> _copy_from_iter inc 0x36e -> 0x395 +0x27 Here a disassembly of _copy_from_iter() from unpatched and patched, marked up for the different iterator-type branches. To summarise: UNPATCHED PATCHED START LEN START LEN ======= ======= ======= ======= Prologue 0 77 0 76 UBUF 77 36 76 36 IOVEC 113 148 112 105 BVEC 261 159 217 163 KVEC 420 125 380 116 XARRAY 545 286 496 374 DISCARD/Epi 831 42 870 42 Return 873 - 912 - The overall change in the entire file, according to size, is: 19855 744 0 20599 5077 build3/lib/iov_iter.o -- before 19739 864 0 20603 507b build3/lib/iov_iter.o -- after David
UNPATCHED <+0>: push %r15 <+2>: push %r14 <+4>: push %r13 <+6>: push %r12 <+8>: push %rbp <+9>: push %rbx <+10>: sub $0x50,%rsp <+14>: mov %rdi,(%rsp) <+18>: mov %gs:0x28,%rax <+27>: mov %rax,0x48(%rsp) <+32>: xor %eax,%eax <+34>: cmpb $0x0,0x3(%rdx) <+38>: je 0xffffffff81779593 <_copy_from_iter+67> <+40>: mov 0x18(%rdx),%rax <+44>: mov %rdx,%r15 <+47>: cmp %rax,%rsi <+50>: cmovbe %rsi,%rax <+54>: test %rax,%rax <+57>: mov %rax,%r13 <+60>: jne 0xffffffff8177959d <_copy_from_iter+77> <+62>: jmp 0xffffffff81779893 <_copy_from_iter+835> <+67>: ud2 <+69>: xor %r13d,%r13d <+72>: jmp 0xffffffff81779893 <_copy_from_iter+835> # ITER_UBUF <+77>: mov (%rdx),%al <+79>: cmp $0x5,%al <+81>: jne 0xffffffff817795c1 <_copy_from_iter+113> <+83>: mov 0x8(%rdx),%rsi <+87>: mov (%rsp),%rdi <+91>: add 0x10(%rdx),%rsi <+95>: mov %r13,%rdx <+98>: call 0xffffffff81777905 <copyin> <+103>: cltq <+105>: sub %rax,%r13 <+108>: jmp 0xffffffff8177988b <_copy_from_iter+827> # ITER_IOVEC <+113>: test %al,%al <+115>: jne 0xffffffff81779655 <_copy_from_iter+261> <+121>: mov 0x10(%rdx),%rbp <+125>: xor %r12d,%r12d <+128>: mov 0x8(%rdx),%rbx <+132>: mov 0x8(%rbp),%rdx <+136>: sub %rbx,%rdx <+139>: cmp %r13,%rdx <+142>: cmova %r13,%rdx <+146>: test %rdx,%rdx <+149>: je 0xffffffff81779619 <_copy_from_iter+201> <+151>: mov 0x0(%rbp),%rsi <+155>: mov (%rsp),%rax <+159>: add %rbx,%rsi <+162>: lea (%rax,%r12,1),%rdi <+166>: call 0xffffffff81777905 <copyin> <+171>: mov %rdx,%rcx <+174>: mov %r13,%r8 <+177>: cltq <+179>: sub %rdx,%r8 <+182>: lea (%r8,%rax,1),%r13 <+186>: sub %rax,%rcx <+189>: add %rcx,%r12 <+192>: add %rcx,%rbx <+195>: cmp 0x8(%rbp),%rbx <+199>: jb 0xffffffff81779626 <_copy_from_iter+214> <+201>: add $0x10,%rbp <+205>: xor %ebx,%ebx <+207>: test %r13,%r13 <+210>: jne 0xffffffff817795d4 <_copy_from_iter+132> <+212>: jmp 0xffffffff81779629 <_copy_from_iter+217> <+214>: mov %rbx,%r13 <+217>: cmpb $0x5,(%r15) <+221>: mov %r13,0x8(%r15) <+225>: lea 0x10(%r15),%rdx <+229>: je 0xffffffff8177963b <_copy_from_iter+235> <+231>: mov 0x10(%r15),%rdx <+235>: mov %rbp,%rax <+238>: mov %rbp,0x10(%r15) <+242>: mov %r12,%r13 <+245>: sub %rdx,%rax <+248>: sar $0x4,%rax <+252>: sub %rax,0x20(%r15) <+256>: jmp 0xffffffff8177988f <_copy_from_iter+831> # ITER_BVEC <+261>: cmp $0x2,%al <+263>: jne 0xffffffff817796f4 <_copy_from_iter+420> <+269>: mov 0x10(%rdx),%r14 <+273>: xor %ebp,%ebp <+275>: mov 0x8(%rdx),%r12d <+279>: mov 0xc(%r14),%ecx <+283>: add %r12d,%ecx <+286>: mov %ecx,%edi <+288>: and $0xfff,%ecx <+294>: shr $0xc,%edi <+297>: shl $0x6,%rdi <+301>: add (%r14),%rdi <+304>: call 0xffffffff81777282 <kmap_local_page> <+309>: mov 0x8(%r14),%ebx <+313>: mov $0x1000,%edx <+318>: mov 0x1(%r15),%dil <+322>: sub %r12d,%ebx <+325>: cmp %r13,%rbx <+328>: cmova %r13,%rbx <+332>: sub %rcx,%rdx <+335>: cmp %rdx,%rbx <+338>: cmova %rdx,%rbx <+342>: lea (%rax,%rcx,1),%rdx <+346>: mov (%rsp),%rax <+350>: mov %rbx,%rcx <+353>: add %ebx,%r12d <+356>: lea (%rax,%rbp,1),%rsi <+360>: add %rbx,%rbp <+363>: call 0xffffffff81779531 <memcpy_from_iter> <+368>: cmp %r12d,0x8(%r14) <+372>: jne 0xffffffff817796cd <_copy_from_iter+381> <+374>: add $0x10,%r14 <+378>: xor %r12d,%r12d <+381>: sub %rbx,%r13 <+384>: jne 0xffffffff81779667 <_copy_from_iter+279> <+386>: mov %r12d,%eax <+389>: mov %rbp,%r13 <+392>: mov %rax,0x8(%r15) <+396>: mov %r14,%rax <+399>: sub 0x10(%r15),%rax <+403>: mov %r14,0x10(%r15) <+407>: sar $0x4,%rax <+411>: sub %rax,0x20(%r15) <+415>: jmp 0xffffffff8177988f <_copy_from_iter+831> # ITER_KVEC <+420>: cmp $0x1,%al <+422>: jne 0xffffffff81779771 <_copy_from_iter+545> <+424>: mov 0x10(%rdx),%r12 <+428>: xor %r14d,%r14d <+431>: mov 0x8(%rdx),%rbp <+435>: mov 0x8(%r12),%rbx <+440>: sub %rbp,%rbx <+443>: cmp %r13,%rbx <+446>: cmova %r13,%rbx <+450>: test %rbx,%rbx <+453>: je 0xffffffff81779742 <_copy_from_iter+498> <+455>: mov (%r12),%rdx <+459>: mov %rbx,%rcx <+462>: sub %rbx,%r13 <+465>: mov (%rsp),%rax <+469>: mov 0x1(%r15),%dil <+473>: add %rbp,%rdx <+476>: add %rbx,%rbp <+479>: lea (%rax,%r14,1),%rsi <+483>: add %rbx,%r14 <+486>: call 0xffffffff81779531 <memcpy_from_iter> <+491>: cmp 0x8(%r12),%rbp <+496>: jb 0xffffffff8177974f <_copy_from_iter+511> <+498>: add $0x10,%r12 <+502>: xor %ebp,%ebp <+504>: test %r13,%r13 <+507>: jne 0xffffffff81779703 <_copy_from_iter+435> <+509>: jmp 0xffffffff81779752 <_copy_from_iter+514> <+511>: mov %rbp,%r13 <+514>: mov %r12,%rax <+517>: sub 0x10(%r15),%rax <+521>: mov %r13,0x8(%r15) <+525>: mov %r14,%r13 <+528>: mov %r12,0x10(%r15) <+532>: sar $0x4,%rax <+536>: sub %rax,0x20(%r15) <+540>: jmp 0xffffffff8177988f <_copy_from_iter+831> # ITER_XARRAY <+545>: cmp $0x3,%al <+547>: jne 0xffffffff8177988f <_copy_from_iter+831> <+553>: mov 0x10(%rdx),%rax <+557>: mov $0x1000,%ebp <+562>: movq $0x3,0x28(%rsp) <+571>: mov 0x8(%rdx),%r14 <+575>: add 0x20(%rdx),%r14 <+579>: xor %edx,%edx <+581>: mov %rdx,0x30(%rsp) <+586>: mov %rax,0x10(%rsp) <+591>: mov %rdx,0x38(%rsp) <+596>: mov %r14,%rax <+599>: mov %rdx,0x40(%rsp) <+604>: shr $0xc,%rax <+608>: mov %rax,0x18(%rsp) <+613>: xor %eax,%eax <+615>: mov %eax,0x20(%rsp) <+619>: mov %r14,%rax <+622>: and $0xfff,%eax <+627>: sub %rax,%rbp <+630>: call 0xffffffff81126bcf <__rcu_read_lock> <+635>: or $0xffffffffffffffff,%rsi <+639>: lea 0x10(%rsp),%rdi <+644>: call 0xffffffff81d5edaf <xas_find> <+649>: mov %r13,0x8(%rsp) <+654>: mov %rax,%rbx <+657>: xor %r13d,%r13d <+660>: test %rbx,%rbx <+663>: je 0xffffffff81779886 <_copy_from_iter+822> <+669>: lea 0x10(%rsp),%rdi <+674>: mov %rbx,%rsi <+677>: call 0xffffffff81777300 <xas_retry> <+682>: test %al,%al <+684>: jne 0xffffffff81779874 <_copy_from_iter+804> <+686>: test $0x1,%bl <+689>: jne 0xffffffff81779824 <_copy_from_iter+724> <+691>: mov %rbx,%rdi <+694>: call 0xffffffff81270e56 <folio_test_hugetlb> <+699>: test %al,%al <+701>: jne 0xffffffff81779824 <_copy_from_iter+724> <+703>: lea (%r14,%r13,1),%rdx <+707>: mov %rbx,%rdi <+710>: call 0xffffffff81777266 <folio_size> <+715>: lea -0x1(%rax),%r12 <+719>: and %rdx,%r12 <+722>: jmp 0xffffffff81779867 <_copy_from_iter+791> <+724>: ud2 <+726>: jmp 0xffffffff81779886 <_copy_from_iter+822> <+728>: mov %r12,%rsi <+731>: mov %rbx,%rdi <+734>: call 0xffffffff817772a7 <kmap_local_folio> <+739>: mov 0x1(%r15),%dil <+743>: mov %rax,%rdx <+746>: mov (%rsp),%rax <+750>: cmp %rbp,0x8(%rsp) <+755>: cmovbe 0x8(%rsp),%rbp <+761>: mov %rbp,%rcx <+764>: lea (%rax,%r13,1),%rsi <+768>: add %rbp,%r13 <+771>: call 0xffffffff81779531 <memcpy_from_iter> <+776>: sub %rbp,0x8(%rsp) <+781>: je 0xffffffff81779886 <_copy_from_iter+822> <+783>: add %rbp,%r12 <+786>: mov $0x1000,%ebp <+791>: mov %rbx,%rdi <+794>: call 0xffffffff81777266 <folio_size> <+799>: cmp %rax,%r12 <+802>: jb 0xffffffff81779828 <_copy_from_iter+728> <+804>: lea 0x10(%rsp),%rdi <+809>: call 0xffffffff81777d61 <xas_next_entry> <+814>: mov %rax,%rbx <+817>: jmp 0xffffffff817797e4 <_copy_from_iter+660> <+822>: call 0xffffffff811299a3 <__rcu_read_unlock> <+827>: add %r13,0x8(%r15) # ITER_DISCARD / default <+831>: sub %r13,0x18(%r15) <+835>: mov 0x48(%rsp),%rax <+840>: sub %gs:0x28,%rax <+849>: je 0xffffffff817798a8 <_copy_from_iter+856> <+851>: call 0xffffffff81d657ac <__stack_chk_fail> <+856>: add $0x50,%rsp <+860>: mov %r13,%rax <+863>: pop %rbx <+864>: pop %rbp <+865>: pop %r12 <+867>: pop %r13 <+869>: pop %r14 <+871>: pop %r15 <+873>: jmp 0xffffffff81d72960 <__x86_return_thunk>
