Commit Graph

1958 Commits

Author SHA1 Message Date
Linus Torvalds
8139548136 Merge branch 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull EFI updates from Ingo Molnar:
 "Changes in this cycle are:

   - support module unload for efivarfs (Mathias Krause)

   - another attempt at moving x86 to libstub taking advantage of the
     __pure attribute (Ard Biesheuvel)

   - add EFI runtime services section to ptdump (Mathias Krause)"

* 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, ptdump: Add section for EFI runtime services
  efi/x86: Move x86 back to libstub
  efivarfs: Allow unloading when build as module
2014-12-10 12:42:16 -08:00
Linus Torvalds
9d0cf6f564 Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 asm updates from Ingo Molnar:
 "Misc changes:

   - context switch micro-optimization
   - debug printout micro-optimization
   - comment enhancements and typo fix"

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86: Replace seq_printf() with seq_puts()
  x86/asm: Fix typo in arch/x86/kernel/asm_offset_64.c
  sched/x86: Add a comment clarifying LDT context switching
  sched/x86_64: Don't save flags on context switch
2014-12-10 12:09:26 -08:00
Linus Torvalds
3eb5b893eb Merge branch 'x86-mpx-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 MPX support from Thomas Gleixner:
 "This enables support for x86 MPX.

  MPX is a new debug feature for bound checking in user space.  It
  requires kernel support to handle the bound tables and decode the
  bound violating instruction in the trap handler"

* 'x86-mpx-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  asm-generic: Remove asm-generic arch_bprm_mm_init()
  mm: Make arch_unmap()/bprm_mm_init() available to all architectures
  x86: Cleanly separate use of asm-generic/mm_hooks.h
  x86 mpx: Change return type of get_reg_offset()
  fs: Do not include mpx.h in exec.c
  x86, mpx: Add documentation on Intel MPX
  x86, mpx: Cleanup unused bound tables
  x86, mpx: On-demand kernel allocation of bounds tables
  x86, mpx: Decode MPX instruction to get bound violation information
  x86, mpx: Add MPX-specific mmap interface
  x86, mpx: Introduce VM_MPX to indicate that a VMA is MPX specific
  x86, mpx: Add MPX to disabled features
  ia64: Sync struct siginfo with general version
  mips: Sync struct siginfo with general version
  mpx: Extend siginfo structure to include bound violation information
  x86, mpx: Rename cfg_reg_u and status_reg
  x86: mpx: Give bndX registers actual names
  x86: Remove arbitrary instruction size limit in instruction decoder
2014-12-10 09:34:43 -08:00
Linus Torvalds
a0e4467726 asm-generic: asm/io.h rewrite
While there normally is no reason to have a pull request for asm-generic
 but have all changes get merged through whichever tree needs them, I do
 have a series for 3.19. There are two sets of patches that change
 significant portions of asm/io.h, and this branch contains both in order
 to resolve the conflicts:
 
 - Will Deacon has done a set of patches to ensure that all architectures
   define {read,write}{b,w,l,q}_relaxed() functions or get them by
   including asm-generic/io.h. These functions are commonly used on ARM
   specific drivers to avoid expensive L2 cache synchronization implied by
   the normal {read,write}{b,w,l,q}, but we need to define them on all
   architectures in order to share the drivers across architectures and
   to enable CONFIG_COMPILE_TEST configurations for them
 
 - Thierry Reding has done an unrelated set of patches that extends
   the asm-generic/io.h file to the degree necessary to make it useful
   on ARM64 and potentially other architectures.
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Merge tag 'asm-generic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

Pull asm-generic asm/io.h rewrite from Arnd Bergmann:
 "While there normally is no reason to have a pull request for
  asm-generic but have all changes get merged through whichever tree
  needs them, I do have a series for 3.19.

  There are two sets of patches that change significant portions of
  asm/io.h, and this branch contains both in order to resolve the
  conflicts:

   - Will Deacon has done a set of patches to ensure that all
     architectures define {read,write}{b,w,l,q}_relaxed() functions or
     get them by including asm-generic/io.h.

     These functions are commonly used on ARM specific drivers to avoid
     expensive L2 cache synchronization implied by the normal
     {read,write}{b,w,l,q}, but we need to define them on all
     architectures in order to share the drivers across architectures
     and to enable CONFIG_COMPILE_TEST configurations for them

   - Thierry Reding has done an unrelated set of patches that extends
     the asm-generic/io.h file to the degree necessary to make it useful
     on ARM64 and potentially other architectures"

* tag 'asm-generic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: (29 commits)
  ARM64: use GENERIC_PCI_IOMAP
  sparc: io: remove duplicate relaxed accessors on sparc32
  ARM: sa11x0: Use void __iomem * in MMIO accessors
  arm64: Use include/asm-generic/io.h
  ARM: Use include/asm-generic/io.h
  asm-generic/io.h: Implement generic {read,write}s*()
  asm-generic/io.h: Reconcile I/O accessor overrides
  /dev/mem: Use more consistent data types
  Change xlate_dev_{kmem,mem}_ptr() prototypes
  ARM: ixp4xx: Properly override I/O accessors
  ARM: ixp4xx: Fix build with IXP4XX_INDIRECT_PCI
  ARM: ebsa110: Properly override I/O accessors
  ARC: Remove redundant PCI_IOBASE declaration
  documentation: memory-barriers: clarify relaxed io accessor semantics
  x86: io: implement dummy relaxed accessor macros for writes
  tile: io: implement dummy relaxed accessor macros for writes
  sparc: io: implement dummy relaxed accessor macros for writes
  powerpc: io: implement dummy relaxed accessor macros for writes
  parisc: io: implement dummy relaxed accessor macros for writes
  mn10300: io: implement dummy relaxed accessor macros for writes
  ...
2014-12-09 17:25:00 -08:00
Rasmus Villemoes
3736708f03 x86: Replace seq_printf() with seq_puts()
seq_puts is a lot cheaper than seq_printf, so use that to print
literal strings.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Link: http://lkml.kernel.org/r/1417208622-12264-1-git-send-email-linux@rasmusvillemoes.dk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-12-08 11:48:15 +01:00
Dave Hansen
68c009c413 x86 mpx: Change return type of get_reg_offset()
get_reg_offset() used to return the register contents themselves
instead of the register offset.  When it did that, it was an
unsigned long.  I changed it to return an integer _offset_
instead of the register.  But, I neglected to change the return
type of the function or the variables in which we store the
result of the call.

This fixes up the code to clear up the warnings from the smatch
bot:

New smatch warnings:
arch/x86/mm/mpx.c:178 mpx_get_addr_ref() warn: unsigned 'addr_offset' is never less than zero.
arch/x86/mm/mpx.c:184 mpx_get_addr_ref() warn: unsigned 'base_offset' is never less than zero.
arch/x86/mm/mpx.c:188 mpx_get_addr_ref() warn: unsigned 'indx_offset' is never less than zero.
arch/x86/mm/mpx.c:196 mpx_get_addr_ref() warn: unsigned 'addr_offset' is never less than zero.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/20141118182343.C3E0C629@viggo.jf.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-11-19 11:54:12 +01:00
Kees Cook
45e2a9d470 x86, mm: Set NX across entire PMD at boot
When setting up permissions on kernel memory at boot, the end of the
PMD that was split from bss remained executable. It should be NX like
the rest. This performs a PMD alignment instead of a PAGE alignment to
get the correct span of memory.

Before:
---[ High Kernel Mapping ]---
...
0xffffffff8202d000-0xffffffff82200000  1868K     RW       GLB NX pte
0xffffffff82200000-0xffffffff82c00000    10M     RW   PSE GLB NX pmd
0xffffffff82c00000-0xffffffff82df5000  2004K     RW       GLB NX pte
0xffffffff82df5000-0xffffffff82e00000    44K     RW       GLB x  pte
0xffffffff82e00000-0xffffffffc0000000   978M                     pmd

After:
---[ High Kernel Mapping ]---
...
0xffffffff8202d000-0xffffffff82200000  1868K     RW       GLB NX pte
0xffffffff82200000-0xffffffff82e00000    12M     RW   PSE GLB NX pmd
0xffffffff82e00000-0xffffffffc0000000   978M                     pmd

[ tglx: Changed it to roundup(_brk_end, PMD_SIZE) and added a comment.
        We really should unmap the reminder along with the holes
        caused by init,initdata etc. but thats a different issue ]

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20141114194737.GA3091@www.outflux.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-11-18 18:32:24 +01:00
Dave Hansen
1de4fa14ee x86, mpx: Cleanup unused bound tables
The previous patch allocates bounds tables on-demand.  As noted in
an earlier description, these can add up to *HUGE* amounts of
memory.  This has caused OOMs in practice when running tests.

This patch adds support for freeing bounds tables when they are no
longer in use.

There are two types of mappings in play when unmapping tables:
 1. The mapping with the actual data, which userspace is
    munmap()ing or brk()ing away, etc...
 2. The mapping for the bounds table *backing* the data
    (is tagged with VM_MPX, see the patch "add MPX specific
    mmap interface").

If userspace use the prctl() indroduced earlier in this patchset
to enable the management of bounds tables in kernel, when it
unmaps the first type of mapping with the actual data, the kernel
needs to free the mapping for the bounds table backing the data.
This patch hooks in at the very end of do_unmap() to do so.
We look at the addresses being unmapped and find the bounds
directory entries and tables which cover those addresses.  If
an entire table is unused, we clear associated directory entry
and free the table.

