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  1. 31 8月, 2018 1 次提交
    • J
      arm64: mm: always enable CONFIG_HOLES_IN_ZONE · f52bb98f
      由 James Morse 提交于 
      Commit 6d526ee2 ("arm64: mm: enable CONFIG_HOLES_IN_ZONE for NUMA")
only enabled HOLES_IN_ZONE for NUMA systems because the NUMA code was
choking on the missing zone for nomap pages. This problem doesn't just
apply to NUMA systems.

If the architecture doesn't set HAVE_ARCH_PFN_VALID, pfn_valid() will
return true if the pfn is part of a valid sparsemem section.

When working with multiple pages, the mm code uses pfn_valid_within()
to test each page it uses within the sparsemem section is valid. On
most systems memory comes in MAX_ORDER_NR_PAGES chunks which all
have valid/initialised struct pages. In this case pfn_valid_within()
is optimised out.

Systems where this isn't true (e.g. due to nomap) should set
HOLES_IN_ZONE and provide HAVE_ARCH_PFN_VALID so that mm tests each
page as it works with it.

Currently non-NUMA arm64 systems can't enable HOLES_IN_ZONE, leading to
a VM_BUG_ON():

| page:fffffdff802e1780 is uninitialized and poisoned
| raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff
| raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff
| page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p))
| ------------[ cut here ]------------
| kernel BUG at include/linux/mm.h:978!
| Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
[...]
| CPU: 1 PID: 25236 Comm: dd Not tainted 4.18.0 #7
| Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
| pstate: 40000085 (nZcv daIf -PAN -UAO)
| pc : move_freepages_block+0x144/0x248
| lr : move_freepages_block+0x144/0x248
| sp : fffffe0071177680
[...]
| Process dd (pid: 25236, stack limit = 0x0000000094cc07fb)
| Call trace:
|  move_freepages_block+0x144/0x248
|  steal_suitable_fallback+0x100/0x16c
|  get_page_from_freelist+0x440/0xb20
|  __alloc_pages_nodemask+0xe8/0x838
|  new_slab+0xd4/0x418
|  ___slab_alloc.constprop.27+0x380/0x4a8
|  __slab_alloc.isra.21.constprop.26+0x24/0x34
|  kmem_cache_alloc+0xa8/0x180
|  alloc_buffer_head+0x1c/0x90
|  alloc_page_buffers+0x68/0xb0
|  create_empty_buffers+0x20/0x1ec
|  create_page_buffers+0xb0/0xf0
|  __block_write_begin_int+0xc4/0x564
|  __block_write_begin+0x10/0x18
|  block_write_begin+0x48/0xd0
|  blkdev_write_begin+0x28/0x30
|  generic_perform_write+0x98/0x16c
|  __generic_file_write_iter+0x138/0x168
|  blkdev_write_iter+0x80/0xf0
|  __vfs_write+0xe4/0x10c
|  vfs_write+0xb4/0x168
|  ksys_write+0x44/0x88
|  sys_write+0xc/0x14
|  el0_svc_naked+0x30/0x34
| Code: aa1303e0 90001a01 91296421 94008902 (d4210000)
| ---[ end trace 1601ba47f6e883fe ]---

Remove the NUMA dependency.

Link: https://www.spinics.net/lists/arm-kernel/msg671851.html
Cc: <stable@vger.kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reported-by: NMikulas Patocka <mpatocka@redhat.com>
Reviewed-by: NPavel Tatashin <pavel.tatashin@microsoft.com>
Tested-by: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NJames Morse <james.morse@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
      f52bb98f
  3. 24 8月, 2018 12 次提交
  5. 23 8月, 2018 13 次提交
    • M
      powerpc/mce: Fix SLB rebolting during MCE recovery path. · 0f52b3a0
      由 Mahesh Salgaonkar 提交于 
      The commit e7e81847 ("powerpc/64s: move machine check SLB flushing
to mm/slb.c") introduced a bug in reloading bolted SLB entries. Unused
bolted entries are stored with .esid=0 in the slb_shadow area, and
that value is now used directly as the RB input to slbmte, which means
the RB[52:63] index field is set to 0, which causes SLB entry 0 to be
cleared.