PATCHED <+0>: push %r15 <+2>: push %r14 <+4>: push %r13 <+6>: push %r12 <+8>: push %rbp <+9>: push %rbx <+10>: sub $0x68,%rsp <+14>: mov %rdi,(%rsp) <+18>: mov %gs:0x28,%rax <+27>: mov %rax,0x60(%rsp) <+32>: xor %eax,%eax <+34>: cmpb $0x0,0x3(%rdx) <+38>: je 0xffffffff8177931e <_copy_from_iter+67> <+40>: mov 0x18(%rdx),%rax <+44>: mov %rdx,%r15 <+47>: cmp %rax,%rsi <+50>: cmovbe %rsi,%rax <+54>: test %rax,%rax <+57>: mov %rax,%rbx <+60>: jne 0xffffffff81779327 <_copy_from_iter+76> <+62>: jmp 0xffffffff81779645 <_copy_from_iter+874> <+67>: ud2 <+69>: xor %ebx,%ebx <+71>: jmp 0xffffffff81779645 <_copy_from_iter+874> # ITER_UBUF <+76>: mov (%rdx),%al <+78>: cmp $0x5,%al <+80>: jne 0xffffffff8177934b <_copy_from_iter+112> <+82>: mov 0x8(%rdx),%rdi <+86>: xor %esi,%esi <+88>: add 0x10(%rdx),%rdi <+92>: mov %rbx,%rdx <+95>: mov (%rsp),%rcx <+99>: call 0xffffffff81778207 <copy_from_user_iter> <+104>: sub %rax,%rbx <+107>: jmp 0xffffffff8177963d <_copy_from_iter+866> # ITER_IOVEC <+112>: test %al,%al <+114>: jne 0xffffffff817793b4 <_copy_from_iter+217> <+116>: mov 0x10(%rdx),%r13 <+120>: xor %r14d,%r14d <+123>: mov 0x8(%rdx),%r12 <+127>: mov 0x8(%r13),%rbp <+131>: sub %r12,%rbp <+134>: cmp %rbx,%rbp <+137>: cmova %rbx,%rbp <+141>: test %rbp,%rbp <+144>: je 0xffffffff8177939b <_copy_from_iter+192> <+146>: mov 0x0(%r13),%rdi <+150>: mov %rbp,%rdx <+153>: mov %r14,%rsi <+156>: sub %rbp,%rbx <+159>: mov (%rsp),%rcx <+163>: add %r12,%rdi <+166>: call 0xffffffff81778207 <copy_from_user_iter> <+171>: mov %rbp,%rdx <+174>: sub %rax,%rdx <+177>: add %rax,%rbx <+180>: add %rdx,%r14 <+183>: add %r12,%rdx <+186>: cmp 0x8(%r13),%rdx <+190>: jb 0xffffffff817793ac <_copy_from_iter+209> <+192>: add $0x10,%r13 <+196>: xor %r12d,%r12d <+199>: test %rbx,%rbx <+202>: jne 0xffffffff8177935a <_copy_from_iter+127> <+204>: jmp 0xffffffff817794bb <_copy_from_iter+480> <+209>: mov %rdx,%rbx <+212>: jmp 0xffffffff817794bb <_copy_from_iter+480> # ITER_BVEC <+217>: cmp $0x2,%al <+219>: jne 0xffffffff81779457 <_copy_from_iter+380> <+225>: mov 0x10(%rdx),%r13 <+229>: xor %r12d,%r12d <+232>: mov 0x8(%rdx),%r14 <+236>: mov 0xc(%r13),%ecx <+240>: mov %r12,%rsi <+243>: mov %r15,%r8 <+246>: add %r14,%rcx <+249>: mov %rcx,%rdi <+252>: and $0xfff,%ecx <+258>: shr $0xc,%rdi <+262>: shl $0x6,%rdi <+266>: add 0x0(%r13),%rdi <+270>: call 0xffffffff81777282 <kmap_local_page> <+275>: mov 0x8(%r13),%ebp <+279>: mov $0x1000,%edx <+284>: lea (%rax,%rcx,1),%rdi <+288>: sub %r14,%rbp <+291>: cmp %rbx,%rbp <+294>: cmova %rbx,%rbp <+298>: sub %rcx,%rdx <+301>: mov (%rsp),%rcx <+305>: cmp %rdx,%rbp <+308>: cmova %rdx,%rbp <+312>: mov %rbp,%rdx <+315>: call 0xffffffff81777934 <memcpy_from_iter_mc> <+320>: mov %rbp,%rdx <+323>: sub %rax,%rdx <+326>: add %rax,%rbx <+329>: add %rdx,%r12 <+332>: add %rdx,%r14 <+335>: mov 0x8(%r13),%edx <+339>: sub %rbp,%rbx <+342>: cmp %rdx,%r14 <+345>: jb 0xffffffff8177943d <_copy_from_iter+354> <+347>: add $0x10,%r13 <+351>: xor %r14d,%r14d <+354>: test %rax,%rax <+357>: jne 0xffffffff81779447 <_copy_from_iter+364> <+359>: test %rbx,%rbx <+362>: jne 0xffffffff817793c7 <_copy_from_iter+236> <+364>: mov %r13,0x10(%r15) <+368>: mov %r12,%rbx <+371>: mov %r14,0x8(%r15) <+375>: jmp 0xffffffff81779641 <_copy_from_iter+870> # ITER_KVEC <+380>: cmp $0x1,%al <+382>: jne 0xffffffff817794cb <_copy_from_iter+496> <+384>: mov 0x10(%rdx),%r13 <+388>: xor %r14d,%r14d <+391>: mov 0x8(%rdx),%r12 <+395>: mov 0x8(%r13),%rbp <+399>: sub %r12,%rbp <+402>: cmp %rbx,%rbp <+405>: cmova %rbx,%rbp <+409>: test %rbp,%rbp <+412>: je 0xffffffff817794aa <_copy_from_iter+463> <+414>: mov 0x0(%r13),%rdi <+418>: mov %rbp,%rdx <+421>: mov %r14,%rsi <+424>: mov %r15,%r8 <+427>: mov (%rsp),%rcx <+431>: sub %rbp,%rbx <+434>: add %r12,%rdi <+437>: call 0xffffffff81777934 <memcpy_from_iter_mc> <+442>: mov %rbp,%rdx <+445>: sub %rax,%rdx <+448>: add %rax,%rbx <+451>: add %rdx,%r14 <+454>: add %rdx,%r12 <+457>: cmp 0x8(%r13),%r12 <+461>: jb 0xffffffff817794b8 <_copy_from_iter+477> <+463>: add $0x10,%r13 <+467>: xor %r12d,%r12d <+470>: test %rbx,%rbx <+473>: jne 0xffffffff81779466 <_copy_from_iter+395> <+475>: jmp 0xffffffff817794bb <_copy_from_iter+480> <+477>: mov %r12,%rbx <+480>: mov %rbx,0x8(%r15) <+484>: mov %r14,%rbx <+487>: mov %r13,0x10(%r15) <+491>: jmp 0xffffffff81779641 <_copy_from_iter+870> # ITER_XARRAY <+496>: cmp $0x3,%al <+498>: jne 0xffffffff81779641 <_copy_from_iter+870> <+504>: movq $0x3,0x40(%rsp) <+513>: mov 0x10(%rdx),%rax <+517>: mov 0x8(%rdx),%r13 <+521>: add 0x20(%rdx),%r13 <+525>: xor %edx,%edx <+527>: mov %rdx,0x48(%rsp) <+532>: mov %rax,0x28(%rsp) <+537>: mov %rdx,0x50(%rsp) <+542>: mov %r13,%rax <+545>: mov %rdx,0x58(%rsp) <+550>: shr $0xc,%rax <+554>: mov %rax,0x30(%rsp) <+559>: xor %eax,%eax <+561>: mov %eax,0x38(%rsp) <+565>: call 0xffffffff81126bcf <__rcu_read_lock> <+570>: or $0xffffffffffffffff,%rsi <+574>: lea 0x28(%rsp),%rdi <+579>: call 0xffffffff81d5ed2f <xas_find> <+584>: xor %ecx,%ecx <+586>: mov %rax,%rbp <+589>: mov %rcx,0x8(%rsp) <+594>: test %rbp,%rbp <+597>: je 0xffffffff81779589 <_copy_from_iter+686> <+599>: lea 0x28(%rsp),%rdi <+604>: mov %rbp,%rsi <+607>: call 0xffffffff81777300 <xas_retry> <+612>: test %al,%al <+614>: jne 0xffffffff81779626 <_copy_from_iter+843> <+620>: test $0x1,%ebp <+626>: jne 0xffffffff81779587 <_copy_from_iter+684> <+628>: mov %rbp,%rdi <+631>: call 0xffffffff81270e56 <folio_test_hugetlb> <+636>: test %al,%al <+638>: jne 0xffffffff81779593 <_copy_from_iter+696> <+640>: mov %rbp,%rdi <+643>: mov %rbx,%r11 <+646>: call 0xffffffff81777266 <folio_size> <+651>: lea -0x1(%rax),%r12 <+655>: call 0xffffffff81777266 <folio_size> <+660>: and %r13,%r12 <+663>: sub %r12,%rax <+666>: cmp %rbx,%rax <+669>: cmova %rbx,%rax <+673>: mov %rax,%r9 <+676>: mov %rax,%r14 <+679>: jmp 0xffffffff81779617 <_copy_from_iter+828> <+684>: ud2 <+686>: mov 0x8(%rsp),%rbx <+691>: jmp 0xffffffff81779638 <_copy_from_iter+861> <+696>: ud2 <+698>: jmp 0xffffffff81779589 <_copy_from_iter+686> <+700>: mov %r12,%rsi <+703>: mov %rbp,%rdi <+706>: mov %r11,0x20(%rsp) <+711>: mov %r15,%r8 <+714>: mov %r9,0x18(%rsp) <+719>: call 0xffffffff817772a7 <kmap_local_folio> <+724>: mov $0x1000,%edx <+729>: mov (%rsp),%rcx <+733>: mov %rax,%rdi <+736>: mov %r12,%rax <+739>: mov 0x8(%rsp),%rsi <+744>: and $0xfff,%eax <+749>: sub %rax,%rdx <+752>: cmp %r14,%rdx <+755>: cmova %r14,%rdx <+759>: mov %rdx,0x10(%rsp) <+764>: call 0xffffffff81777934 <memcpy_from_iter_mc> <+769>: mov 0x10(%rsp),%rdx <+774>: mov 0x8(%rsp),%rbx <+779>: mov %rax,%rsi <+782>: mov 0x20(%rsp),%r11 <+787>: mov %rdx,%rcx <+790>: sub %rdx,%rsi <+793>: sub %rax,%rcx <+796>: add %rcx,%rbx <+799>: add %rsi,%r11 <+802>: test %rax,%rax <+805>: jne 0xffffffff81779638 <_copy_from_iter+861> <+807>: test %r11,%r11 <+810>: je 0xffffffff81779638 <_copy_from_iter+861> <+812>: mov 0x18(%rsp),%r9 <+817>: add %rsi,%r14 <+820>: add %rcx,%r12 <+823>: mov %rbx,0x8(%rsp) <+828>: test %r14,%r14 <+831>: jne 0xffffffff81779597 <_copy_from_iter+700> <+837>: add %r9,%r13 <+840>: mov %r11,%rbx <+843>: lea 0x28(%rsp),%rdi <+848>: call 0xffffffff81777d00 <xas_next_entry> <+853>: mov %rax,%rbp <+856>: jmp 0xffffffff8177952d <_copy_from_iter+594> <+861>: call 0xffffffff811299a3 <__rcu_read_unlock> <+866>: add %rbx,0x8(%r15) # ITER_DISCARD / default <+870>: sub %rbx,0x18(%r15) <+874>: mov 0x60(%rsp),%rax <+879>: sub %gs:0x28,%rax <+888>: je 0xffffffff8177965a <_copy_from_iter+895> <+890>: call 0xffffffff81d6572c <__stack_chk_fail> <+895>: add $0x68,%rsp <+899>: mov %rbx,%rax <+902>: pop %rbx <+903>: pop %rbp <+904>: pop %r12 <+906>: pop %r13 <+908>: pop %r14 <+910>: pop %r15 <+912>: jmp 0xffffffff81d728e0 <__x86_return_thunk>
