant bit of each byte being 0 denoting # *last* most significant digit. See "Variable Length Data" in the # DWARF specification, numbered 7.6 at least in versions 3 and 4. sub sleb128 { use integer; # get right shift extend sign my $val = shift; my $sign = ($val < 0) ? -1 : 0; my @ret = (); while(1) { push @ret, $val&0x7f; # see if remaining bits are same and equal to most # significant bit of the current digit, if so, it's # last digit... last if (($val>>6) == $sign); @ret[-1] |= 0x80; $val >>= 7; } return @ret; } sub uleb128 { my $val = shift; my @ret = (); while(1) { push @ret, $val&0x7f; # see if it's last significant digit... last if (($val >>= 7) == 0); @ret[-1] |= 0x80; } return @ret; } sub const { my $val = shift; if ($val >= 0 && $val < 32) { return ($DW_OP_complex{lit0}+$val); } return ($DW_OP_complex{consts}, sleb128($val)); } sub reg { my $val = shift; return if ($val !~ m/^(%r\w+)(?:([\+\-])((?:0x)?[0-9a-f]+))?/); my $reg = $DW_reg_idx{$1}; my $off = eval ("0 $2 $3"); return (($DW_OP_complex{breg0} + $reg), sleb128($off)); # Yes, we use DW_OP_bregX+0 to push register value and not # DW_OP_regX, because latter would require even DW_OP_piece, # which would be a waste under the circumstances. If you have # to use DWP_OP_reg, use "regx:N"... } sub cfa_expression { my $line = shift; my @ret; foreach my $token (split(/,\s*/,$line)) { if ($token =~ /^%r/) { push @ret,reg($token); } elsif ($token =~ /((?:0x)?[0-9a-f]+)\((%r\w+)\)/) { push @ret,reg("$2+$1"); } elsif ($token =~ /(\w+):(\-?(?:0x)?[0-9a-f]+)(U?)/i) { my $i = 1*eval($2); push @ret,$DW_OP_complex{$1}, ($3 ? uleb128($i) : sleb128($i)); } elsif (my $i = 1*eval($token) or $token eq "0") { if ($token =~ /^\+/) { push @ret,$DW_OP_complex{plus_uconst},uleb128($i); } else { push @ret,const($i); } } else { push @ret,$DW_OP_simple{$token}; } } # Finally we return DW_CFA_def_cfa_expression, 15, followed by # length of the expression and of course the expression itself. return (15,scalar(@ret),@ret); } sub re { my ($class, $line) = @_; my $self = {}; my $ret; if ($$line =~ s/^\s*\.cfi_(\w+)\s*//) { bless $self,$class; $ret = $self; undef $self->{value}; my $dir = $1; SWITCH: for ($dir) { # What is $cfa_rsp? Effectively it's difference between %rsp # value and current CFA, Canonical Frame Address, which is # why it starts with -8. Recall that CFA is top of caller's # stack... /startproc/ && do { ($cfa_reg, $cfa_rsp) = ("%rsp", -8); last; }; /endproc/ && do { ($cfa_reg, $cfa_rsp) = ("%rsp", 0); last; }; /def_cfa_register/ && do { $cfa_reg = $$line; last; }; /def_cfa_offset/ && do { $cfa_rsp = -1*eval($$line) if ($cfa_reg eq "%rsp"); last; }; /adjust_cfa_offset/ && do { $cfa_rsp -= 1*eval($$line) if ($cfa_reg eq "%rsp"); last; }; /def_cfa/ && do { if ($$line =~ /(%r\w+)\s*,\s*(.+)/) { $cfa_reg = $1; $cfa_rsp = -1*eval($2) if ($cfa_reg eq "%rsp"); } last; }; /push/ && do { $dir = undef; $cfa_rsp -= 8; if ($cfa_reg eq "%rsp") { $self->{value} = ".cfi_adjust_cfa_offset\t8\n"; } $self->{value} .= ".cfi_offset\t$$line,$cfa_rsp"; last; }; /pop/ && do { $dir = undef; $cfa_rsp += 8; if ($cfa_reg eq "%rsp") { $self->{value} = ".cfi_adjust_cfa_offset\t-8\n"; } $self->{value} .