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  1. 05 6月, 2015 2 次提交
  3. 04 6月, 2015 7 次提交
    • I
      x86/asm/entry: Move the vsyscall code to arch/x86/entry/vsyscall/ · 00398a00
      由 Ingo Molnar 提交于 
      The vsyscall code is entry code too, so move it to arch/x86/entry/vsyscall/.

Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      00398a00
    • I
      x86/asm/entry: Move the arch/x86/syscalls/ definitions to arch/x86/entry/syscalls/ · 1f57d5d8
      由 Ingo Molnar 提交于 
      The build time generated syscall definitions are entry code related, move
them into the arch/x86/entry/ directory.

Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      1f57d5d8
    • I
      x86/asm/entry: Move arch/x86/include/asm/calling.h to arch/x86/entry/ · d36f9479
      由 Ingo Molnar 提交于 
      asm/calling.h is private to the entry code, make this more apparent
by moving it to the new arch/x86/entry/ directory.

Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      d36f9479
    • I
      x86/asm/entry: Move the 'thunk' functions to arch/x86/entry/ · e6b93f4e
      由 Ingo Molnar 提交于 
      These are all calling x86 entry code functions, so move them close
to other entry code.

Change lib-y to obj-y: there's no real difference between the two
as we don't really drop any of them during the linking stage, and
obj-y is the more common approach for core kernel object code.

Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      e6b93f4e
    • I
      x86/asm/entry, x86/vdso: Move the vDSO code to arch/x86/entry/vdso/ · d603c8e1
      由 Ingo Molnar 提交于 
      Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      d603c8e1
    • I
      x86/asm/entry: Move the compat syscall entry code to arch/x86/entry/ · 19a433f4
      由 Ingo Molnar 提交于 
      Move the ia32entry.S file over into arch/x86/entry/.

Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      19a433f4
    • I
      x86/asm/entry: Move entry_64.S and entry_32.S to arch/x86/entry/ · 905a36a2
      由 Ingo Molnar 提交于 
      Create a new directory hierarchy for the low level x86 entry code:

    arch/x86/entry/*

This will host all the low level glue that is currently scattered
all across arch/x86/.

Start with entry_64.S and entry_32.S.

Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      905a36a2
  5. 02 6月, 2015 3 次提交
    • J
      x86/asm/entry/64: Fold identical code paths · 2f63b9db
      由 Jan Beulich 提交于 
      retint_kernel doesn't require %rcx to be pointing to thread info
(anymore?), and the code on the two alternative paths is - not
really surprisingly - identical.
Signed-off-by: NJan Beulich <jbeulich@suse.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/556C664F020000780007FB64@mail.emea.novell.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      2f63b9db
    • J
      x86/asm/entry/64: Use negative immediates for stack adjustments · 2bf557ea
      由 Jan Beulich 提交于 
      Doing so allows adjustments by 128 bytes (occurring for
REMOVE_PT_GPREGS_FROM_STACK 8 uses) to be expressed with a
single byte immediate.
Signed-off-by: NJan Beulich <jbeulich@suse.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/556C660F020000780007FB60@mail.emea.novell.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      2bf557ea
    • I
      x86/debug: Remove perpetually broken, unmaintainable dwarf annotations · 131484c8
      由 Ingo Molnar 提交于 
      So the dwarf2 annotations in low level assembly code have
become an increasing hindrance: unreadable, messy macros
mixed into some of the most security sensitive code paths
of the Linux kernel.

These debug info annotations don't even buy the upstream
kernel anything: dwarf driven stack unwinding has caused
problems in the past so it's out of tree, and the upstream
kernel only uses the much more robust framepointers based
stack unwinding method.

In addition to that there's a steady, slow bitrot going
on with these annotations, requiring frequent fixups.
There's no tooling and no functionality upstream that
keeps it correct.

So burn down the sick forest, allowing new, healthier growth:

   27 files changed, 350 insertions(+), 1101 deletions(-)

Someone who has the willingness and time to do this
properly can attempt to reintroduce dwarf debuginfo in x86
assembly code plus dwarf unwinding from first principles,
with the following conditions:

 - it should be maximally readable, and maximally low-key to
   'ordinary' code reading and maintenance.