Fix this by storing the index bits in the unused bolted entries, which
directs the slbmte to the right place.

The SLB shadow area is also used by the hypervisor, but PAPR is okay
with that, from LoPAPR v1.1, 14.11.1.3 SLB Shadow Buffer:

  Note: SLB is filled sequentially starting at index 0
  from the shadow buffer ignoring the contents of
  RB field bits 52-63

Fixes: e7e81847 ("powerpc/64s: move machine check SLB flushing to mm/slb.c")
Signed-off-by: NMahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Reviewed-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      0f52b3a0
    • P
      KVM: PPC: Book3S: Fix guest DMA when guest partially backed by THP pages · 8cfbdbdc
      由 Paul Mackerras 提交于 
      Commit 76fa4975 ("KVM: PPC: Check if IOMMU page is contained in
the pinned physical page", 2018-07-17) added some checks to ensure
that guest DMA mappings don't attempt to map more than the guest is
entitled to access. However, errors in the logic mean that legitimate
guest requests to map pages for DMA are being denied in some
situations. Specifically, if the first page of the range passed to
mm_iommu_get() is mapped with a normal page, and subsequent pages are
mapped with transparent huge pages, we end up with mem->pageshift ==
0. That means that the page size checks in mm_iommu_ua_to_hpa() and
mm_iommu_up_to_hpa_rm() will always fail for every page in that
region, and thus the guest can never map any memory in that region for
DMA, typically leading to a flood of error messages like this:

  qemu-system-ppc64: VFIO_MAP_DMA: -22
  qemu-system-ppc64: vfio_dma_map(0x10005f47780, 0x800000000000000, 0x10000, 0x7fff63ff0000) = -22 (Invalid argument)

The logic errors in mm_iommu_get() are:

  (a) use of 'ua' not 'ua + (i << PAGE_SHIFT)' in the find_linux_pte()
      call (meaning that find_linux_pte() returns the pte for the
      first address in the range, not the address we are currently up
      to);
  (b) use of 'pageshift' as the variable to receive the hugepage shift
      returned by find_linux_pte() - for a normal page this gets set
      to 0, leading to us setting mem->pageshift to 0 when we conclude
      that the pte returned by find_linux_pte() didn't match the page
      we were looking at;
  (c) comparing 'compshift', which is a page order, i.e. log base 2 of
      the number of pages, with 'pageshift', which is a log base 2 of
      the number of bytes.

To fix these problems, this patch introduces 'cur_ua' to hold the
current user address and uses that in the find_linux_pte() call;
introduces 'pteshift' to hold the hugepage shift found by
find_linux_pte(); and compares 'pteshift' with 'compshift +
PAGE_SHIFT' rather than 'compshift'.

The patch also moves the local_irq_restore to the point after the PTE
pointer returned by find_linux_pte() has been dereferenced because
otherwise the PTE could change underneath us, and adds a check to
avoid doing the find_linux_pte() call once mem->pageshift has been
reduced to PAGE_SHIFT, as an optimization.

Fixes: 76fa4975 ("KVM: PPC: Check if IOMMU page is contained in the pinned physical page")
Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      8cfbdbdc
    • A
      powerpc/mm/radix: Only need the Nest MMU workaround for R -> RW transition · f08d08f3
      由 Aneesh Kumar K.V 提交于 
      The Nest MMU workaround is only needed for RW upgrades. Avoid doing
that for other PTE updates.

We also avoid clearing the PTE while marking it invalid. This is
because other page table walkers will find this PTE none and can
result in unexpected behaviour due to that. Instead we clear
_PAGE_PRESENT and set the software PTE bit _PAGE_INVALID.
pte_present() is already updated to check for both bits. This makes
sure page table walkers will find the PTE present and things like
pte_pfn(pte) returns the right value.