= ".cfi_restore\t$$line"; last; }; /cfa_expression/ && do { $dir = undef; $self->{value} = ".cfi_escape\t" . join(",", map(sprintf("0x%02x", $_), cfa_expression($$line))); last; }; } $self->{value} = ".cfi_$dir\t$$line" if ($dir); $$line = ""; } return $ret; } sub out { my $self = shift; return ($elf ? $self->{value} : undef); } } { package directive; # pick up directives, which start with . sub re { my ($class, $line) = @_; my $self = {}; my $ret; my $dir; # chain-call to cfi_directive $ret = cfi_directive->re($line) and return $ret; if ($$line =~ /^\s*(\.\w+)/) { bless $self,$class; $dir = $1; $ret = $self; undef $self->{value}; $$line = substr($$line,@+[0]); $$line =~ s/^\s+//; SWITCH: for ($dir) { /\.global|\.globl|\.extern/ && do { $globals{$$line} = $prefix . $$line; $$line = $globals{$$line} if ($prefix); last; }; /\.type/ && do { my ($sym,$type,$narg) = split(',',$$line); if ($type eq "\@function") { undef $current_function; $current_function->{name} = $sym; $current_function->{abi} = "svr4"; $current_function->{narg} = $narg; $current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE"; } elsif ($type eq "\@abi-omnipotent") { undef $current_function; $current_function->{name} = $sym; $current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE"; } $$line =~ s/\@abi\-omnipotent/\@function/; $$line =~ s/\@function.*/\@function/; last; }; /\.asciz/ && do { if ($$line =~ /^"(.*)"$/) { $dir = ".byte"; $$line = join(",",unpack("C*",$1),0); } last; }; /\.rva|\.long|\.quad/ && do { $$line =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei; $$line =~ s/\.L/$decor/g; last; }; } if ($gas) { $self->{value} = $dir . "\t" . $$line; if ($dir =~ /\.extern/) { $self->{value} = ""; # swallow extern } elsif (!$elf && $dir =~ /\.type/) { $self->{value} = ""; $self->{value} = ".def\t" . ($globals{$1} or $1) . ";\t" . (defined($globals{$1})?".scl 2;":".scl 3;") . "\t.type 32;\t.endef" if ($win64 && $$line =~ /([^,]+),\@function/); } elsif (!$elf && $dir =~ /\.size/) { $self->{value} = ""; if (defined($current_function)) { $self->{value} .= "${decor}SEH_end_$current_function->{name}:" if ($win64 && $current_function->{abi} eq "svr4"); undef $current_function; } } elsif (!$elf && $dir =~ /\.align/) { $self->{value} = ".p2align\t" . (log($$line)/log(2)); } elsif ($dir eq ".section") { $current_segment=$$line; if (!$elf && $current_segment eq ".init") { if ($flavour eq "macosx") { $self->{value} = ".mod_init_func"; } elsif ($flavour eq "mingw64") { $self->{value} = ".section\t.ctors"; } } } elsif ($dir =~ /\.(text|data)/) { $current_segment=".$1"; } elsif ($dir =~ /\.hidden/) { if ($flavour eq "macosx") { $self->{value} = ".private_extern\t$prefix$$line"; } elsif ($flavour eq "mingw64") { $self->{value} = ""; } } elsif ($dir =~ /\.comm/) { $self->{value} = "$dir\t$prefix$$line"; $self->{value} =~ s|,([0-9]+),([0-9]+)$|",$1,".log($2)/log(2)|e if ($flavour eq "macosx"); } $$line = ""; return $self; } # non-gas case or nasm/masm SWITCH: for ($dir) { /\.text/ && do { my $v=undef; if ($nasm) { $v="section .text code align=64\n"; } else { $v="$current_segment\tENDS\n" if ($current_segment); $current_segment = ".text\$"; $v.="$current_segment\tSEGMENT "; $v.=$masm>=$masmref ? "ALIGN(256)" : "PAGE"; $v.=" 'CODE'"; } $self->{value} = $v; last; }; /\.data/ && do { my $v=undef; if ($nasm) { $v="section .data data align=8\n"; } else { $v="$current_segment\tENDS\n" if ($current_segment); $current_segment = "_DATA"; $v.="$current_segment\tSEGMENT"; } $self->{value} = $v; last; }; /\.section/ && do { my $v=undef; $$line =~ s/([^,]*).*/$1/; $$line = ".CRT\$XCU" if ($$line eq ".init"); if ($nasm) { $v="section $$line"; if ($$line=~/\.