 - find a build time method to insert dwarf annotations
   automatically in the most common cases, for pop/push
   instructions that manipulate the stack pointer. This could
   be done for example via a preprocessing step that just
   looks for common patterns - plus special annotations for
   the few cases where we want to depart from the default.
   We have hundreds of CFI annotations, so automating most of
   that makes sense.

 - it should come with build tooling checks that ensure that
   CFI annotations are sensible. We've seen such efforts from
   the framepointer side, and there's no reason it couldn't be
   done on the dwarf side.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      131484c8
  7. 24 5月, 2015 1 次提交
    • A
      x86/asm/irq: Stop relying on magic JMP behavior for early_idt_handlers · cdeb6048
      由 Andy Lutomirski 提交于 
      The early_idt_handlers asm code generates an array of entry
points spaced nine bytes apart.  It's not really clear from that
code or from the places that reference it what's going on, and
the code only works in the first place because GAS never
generates two-byte JMP instructions when jumping to global
labels.

Clean up the code to generate the correct array stride (member size)
explicitly. This should be considerably more robust against
screw-ups, as GAS will warn if a .fill directive has a negative
count.  Using '. =' to advance would have been even more robust
(it would generate an actual error if it tried to move
backwards), but it would pad with nulls, confusing anyone who
tries to disassemble the code.  The new scheme should be much
clearer to future readers.

While we're at it, improve the comments and rename the array and
common code.

Binutils may start relaxing jumps to non-weak labels.  If so,
this change will fix our build, and we may need to backport this
change.

Before, on x86_64:

  0000000000000000 <early_idt_handlers>:
     0:   6a 00                   pushq  $0x0
     2:   6a 00                   pushq  $0x0
     4:   e9 00 00 00 00          jmpq   9 <early_idt_handlers+0x9>
                          5: R_X86_64_PC32        early_idt_handler-0x4
  ...
    48:   66 90                   xchg   %ax,%ax
    4a:   6a 08                   pushq  $0x8
    4c:   e9 00 00 00 00          jmpq   51 <early_idt_handlers+0x51>
                          4d: R_X86_64_PC32       early_idt_handler-0x4
  ...
   117:   6a 00                   pushq  $0x0
   119:   6a 1f                   pushq  $0x1f
   11b:   e9 00 00 00 00          jmpq   120 <early_idt_handler>
                          11c: R_X86_64_PC32      early_idt_handler-0x4

After:

  0000000000000000 <early_idt_handler_array>:
     0:   6a 00                   pushq  $0x0
     2:   6a 00                   pushq  $0x0
     4:   e9 14 01 00 00          jmpq   11d <early_idt_handler_common>
  ...
    48:   6a 08                   pushq  $0x8
    4a:   e9 d1 00 00 00          jmpq   120 <early_idt_handler_common>
    4f:   cc                      int3
    50:   cc                      int3
  ...
   117:   6a 00                   pushq  $0x0
   119:   6a 1f                   pushq  $0x1f
   11b:   eb 03                   jmp    120 <early_idt_handler_common>
   11d:   cc                      int3
   11e:   cc                      int3
   11f:   cc                      int3
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Acked-by: NH. Peter Anvin <hpa@linux.intel.com>
Cc: Binutils <binutils@sourceware.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H.J. Lu <hjl.tools@gmail.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/ac027962af343b0c599cbfcf50b945ad2ef3d7a8.1432336324.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      cdeb6048
  9. 17 5月, 2015 3 次提交
    • D
      x86/asm/entry/64: Use shorter MOVs from segment registers · adeb5537
      由 Denys Vlasenko 提交于 
      The "movw %ds,%cx" instruction needs a 0x66 prefix, while
"movl %ds,%ecx" does not.

The difference is that latter form (on 64-bit CPUs)
overwrites the entire %ecx, not only its lower half.

But subsequent code doesn't depend on the value of upper
half of %ecx, so we can safely use the shorter instruction.