Based on an original patch from Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      f08d08f3
    • A
      powerpc/mm/books3s: Add new pte bit to mark pte temporarily invalid. · bd0dbb73
      由 Aneesh Kumar K.V 提交于 
      When splitting a huge pmd pte, we need to mark the pmd entry invalid. We
can do that by clearing _PAGE_PRESENT bit. But then that will be taken as a
swap pte. In order to differentiate between the two use a software pte bit
when invalidating.

For regular pte, due to bd5050e3 ("powerpc/mm/radix: Change pte relax
sequence to handle nest MMU hang") we need to mark the pte entry invalid when
relaxing access permission. Instead of marking pte_none which can result in
different page table walk routines possibly skipping this pte entry, invalidate
it but still keep it marked present.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      bd0dbb73
    • C
      powerpc/nohash: fix pte_access_permitted() · 810e9f86
      由 Christophe Leroy 提交于 
      Commit 5769beaf ("powerpc/mm: Add proper pte access check helper
for other platforms") replaced generic pte_access_permitted() by an
arch specific one.

The generic one is defined as
(pte_present(pte) && (!(write) || pte_write(pte)))

The arch specific one is open coded checking that _PAGE_USER and
_PAGE_WRITE (_PAGE_RW) flags are set, but lacking to check that
_PAGE_RO and _PAGE_PRIVILEGED are unset, leading to a useless test
on targets like the 8xx which defines _PAGE_RW and _PAGE_USER as 0.

Commit 5fa5b16b ("powerpc/mm/hugetlb: Use pte_access_permitted
for hugetlb access check") replaced some tests performed with
pte helpers by a call to pte_access_permitted(), leading to the same
issue.

This patch rewrites powerpc/nohash pte_access_permitted()
using pte helpers.

Fixes: 5769beaf ("powerpc/mm: Add proper pte access check helper for other platforms")
Fixes: 5fa5b16b ("powerpc/mm/hugetlb: Use pte_access_permitted for hugetlb access check")
Cc: stable@vger.kernel.org # v4.15+
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      810e9f86
    • P
      x86/mm/tlb: Revert the recent lazy TLB patches · 52a288c7
      由 Peter Zijlstra 提交于 
      Revert commits:

  95b0e635 x86/mm/tlb: Always use lazy TLB mode
  64482aaf x86/mm/tlb: Only send page table free TLB flush to lazy TLB CPUs
  ac031589 x86/mm/tlb: Make lazy TLB mode lazier
  61d0beb5 x86/mm/tlb: Restructure switch_mm_irqs_off()
  2ff6ddf1 x86/mm/tlb: Leave lazy TLB mode at page table free time

In order to simplify the TLB invalidate fixes for x86 and unify the
parts that need backporting.  We'll try again later.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: NRik van Riel <riel@surriel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      52a288c7
    • N
      include/linux/compiler*.h: make compiler-*.h mutually exclusive · 815f0ddb
      由 Nick Desaulniers 提交于 
      Commit cafa0010 ("Raise the minimum required gcc version to 4.6")
recently exposed a brittle part of the build for supporting non-gcc
compilers.

Both Clang and ICC define __GNUC__, __GNUC_MINOR__, and
__GNUC_PATCHLEVEL__ for quick compatibility with code bases that haven't
added compiler specific checks for __clang__ or __INTEL_COMPILER.

This is brittle, as they happened to get compatibility by posing as a
certain version of GCC.  This broke when upgrading the minimal version
of GCC required to build the kernel, to a version above what ICC and
Clang claim to be.

Rather than always including compiler-gcc.h then undefining or
redefining macros in compiler-intel.h or compiler-clang.h, let's
separate out the compiler specific macro definitions into mutually
exclusive headers, do more proper compiler detection, and keep shared
definitions in compiler_types.h.