([px])data/) { $v.=" rdata align="; $v.=$1 eq "p"? 4 : 8; } elsif ($$line=~/\.CRT\$/i) { $v.=" rdata align=8"; } } else { $v="$current_segment\tENDS\n" if ($current_segment); $v.="$$line\tSEGMENT"; if ($$line=~/\.([px])data/) { $v.=" READONLY"; $v.=" ALIGN(".($1 eq "p" ? 4 : 8).")" if ($masm>=$masmref); } elsif ($$line=~/\.CRT\$/i) { $v.=" READONLY "; $v.=$masm>=$masmref ? "ALIGN(8)" : "DWORD"; } } $current_segment = $$line; $self->{value} = $v; last; }; /\.extern/ && do { $self->{value} = "EXTERN\t".$$line; $self->{value} .= ":NEAR" if ($masm); last; }; /\.globl|.global/ && do { $self->{value} = $masm?"PUBLIC":"global"; $self->{value} .= "\t".$$line; last; }; /\.size/ && do { if (defined($current_function)) { undef $self->{value}; if ($current_function->{abi} eq "svr4") { $self->{value}="${decor}SEH_end_$current_function->{name}:"; $self->{value}.=":\n" if($masm); } $self->{value}.="$current_function->{name}\tENDP" if($masm && $current_function->{name}); undef $current_function; } last; }; /\.align/ && do { my $max = ($masm && $masm>=$masmref) ? 256 : 4096; $self->{value} = "ALIGN\t".($$line>$max?$max:$$line); last; }; /\.(value|long|rva|quad)/ && do { my $sz = substr($1,0,1); my @arr = split(/,\s*/,$$line); my $last = pop(@arr); my $conv = sub { my $var=shift; $var=~s/^(0b[0-1]+)/oct($1)/eig; $var=~s/^0x([0-9a-f]+)/0$1h/ig if ($masm); if ($sz eq "D" && ($current_segment=~/.[px]data/ || $dir eq ".rva")) { $var=~s/^([_a-z\$\@][_a-z0-9\$\@]*)/$nasm?"$1 wrt ..imagebase":"imagerel $1"/egi; } $var; }; $sz =~ tr/bvlrq/BWDDQ/; $self->{value} = "\tD$sz\t"; for (@arr) { $self->{value} .= &$conv($_).","; } $self->{value} .= &$conv($last); last; }; /\.byte/ && do { my @str=split(/,\s*/,$$line); map(s/(0b[0-1]+)/oct($1)/eig,@str); map(s/0x([0-9a-f]+)/0$1h/ig,@str) if ($masm); while ($#str>15) { $self->{value}.="DB\t" .join(",",@str[0..15])."\n"; foreach (0..15) { shift @str; } } $self->{value}.="DB\t" .join(",",@str) if (@str); last; }; /\.comm/ && do { my @str=split(/,\s*/,$$line); my $v=undef; if ($nasm) { $v.="common $prefix@str[0] @str[1]"; } else { $v="$current_segment\tENDS\n" if ($current_segment); $current_segment = "_DATA"; $v.="$current_segment\tSEGMENT\n"; $v.="COMM @str[0]:DWORD:".@str[1]/4; } $self->{value} = $v; last; }; } $$line = ""; } $ret; } sub out { my $self = shift; $self->{value}; } } # Upon initial x86_64 introduction SSE>2 extensions were not introduced # yet. In order not to be bothered by tracing exact assembler versions, # but at the same time to provide a bare security minimum of AES-NI, we # hard-code some instructions. Extensions past AES-NI on the other hand # are traced by examining assembler version in individual perlasm # modules... my %regrm = ( "%eax"=>0, "%ecx"=>1, "%edx"=>2, "%ebx"=>3, "%esp"=>4, "%ebp"=>5, "%esi"=>6, "%edi"=>7 ); sub rex { my $opcode=shift; my ($dst,$src,$rex)=@_; $rex|=0x04 if($dst>=8); $rex|=0x01 if($src>=8); push @$opcode,($rex|0x40) if ($rex); } my $movq = sub { # elderly gas can't handle inter-register movq my $arg = shift; my @opcode=(0x66); if ($arg =~ /%xmm([0-9]+),\s*%r(\w+)/) { my ($src,$dst)=($1,$2); if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; } rex(\@opcode,$src,$dst,0x8); push @opcode,0x0f,0x7e; push @opcode,0xc0|(($src&7)<<3)|($dst&7); # ModR/M @opcode; } elsif ($arg =~ /%r(\w+),\s*%xmm([0-9]+)/) { my ($src,$dst)=($2,$1); if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; } rex(\@opcode,$src,$dst,0x8); push @opcode,0x0f,0x6e; push @opcode,0xc0|(($src&7)<<3)|($dst&7); # ModR/M @opcode; } else { (); } }; my $pextrd = sub { if (shift =~ /\$([0-9]+),\s*%xmm([0-9]+),\s*(%\w+)/) { my @opcode=(0x66); my $imm=$1; my $src=$2; my $dst=$3; if ($dst =~ /%r([0-9]+)d/) { $dst = $1; } elsif ($dst =~ /%e/) { $dst = $regrm{$dst}; } rex(\@opcode,$src,$dst); push @opcode,0x0f,0x3a,0x16; push @opcode,0xc0|(($src&7)<<3)|($dst&7); # ModR/M push @opcode,$imm; @opcode; } else { (); } }; my $pinsrd = sub { if (shift =~ /\$([0-9]+),\s*(%\w+),\s*%xmm([0-9]+)/) { my @opcode=(0x66); my $imm=$1; my $src=$2; my $dst=$3; if ($src =~ /%r([0-9]+)/) { $src = $1; } elsif ($src =~ /%e/) { $src = $regrm{$src}; } rex(\@opcode,$dst,$src); push @opcode,0x0f,0x3a,0x22; push @opcode,0xc0|(($dst&7)<<3)|($src&7); # ModR/M push @opcode,$imm; @opcode; } else { (); } }; my $pshufb = sub { if (shift =~ /%xmm([0-9]+),\s*%xmm([0-9]+)/) { my @opcode=(0x66); rex(\@opcode,$2,$1); push @opcode,0x0f,0x38,0x00; push @opcode,0xc0|($1&7)|(($2&7)<<3); # ModR/M @opcode; } else { (); } }; my $palignr = sub { if (shift =~ /\$([0-9]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) { my @opcode=(0x66); rex(\@opcode,$3,$2); push @opcode,0x0f,0x3a,0x0f; push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M push @opcode,$1; @opcode; } else { (); } }; my $pclmulqdq = sub { if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) { my @opcode=(0x66); rex(\@opcode,$3,$2); push @opcode,0x0f,0x3a,0x44; push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M my $c=$1; push @opcode,$c=~/^0/?oct($c):$c; @opcode; } else { (); } }; my $rdrand = sub { if (shift =~ /%[er](\w+)/) { my @opcode=(); my $dst=$1; if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; } rex(\@opcode,0,$dst,8); push @opcode,0x0f,0xc7,0xf0|($dst&7); @opcode; } else { (); } }; my $rdseed = sub { if (shift =~ /%[er](\w+)/) { my @opcode=(); my $dst=$1; if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; } rex(\@opcode,0,$dst,8); push @opcode,0x0f,0xc7,0xf8|($dst&7); @opcode; } else { (); } }; # Not all AVX-capable assemblers recognize AMD XOP extension. Since we # are using only two instructions hand-code them in order to be excused # from chasing assembler versions... sub rxb { my $opcode=shift; my ($dst,$src1,$src2,$rxb)=@_; $rxb|=0x7<<5; $rxb&=~(0x04<<5) if($dst>=8); $rxb&=~(0x01<<5) if($src1>=8); $rxb&=~(0x02<<5) if($src2>=8); push @$opcode,$rxb; } my $vprotd = sub { if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) { my @opcode=(0x8f); rxb(\@opcode,$3,$2,-1,0x08); push @opcode,0x78,0xc2; push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M my $c=$1; push @opcode,$c=~/^0/?oct($c):$c; @opcode; } else { (); } }; my $vprotq = sub { if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) { my @opcode=(0x8f); rxb(\@opcode,$3,$2,-1,0x08); push @opcode,0x78,0xc3; push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M my $c=$1; push @opcode,$c=~/^0/?oct($c):$c; @opcode; } else { (); } }; # Intel Control-flow Enforcement Technology extension. All functions and # indirect branch targets will have to start with this instruction... my $endbranch = sub { (0xf3,0x0f,0x1e,0xfa); }; ######################################################################## if ($nasm) { print <<___; default rel %define XMMWORD %define YMMWORD %define ZMMWORD ___ } elsif ($masm) { print <<___; OPTION DOTNAME ___ } while(defined(my $line=<>)) { $line =~ s|\R$||; # Better chomp $line =~ s|[#!](?!include)(?!ifdef)(?!endif).