The new code is also faster than the old one - now we don't
depend on the old value of %ecx, but this code fragment is
not performance-critical so it does not matter much.
Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1431722346-26585-1-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      adeb5537
    • B
      x86/asm/head*.S: Change global labels to local · e839004b
      由 Borislav Petkov 提交于 
      Make the disassembly look less confusing:

  -- head_64.o.before.asm
  ++ head_64.o.after.asm
   0000000000000120 <early_idt_handler>:
    120:	fc                   	cld
    121:	83 3c 24 02          	cmpl   $0x2,(%rsp)
  - 125:	0f 84 9d 00 00 00    	je     1c8 <is_nmi>
  + 125:	0f 84 9d 00 00 00    	je     1c8 <early_idt_handler+0xa8>
    12b:	83 3d 00 00 00 00 02 	cmpl   $0x2,0x0(%rip)        # 132 <early_idt_handler+0x12>
    132:	74 7e                	je     1b2 <early_idt_handler+0x92>
    134:	ff 05 00 00 00 00    	incl   0x0(%rip)        # 13a <early_idt_handler+0x1a>
  @@ -1198,9 +1198,7 @@ Disassembly of section .init.text:
    1bf:	5a                   	pop    %rdx
    1c0:	59                   	pop    %rcx
    1c1:	58                   	pop    %rax
  - 1c2:	ff 0d 00 00 00 00    	decl   0x0(%rip)        # 1c8 <is_nmi>
  -
  -00000000000001c8 <is_nmi>:
  + 1c2:	ff 0d 00 00 00 00    	decl   0x0(%rip)        # 1c8 <early_idt_handler+0xa8>
    1c8:	48 83 c4 10          	add    $0x10,%rsp
    1cc:	48 cf                	iretq

  -- head_32.o.before.asm
  ++ head_32.o.after.asm
   0000016c <early_idt_handler>:
    16c:  fc                      cld
    16d:  83 3c 24 02             cmpl   $0x2,(%esp)
  - 171:  74 73                   je     1e6 <is_nmi>
  + 171:  74 73                   je     1e6 <ex_entry+0xc>
    173:  36 83 3d 00 00 00 00    cmpl   $0x2,%ss:0x0
    17a:  02
    17b:  74 5a                   je     1d7 <hlt_loop>
  @@ -483,8 +483,6 @@ Disassembly of section .init.text:
    1dd:  59                      pop    %ecx
    1de:  58                      pop    %eax
    1df:  36 ff 0d 00 00 00 00    decl   %ss:0x0
  -
  -000001e6 <is_nmi>:
    1e6:  83 c4 08                add    $0x8,%esp
    1e9:  cf                      iret
    1ea:  66 90                   xchg   %ax,%ax

No functionality change.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1431793079-11153-1-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>
      e839004b
    • I
      x86: Pack loops tightly as well · 52648e83
      由 Ingo Molnar 提交于 
      Packing loops tightly (-falign-loops=1) is beneficial to code size:

     text        data    bss     dec              filename
 12566391        1617840 1089536 15273767         vmlinux.align.16-byte
 12224951        1617840 1089536 14932327         vmlinux.align.1-byte
 11976567        1617840 1089536 14683943         vmlinux.align.1-byte.funcs-1-byte
 11903735        1617840 1089536 14611111         vmlinux.align.1-byte.funcs-1-byte.loops-1-byte

Which reduces the size of the kernel by another 0.6%, so the
the total combined size reduction of the alignment-packing
patches is ~5.5%.

The x86 decoder bandwidth and caching arguments laid out in:

  be6cb027 ("x86: Align jump targets to 1-byte boundaries")

apply to loop alignment as well.

Furtermore, modern CPU uarchs have a loop cache/buffer that
is a L0 cache before even any uop cache, covering a few
dozen most recently executed instructions.

This loop cache generally does not have the 16-byte alignment
restrictions of the uop cache.

Now loop alignment can still be beneficial if:

 - a loop is cache-hot and its surroundings are not.

 - if the loop is so cache hot that the instruction
   flow becomes x86 decoder bandwidth limited

But loop alignment is harmful if:

 - a loop is cache-cold

 - a loop's surroundings are cache-hot as well

 - two cache-hot loops are close to each other

 - if the loop fits into the loop cache

 - if the code flow is not decoder bandwidth limited

and I'd argue that the latter five scenarios are much
more common in the kernel, as our hottest loops are
typically:

 - pointer chasing: this should fit into the loop cache
   in most cases and is typically data cache and address
   generation limited

 - generic memory ops (memset, memcpy, etc.): these generally
   fit into the loop cache as well, and are likewise data
   cache limited.