Fixes: cafa0010 ("Raise the minimum required gcc version to 4.6")
Reported-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Suggested-by: NEli Friedman <efriedma@codeaurora.org>
Suggested-by: NJoe Perches <joe@perches.com>
Signed-off-by: NNick Desaulniers <ndesaulniers@google.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      815f0ddb
    • T
      ia64: Fix allnoconfig section mismatch for ioc_init/ioc_iommu_info · 2edd73a4
      由 Tony Luck 提交于 
      This has been broken for an embarassingly long time (since v4.4).

Just needs a couple of __init tags on functions to make the sections
match up.
Signed-off-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      2edd73a4
    • A
      module: use relative references for __ksymtab entries · 7290d580
      由 Ard Biesheuvel 提交于 
      An ordinary arm64 defconfig build has ~64 KB worth of __ksymtab entries,
each consisting of two 64-bit fields containing absolute references, to
the symbol itself and to a char array containing its name, respectively.

When we build the same configuration with KASLR enabled, we end up with an
additional ~192 KB of relocations in the .init section, i.e., one 24 byte
entry for each absolute reference, which all need to be processed at boot
time.

Given how the struct kernel_symbol that describes each entry is completely
local to module.c (except for the references emitted by EXPORT_SYMBOL()
itself), we can easily modify it to contain two 32-bit relative references
instead.  This reduces the size of the __ksymtab section by 50% for all
64-bit architectures, and gets rid of the runtime relocations entirely for
architectures implementing KASLR, either via standard PIE linking (arm64)
or using custom host tools (x86).

Note that the binary search involving __ksymtab contents relies on each
section being sorted by symbol name.  This is implemented based on the
input section names, not the names in the ksymtab entries, so this patch
does not interfere with that.

Given that the use of place-relative relocations requires support both in
the toolchain and in the module loader, we cannot enable this feature for
all architectures.  So make it dependent on whether
CONFIG_HAVE_ARCH_PREL32_RELOCATIONS is defined.

Link: http://lkml.kernel.org/r/20180704083651.24360-4-ard.biesheuvel@linaro.orgSigned-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: NJessica Yu <jeyu@kernel.org>
Acked-by: NMichael Ellerman <mpe@ellerman.id.au>
Reviewed-by: NWill Deacon <will.deacon@arm.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morris <james.morris@microsoft.com>
Cc: James Morris <jmorris@namei.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      7290d580
    • A
      module: allow symbol exports to be disabled · f922c4ab
      由 Ard Biesheuvel 提交于 
      To allow existing C code to be incorporated into the decompressor or the
UEFI stub, introduce a CPP macro that turns all EXPORT_SYMBOL_xxx
declarations into nops, and #define it in places where such exports are
undesirable.  Note that this gets rid of a rather dodgy redefine of
linux/export.h's header guard.

Link: http://lkml.kernel.org/r/20180704083651.24360-3-ard.biesheuvel@linaro.orgSigned-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: NNicolas Pitre <nico@linaro.org>
Acked-by: NMichael Ellerman <mpe@ellerman.id.au>
Reviewed-by: NWill Deacon <will.deacon@arm.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morris <james.morris@microsoft.com>
Cc: James Morris <jmorris@namei.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      f922c4ab
    • A
      arch: enable relative relocations for arm64, power and x86 · 271ca788
      由 Ard Biesheuvel 提交于 
      Patch series "add support for relative references in special sections", v10.

This adds support for emitting special sections such as initcall arrays,
PCI fixups and tracepoints as relative references rather than absolute
references.  This reduces the size by 50% on 64-bit architectures, but
more importantly, it removes the need for carrying relocation metadata for
these sections in relocatable kernels (e.g., for KASLR) that needs to be
fixed up at boot time.  On arm64, this reduces the vmlinux footprint of
such a reference by 8x (8 byte absolute reference + 24 byte RELA entry vs
4 byte relative reference)

Patch #3 was sent out before as a single patch.  This series supersedes
the previous submission.  This version makes relative ksymtab entries
dependent on the new Kconfig symbol HAVE_ARCH_PREL32_RELOCATIONS rather
than trying to infer from kbuild test robot replies for which
architectures it should be blacklisted.