Once we unmap the bounds table, we would have a bounds directory
entry pointing at empty address space. That address space might
now be allocated for some other (random) use, and the MPX
hardware might now try to walk it as if it were a bounds table.
That would be bad.  So any unmapping of an enture bounds table
has to be accompanied by a corresponding write to the bounds
directory entry to invalidate it.  That write to the bounds
directory can fault, which causes the following problem:

Since we are doing the freeing from munmap() (and other paths
like it), we hold mmap_sem for write. If we fault, the page
fault handler will attempt to acquire mmap_sem for read and
we will deadlock.  To avoid the deadlock, we pagefault_disable()
when touching the bounds directory entry and use a
get_user_pages() to resolve the fault.

The unmapping of bounds tables happends under vm_munmap().  We
also (indirectly) call vm_munmap() to _do_ the unmapping of the
bounds tables.  We avoid unbounded recursion by disallowing
freeing of bounds tables *for* bounds tables.  This would not
occur normally, so should not have any practical impact.  Being
strict about it here helps ensure that we do not have an
exploitable stack overflow.

Based-on-patch-by: Qiaowei Ren <qiaowei.ren@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-mm@kvack.org
Cc: linux-mips@linux-mips.org
Cc: Dave Hansen <dave@sr71.net>
Link: http://lkml.kernel.org/r/20141114151831.E4531C4A@viggo.jf.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-11-18 00:58:54 +01:00
Dave Hansen
fe3d197f84 x86, mpx: On-demand kernel allocation of bounds tables
This is really the meat of the MPX patch set.  If there is one patch to
review in the entire series, this is the one.  There is a new ABI here
and this kernel code also interacts with userspace memory in a
relatively unusual manner.  (small FAQ below).

Long Description:

This patch adds two prctl() commands to provide enable or disable the
management of bounds tables in kernel, including on-demand kernel
allocation (See the patch "on-demand kernel allocation of bounds tables")
and cleanup (See the patch "cleanup unused bound tables"). Applications
do not strictly need the kernel to manage bounds tables and we expect
some applications to use MPX without taking advantage of this kernel
support. This means the kernel can not simply infer whether an application
needs bounds table management from the MPX registers.  The prctl() is an
explicit signal from userspace.

PR_MPX_ENABLE_MANAGEMENT is meant to be a signal from userspace to
require kernel's help in managing bounds tables.

PR_MPX_DISABLE_MANAGEMENT is the opposite, meaning that userspace don't
want kernel's help any more. With PR_MPX_DISABLE_MANAGEMENT, the kernel
won't allocate and free bounds tables even if the CPU supports MPX.

PR_MPX_ENABLE_MANAGEMENT will fetch the base address of the bounds
directory out of a userspace register (bndcfgu) and then cache it into
a new field (->bd_addr) in  the 'mm_struct'.  PR_MPX_DISABLE_MANAGEMENT
will set "bd_addr" to an invalid address.  Using this scheme, we can
use "bd_addr" to determine whether the management of bounds tables in
kernel is enabled.

Also, the only way to access that bndcfgu register is via an xsaves,
which can be expensive.  Caching "bd_addr" like this also helps reduce
the cost of those xsaves when doing table cleanup at munmap() time.
Unfortunately, we can not apply this optimization to #BR fault time
because we need an xsave to get the value of BNDSTATUS.

==== Why does the hardware even have these Bounds Tables? ====

MPX only has 4 hardware registers for storing bounds information.
If MPX-enabled code needs more than these 4 registers, it needs to
spill them somewhere. It has two special instructions for this
which allow the bounds to be moved between the bounds registers
and some new "bounds tables".

They are similar conceptually to a page fault and will be raised by
the MPX hardware during both bounds violations or when the tables
are not present. This patch handles those #BR exceptions for
not-present tables by carving the space out of the normal processes
address space (essentially calling the new mmap() interface indroduced
earlier in this patch set.) and then pointing the bounds-directory
over to it.

The tables *need* to be accessed and controlled by userspace because
the instructions for moving bounds in and out of them are extremely
frequent. They potentially happen every time a register pointing to
memory is dereferenced. Any direct kernel involvement (like a syscall)
to access the tables would obviously destroy performance.

==== Why not do this in userspace? ====

This patch is obviously doing this allocation in the kernel.
However, MPX does not strictly *require* anything in the kernel.
It can theoretically be done completely from userspace. Here are
a few ways this *could* be done. I don't think any of them are
practical in the real-world, but here they are.

Q: Can virtual space simply be reserved for the bounds tables so
   that we never have to allocate them?
A: As noted earlier, these tables are *HUGE*. An X-GB virtual
   area needs 4*X GB of virtual space, plus 2GB for the bounds
   directory. If we were to preallocate them for the 128TB of
   user virtual address space, we would need to reserve 512TB+2GB,
   which is larger than the entire virtual address space today.
   This means they can not be reserved ahead of time. Also, a
   single process's pre-popualated bounds directory consumes 2GB
   of virtual *AND* physical memory. IOW, it's completely
   infeasible to prepopulate bounds directories.

Q: Can we preallocate bounds table space at the same time memory
   is allocated which might contain pointers that might eventually
   need bounds tables?
A: This would work if we could hook the site of each and every
   memory allocation syscall. This can be done for small,
   constrained applications. But, it isn't practical at a larger
   scale since a given app has no way of controlling how all the
   parts of the app might allocate memory (think libraries). The
   kernel is really the only place to intercept these calls.

Q: Could a bounds fault be handed to userspace and the tables
   allocated there in a signal handler instead of in the kernel?
A: (thanks to tglx) mmap() is not on the list of safe async
   handler functions and even if mmap() would work it still
   requires locking or nasty tricks to keep track of the
   allocation state there.

Having ruled out all of the userspace-only approaches for managing
bounds tables that we could think of, we create them on demand in
the kernel.

Based-on-patch-by: Qiaowei Ren <qiaowei.ren@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-mm@kvack.org
Cc: linux-mips@linux-mips.org
Cc: Dave Hansen <dave@sr71.net>
Link: http://lkml.kernel.org/r/20141114151829.AD4310DE@viggo.jf.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-11-18 00:58:53 +01:00
Dave Hansen
fcc7ffd679 x86, mpx: Decode MPX instruction to get bound violation information
This patch sets bound violation fields of siginfo struct in #BR
exception handler by decoding the user instruction and constructing
the faulting pointer.

We have to be very careful when decoding these instructions.  They
are completely controlled by userspace and may be changed at any
time up to and including the point where we try to copy them in to
the kernel.  They may or may not be MPX instructions and could be
completely invalid for all we know.

Note: This code is based on Qiaowei Ren's specialized MPX
decoder, but uses the generic decoder whenever possible.  It was
tested for robustness by generating a completely random data
stream and trying to decode that stream.  I also unmapped random
pages inside the stream to test the "partial instruction" short
read code.

We kzalloc() the siginfo instead of stack allocating it because
we need to memset() it anyway, and doing this makes it much more
clear when it got initialized by the MPX instruction decoder.

Changes from the old decoder:
 * Use the generic decoder instead of custom functions.  Saved
   ~70 lines of code overall.
 * Remove insn->addr_bytes code (never used??)
 * Make sure never to possibly overflow the regoff[] array, plus
   check the register range correctly in 32 and 64-bit modes.
 * Allow get_reg() to return an error and have mpx_get_addr_ref()
   handle when it sees errors.
 * Only call insn_get_*() near where we actually use the values
   instead if trying to call them all at once.
 * Handle short reads from copy_from_user() and check the actual
   number of read bytes against what we expect from
   insn_get_length().  If a read stops in the middle of an
   instruction, we error out.
 * Actually check the opcodes intead of ignoring them.
 * Dynamically kzalloc() siginfo_t so we don't leak any stack
   data.
 * Detect and handle decoder failures instead of ignoring them.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Based-on-patch-by: Qiaowei Ren <qiaowei.ren@intel.com>
Cc: linux-mm@kvack.org
Cc: linux-mips@linux-mips.org
Cc: Dave Hansen <dave@sr71.net>
Link: http://lkml.kernel.org/r/20141114151828.5BDD0915@viggo.jf.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-11-18 00:58:53 +01:00
Qiaowei Ren
57319d80e1 x86, mpx: Add MPX-specific mmap interface
We have chosen to perform the allocation of bounds tables in
kernel (See the patch "on-demand kernel allocation of bounds
tables") and to mark these VMAs with VM_MPX.

However, there is currently no suitable interface to actually do
this.  Existing interfaces, like do_mmap_pgoff(), have no way to
set a modified ->vm_ops or ->vm_flags and don't hold mmap_sem
long enough to let a caller do it.

This patch wraps mmap_region() and hold mmap_sem long enough to
make the modifications to the VMA which we need.

Also note the 32/64-bit #ifdef in the header.  We actually need
to do this at runtime eventually.  But, for now, we don't support
running 32-bit binaries on 64-bit kernels.  Support for this will
come in later patches.

Signed-off-by: Qiaowei Ren <qiaowei.ren@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-mm@kvack.org
Cc: linux-mips@linux-mips.org
Cc: Dave Hansen <dave@sr71.net>
Link: http://lkml.kernel.org/r/20141114151827.CE440F67@viggo.jf.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-11-18 00:58:53 +01:00
Ingo Molnar
595247f61f * Support module unload for efivarfs - Mathias Krause
* Another attempt at moving x86 to libstub taking advantage of the
    __pure attribute - Ard Biesheuvel
 
  * Add EFI runtime services section to ptdump - Mathias Krause
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Merge tag 'efi-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into x86/efi

Pull EFI updates for v3.19 from Matt Fleming:

 - Support module unload for efivarfs - Mathias Krause

 - Another attempt at moving x86 to libstub taking advantage of the
   __pure attribute - Ard Biesheuvel

 - Add EFI runtime services section to ptdump - Mathias Krause

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-11-16 10:48:53 +01:00
Mathias Krause
8266e31ed0 x86, ptdump: Add section for EFI runtime services
In commit 3891a04aaf ("x86-64, espfix: Don't leak bits 31:16 of %esp
returning..") the "ESPFix Area" was added to the page table dump special
sections. That area, though, has a limited amount of entries printed.