*$||; # get rid of asm-style comments... $line =~ s|/\*.*\*/||; # ... and C-style comments... $line =~ s|^\s+||; # ... and skip white spaces in beginning $line =~ s|\s+$||; # ... and at the end if (my $label=label->re(\$line)) { print $label->out(); } if (my $directive=directive->re(\$line)) { printf "%s",$directive->out(); } elsif (my $opcode=opcode->re(\$line)) { my $asm = eval("\$".$opcode->mnemonic()); if ((ref($asm) eq 'CODE') && scalar(my @bytes=&$asm($line))) { print $gas?".byte\t":"DB\t",join(',',@bytes),"\n"; next; } my @args; ARGUMENT: while (1) { my $arg; ($arg=register->re(\$line, $opcode))|| ($arg=const->re(\$line)) || ($arg=ea->re(\$line, $opcode)) || ($arg=expr->re(\$line, $opcode)) || last ARGUMENT; push @args,$arg; last ARGUMENT if ($line !~ /^,/); $line =~ s/^,\s*//; } # ARGUMENT: if ($#args>=0) { my $insn; my $sz=$opcode->size(); if ($gas) { $insn = $opcode->out($#args>=1?$args[$#args]->size():$sz); @args = map($_->out($sz),@args); printf "\t%s\t%s",$insn,join(",",@args); } else { $insn = $opcode->out(); foreach (@args) { my $arg = $_->out(); # $insn.=$sz compensates for movq, pinsrw, ... if ($arg =~ /^xmm[0-9]+$/) { $insn.=$sz; $sz="x" if(!$sz); last; } if ($arg =~ /^ymm[0-9]+$/) { $insn.=$sz; $sz="y" if(!$sz); last; } if ($arg =~ /^zmm[0-9]+$/) { $insn.=$sz; $sz="z" if(!$sz); last; } if ($arg =~ /^mm[0-9]+$/) { $insn.=$sz; $sz="q" if(!$sz); last; } } @args = reverse(@args); undef $sz if ($nasm && $opcode->mnemonic() eq "lea"); printf "\t%s\t%s",$insn,join(",",map($_->out($sz),@args)); } } else { printf "\t%s",$opcode->out(); } } print $line,"\n"; } print "\n$current_segment\tENDS\n" if ($current_segment && $masm); print "END\n" if ($masm); close STDOUT; ################################################# # Cross-reference x86_64 ABI "card" # # Unix Win64 # %rax * * # %rbx - - # %rcx #4 #1 # %rdx #3 #2 # %rsi #2 - # %rdi #1 - # %rbp - - # %rsp - - # %r8 #5 #3 # %r9 #6 #4 # %r10 * * # %r11 * * # %r12 - - # %r13 - - # %r14 - - # %r15 - - # # (*) volatile register # (-) preserved by callee # (#) Nth argument, volatile # # In Unix terms top of stack is argument transfer area for arguments # which could not be accommodated in registers. Or in other words 7th # [integer] argument resides at 8(%rsp) upon function entry point. # 128 bytes above %rsp constitute a "red zone" which is not touched # by signal handlers and can be used as temporal storage without # allocating a frame. # # In Win64 terms N*8 bytes on top of stack is argument transfer area, # which belongs to/can be overwritten by callee. N is the number of # arguments passed to callee, *but* not less than 4! This means that # upon function entry point 5th argument resides at 40(%rsp), as well # as that 32 bytes from 8(%rsp) can always be used as temporal # storage [without allocating a frame]. One can actually argue that # one can assume a "red zone" above stack pointer under Win64 as well. # Point is that at apparently no occasion Windows kernel would alter # the area above user stack pointer in true asynchronous manner... # # All the above means that if assembler programmer adheres to Unix # register and stack layout, but disregards the "red zone" existence, # it's possible to use following prologue and epilogue to "gear" from # Unix to Win64 ABI in leaf functions with