So this patch packs loop addresses tightly as well.
Acked-by: NDenys Vlasenko <dvlasenk@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Link: http://lkml.kernel.org/r/20150410123017.GB19918@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      52648e83
  11. 15 5月, 2015 1 次提交
    • I
      x86: Align jump targets to 1-byte boundaries · be6cb027
      由 Ingo Molnar 提交于 
      The following NOP in a hot function caught my attention:

  >   5a:	66 0f 1f 44 00 00    	nopw   0x0(%rax,%rax,1)

That's a dead NOP that bloats the function a bit, added for the
default 16-byte alignment that GCC applies for jump targets.

I realize that x86 CPU manufacturers recommend 16-byte jump
target alignments (it's in the Intel optimization manual),
to help their relatively narrow decoder prefetch alignment
and uop cache constraints, but the cost of that is very
significant:

        text           data       bss         dec      filename
    12566391        1617840   1089536    15273767      vmlinux.align.16-byte
    12224951        1617840   1089536    14932327      vmlinux.align.1-byte

By using 1-byte jump target alignment (i.e. no alignment at all)
we get an almost 3% reduction in kernel size (!) - and a
probably similar reduction in I$ footprint.

Now, the usual justification for jump target alignment is the
following:

 - modern decoders tend to have 16-byte (effective) decoder
   prefetch windows. (AMD documents it higher but measurements
   suggest the effective prefetch window on curretn uarchs is
   still around 16 bytes)

 - on Intel there's also the uop-cache with cachelines that have
   16-byte granularity and limited associativity.

 - older x86 uarchs had a penalty for decoder fetches that crossed
   16-byte boundaries. These limits are mostly gone from recent
   uarchs.

So if a forward jump target is aligned to cacheline boundary then
prefetches will start from a new prefetch-cacheline and there's
higher chance for decoding in fewer steps and packing tightly.

But I think that argument is flawed for typical optimized kernel
code flows: forward jumps often go to 'cold' (uncommon) pieces
of code, and  aligning cold code to cache lines does not bring a
lot of advantages  (they are uncommon), while it causes
collateral damage:

 - their alignment 'spreads out' the cache footprint, it shifts
   followup hot code further out

 - plus it slows down even 'cold' code that immediately follows 'hot'
   code (like in the above case), which could have benefited from the
   partial cacheline that comes off the end of hot code.

But even in the cache-hot case the 16 byte alignment brings
disadvantages:

 - it spreads out the cache footprint, possibly making the code
   fall out of the L1 I$.

 - On Intel CPUs, recent microarchitectures have plenty of
   uop cache (typically doubling every 3 years) - while the
   size of the L1 cache grows much less aggressively. So
   workloads are rarely uop cache limited.

The only situation where alignment might matter are tight
loops that could fit into a single 16 byte chunk - but those
are pretty rare in the kernel: if they exist they tend
to be pointer chasing or generic memory ops, which both tend
to be cache miss (or cache allocation) intensive and are not
decoder bandwidth limited.

So the balance of arguments strongly favors packing kernel
instructions tightly versus maximizing for decoder bandwidth:
this patch changes the jump target alignment from 16 bytes
to 1 byte (tightly packed, unaligned).
Acked-by: NDenys Vlasenko <dvlasenk@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Link: http://lkml.kernel.org/r/20150410120846.GA17101@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      be6cb027
  13. 14 5月, 2015 3 次提交
  15. 13 5月, 2015 1 次提交
  17. 11 5月, 2015 3 次提交
    • S
      perf/x86/rapl: Enable Broadwell-U RAPL support · 44b11fee
      由 Stephane Eranian 提交于 
      This patch enables RAPL counters (energy consumption counters)
support for Intel Broadwell-U processors (Model 61):

To use:

  $ perf stat -a -I 1000 -e power/energy-cores/,power/energy-pkg/,power/energy-ram/ sleep 10
Signed-off-by: NStephane Eranian <eranian@google.com>
Cc: <stable@vger.kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: jacob.jun.pan@linux.intel.com
Cc: kan.liang@intel.com
Cc: peterz@infradead.org
Cc: sonnyrao@chromium.org
Link: http://lkml.kernel.org/r/20150423070709.GA4970@thinkpadSigned-off-by: NIngo Molnar <mingo@kernel.org>
      44b11fee
    • B
      x86/alternatives: Switch AMD F15h and later to the P6 NOPs · f21262b8
      由 Borislav Petkov 提交于 
      Software optimization guides for both F15h and F16h cite those
NOPs as the optimal ones. A microbenchmark confirms that
actually even older families are better with the single-insn
NOPs so switch to them for the alternatives.