The EFI runtime services are, unfortunately, located in-between the
espfix area and the high kernel memory mapping. Due to the enforced
limitation for the espfix area, the EFI mappings won't be printed in the
page table dump.

To make the ESP runtime service mappings visible again, provide them a
dedicated entry.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2014-11-11 22:28:57 +00:00
Thierry Reding
4707a341b4 /dev/mem: Use more consistent data types
The xlate_dev_{kmem,mem}_ptr() functions take either a physical address
or a kernel virtual address, so data types should be phys_addr_t and
void *. They both return a kernel virtual address which is only ever
used in calls to copy_{from,to}_user(), so make variables that store it
void * rather than char * for consistency.

Also only define a weak unxlate_dev_mem_ptr() function if architectures
haven't overridden them in the asm/io.h header file.

Signed-off-by: Thierry Reding <treding@nvidia.com>
2014-11-10 15:59:21 +01:00
Dexuan Cui
d1cd121083 x86, pageattr: Prevent overflow in slow_virt_to_phys() for X86_PAE
pte_pfn() returns a PFN of long (32 bits in 32-PAE), so "long <<
PAGE_SHIFT" will overflow for PFNs above 4GB.

Due to this issue, some Linux 32-PAE distros, running as guests on Hyper-V,
with 5GB memory assigned, can't load the netvsc driver successfully and
hence the synthetic network device can't work (we can use the kernel parameter
mem=3000M to work around the issue).

Cast pte_pfn() to phys_addr_t before shifting.

Fixes: "commit d765653445: x86, mm: Create slow_virt_to_phys()"
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: gregkh@linuxfoundation.org
Cc: linux-mm@kvack.org
Cc: olaf@aepfle.de
Cc: apw@canonical.com
Cc: jasowang@redhat.com
Cc: dave.hansen@intel.com
Cc: riel@redhat.com
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1414580017-27444-1-git-send-email-decui@microsoft.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-10-29 10:57:21 +01:00
Linus Torvalds
0429fbc0bd Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
Pull percpu consistent-ops changes from Tejun Heo:
 "Way back, before the current percpu allocator was implemented, static
  and dynamic percpu memory areas were allocated and handled separately
  and had their own accessors.  The distinction has been gone for many
  years now; however, the now duplicate two sets of accessors remained
  with the pointer based ones - this_cpu_*() - evolving various other
  operations over time.  During the process, we also accumulated other
  inconsistent operations.

  This pull request contains Christoph's patches to clean up the
  duplicate accessor situation.  __get_cpu_var() uses are replaced with
  with this_cpu_ptr() and __this_cpu_ptr() with raw_cpu_ptr().

  Unfortunately, the former sometimes is tricky thanks to C being a bit
  messy with the distinction between lvalues and pointers, which led to
  a rather ugly solution for cpumask_var_t involving the introduction of
  this_cpu_cpumask_var_ptr().

  This converts most of the uses but not all.  Christoph will follow up
  with the remaining conversions in this merge window and hopefully
  remove the obsolete accessors"

* 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (38 commits)
  irqchip: Properly fetch the per cpu offset
  percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t -fix
  ia64: sn_nodepda cannot be assigned to after this_cpu conversion. Use __this_cpu_write.
  percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t
  Revert "powerpc: Replace __get_cpu_var uses"
  percpu: Remove __this_cpu_ptr
  clocksource: Replace __this_cpu_ptr with raw_cpu_ptr
  sparc: Replace __get_cpu_var uses
  avr32: Replace __get_cpu_var with __this_cpu_write
  blackfin: Replace __get_cpu_var uses
  tile: Use this_cpu_ptr() for hardware counters
  tile: Replace __get_cpu_var uses
  powerpc: Replace __get_cpu_var uses
  alpha: Replace __get_cpu_var
  ia64: Replace __get_cpu_var uses
  s390: cio driver &__get_cpu_var replacements
  s390: Replace __get_cpu_var uses
  mips: Replace __get_cpu_var uses
  MIPS: Replace __get_cpu_var uses in FPU emulator.
  arm: Replace __this_cpu_ptr with raw_cpu_ptr
  ...
2014-10-15 07:48:18 +02:00
Linus Torvalds
dfe2c6dcc8 Merge branch 'akpm' (patches from Andrew Morton)
Merge second patch-bomb from Andrew Morton:
 - a few hotfixes
 - drivers/dma updates
 - MAINTAINERS updates
 - Quite a lot of lib/ updates
 - checkpatch updates
 - binfmt updates
 - autofs4
 - drivers/rtc/
 - various small tweaks to less used filesystems
 - ipc/ updates
 - kernel/watchdog.c changes

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (135 commits)
  mm: softdirty: enable write notifications on VMAs after VM_SOFTDIRTY cleared
  kernel/param: consolidate __{start,stop}___param[] in <linux/moduleparam.h>
  ia64: remove duplicate declarations of __per_cpu_start[] and __per_cpu_end[]
  frv: remove unused declarations of __start___ex_table and __stop___ex_table
  kvm: ensure hard lockup detection is disabled by default
  kernel/watchdog.c: control hard lockup detection default
  staging: rtl8192u: use %*pEn to escape buffer
  staging: rtl8192e: use %*pEn to escape buffer
  staging: wlan-ng: use %*pEhp to print SN
  lib80211: remove unused print_ssid()
  wireless: hostap: proc: print properly escaped SSID
  wireless: ipw2x00: print SSID via %*pE
  wireless: libertas: print esaped string via %*pE
  lib/vsprintf: add %*pE[achnops] format specifier
  lib / string_helpers: introduce string_escape_mem()
  lib / string_helpers: refactoring the test suite
  lib / string_helpers: move documentation to c-file
  include/linux: remove strict_strto* definitions
  arch/x86/mm/numa.c: fix boot failure when all nodes are hotpluggable
  fs: check bh blocknr earlier when searching lru
  ...
2014-10-14 03:54:50 +02:00
Linus Torvalds
df133e8fa8 Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 mm updates from Ingo Molnar:
 "This tree includes the following changes:

   - fix memory hotplug
   - fix hibernation bootup memory layout assumptions
   - fix hyperv numa guest kernel messages
   - remove dead code
   - update documentation"

* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: Update memory map description to list hypervisor-reserved area
  x86/mm, hibernate: Do not assume the first e820 area to be RAM
  x86/mm/numa: Drop dead code and rename setup_node_data() to setup_alloc_data()
  x86/mm/hotplug: Modify PGD entry when removing memory
  x86/mm/hotplug: Pass sync_global_pgds() a correct argument in remove_pagetable()
  x86: Remove set_pmd_pfn
2014-10-14 02:22:41 +02:00
Xishi Qiu
bd5cfb8977 arch/x86/mm/numa.c: fix boot failure when all nodes are hotpluggable
If all the nodes are marked hotpluggable, alloc node data will fail.
Because __next_mem_range_rev() will skip the hotpluggable memory
regions.  numa_clear_kernel_node_hotplug() is called after alloc node
data.

numa_init()
    ...
    ret = init_func();  // this will mark hotpluggable flag from SRAT
    ...
    memblock_set_bottom_up(false);
    ...
    ret = numa_register_memblks(&numa_meminfo);  // this will alloc node data(pglist_data)
    ...
    numa_clear_kernel_node_hotplug();  // in case all the nodes are hotpluggable
    ...

numa_register_memblks()
    setup_node_data()
        memblock_find_in_range_node()
            __memblock_find_range_top_down()
                for_each_mem_range_rev()
                    __next_mem_range_rev()

This patch moves numa_clear_kernel_node_hotplug() into
numa_register_memblks(), clear kernel node hotpluggable flag before
alloc node data, then alloc node data won't fail even all the nodes
are hotpluggable.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-14 02:18:26 +02:00
Mike Travis
906e36c5c7 x86: use optimized ioresource lookup in ioremap function
Use the optimized ioresource lookup, "region_is_ram", for the ioremap
function.  If the region is not found, it falls back to the
"page_is_ram" function.  If it is found and it is RAM, then the usual
warning message is issued, and the ioremap operation is aborted.
Otherwise, the ioremap operation continues.

Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Alex Thorlton <athorlton@sgi.com>
Reviewed-by: Cliff Wickman <cpw@sgi.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-14 02:18:22 +02:00
Linus Torvalds
faafcba3b5 Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
 "The main changes in this cycle were:

   - Optimized support for Intel "Cluster-on-Die" (CoD) topologies (Dave
     Hansen)

   - Various sched/idle refinements for better idle handling (Nicolas
     Pitre, Daniel Lezcano, Chuansheng Liu, Vincent Guittot)

   - sched/numa updates and optimizations (Rik van Riel)

   - sysbench speedup (Vincent Guittot)

   - capacity calculation cleanups/refactoring (Vincent Guittot)

   - Various cleanups to thread group iteration (Oleg Nesterov)

   - Double-rq-lock removal optimization and various refactorings
     (Kirill Tkhai)

   - various sched/deadline fixes

  ... and lots of other changes"

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (72 commits)
  sched/dl: Use dl_bw_of() under rcu_read_lock_sched()
  sched/fair: Delete resched_cpu() from idle_balance()
  sched, time: Fix build error with 64 bit cputime_t on 32 bit systems
  sched: Improve sysbench performance by fixing spurious active migration
  sched/x86: Fix up typo in topology detection
  x86, sched: Add new topology for multi-NUMA-node CPUs
  sched/rt: Use resched_curr() in task_tick_rt()
  sched: Use rq->rd in sched_setaffinity() under RCU read lock
  sched: cleanup: Rename 'out_unlock' to 'out_free_new_mask'
  sched: Use dl_bw_of() under RCU read lock
  sched/fair: Remove duplicate code from can_migrate_task()
  sched, mips, ia64: Remove __ARCH_WANT_UNLOCKED_CTXSW
  sched: print_rq(): Don't use tasklist_lock
  sched: normalize_rt_tasks(): Don't use _irqsave for tasklist_lock, use task_rq_lock()
  sched: Fix the task-group check in tg_has_rt_tasks()
  sched/fair: Leverage the idle state info when choosing the "idlest" cpu
  sched: Let the scheduler see CPU idle states
  sched/deadline: Fix inter- exclusive cpusets migrations
  sched/deadline: Clear dl_entity params when setscheduling to different class
  sched/numa: Kill the wrong/dead TASK_DEAD check in task_numa_fault()
  ...
2014-10-13 16:23:15 +02:00
David Vrabel
f955371ca9 x86: remove the Xen-specific _PAGE_IOMAP PTE flag
The _PAGE_IO_MAP PTE flag was only used by Xen PV guests to mark PTEs
that were used to map I/O regions that are 1:1 in the p2m.  This
allowed Xen to obtain the correct PFN when converting the MFNs read
from a PTE back to their PFN.