not more than 6 arguments. # # omnipotent_function: # ifdef WIN64 # movq %rdi,8(%rsp) # movq %rsi,16(%rsp) # movq %rcx,%rdi ; if 1st argument is actually present # movq %rdx,%rsi ; if 2nd argument is actually ... # movq %r8,%rdx ; if 3rd argument is ... # movq %r9,%rcx ; if 4th argument ... # movq 40(%rsp),%r8 ; if 5th ... # movq 48(%rsp),%r9 ; if 6th ... # endif # ... # ifdef WIN64 # movq 8(%rsp),%rdi # movq 16(%rsp),%rsi # endif # ret # ################################################# # Win64 SEH, Structured Exception Handling. # # Unlike on Unix systems(*) lack of Win64 stack unwinding information # has undesired side-effect at run-time: if an exception is raised in # assembler subroutine such as those in question (basically we're # referring to segmentation violations caused by malformed input # parameters), the application is briskly terminated without invoking # any exception handlers, most notably without generating memory dump # or any user notification whatsoever. This poses a problem. It's # possible to address it by registering custom language-specific # handler that would restore processor context to the state at # subroutine entry point and return "exception is not handled, keep # unwinding" code. Writing such handler can be a challenge... But it's # doable, though requires certain coding convention. Consider following # snippet: # # .type function,@function # function: # movq %rsp,%rax # copy rsp to volatile register # pushq %r15 # save non-volatile registers # pushq %rbx # pushq %rbp # movq %rsp,%r11 # subq %rdi,%r11 # prepare [variable] stack frame # andq $-64,%r11 # movq %rax,0(%r11) # check for exceptions # movq %r11,%rsp # allocate [variable] stack frame # movq %rax,0(%rsp) # save original rsp value # magic_point: # ... # movq 0(%rsp),%rcx # pull original rsp value # movq -24(%rcx),%rbp # restore non-volatile registers # movq -16(%rcx),%rbx # movq -8(%rcx),%r15 # movq %rcx,%rsp # restore original rsp # magic_epilogue: # ret # .size function,.-function # # The key is that up to magic_point copy of original rsp value remains # in chosen volatile register and no non-volatile register, except for # rsp, is modified. While past magic_point rsp remains constant till # the very end of the function. In this case custom language-specific # exception handler would look like this: # # EXCEPTION_DISPOSITION handler (EXCEPTION_RECORD *rec,ULONG64 frame, # CONTEXT *context,DISPATCHER_CONTEXT *disp) # { ULONG64 *rsp = (ULONG64 *)context->Rax; # ULONG64 rip = context->Rip; # # if (rip >= magic_point) # { rsp = (ULONG64 *)context->Rsp; # if (rip < magic_epilogue) # { rsp = (ULONG64 *)rsp[0]; # context->Rbp = rsp[-3]; # context->Rbx = rsp[-2]; # context->R15 = rsp[-1]; # } # } # context->Rsp = (ULONG64)rsp; # context->Rdi = rsp[1]; # context->Rsi = rsp[2]; # # memcpy (disp->ContextRecord,context,sizeof(CONTEXT)); # RtlVirtualUnwind(UNW_FLAG_NHANDLER,disp->ImageBase, # dips->ControlPc,disp->FunctionEntry,disp->ContextRecord, # &disp->HandlerData,&disp->EstablisherFrame,NULL); # return ExceptionContinueSearch; # } # # It's appropriate to implement this handler in assembler, directly in # function's module. In order to do that one has to know members' # offsets in CONTEXT and DISPATCHER_CONTEXT structures and some constant # values. Here they are: # # CONTEXT.Rax 120 # CONTEXT.Rcx 128 # CONTEXT.Rdx 136 # CONTEXT.Rbx 144 # CONTEXT.Rsp 152 # CONTEXT.Rbp 