Patch #1 introduces the new Kconfig symbol HAVE_ARCH_PREL32_RELOCATIONS,
and sets it for the main architectures that are expected to benefit the
most from this feature, i.e., 64-bit architectures or ones that use
runtime relocations.

Patch #2 add support for #define'ing __DISABLE_EXPORTS to get rid of
ksymtab/kcrctab sections in decompressor and EFI stub objects when
rebuilding existing C files to run in a different context.

Patches #4 - #6 implement relative references for initcalls, PCI fixups
and tracepoints, respectively, all of which produce sections with order
~1000 entries on an arm64 defconfig kernel with tracing enabled.  This
means we save about 28 KB of vmlinux space for each of these patches.

[From the v7 series blurb, which included the jump_label patches as well]:

  For the arm64 kernel, all patches combined reduce the memory footprint
  of vmlinux by about 1.3 MB (using a config copied from Ubuntu that has
  KASLR enabled), of which ~1 MB is the size reduction of the RELA section
  in .init, and the remaining 300 KB is reduction of .text/.data.

This patch (of 6):

Before updating certain subsystems to use place relative 32-bit
relocations in special sections, to save space and reduce the number of
absolute relocations that need to be processed at runtime by relocatable
kernels, introduce the Kconfig symbol and define it for some architectures
that should be able to support and benefit from it.

Link: http://lkml.kernel.org/r/20180704083651.24360-2-ard.biesheuvel@linaro.orgSigned-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: NMichael Ellerman <mpe@ellerman.id.au>
Reviewed-by: NWill Deacon <will.deacon@arm.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: James Morris <jmorris@namei.org>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Cc: James Morris <james.morris@microsoft.com>
Cc: Jessica Yu <jeyu@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      271ca788
    • A
      mm: zero out the vma in vma_init() · a670468f
      由 Andrew Morton 提交于 
      Rather than in vm_area_alloc().  To ensure that the various oddball
stack-based vmas are in a good state.  Some of the callers were zeroing
them out, others were not.
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a670468f
    • M
      mm, oom: distinguish blockable mode for mmu notifiers · 93065ac7
      由 Michal Hocko 提交于 
      There are several blockable mmu notifiers which might sleep in
mmu_notifier_invalidate_range_start and that is a problem for the
oom_reaper because it needs to guarantee a forward progress so it cannot
depend on any sleepable locks.

Currently we simply back off and mark an oom victim with blockable mmu
notifiers as done after a short sleep.  That can result in selecting a new
oom victim prematurely because the previous one still hasn't torn its
memory down yet.

We can do much better though.  Even if mmu notifiers use sleepable locks
there is no reason to automatically assume those locks are held.  Moreover
majority of notifiers only care about a portion of the address space and
there is absolutely zero reason to fail when we are unmapping an unrelated
range.  Many notifiers do really block and wait for HW which is harder to
handle and we have to bail out though.

This patch handles the low hanging fruit.
__mmu_notifier_invalidate_range_start gets a blockable flag and callbacks
are not allowed to sleep if the flag is set to false.  This is achieved by
using trylock instead of the sleepable lock for most callbacks and
continue as long as we do not block down the call chain.

I think we can improve that even further because there is a common pattern
to do a range lookup first and then do something about that.  The first
part can be done without a sleeping lock in most cases AFAICS.

The oom_reaper end then simply retries if there is at least one notifier
which couldn't make any progress in !blockable mode.  A retry loop is
already implemented to wait for the mmap_sem and this is basically the
same thing.

The simplest way for driver developers to test this code path is to wrap
userspace code which uses these notifiers into a memcg and set the hard
limit to hit the oom.  This can be done e.g.  after the test faults in all
the mmu notifier managed memory and set the hard limit to something really
small.  Then we are looking for a proper process tear down.