Xen guests no longer use _PAGE_IOMAP for this. Instead mfn_to_pfn()
returns the correct PFN by using a combination of the m2p and p2m to
determine if an MFN corresponds to a 1:1 mapping in the the p2m.

Remove _PAGE_IOMAP, replacing it with _PAGE_UNUSED2 to allow for
future uses of the PTE flag.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
2014-09-23 13:36:20 +00:00
David Vrabel
3166851142 x86: skip check for spurious faults for non-present faults
If a fault on a kernel address is due to a non-present page, then it
cannot be the result of stale TLB entry from a protection change (RO
to RW or NX to X).  Thus the pagetable walk in spurious_fault() can be
skipped.

See the initial if in spurious_fault() and the tests in
spurious_fault_check()) for the set of possible error codes checked
for spurious faults.  These are:

         IRUWP
Before   x00xx && ( 1xxxx || xxx1x )
After  ( 10001 || 00011 ) && ( 1xxxx || xxx1x )

Thus the new condition is a subset of the previous one, excluding only
non-present faults (I == 1 and W == 1 are mutually exclusive).

This avoids spurious_fault() oopsing in some cases if the pagetables
it attempts to walk are not accessible.  This obscures the location of
the original fault.

This also fixes a crash with Xen PV guests when they access entries in
the M2P corresponding to device MMIO regions.  The M2P is mapped
(read-only) by Xen into the kernel address space of the guest and this
mapping may contains holes for non-RAM regions.  Read faults will
result in calls to spurious_fault(), but because the page tables for
the M2P mappings are not accessible by the guest the pagetable walk
would fault.

This was not normally a problem as MMIO mappings would not normally
result in a M2P lookup because of the use of the _PAGE_IOMAP bit the
PTE.  However, removing the _PAGE_IOMAP bit requires M2P lookups for
MMIO mappings as well.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
2014-09-23 13:36:20 +00:00
Aaron Tomlin
a70857e46d sched: Add helper for task stack page overrun checking
This facility is used in a few places so let's introduce
a helper function to improve code readability.

Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: aneesh.kumar@linux.vnet.ibm.com
Cc: dzickus@redhat.com
Cc: bmr@redhat.com
Cc: jcastillo@redhat.com
Cc: oleg@redhat.com
Cc: riel@redhat.com
Cc: prarit@redhat.com
Cc: jgh@redhat.com
Cc: minchan@kernel.org
Cc: mpe@ellerman.id.au
Cc: tglx@linutronix.de
Cc: hannes@cmpxchg.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1410527779-8133-3-git-send-email-atomlin@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-19 12:35:23 +02:00
Aaron Tomlin
d4311ff1a8 init/main.c: Give init_task a canary
Tasks get their end of stack set to STACK_END_MAGIC with the
aim to catch stack overruns. Currently this feature does not
apply to init_task. This patch removes this restriction.

Note that a similar patch was posted by Prarit Bhargava
some time ago but was never merged:

  http://marc.info/?l=linux-kernel&m=127144305403241&w=2

Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: aneesh.kumar@linux.vnet.ibm.com
Cc: dzickus@redhat.com
Cc: bmr@redhat.com
Cc: jcastillo@redhat.com
Cc: jgh@redhat.com
Cc: minchan@kernel.org
Cc: tglx@linutronix.de
Cc: hannes@cmpxchg.org
Cc: Alex Thorlton <athorlton@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Daeseok Youn <daeseok.youn@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Fabian Frederick <fabf@skynet.be>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Michael Opdenacker <michael.opdenacker@free-electrons.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1410527779-8133-2-git-send-email-atomlin@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-19 12:35:22 +02:00
Luiz Capitulino
8b375f64dc x86/mm/numa: Drop dead code and rename setup_node_data() to setup_alloc_data()
The setup_node_data() function allocates a pg_data_t object,
inserts it into the node_data[] array and initializes the
following fields: node_id, node_start_pfn and
node_spanned_pages.

However, a few function calls later during the kernel boot,
free_area_init_node() re-initializes those fields, possibly with
setup_node_data() is not used.

This causes a small glitch when running Linux as a hyperv numa
guest:

  SRAT: PXM 0 -> APIC 0x00 -> Node 0
  SRAT: PXM 0 -> APIC 0x01 -> Node 0
  SRAT: PXM 1 -> APIC 0x02 -> Node 1
  SRAT: PXM 1 -> APIC 0x03 -> Node 1
  SRAT: Node 0 PXM 0 [mem 0x00000000-0x7fffffff]
  SRAT: Node 1 PXM 1 [mem 0x80200000-0xf7ffffff]
  SRAT: Node 1 PXM 1 [mem 0x100000000-0x1081fffff]
  NUMA: Node 1 [mem 0x80200000-0xf7ffffff] + [mem 0x100000000-0x1081fffff] -> [mem 0x80200000-0x1081fffff]
  Initmem setup node 0 [mem 0x00000000-0x7fffffff]
    NODE_DATA [mem 0x7ffdc000-0x7ffeffff]
  Initmem setup node 1 [mem 0x80800000-0x1081fffff]
    NODE_DATA [mem 0x1081ea000-0x1081fdfff]
  crashkernel: memory value expected
   [ffffea0000000000-ffffea0001ffffff] PMD -> [ffff88007de00000-ffff88007fdfffff] on node 0
   [ffffea0002000000-ffffea00043fffff] PMD -> [ffff880105600000-ffff8801077fffff] on node 1
  Zone ranges:
    DMA      [mem 0x00001000-0x00ffffff]
    DMA32    [mem 0x01000000-0xffffffff]
    Normal   [mem 0x100000000-0x1081fffff]
  Movable zone start for each node
  Early memory node ranges
    node   0: [mem 0x00001000-0x0009efff]
    node   0: [mem 0x00100000-0x7ffeffff]
    node   1: [mem 0x80200000-0xf7ffffff]
    node   1: [mem 0x100000000-0x1081fffff]
  On node 0 totalpages: 524174
    DMA zone: 64 pages used for memmap
    DMA zone: 21 pages reserved
    DMA zone: 3998 pages, LIFO batch:0
    DMA32 zone: 8128 pages used for memmap
    DMA32 zone: 520176 pages, LIFO batch:31
  On node 1 totalpages: 524288
    DMA32 zone: 7672 pages used for memmap
    DMA32 zone: 491008 pages, LIFO batch:31
    Normal zone: 520 pages used for memmap
    Normal zone: 33280 pages, LIFO batch:7

In this dmesg, the SRAT table reports that the memory range for
node 1 starts at 0x80200000.  However, the line starting with
"Initmem" reports that node 1 memory range starts at 0x80800000.
 The "Initmem" line is reported by setup_node_data() and is
wrong, because the kernel ends up using the range as reported in
the SRAT table.

This commit drops all that dead code from setup_node_data(),
renames it to alloc_node_data() and adds a printk() to
free_area_init_node() so that we report a node's memory range
accurately.

Here's the same dmesg section with this patch applied:

   SRAT: PXM 0 -> APIC 0x00 -> Node 0
   SRAT: PXM 0 -> APIC 0x01 -> Node 0
   SRAT: PXM 1 -> APIC 0x02 -> Node 1
   SRAT: PXM 1 -> APIC 0x03 -> Node 1
   SRAT: Node 0 PXM 0 [mem 0x00000000-0x7fffffff]
   SRAT: Node 1 PXM 1 [mem 0x80200000-0xf7ffffff]
   SRAT: Node 1 PXM 1 [mem 0x100000000-0x1081fffff]
   NUMA: Node 1 [mem 0x80200000-0xf7ffffff] + [mem 0x100000000-0x1081fffff] -> [mem 0x80200000-0x1081fffff]
   NODE_DATA(0) allocated [mem 0x7ffdc000-0x7ffeffff]
   NODE_DATA(1) allocated [mem 0x1081ea000-0x1081fdfff]
   crashkernel: memory value expected
    [ffffea0000000000-ffffea0001ffffff] PMD -> [ffff88007de00000-ffff88007fdfffff] on node 0
    [ffffea0002000000-ffffea00043fffff] PMD -> [ffff880105600000-ffff8801077fffff] on node 1
   Zone ranges:
     DMA      [mem 0x00001000-0x00ffffff]
     DMA32    [mem 0x01000000-0xffffffff]
     Normal   [mem 0x100000000-0x1081fffff]
   Movable zone start for each node
   Early memory node ranges
     node   0: [mem 0x00001000-0x0009efff]
     node   0: [mem 0x00100000-0x7ffeffff]
     node   1: [mem 0x80200000-0xf7ffffff]
     node   1: [mem 0x100000000-0x1081fffff]
   Initmem setup node 0 [mem 0x00001000-0x7ffeffff]
   On node 0 totalpages: 524174
     DMA zone: 64 pages used for memmap
     DMA zone: 21 pages reserved
     DMA zone: 3998 pages, LIFO batch:0
     DMA32 zone: 8128 pages used for memmap
     DMA32 zone: 520176 pages, LIFO batch:31
   Initmem setup node 1 [mem 0x80200000-0x1081fffff]
   On node 1 totalpages: 524288
     DMA32 zone: 7672 pages used for memmap
     DMA32 zone: 491008 pages, LIFO batch:31
     Normal zone: 520 pages used for memmap
     Normal zone: 33280 pages, LIFO batch:7

This commit was tested on a two node bare-metal NUMA machine and
Linux as a numa guest on hyperv and qemu/kvm.