Cycles count below includes the loop overhead of the measurement
but that overhead is the same with all runs.

	F10h, revE:
	-----------
	Running NOP tests, 1000 NOPs x 1000000 repetitions

	K8:
			      90     288.212282 cycles
			   66 90     288.220840 cycles
			66 66 90     288.219447 cycles
		     66 66 66 90     288.223204 cycles
		  66 66 90 66 90     571.393424 cycles
	       66 66 90 66 66 90     571.374919 cycles
	    66 66 66 90 66 66 90     572.249281 cycles
	 66 66 66 90 66 66 66 90     571.388651 cycles

	P6:
			      90     288.214193 cycles
			   66 90     288.225550 cycles
			0f 1f 00     288.224441 cycles
		     0f 1f 40 00     288.225030 cycles
		  0f 1f 44 00 00     288.233558 cycles
	       66 0f 1f 44 00 00     324.792342 cycles
	    0f 1f 80 00 00 00 00     325.657462 cycles
	 0f 1f 84 00 00 00 00 00     430.246643 cycles

	F14h:
	----
	Running NOP tests, 1000 NOPs x 1000000 repetitions

	K8:
			      90     510.404890 cycles
			   66 90     510.432117 cycles
			66 66 90     510.561858 cycles
		     66 66 66 90     510.541865 cycles
		  66 66 90 66 90    1014.192782 cycles
	       66 66 90 66 66 90    1014.226546 cycles
	    66 66 66 90 66 66 90    1014.334299 cycles
	 66 66 66 90 66 66 66 90    1014.381205 cycles

	P6:
			      90     510.436710 cycles
			   66 90     510.448229 cycles
			0f 1f 00     510.545100 cycles
		     0f 1f 40 00     510.502792 cycles
		  0f 1f 44 00 00     510.589517 cycles
	       66 0f 1f 44 00 00     510.611462 cycles
	    0f 1f 80 00 00 00 00     511.166794 cycles
	 0f 1f 84 00 00 00 00 00     511.651641 cycles

	F15h:
	-----
	Running NOP tests, 1000 NOPs x 1000000 repetitions

	K8:
			      90     243.128396 cycles
			   66 90     243.129883 cycles
			66 66 90     243.131631 cycles
		     66 66 66 90     242.499324 cycles
		  66 66 90 66 90     481.829083 cycles
	       66 66 90 66 66 90     481.884413 cycles
	    66 66 66 90 66 66 90     481.851446 cycles
	 66 66 66 90 66 66 66 90     481.409220 cycles

	P6:
			      90     243.127026 cycles
			   66 90     243.130711 cycles
			0f 1f 00     243.122747 cycles
		     0f 1f 40 00     242.497617 cycles
		  0f 1f 44 00 00     245.354461 cycles
	       66 0f 1f 44 00 00     361.930417 cycles
	    0f 1f 80 00 00 00 00     362.844944 cycles
	 0f 1f 84 00 00 00 00 00     480.514948 cycles

	F16h:
	-----
	Running NOP tests, 1000 NOPs x 1000000 repetitions

	K8:
			      90     507.793298 cycles
			   66 90     507.789636 cycles
			66 66 90     507.826490 cycles
		     66 66 66 90     507.859075 cycles
		  66 66 90 66 90    1008.663129 cycles
	       66 66 90 66 66 90    1008.696259 cycles
	    66 66 66 90 66 66 90    1008.692517 cycles
	 66 66 66 90 66 66 66 90    1008.755399 cycles

	P6:
			      90     507.795232 cycles
			   66 90     507.794761 cycles
			0f 1f 00     507.834901 cycles
		     0f 1f 40 00     507.822629 cycles
		  0f 1f 44 00 00     507.838493 cycles
	       66 0f 1f 44 00 00     507.908597 cycles
	    0f 1f 80 00 00 00 00     507.946417 cycles
	 0f 1f 84 00 00 00 00 00     507.954960 cycles
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Aravind Gopalakrishnan <aravind.gopalakrishnan@amd.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1431332153-18566-2-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>
      f21262b8
    • O
      x86/vdso: Fix 'make bzImage' on older distros · ef7254a5
      由 Oleg Nesterov 提交于 
      Change HOST_EXTRACFLAGS to include arch/x86/include/uapi along
with include/uapi.