[akpm@linux-foundation.org: coding style fixes]
[akpm@linux-foundation.org: minor code simplification]
Link: http://lkml.kernel.org/r/20180716115058.5559-1-mhocko@kernel.orgSigned-off-by: NMichal Hocko <mhocko@suse.com>
Acked-by: Christian König <christian.koenig@amd.com> # AMD notifiers
Acked-by: Leon Romanovsky <leonro@mellanox.com> # mlx and umem_odp
Reported-by: NDavid Rientjes <rientjes@google.com>
Cc: "David (ChunMing) Zhou" <David1.Zhou@amd.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Mike Marciniszyn <mike.marciniszyn@intel.com>
Cc: Dennis Dalessandro <dennis.dalessandro@intel.com>
Cc: Sudeep Dutt <sudeep.dutt@intel.com>
Cc: Ashutosh Dixit <ashutosh.dixit@intel.com>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      93065ac7
  7. 22 8月, 2018 14 次提交
    • P
      KVM: VMX: fixes for vmentry_l1d_flush module parameter · 0027ff2a
      由 Paolo Bonzini 提交于 
      Two bug fixes:

1) missing entries in the l1d_param array; this can cause a host crash
if an access attempts to reach the missing entry. Future-proof the get
function against any overflows as well.  However, the two entries
VMENTER_L1D_FLUSH_EPT_DISABLED and VMENTER_L1D_FLUSH_NOT_REQUIRED must
not be accepted by the parse function, so disable them there.

2) invalid values must be rejected even if the CPU does not have the
bug, so test for them before checking boot_cpu_has(X86_BUG_L1TF)

... and a small refactoring, since the .cmd field is redundant with
the index in the array.
Reported-by: NBandan Das <bsd@redhat.com>
Cc: stable@vger.kernel.org
Fixes: a7b9020bSigned-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      0027ff2a
    • T
      KVM: x86: SVM: Call x86_spec_ctrl_set_guest/host() with interrupts disabled · 024d83ca
      由 Thomas Gleixner 提交于 
      Mikhail reported the following lockdep splat:

WARNING: possible irq lock inversion dependency detected
CPU 0/KVM/10284 just changed the state of lock:
  000000000d538a88 (&st->lock){+...}, at:
  speculative_store_bypass_update+0x10b/0x170

but this lock was taken by another, HARDIRQ-safe lock
in the past:

(&(&sighand->siglock)->rlock){-.-.}

   and interrupts could create inverse lock ordering between them.

Possible interrupt unsafe locking scenario:

    CPU0                    CPU1
    ----                    ----
   lock(&st->lock);
                           local_irq_disable();
                           lock(&(&sighand->siglock)->rlock);
                           lock(&st->lock);
    <Interrupt>
     lock(&(&sighand->siglock)->rlock);
     *** DEADLOCK ***

The code path which connects those locks is:

   speculative_store_bypass_update()
   ssb_prctl_set()
   do_seccomp()
   do_syscall_64()

In svm_vcpu_run() speculative_store_bypass_update() is called with
interupts enabled via x86_virt_spec_ctrl_set_guest/host().

This is actually a false positive, because GIF=0 so interrupts are
disabled even if IF=1; however, we can easily move the invocations of
x86_virt_spec_ctrl_set_guest/host() into the interrupt disabled region to
cure it, and it's a good idea to keep the GIF=0/IF=1 area as small
and self-contained as possible.

Fixes: 1f50ddb4 ("x86/speculation: Handle HT correctly on AMD")
Reported-by: NMikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NMikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: kvm@vger.kernel.org
Cc: x86@kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      024d83ca
    • S
      KVM: vmx: Inject #UD for SGX ENCLS instruction in guest · 0b665d30
      由 Sean Christopherson 提交于 
      Virtualization of Intel SGX depends on Enclave Page Cache (EPC)
management that is not yet available in the kernel, i.e. KVM support
for exposing SGX to a guest cannot be added until basic support
for SGX is upstreamed, which is a WIP[1].