PS: The wrong memory range reported by setup_node_data() seems to be
    harmless in the current kernel because it's just not used.  However,
    that bad range is used in kernel 2.6.32 to initialize the old boot
    memory allocator, which causes a crash during boot.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-16 08:55:10 +02:00
Yasuaki Ishimatsu
9661d5bcd0 x86/mm/hotplug: Modify PGD entry when removing memory
When hot-adding/removing memory, sync_global_pgds() is called
for synchronizing PGD to PGD entries of all processes MM.  But
when hot-removing memory, sync_global_pgds() does not work
correctly.

At first, sync_global_pgds() checks whether target PGD is none
or not.  And if PGD is none, the PGD is skipped.  But when
hot-removing memory, PGD may be none since PGD may be cleared by
free_pud_table().  So when sync_global_pgds() is called after
hot-removing memory, sync_global_pgds() should not skip PGD even
if the PGD is none.  And sync_global_pgds() must clear PGD
entries of all processes MM.

Currently sync_global_pgds() does not clear PGD entries of all
processes MM when hot-removing memory.  So when hot adding
memory which is same memory range as removed memory after
hot-removing memory, following call traces are shown:

 kernel BUG at arch/x86/mm/init_64.c:206!
 ...
 [<ffffffff815e0c80>] kernel_physical_mapping_init+0x1b2/0x1d2
 [<ffffffff815ced94>] init_memory_mapping+0x1d4/0x380
 [<ffffffff8104aebd>] arch_add_memory+0x3d/0xd0
 [<ffffffff815d03d9>] add_memory+0xb9/0x1b0
 [<ffffffff81352415>] acpi_memory_device_add+0x1af/0x28e
 [<ffffffff81325dc4>] acpi_bus_device_attach+0x8c/0xf0
 [<ffffffff813413b9>] acpi_ns_walk_namespace+0xc8/0x17f
 [<ffffffff81325d38>] ? acpi_bus_type_and_status+0xb7/0xb7
 [<ffffffff81325d38>] ? acpi_bus_type_and_status+0xb7/0xb7
 [<ffffffff813418ed>] acpi_walk_namespace+0x95/0xc5
 [<ffffffff81326b4c>] acpi_bus_scan+0x9a/0xc2
 [<ffffffff81326bff>] acpi_scan_bus_device_check+0x8b/0x12e
 [<ffffffff81326cb5>] acpi_scan_device_check+0x13/0x15
 [<ffffffff81320122>] acpi_os_execute_deferred+0x25/0x32
 [<ffffffff8107e02b>] process_one_work+0x17b/0x460
 [<ffffffff8107edfb>] worker_thread+0x11b/0x400
 [<ffffffff8107ece0>] ? rescuer_thread+0x400/0x400
 [<ffffffff81085aef>] kthread+0xcf/0xe0
 [<ffffffff81085a20>] ? kthread_create_on_node+0x140/0x140
 [<ffffffff815fc76c>] ret_from_fork+0x7c/0xb0
 [<ffffffff81085a20>] ? kthread_create_on_node+0x140/0x140

This patch clears PGD entries of all processes MM when
sync_global_pgds() is called after hot-removing memory

Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-16 08:55:09 +02:00
Yasuaki Ishimatsu
5255e0a79f x86/mm/hotplug: Pass sync_global_pgds() a correct argument in remove_pagetable()
When hot-adding memory after hot-removing memory, following call
traces are shown:

  kernel BUG at arch/x86/mm/init_64.c:206!
  ...
 [<ffffffff815e0c80>] kernel_physical_mapping_init+0x1b2/0x1d2
 [<ffffffff815ced94>] init_memory_mapping+0x1d4/0x380
 [<ffffffff8104aebd>] arch_add_memory+0x3d/0xd0
 [<ffffffff815d03d9>] add_memory+0xb9/0x1b0
 [<ffffffff81352415>] acpi_memory_device_add+0x1af/0x28e
 [<ffffffff81325dc4>] acpi_bus_device_attach+0x8c/0xf0
 [<ffffffff813413b9>] acpi_ns_walk_namespace+0xc8/0x17f
 [<ffffffff81325d38>] ? acpi_bus_type_and_status+0xb7/0xb7
 [<ffffffff81325d38>] ? acpi_bus_type_and_status+0xb7/0xb7
 [<ffffffff813418ed>] acpi_walk_namespace+0x95/0xc5
 [<ffffffff81326b4c>] acpi_bus_scan+0x9a/0xc2
 [<ffffffff81326bff>] acpi_scan_bus_device_check+0x8b/0x12e
 [<ffffffff81326cb5>] acpi_scan_device_check+0x13/0x15
 [<ffffffff81320122>] acpi_os_execute_deferred+0x25/0x32
 [<ffffffff8107e02b>] process_one_work+0x17b/0x460
 [<ffffffff8107edfb>] worker_thread+0x11b/0x400
 [<ffffffff8107ece0>] ? rescuer_thread+0x400/0x400
 [<ffffffff81085aef>] kthread+0xcf/0xe0
 [<ffffffff81085a20>] ? kthread_create_on_node+0x140/0x140
 [<ffffffff815fc76c>] ret_from_fork+0x7c/0xb0
 [<ffffffff81085a20>] ? kthread_create_on_node+0x140/0x140

The patch-set fixes the issue.

This patch (of 2):

remove_pagetable() gets start argument and passes the argument
to sync_global_pgds().  In this case, the argument must not be
modified.  If the argument is modified and passed to
sync_global_pgds(), sync_global_pgds() does not correctly
synchronize PGD to PGD entries of all processes MM since
synchronized range of memory [start, end] is wrong.

Unfortunately the start argument is modified in
remove_pagetable().  So this patch fixes the issue.

Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-16 08:55:08 +02:00
Jan-Simon Möller
cc99535eb4 x86/mm: Apply the section attribute to the variable, not its type
This fixes a compilation error in clang in that a linker section
attribute can't be added to a type:

  arch/x86/mm/mmap.c:34:8: error: '__section__' attribute only applies to functions and global variables struct __read_mostly
  ...

By moving the section attribute to the variable declaration, the
desired effect is achieved.

Signed-off-by: Jan-Simon Möller <dl9pf@gmx.de>
Signed-off-by: Behan Webster <behanw@converseincode.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409959005-11479-1-git-send-email-behanw@converseincode.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-09 07:13:39 +02:00
Mathias Krause
8a5a5d1530 x86-64, ptdump: Mark espfix area only if existent
We should classify the espfix area as such only if we actually have
enabled the corresponding option. Otherwise the page table dump might
look confusing.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Link: http://lkml.kernel.org/r/1410114629-24523-1-git-send-email-minipli@googlemail.com
Cc: Arjan van de Ven <arjan.van.de.ven@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2014-09-08 11:57:34 -07:00
Matthew Wilcox
bb693f13a0 x86: Remove set_pmd_pfn
The last user of set_pmd_pfn() went away in commit f03574f2d5, so this
has been dead code for over a year.

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

 arch/x86/include/asm/pgtable_32.h |    3 ---
 arch/x86/mm/pgtable_32.c          |   35 -----------------------------------
 2 files changed, 38 deletions(-)
2014-09-01 10:15:31 +02:00
Christoph Lameter
89cbc76768 x86: Replace __get_cpu_var uses
__get_cpu_var() is used for multiple purposes in the kernel source. One of
them is address calculation via the form &__get_cpu_var(x).  This calculates
the address for the instance of the percpu variable of the current processor
based on an offset.

Other use cases are for storing and retrieving data from the current
processors percpu area.  __get_cpu_var() can be used as an lvalue when
writing data or on the right side of an assignment.

__get_cpu_var() is defined as :

#define __get_cpu_var(var) (*this_cpu_ptr(&(var)))

__get_cpu_var() always only does an address determination. However, store
and retrieve operations could use a segment prefix (or global register on
other platforms) to avoid the address calculation.

this_cpu_write() and this_cpu_read() can directly take an offset into a
percpu area and use optimized assembly code to read and write per cpu
variables.

This patch converts __get_cpu_var into either an explicit address
calculation using this_cpu_ptr() or into a use of this_cpu operations that
use the offset.  Thereby address calculations are avoided and less registers
are used when code is generated.