This looks more consistent, and this fixes "make bzImage" on my
old distro which doesn't have asm/bitsperlong.h in /usr/include/.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Acked-by: NAndy Lutomirski <luto@kernel.org>
Cc: <stable@vger.kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 6f121e54 ("x86, vdso: Reimplement vdso.so preparation in build-time C")
Link: http://lkml.kernel.org/r/1431332153-18566-6-git-send-email-bp@alien8.de
Link: http://lkml.kernel.org/r/20150507165835.GB18652@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      ef7254a5
  19. 10 5月, 2015 4 次提交
  21. 08 5月, 2015 7 次提交
    • D
      x86/entry: Define 'cpu_current_top_of_stack' for 64-bit code · 3a23208e
      由 Denys Vlasenko 提交于 
      32-bit code has PER_CPU_VAR(cpu_current_top_of_stack).
64-bit code uses somewhat more obscure: PER_CPU_VAR(cpu_tss + TSS_sp0).

Define the 'cpu_current_top_of_stack' macro on CONFIG_X86_64
as well so that the PER_CPU_VAR(cpu_current_top_of_stack)
expression can be used in both 32-bit and 64-bit code.
Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1429889495-27850-3-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      3a23208e
    • D
      x86/entry: Remove unused 'kernel_stack' per-cpu variable · fed7c3f0
      由 Denys Vlasenko 提交于 
      Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com>
Acked-by: NAndy Lutomirski <luto@kernel.org>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1429889495-27850-2-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      fed7c3f0
    • D
      x86/entry: Stop using PER_CPU_VAR(kernel_stack) · 63332a84
      由 Denys Vlasenko 提交于 
      PER_CPU_VAR(kernel_stack) is redundant:

  - On the 64-bit build, we can use PER_CPU_VAR(cpu_tss + TSS_sp0).
  - On the 32-bit build, we can use PER_CPU_VAR(cpu_current_top_of_stack).

PER_CPU_VAR(kernel_stack) will be deleted by a separate change.
Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1429889495-27850-1-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      63332a84
    • D
      x86: Force inlining of atomic ops · 2a4e90b1
      由 Denys Vlasenko 提交于 
      With both gcc 4.7.2 and 4.9.2, sometimes gcc mysteriously
doesn't inline very small functions we expect to be inlined:

$ nm --size-sort vmlinux | grep -iF ' t ' | uniq -c | grep -v '^
*1 ' | sort -rn     473 000000000000000b t spin_unlock_irqrestore
    449 000000000000005f t rcu_read_unlock
    355 0000000000000009 t atomic_inc                <== THIS
    353 000000000000006e t rcu_read_lock
    350 0000000000000075 t rcu_read_lock_sched_held
    291 000000000000000b t spin_unlock
    266 0000000000000019 t arch_local_irq_restore
    215 000000000000000b t spin_lock
    180 0000000000000011 t kzalloc
    165 0000000000000012 t list_add_tail
    161 0000000000000019 t arch_local_save_flags
    153 0000000000000016 t test_and_set_bit
    134 000000000000000b t spin_unlock_irq
    134 0000000000000009 t atomic_dec                <== THIS
    130 000000000000000b t spin_unlock_bh
    122 0000000000000010 t brelse
    120 0000000000000016 t test_and_clear_bit
    120 000000000000000b t spin_lock_irq
    119 000000000000001e t get_dma_ops
    117 0000000000000053 t cpumask_next
    116 0000000000000036 t kref_get
    114 000000000000001a t schedule_work
    106 000000000000000b t spin_lock_bh
    103 0000000000000019 t arch_local_irq_disable
...