160 # CONTEXT.Rsi 168 # CONTEXT.Rdi 176 # CONTEXT.R8 184 # CONTEXT.R9 192 # CONTEXT.R10 200 # CONTEXT.R11 208 # CONTEXT.R12 216 # CONTEXT.R13 224 # CONTEXT.R14 232 # CONTEXT.R15 240 # CONTEXT.Rip 248 # CONTEXT.Xmm6 512 # sizeof(CONTEXT) 1232 # DISPATCHER_CONTEXT.ControlPc 0 # DISPATCHER_CONTEXT.ImageBase 8 # DISPATCHER_CONTEXT.FunctionEntry 16 # DISPATCHER_CONTEXT.EstablisherFrame 24 # DISPATCHER_CONTEXT.TargetIp 32 # DISPATCHER_CONTEXT.ContextRecord 40 # DISPATCHER_CONTEXT.LanguageHandler 48 # DISPATCHER_CONTEXT.HandlerData 56 # UNW_FLAG_NHANDLER 0 # ExceptionContinueSearch 1 # # In order to tie the handler to the function one has to compose # couple of structures: one for .xdata segment and one for .pdata. # # UNWIND_INFO structure for .xdata segment would be # # function_unwind_info: # .byte 9,0,0,0 # .rva handler # # This structure designates exception handler for a function with # zero-length prologue, no stack frame or frame register. # # To facilitate composing of .pdata structures, auto-generated "gear" # prologue copies rsp value to rax and denotes next instruction with # .LSEH_begin_{function_name} label. This essentially defines the SEH # styling rule mentioned in the beginning. Position of this label is # chosen in such manner that possible exceptions raised in the "gear" # prologue would be accounted to caller and unwound from latter's frame. # End of function is marked with respective .LSEH_end_{function_name} # label. To summarize, .pdata segment would contain # # .rva .LSEH_begin_function # .rva .LSEH_end_function # .rva function_unwind_info # # Reference to function_unwind_info from .xdata segment is the anchor. # In case you wonder why references are 32-bit .rvas and not 64-bit # .quads. References put into these two segments are required to be # *relative* to the base address of the current binary module, a.k.a. # image base. No Win64 module, be it .exe or .dll, can be larger than # 2GB and thus such relative references can be and are accommodated in # 32 bits. # # Having reviewed the example function code, one can argue that "movq # %rsp,%rax" above is redundant. It is not! Keep in mind that on Unix # rax would contain an undefined value. If this "offends" you, use # another register and refrain from modifying rax till magic_point is # reached, i.e. as if it was a non-volatile register. If more registers # are required prior [variable] frame setup is completed, note that # nobody says that you can have only one "magic point." You can # "liberate" non-volatile registers by denoting last stack off-load # instruction and reflecting it in finer grade unwind logic in handler. # After all, isn't it why it's called *language-specific* handler... # # SE handlers are also involved in unwinding stack when executable is # profiled or debugged. Profiling implies additional limitations that # are too subtle to discuss here. For now it's sufficient to say that # in order to simplify handlers one should either a) offload original # %rsp to stack (like discussed above); or b) if you have a register to # spare for frame pointer, choose volatile one. # # (*) Note that we're talking about run-time, not debug-time. Lack of # unwind information makes debugging hard on both Windows and # Unix. "Unlike" refers to the fact that on Unix signal handler # will always be invoked, core dumped and appropriate exit code # returned to parent (for user notification).