Transformations done to __get_cpu_var()

1. Determine the address of the percpu instance of the current processor.

	DEFINE_PER_CPU(int, y);
	int *x = &__get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(&y);

2. Same as #1 but this time an array structure is involved.

	DEFINE_PER_CPU(int, y[20]);
	int *x = __get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(y);

3. Retrieve the content of the current processors instance of a per cpu
variable.

	DEFINE_PER_CPU(int, y);
	int x = __get_cpu_var(y)

   Converts to

	int x = __this_cpu_read(y);

4. Retrieve the content of a percpu struct

	DEFINE_PER_CPU(struct mystruct, y);
	struct mystruct x = __get_cpu_var(y);

   Converts to

	memcpy(&x, this_cpu_ptr(&y), sizeof(x));

5. Assignment to a per cpu variable

	DEFINE_PER_CPU(int, y)
	__get_cpu_var(y) = x;

   Converts to

	__this_cpu_write(y, x);

6. Increment/Decrement etc of a per cpu variable

	DEFINE_PER_CPU(int, y);
	__get_cpu_var(y)++

   Converts to

	__this_cpu_inc(y)

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2014-08-26 13:45:49 -04:00
Ingo Molnar
80b304fd00 * WARN_ON(!spin_is_locked()) always triggers on non-SMP machines.
Swap it for the more canonical lockdep_assert_held() which always
    does the right thing - Guenter Roeck
 
  * Assign the correct value to efi.runtime_version on arm64 so that all
    the runtime services can be invoked - Semen Protsenko
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Merge tag 'efi-urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into x86/urgent

Pull EFI fixes from Matt Fleming:

 * WARN_ON(!spin_is_locked()) always triggers on non-SMP machines.
   Swap it for the more canonical lockdep_assert_held() which always
   does the right thing - Guenter Roeck

 * Assign the correct value to efi.runtime_version on arm64 so that all
   the runtime services can be invoked - Semen Protsenko

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-08-22 10:04:15 +02:00
Jeremiah Mahler
86426851c3 x86/mm: Fix sparse 'tlb_single_page_flush_ceiling' warning and make the variable read-mostly
A sparse warning is generated about
'tlb_single_page_flush_ceiling' not being declared.

  arch/x86/mm/tlb.c:177:15: warning: symbol
  'tlb_single_page_flush_ceiling' was not declared. Should it be static?

Since it isn't used anywhere outside this file, fix the warning
by making it static.

Also, optimize the use of this variable by adding the
__read_mostly directive, as suggested by David Rientjes.

Suggested-by: David Rientjes <rientjes@google.com>
Signed-off-by: Jeremiah Mahler <jmmahler@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Link: http://lkml.kernel.org/r/1407569913-4035-1-git-send-email-jmmahler@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-08-10 09:07:18 +02:00
Dave Hansen
7c7f1547b6 x86/mm: Fix RCU splat from new TLB tracepoints
Dave Jones reported seeing a bug from one of my TLB tracepoints:

        http://lkml.kernel.org/r/20140806181801.GA4605@redhat.com

According to Paul McKenney, the right way to fix this is adding
an _rcuidle suffix to the tracepoint.

        http://lkml.kernel.org/r/20140807065055.GA5821@linux.vnet.ibm.com

This patch does just that.

Reported-by: Dave Jones <davej@redhat.com>,
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140807175841.5C92D878@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-08-08 10:35:00 +02:00
Wang Nan
03d4be6460 memory-hotplug: x86_32: suitable memory should go to ZONE_MOVABLE
This patch introduces zone_for_memory() to arch_add_memory() on x86_32
to ensure new, higher memory added into ZONE_MOVABLE if movable zone has
already setup.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Mel Gorman" <mgorman@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:21 -07:00
Wang Nan
9bfc411385 memory-hotplug: x86_64: suitable memory should go to ZONE_MOVABLE
This patch introduces zone_for_memory() to arch_add_memory() on x86_64
to ensure new, higher memory added into ZONE_MOVABLE if movable zone has
already setup.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Mel Gorman" <mgorman@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:21 -07:00
Paul Cassella
9a95f3cf7b mm: describe mmap_sem rules for __lock_page_or_retry() and callers
Add a comment describing the circumstances in which
__lock_page_or_retry() will or will not release the mmap_sem when
returning 0.

Add comments to lock_page_or_retry()'s callers (filemap_fault(),
do_swap_page()) noting the impact on VM_FAULT_RETRY returns.

Add comments on up the call tree, particularly replacing the false "We
return with mmap_sem still held" comments.

Signed-off-by: Paul Cassella <cassella@cray.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 18:01:20 -07:00
Linus Torvalds
ce47479632 Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 mm changes from Ingo Molnar:
 "The main change in this cycle is the rework of the TLB range flushing
  code, to simplify, fix and consolidate the code.  By Dave Hansen"

* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: Set TLB flush tunable to sane value (33)
  x86/mm: New tunable for single vs full TLB flush
  x86/mm: Add tracepoints for TLB flushes
  x86/mm: Unify remote INVLPG code
  x86/mm: Fix missed global TLB flush stat
  x86/mm: Rip out complicated, out-of-date, buggy TLB flushing
  x86/mm: Clean up the TLB flushing code
  x86/smep: Be more informative when signalling an SMEP fault
2014-08-04 17:15:45 -07:00
Dave Hansen
a5102476a2 x86/mm: Set TLB flush tunable to sane value (33)
This has been run through Intel's LKP tests across a wide range
of modern sytems and workloads and it wasn't shown to make a
measurable performance difference positive or negative.

Now that we have some shiny new tracepoints, we can actually
figure out what the heck is going on.

During a kernel compile, 60% of the flush_tlb_mm_range() calls
are for a single page.  It breaks down like this:

 size   percent  percent<=
  V        V        V
GLOBAL:   2.20%   2.20% avg cycles:  2283
     1:  56.92%  59.12% avg cycles:  1276
     2:  13.78%  72.90% avg cycles:  1505
     3:   8.26%  81.16% avg cycles:  1880
     4:   7.41%  88.58% avg cycles:  2447
     5:   1.73%  90.31% avg cycles:  2358
     6:   1.32%  91.63% avg cycles:  2563
     7:   1.14%  92.77% avg cycles:  2862
     8:   0.62%  93.39% avg cycles:  3542
     9:   0.08%  93.47% avg cycles:  3289
    10:   0.43%  93.90% avg cycles:  3570
    11:   0.20%  94.10% avg cycles:  3767
    12:   0.08%  94.18% avg cycles:  3996
    13:   0.03%  94.20% avg cycles:  4077
    14:   0.02%  94.23% avg cycles:  4836
    15:   0.04%  94.26% avg cycles:  5699
    16:   0.06%  94.32% avg cycles:  5041
    17:   0.57%  94.89% avg cycles:  5473
    18:   0.02%  94.91% avg cycles:  5396
    19:   0.03%  94.95% avg cycles:  5296
    20:   0.02%  94.96% avg cycles:  6749
    21:   0.18%  95.14% avg cycles:  6225
    22:   0.01%  95.15% avg cycles:  6393
    23:   0.01%  95.16% avg cycles:  6861
    24:   0.12%  95.28% avg cycles:  6912
    25:   0.05%  95.32% avg cycles:  7190
    26:   0.01%  95.33% avg cycles:  7793
    27:   0.01%  95.34% avg cycles:  7833
    28:   0.01%  95.35% avg cycles:  8253
    29:   0.08%  95.42% avg cycles:  8024
    30:   0.03%  95.45% avg cycles:  9670
    31:   0.01%  95.46% avg cycles:  8949
    32:   0.01%  95.46% avg cycles:  9350
    33:   3.11%  98.57% avg cycles:  8534
    34:   0.02%  98.60% avg cycles: 10977
    35:   0.02%  98.62% avg cycles: 11400

We get in to dimishing returns pretty quickly.  On pre-IvyBridge
CPUs, we used to set the limit at 8 pages, and it was set at 128
on IvyBrige.  That 128 number looks pretty silly considering that
less than 0.5% of the flushes are that large.

The previous code tried to size this number based on the size of
the TLB.  Good idea, but it's error-prone, needs maintenance
(which it didn't get up to now), and probably would not matter in
practice much.

Settting it to 33 means that we cover the mallopt
M_TRIM_THRESHOLD, which is the most universally common size to do
flushes.

That's the short version.  Here's the long one for why I chose 33:

1. These numbers have a constant bias in the timestamps from the
   tracing.  Probably counts for a couple hundred cycles in each of
   these tests, but it should be fairly _even_ across all of them.
   The smallest delta between the tracepoints I have ever seen is
   335 cycles.  This is one reason the cycles/page cost goes down in
   general as the flushes get larger.  The true cost is nearer to
   100 cycles.
2. A full flush is more expensive than a single invlpg, but not
   by much (single percentages).
3. A dtlb miss is 17.1ns (~45 cycles) and a itlb miss is 13.0ns
   (~34 cycles).  At those rates, refilling the 512-entry dTLB takes
   22,000 cycles.
4. 22,000 cycles is approximately the equivalent of doing 85
   invlpg operations.  But, the odds are that the TLB can
   actually be filled up faster than that because TLB misses that
   are close in time also tend to leverage the same caches.
6. ~98% of flushes are <=33 pages.  There are a lot of flushes of
   33 pages, probably because libc's M_TRIM_THRESHOLD is set to
   128k (32 pages)
7. I've found no consistent data to support changing the IvyBridge
   vs. SandyBridge tunable by a factor of 16

I used the performance counters on this hardware (IvyBridge i5-3320M)
to figure out the tlb miss costs:

ocperf.py stat -e dtlb_load_misses.walk_duration,dtlb_load_misses.walk_completed,dtlb_store_misses.walk_duration,dtlb_store_misses.walk_completed,itlb_misses.walk_duration,itlb_misses.walk_completed,itlb.itlb_flush

     7,720,030,970      dtlb_load_misses_walk_duration                                    [57.13%]
       169,856,353      dtlb_load_misses_walk_completed                                    [57.15%]
       708,832,859      dtlb_store_misses_walk_duration                                    [57.17%]
        19,346,823      dtlb_store_misses_walk_completed                                    [57.17%]
     2,779,687,402      itlb_misses_walk_duration                                    [57.15%]
        82,241,148      itlb_misses_walk_completed                                    [57.13%]
           770,717      itlb_itlb_flush                                              [57.11%]

Show that a dtlb miss is 17.1ns (~45 cycles) and a itlb miss is 13.0ns
(~34 cycles).  At those rates, refilling the 512-entry dTLB takes
22,000 cycles.  On a SandyBridge system with more cores and larger
caches, those are dtlb=13.4ns and itlb=9.5ns.