Note sizes of marked functions. They are merely 9 bytes long!
Selecting function with 'atomic' in their names:

    355 0000000000000009 t atomic_inc
    134 0000000000000009 t atomic_dec
     98 0000000000000014 t atomic_dec_and_test
     31 000000000000000e t atomic_add_return
     27 000000000000000a t atomic64_inc
     26 000000000000002f t kmap_atomic
     24 0000000000000009 t atomic_add
     12 0000000000000009 t atomic_sub
     10 0000000000000021 t __atomic_add_unless
     10 000000000000000a t atomic64_add
      5 000000000000001f t __atomic_add_unless.constprop.7
      5 000000000000000a t atomic64_dec
      4 000000000000001f t __atomic_add_unless.constprop.18
      4 000000000000001f t __atomic_add_unless.constprop.12
      4 000000000000001f t __atomic_add_unless.constprop.10
      3 000000000000001f t __atomic_add_unless.constprop.13
      3 0000000000000011 t atomic64_add_return
      2 000000000000001f t __atomic_add_unless.constprop.9
      2 000000000000001f t __atomic_add_unless.constprop.8
      2 000000000000001f t __atomic_add_unless.constprop.6
      2 000000000000001f t __atomic_add_unless.constprop.5
      2 000000000000001f t __atomic_add_unless.constprop.3
      2 000000000000001f t __atomic_add_unless.constprop.22
      2 000000000000001f t __atomic_add_unless.constprop.14
      2 000000000000001f t __atomic_add_unless.constprop.11
      2 000000000000001e t atomic_dec_if_positive
      2 0000000000000014 t atomic_inc_and_test
      2 0000000000000011 t atomic_add_return.constprop.4
      2 0000000000000011 t atomic_add_return.constprop.17
      2 0000000000000011 t atomic_add_return.constprop.16
      2 000000000000000d t atomic_inc.constprop.4
      2 000000000000000c t atomic_cmpxchg

This patch fixes this for x86 atomic ops via
s/inline/__always_inline/. This decreases allyesconfig kernel by
about 25k:

    text     data      bss       dec     hex filename
82399481 22255416 20627456 125282353 777a831 vmlinux.before
82375570 22255544 20627456 125258570 7774b4a vmlinux
Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1431080762-17797-1-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      2a4e90b1
    • K
      perf/x86/intel: Fix SLM cache event list · 6d374056
      由 Kan Liang 提交于 
      iTLB-load-misses and LLC-load-misses count incorrectly on SLM.

There is no ITLB.MISSES support on SLM. Event PAGE_WALKS.I_SIDE_WALK
should be used to count iTLB-load-misses. This event counts when an
instruction (I) page walk is completed or started. Since a page walk
implies a TLB miss, the number of TLB misses can be counted by counting
the number of pagewalks.

DMND_DATA_RD counts both demand and DCU prefetch data reads. However,
LLC-load-misses should only count demand reads. There is no way to not
include prefetches with a single counter on SLM. So the LLC-load-misses
support should be removed on SLM.
Signed-off-by: NKan Liang <kan.liang@intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1429608881-5055-1-git-send-email-kan.liang@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      6d374056
    • D
      x86/asm/entry/64: Clean up usage of TEST insns · 03335e95
      由 Denys Vlasenko 提交于 
      By the nature of TEST operation, it is often possible
to test a narrower part of the operand:

    "testl $3, mem"  -> "testb $3, mem"

This results in shorter insns, because TEST insn has no
sign-entending byte-immediate forms unlike other ALU ops.

   text	   data	    bss	    dec	    hex	filename
  11674	      0	      0	  11674	   2d9a	entry_64.o.before
  11658	      0	      0	  11658	   2d8a	entry_64.o

Changes in object code:

-	f7 84 24 88 00 00 00 03 00 00 00 	testl  $0x3,0x88(%rsp)
+	f6 84 24 88 00 00 00 03	         	testb  $0x3,0x88(%rsp)
-	f7 44 24 68 03 00 00 00          	testl  $0x3,0x68(%rsp)
+	f6 44 24 68 03                  	testb  $0x3,0x68(%rsp)
-	f7 84 24 90 00 00 00 03 00 00 00	testl  $0x3,0x90(%rsp)
+	f6 84 24 90 00 00 00 03         	testb  $0x3,0x90(%rsp)
Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com>
Acked-by: NAndy Lutomirski <luto@kernel.org>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1430140912-7960-2-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      03335e95
    • D
      x86/asm/entry/64: Tidy up JZ insns after TESTs · dde74f2e
      由 Denys Vlasenko 提交于 
      After TESTs, use logically correct JZ/JNZ mnemonics instead of
JE/JNE. This doesn't change code.
Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com>
Acked-by: NAndy Lutomirski <luto@kernel.org>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1430140912-7960-1-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      dde74f2e
  23. 06 5月, 2015 5 次提交