cat perf.stat.txt | perl -pe 's/,//g'
	| awk '/itlb_misses_walk_duration/ { icyc+=$1 }
		/itlb_misses_walk_completed/ { imiss+=$1 }
		/dtlb_.*_walk_duration/ { dcyc+=$1 }
		/dtlb_.*.*completed/ { dmiss+=$1 }
		END {print "itlb cyc/miss: ", icyc/imiss, " dtlb cyc/miss: ", dcyc/dmiss, "   -----    ", icyc,imiss, dcyc,dmiss }

On Westmere CPUs, the counters to use are: itlb_flush,itlb_misses.walk_cycles,itlb_misses.any,dtlb_misses.walk_cycles,dtlb_misses.any

The assumptions that this code went in under:
https://lkml.org/lkml/2012/6/12/119 say that a flush and a refill are
about 100ns.  Being generous, that is over by a factor of 6 on the
refill side, although it is fairly close on the cost of an invlpg.
An increase of a single invlpg operation seems to lengthen the flush
range operation by about 200 cycles.  Here is one example of the data
collected for flushing 10 and 11 pages (full data are below):

    10:   0.43%  93.90% avg cycles:  3570 cycles/page:  357 samples: 4714
    11:   0.20%  94.10% avg cycles:  3767 cycles/page:  342 samples: 2145

How to generate this table:

	echo 10000 > /sys/kernel/debug/tracing/buffer_size_kb
	echo x86-tsc > /sys/kernel/debug/tracing/trace_clock
	echo 'reason != 0' > /sys/kernel/debug/tracing/events/tlb/tlb_flush/filter
	echo 1 > /sys/kernel/debug/tracing/events/tlb/tlb_flush/enable

Pipe the trace output in to this script:

	http://sr71.net/~dave/intel/201402-tlb/trace-time-diff-process.pl.txt

Note that these data were gathered with the invlpg threshold set to
150 pages.  Only data points with >=50 of samples were printed:

Flush    % of     %<=
in       flush    this
pages      es     size
------------------------------------------------------------------------------
    -1:   2.20%   2.20% avg cycles:  2283 cycles/page: xxxx samples: 23960
     1:  56.92%  59.12% avg cycles:  1276 cycles/page: 1276 samples: 620895
     2:  13.78%  72.90% avg cycles:  1505 cycles/page:  752 samples: 150335
     3:   8.26%  81.16% avg cycles:  1880 cycles/page:  626 samples: 90131
     4:   7.41%  88.58% avg cycles:  2447 cycles/page:  611 samples: 80877
     5:   1.73%  90.31% avg cycles:  2358 cycles/page:  471 samples: 18885
     6:   1.32%  91.63% avg cycles:  2563 cycles/page:  427 samples: 14397
     7:   1.14%  92.77% avg cycles:  2862 cycles/page:  408 samples: 12441
     8:   0.62%  93.39% avg cycles:  3542 cycles/page:  442 samples: 6721
     9:   0.08%  93.47% avg cycles:  3289 cycles/page:  365 samples: 917
    10:   0.43%  93.90% avg cycles:  3570 cycles/page:  357 samples: 4714
    11:   0.20%  94.10% avg cycles:  3767 cycles/page:  342 samples: 2145
    12:   0.08%  94.18% avg cycles:  3996 cycles/page:  333 samples: 864
    13:   0.03%  94.20% avg cycles:  4077 cycles/page:  313 samples: 289
    14:   0.02%  94.23% avg cycles:  4836 cycles/page:  345 samples: 236
    15:   0.04%  94.26% avg cycles:  5699 cycles/page:  379 samples: 390
    16:   0.06%  94.32% avg cycles:  5041 cycles/page:  315 samples: 643
    17:   0.57%  94.89% avg cycles:  5473 cycles/page:  321 samples: 6229
    18:   0.02%  94.91% avg cycles:  5396 cycles/page:  299 samples: 224
    19:   0.03%  94.95% avg cycles:  5296 cycles/page:  278 samples: 367
    20:   0.02%  94.96% avg cycles:  6749 cycles/page:  337 samples: 185
    21:   0.18%  95.14% avg cycles:  6225 cycles/page:  296 samples: 1964
    22:   0.01%  95.15% avg cycles:  6393 cycles/page:  290 samples: 83
    23:   0.01%  95.16% avg cycles:  6861 cycles/page:  298 samples: 61
    24:   0.12%  95.28% avg cycles:  6912 cycles/page:  288 samples: 1307
    25:   0.05%  95.32% avg cycles:  7190 cycles/page:  287 samples: 533
    26:   0.01%  95.33% avg cycles:  7793 cycles/page:  299 samples: 94
    27:   0.01%  95.34% avg cycles:  7833 cycles/page:  290 samples: 66
    28:   0.01%  95.35% avg cycles:  8253 cycles/page:  294 samples: 73
    29:   0.08%  95.42% avg cycles:  8024 cycles/page:  276 samples: 846
    30:   0.03%  95.45% avg cycles:  9670 cycles/page:  322 samples: 296
    31:   0.01%  95.46% avg cycles:  8949 cycles/page:  288 samples: 79
    32:   0.01%  95.46% avg cycles:  9350 cycles/page:  292 samples: 60
    33:   3.11%  98.57% avg cycles:  8534 cycles/page:  258 samples: 33936
    34:   0.02%  98.60% avg cycles: 10977 cycles/page:  322 samples: 268
    35:   0.02%  98.62% avg cycles: 11400 cycles/page:  325 samples: 177
    36:   0.01%  98.63% avg cycles: 11504 cycles/page:  319 samples: 161
    37:   0.02%  98.65% avg cycles: 11596 cycles/page:  313 samples: 182
    38:   0.02%  98.66% avg cycles: 11850 cycles/page:  311 samples: 195
    39:   0.01%  98.68% avg cycles: 12158 cycles/page:  311 samples: 128
    40:   0.01%  98.68% avg cycles: 11626 cycles/page:  290 samples: 78
    41:   0.04%  98.73% avg cycles: 11435 cycles/page:  278 samples: 477
    42:   0.01%  98.73% avg cycles: 12571 cycles/page:  299 samples: 74
    43:   0.01%  98.74% avg cycles: 12562 cycles/page:  292 samples: 78
    44:   0.01%  98.75% avg cycles: 12991 cycles/page:  295 samples: 108
    45:   0.01%  98.76% avg cycles: 13169 cycles/page:  292 samples: 78
    46:   0.02%  98.78% avg cycles: 12891 cycles/page:  280 samples: 261
    47:   0.01%  98.79% avg cycles: 13099 cycles/page:  278 samples: 67
    48:   0.01%  98.80% avg cycles: 13851 cycles/page:  288 samples: 77
    49:   0.01%  98.80% avg cycles: 13749 cycles/page:  280 samples: 66
    50:   0.01%  98.81% avg cycles: 13949 cycles/page:  278 samples: 73
    52:   0.00%  98.82% avg cycles: 14243 cycles/page:  273 samples: 52
    54:   0.01%  98.83% avg cycles: 15312 cycles/page:  283 samples: 87
    55:   0.01%  98.84% avg cycles: 15197 cycles/page:  276 samples: 109
    56:   0.02%  98.86% avg cycles: 15234 cycles/page:  272 samples: 208
    57:   0.00%  98.86% avg cycles: 14888 cycles/page:  261 samples: 53
    58:   0.01%  98.87% avg cycles: 15037 cycles/page:  259 samples: 59
    59:   0.01%  98.87% avg cycles: 15752 cycles/page:  266 samples: 63
    62:   0.00%  98.89% avg cycles: 16222 cycles/page:  261 samples: 54
    64:   0.02%  98.91% avg cycles: 17179 cycles/page:  268 samples: 248
    65:   0.12%  99.03% avg cycles: 18762 cycles/page:  288 samples: 1324
    85:   0.00%  99.10% avg cycles: 21649 cycles/page:  254 samples: 50
   127:   0.01%  99.18% avg cycles: 32397 cycles/page:  255 samples: 75
   128:   0.13%  99.31% avg cycles: 31711 cycles/page:  247 samples: 1466
   129:   0.18%  99.49% avg cycles: 33017 cycles/page:  255 samples: 1927
   181:   0.33%  99.84% avg cycles:  2489 cycles/page:   13 samples: 3547
   256:   0.05%  99.91% avg cycles:  2305 cycles/page:    9 samples: 550
   512:   0.03%  99.95% avg cycles:  2133 cycles/page:    4 samples: 304
  1512:   0.01%  99.99% avg cycles:  3038 cycles/page:    2 samples: 65

Here are the tlb counters during a 10-second slice of a kernel compile
for a SandyBridge system.  It's better than IvyBridge, but probably
due to the larger caches since this was one of the 'X' extreme parts.

    10,873,007,282      dtlb_load_misses_walk_duration
       250,711,333      dtlb_load_misses_walk_completed
     1,212,395,865      dtlb_store_misses_walk_duration
        31,615,772      dtlb_store_misses_walk_completed
     5,091,010,274      itlb_misses_walk_duration
       163,193,511      itlb_misses_walk_completed
         1,321,980      itlb_itlb_flush

      10.008045158 seconds time elapsed

# cat perf.stat.1392743721.txt | perl -pe 's/,//g' | awk '/itlb_misses_walk_duration/ { icyc+=$1 } /itlb_misses_walk_completed/ { imiss+=$1 } /dtlb_.*_walk_duration/ { dcyc+=$1 } /dtlb_.*.*completed/ { dmiss+=$1 } END {print "itlb cyc/miss: ", icyc/imiss/3.3, " dtlb cyc/miss: ", dcyc/dmiss/3.3, "   -----    ", icyc,imiss, dcyc,dmiss }'
itlb ns/miss:  9.45338  dtlb ns/miss:  12.9716

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: http://lkml.kernel.org/r/20140731154103.10C1115E@viggo.jf.intel.com
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-07-31 08:48:51 -07:00
Dave Hansen
2d040a1ce9 x86/mm: New tunable for single vs full TLB flush
Most of the logic here is in the documentation file.  Please take
a look at it.

I know we've come full-circle here back to a tunable, but this
new one is *WAY* simpler.  I challenge anyone to describe in one
sentence how the old one worked.  Here's the way the new one
works:

	If we are flushing more pages than the ceiling, we use
	the full flush, otherwise we use per-page flushes.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: http://lkml.kernel.org/r/20140731154101.12B52CAF@viggo.jf.intel.com
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-07-31 08:48:51 -07:00
Dave Hansen
d17d8f9ded x86/mm: Add tracepoints for TLB flushes
We don't have any good way to figure out what kinds of flushes
are being attempted.  Right now, we can try to use the vm
counters, but those only tell us what we actually did with the
hardware (one-by-one vs full) and don't tell us what was actually
_requested_.

This allows us to select out "interesting" TLB flushes that we
might want to optimize (like the ranged ones) and ignore the ones
that we have very little control over (the ones at context
switch).

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: http://lkml.kernel.org/r/20140731154059.4C96CBA5@viggo.jf.intel.com
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-07-31 08:48:51 -07:00
Dave Hansen
a23421f111 x86/mm: Unify remote INVLPG code
There are currently three paths through the remote flush code:

1. full invalidation
2. single page invalidation using invlpg
3. ranged invalidation using invlpg

This takes 2 and 3 and combines them in to a single path by
making the single-page one just be the start and end be start
plus a single page.  This makes placement of our tracepoint easier.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: http://lkml.kernel.org/r/20140731154058.E0F90408@viggo.jf.intel.com
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-07-31 08:48:51 -07:00
Dave Hansen
9dfa6dee53 x86/mm: Fix missed global TLB flush stat
If we take the

	if (end == TLB_FLUSH_ALL || vmflag & VM_HUGETLB) {
		local_flush_tlb();
		goto out;
	}

path out of flush_tlb_mm_range(), we will have flushed the tlb,
but not incremented NR_TLB_LOCAL_FLUSH_ALL.  This unifies the
way out of the function so that we always take a single path when
doing a full tlb flush.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: http://lkml.kernel.org/r/20140731154056.FF763B76@viggo.jf.intel.com
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-07-31 08:48:50 -07:00
Dave Hansen
e9f4e0a9fe x86/mm: Rip out complicated, out-of-date, buggy TLB flushing
I think the flush_tlb_mm_range() code that tries to tune the
flush sizes based on the CPU needs to get ripped out for
several reasons:

1. It is obviously buggy.  It uses mm->total_vm to judge the
   task's footprint in the TLB.  It should certainly be using
   some measure of RSS, *NOT* ->total_vm since only resident
   memory can populate the TLB.
2. Haswell, and several other CPUs are missing from the
   intel_tlb_flushall_shift_set() function.  Thus, it has been
   demonstrated to bitrot quickly in practice.
3. It is plain wrong in my vm:
	[    0.037444] Last level iTLB entries: 4KB 0, 2MB 0, 4MB 0
	[    0.037444] Last level dTLB entries: 4KB 0, 2MB 0, 4MB 0
	[    0.037444] tlb_flushall_shift: 6
   Which leads to it to never use invlpg.
4. The assumptions about TLB refill costs are wrong:
	http://lkml.kernel.org/r/1337782555-8088-3-git-send-email-alex.shi@intel.com
    (more on this in later patches)
5. I can not reproduce the original data: https://lkml.org/lkml/2012/5/17/59
   I believe the sample times were too short.  Running the
   benchmark in a loop yields times that vary quite a bit.

Note that this leaves us with a static ceiling of 1 page.  This
is a conservative, dumb setting, and will be revised in a later
patch.

This also removes the code which attempts to predict whether we
are flushing data or instructions.  We expect instruction flushes
to be relatively rare and not worth tuning for explicitly.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: http://lkml.kernel.org/r/20140731154055.ABC88E89@viggo.jf.intel.com
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-07-31 08:48:50 -07:00
Dave Hansen
4995ab9cf5 x86/mm: Clean up the TLB flushing code
The

	if (cpumask_any_but(mm_cpumask(mm), smp_processor_id()) < nr_cpu_ids)

line of code is not exactly the easiest to audit, especially when
it ends up at two different indentation levels.  This eliminates
one of the the copy-n-paste versions.  It also gives us a unified
exit point for each path through this function.  We need this in
a minute for our tracepoint.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: http://lkml.kernel.org/r/20140731154054.44F1CDDC@viggo.jf.intel.com
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-07-31 08:48:50 -07:00
Linus Torvalds
3737a12761 Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull more perf updates from Ingo Molnar:
 "A second round of perf updates:

   - wide reaching kprobes sanitization and robustization, with the hope
     of fixing all 'probe this function crashes the kernel' bugs, by
     Masami Hiramatsu.

   - uprobes updates from Oleg Nesterov: tmpfs support, corner case
     fixes and robustization work.

   - perf tooling updates and fixes from Jiri Olsa, Namhyung Ki, Arnaldo
     et al:
        * Add support to accumulate hist periods (Namhyung Kim)
        * various fixes, refactorings and enhancements"

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (101 commits)
  perf: Differentiate exec() and non-exec() comm events
  perf: Fix perf_event_comm() vs. exec() assumption
  uprobes/x86: Rename arch_uprobe->def to ->defparam, minor comment updates
  perf/documentation: Add description for conditional branch filter
  perf/x86: Add conditional branch filtering support
  perf/tool: Add conditional branch filter 'cond' to perf record
  perf: Add new conditional branch filter 'PERF_SAMPLE_BRANCH_COND'
  uprobes: Teach copy_insn() to support tmpfs
  uprobes: Shift ->readpage check from __copy_insn() to uprobe_register()
  perf/x86: Use common PMU interrupt disabled code
  perf/ARM: Use common PMU interrupt disabled code
  perf: Disable sampled events if no PMU interrupt
  perf: Fix use after free in perf_remove_from_context()
  perf tools: Fix 'make help' message error
  perf record: Fix poll return value propagation
  perf tools: Move elide bool into perf_hpp_fmt struct
  perf tools: Remove elide setup for SORT_MODE__MEMORY mode
  perf tools: Fix "==" into "=" in ui_browser__warning assignment
  perf tools: Allow overriding sysfs and proc finding with env var
  perf tools: Consider header files outside perf directory in tags target
  ...
2014-06-12 19:18:49 -07:00
Jiri Kosina
eff50c347f x86/smep: Be more informative when signalling an SMEP fault
If pagefault triggers due to SMEP triggering, it can't be really easily
distinguished from any other oops-causing pagefault, which might lead to quite
some confusion when trying to understand the reason for the oops.

Print an explanatory message in case the fault happened during instruction
fetch for _PAGE_USER page which is present and executable on SMEP-enabled CPUs.

This is consistent with what we are doing for NX already; in addition to
immediately seeing from the oops what might be happening, it can even easily
give a good indication to sysadmins who are carefully monitoring their kernel
logs that someone might be trying to pwn them.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Link: http://lkml.kernel.org/r/alpine.LNX.2.00.1406102248490.1321@pobox.suse.cz
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-06-11 17:55:30 -07:00
Linus Torvalds
a0abcf2e8f Merge branch 'x86/vdso' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into next
Pull x86 cdso updates from Peter Anvin:
 "Vdso cleanups and improvements largely from Andy Lutomirski.  This
  makes the vdso a lot less ''special''"

* 'x86/vdso' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/vdso, build: Make LE access macros clearer, host-safe
  x86/vdso, build: Fix cross-compilation from big-endian architectures
  x86/vdso, build: When vdso2c fails, unlink the output
  x86, vdso: Fix an OOPS accessing the HPET mapping w/o an HPET
  x86, mm: Replace arch_vma_name with vm_ops->name for vsyscalls
  x86, mm: Improve _install_special_mapping and fix x86 vdso naming
  mm, fs: Add vm_ops->name as an alternative to arch_vma_name
  x86, vdso: Fix an OOPS accessing the HPET mapping w/o an HPET
  x86, vdso: Remove vestiges of VDSO_PRELINK and some outdated comments
  x86, vdso: Move the vvar and hpet mappings next to the 64-bit vDSO
  x86, vdso: Move the 32-bit vdso special pages after the text
  x86, vdso: Reimplement vdso.so preparation in build-time C
  x86, vdso: Move syscall and sysenter setup into kernel/cpu/common.c
  x86, vdso: Clean up 32-bit vs 64-bit vdso params
  x86, mm: Ensure correct alignment of the fixmap
2014-06-05 08:05:29 -07:00
Linus Torvalds
2071b3e34f Merge branch 'x86/espfix' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into next
Pull x86-64 espfix changes from Peter Anvin:
 "This is the espfix64 code, which fixes the IRET information leak as
  well as the associated functionality problem.  With this code applied,
  16-bit stack segments finally work as intended even on a 64-bit
  kernel.

  Consequently, this patchset also removes the runtime option that we
  added as an interim measure.

  To help the people working on Linux kernels for very small systems,
  this patchset also makes these compile-time configurable features"

* 'x86/espfix' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Revert "x86-64, modify_ldt: Make support for 16-bit segments a runtime option"
  x86, espfix: Make it possible to disable 16-bit support
  x86, espfix: Make espfix64 a Kconfig option, fix UML
  x86, espfix: Fix broken header guard
  x86, espfix: Move espfix definitions into a separate header file
  x86-32, espfix: Remove filter for espfix32 due to race
  x86-64, espfix: Don't leak bits 31:16 of %esp returning to 16-bit stack
2014-06-05 07:46:15 -07:00