Until SGX is properly supported in KVM, ensure a guest sees expected
behavior for ENCLS, i.e. all ENCLS #UD.  Because SGX does not have a
true software enable bit, e.g. there is no CR4.SGXE bit, the ENCLS
instruction can be executed[1] by the guest if SGX is supported by the
system.  Intercept all ENCLS leafs (via the ENCLS- exiting control and
field) and unconditionally inject #UD.

[1] https://www.spinics.net/lists/kvm/msg171333.html or
    https://lkml.org/lkml/2018/7/3/879

[2] A guest can execute ENCLS in the sense that ENCLS will not take
    an immediate #UD, but no ENCLS will ever succeed in a guest
    without explicit support from KVM (map EPC memory into the guest),
    unless KVM has a *very* egregious bug, e.g. accidentally mapped
    EPC memory into the guest SPTEs.  In other words this patch is
    needed only to prevent the guest from seeing inconsistent behavior,
    e.g. #GP (SGX not enabled in Feature Control MSR) or #PF (leaf
    operand(s) does not point at EPC memory) instead of #UD on ENCLS.
    Intercepting ENCLS is not required to prevent the guest from truly
    utilizing SGX.
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20180814163334.25724-3-sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      0b665d30
    • S
      KVM: vmx: Add defines for SGX ENCLS exiting · 802ec461
      由 Sean Christopherson 提交于 
      Hardware support for basic SGX virtualization adds a new execution
control (ENCLS_EXITING), VMCS field (ENCLS_EXITING_BITMAP) and exit
reason (ENCLS), that enables a VMM to intercept specific ENCLS leaf
functions, e.g. to inject faults when the VMM isn't exposing SGX to
a VM.  When ENCLS_EXITING is enabled, the VMM can set/clear bits in
the bitmap to intercept/allow ENCLS leaf functions in non-root, e.g.
setting bit 2 in the ENCLS_EXITING_BITMAP will cause ENCLS[EINIT]
to VMExit(ENCLS).

Note: EXIT_REASON_ENCLS was previously added by commit 1f519992
("KVM: VMX: add missing exit reasons").
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20180814163334.25724-2-sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      802ec461
    • Y
      x86/kvm/vmx: Fix coding style in vmx_setup_l1d_flush() · d806afa4
      由 Yi Wang 提交于 
      Substitute spaces with tab. No functional changes.
Signed-off-by: NYi Wang <wang.yi59@zte.com.cn>
Reviewed-by: NJiang Biao <jiang.biao2@zte.com.cn>
Message-Id: <1534398159-48509-1-git-send-email-wang.yi59@zte.com.cn>
Cc: stable@vger.kernel.org # L1TF
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      d806afa4
    • A
      x86: kvm: avoid unused variable warning · 7288bde1
      由 Arnd Bergmann 提交于 
      Removing one of the two accesses of the maxphyaddr variable led to
a harmless warning:

arch/x86/kvm/x86.c: In function 'kvm_set_mmio_spte_mask':
arch/x86/kvm/x86.c:6563:6: error: unused variable 'maxphyaddr' [-Werror=unused-variable]

Removing the #ifdef seems to be the nicest workaround, as it
makes the code look cleaner than adding another #ifdef.

Fixes: 28a1f3ac ("kvm: x86: Set highest physical address bits in non-present/reserved SPTEs")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Cc: stable@vger.kernel.org # L1TF
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      7288bde1
    • Y
      h8300: fix IRQ no · 4bdf61cc
      由 Yoshinori Sato 提交于 
      Old timer handler use 24 (Compare match A).
But current timer handler use 26 (Overflow).
Signed-off-by: NYoshinori Sato <ysato@users.sourceforge.jp>
      4bdf61cc
    • R
      arch/h8300: add a defconfig target · 7b291be8
      由 Randy Dunlap 提交于 
      Make the "defconfig" target valid for arch/h8300.  Currently
"make ARCH=h8300 defconfig" produces:

*** Can't find default configuration "arch/h8300/defconfig"!
../scripts/kconfig/Makefile:87: recipe for target 'defconfig' failed

By adding a value for KBUILD_DEFCONFIG, "make ARCH=h8300 defconfig"
successfully produces a kernel .config file:

*** Default configuration is based on 'edosk2674_defconfig'

This is useful for Kconfig editing/testing.
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: uclinux-h8-devel@lists.sourceforge.jp (moderated for non-subscribers)
Signed-off-by: NYoshinori Sato <ysato@users.sourceforge.jp>
      7b291be8
    • R
      arch/h8300: eliminate kgbd.c warning · ce156feb
      由 Randy Dunlap 提交于 
      Drop the "const" qualifier from arch_kgdb_ops to eliminate the gcc
warning (gcc version is 8.1.0).

arch/h8300/kernel/kgdb.c:132:24: error: conflicting type qualifiers for 'arch_kgdb_ops'
 const struct kgdb_arch arch_kgdb_ops = {
In file included from ../arch/h8300/kernel/kgdb.c:12:
../include/linux/kgdb.h:284:26: note: previous declaration of 'arch_kgdb_ops' was here
 extern struct kgdb_arch  arch_kgdb_ops;
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: uclinux-h8-devel@lists.sourceforge.jp
Signed-off-by: NYoshinori Sato <ysato@users.sourceforge.jp>
      ce156feb
    • R
      arch/h8300: eliminate ptrace.h warnings · cfa2d688
      由 Randy Dunlap 提交于 
      Add a "struct task_struct;" stub to arch/h8300's ptrace.h header to
eliminate gcc warnings (gcc version is 8.1.0).

../arch/h8300/include/asm/ptrace.h:32:34: warning: 'struct task_struct' declared inside parameter list will not be visible outside of this definition or declaration
 extern long h8300_get_reg(struct task_struct *task, int regno);
../arch/h8300/include/asm/ptrace.h:33:33: warning: 'struct task_struct' declared inside parameter list will not be visible outside of this definition or declaration
 extern int h8300_put_reg(struct task_struct *task, int regno,
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: uclinux-h8-devel@lists.sourceforge.jp
Signed-off-by: NYoshinori Sato <ysato@users.sourceforge.jp>
      cfa2d688
    • L
      h8300:let the checker know that size_t is ulong · 1b803a35
      由 Luc Van Oostenryck 提交于 
      All 64bit archs use unsigned long for size_t and most 32bit
archs use 'unsigned int'. By default, this is what is assumed
by sparse.

However, on h8300 (a 32bit arch) size_t is unsigned long which
can led sparse to emit wrong warnings.

Fix this by passing to sparse the flag -msize-long, telling it
that size_t is unsigned long.
Signed-off-by: NLuc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: NYoshinori Sato <ysato@users.sourceforge.jp>
      1b803a35
    • W
      h8300: Don't include linux/kernel.h in asm/atomic.h · 9819d4e4
      由 Will Deacon 提交于 
      linux/kernel.h isn't needed by asm/atomic.h and will result in circular
dependencies when the asm-generic atomic bitops are built around the
tomic_long_t interface.

Remove the broad include and replace it with linux/compiler.h for
READ_ONCE etc and asm/irqflags.h for arch_local_irq_save etc.

Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NYoshinori Sato <ysato@users.sourceforge.jp>
      9819d4e4
    • R
      h8300: remove unnecessary of_platform_populate call · ec3d5f16
      由 Rob Herring 提交于 
      The DT core will call of_platform_populate, so it is not necessary for
arch specific code to call it unless there are custom match entries,
auxdata or parent device. Neither of those apply here, so remove the call.

Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: uclinux-h8-devel@lists.sourceforge.jp
Signed-off-by: NRob Herring <robh@kernel.org>
Signed-off-by: NYoshinori Sato <ysato@users.sourceforge.jp>
      ec3d5f16
    • G
      h8300: Correct signature of test_bit() · 5743ee22
      由 Geert Uytterhoeven 提交于 
          mm/filemap.c: In function 'clear_bit_unlock_is_negative_byte':
    mm/filemap.c:1181:30: warning: passing argument 2 of 'test_bit' discards 'volatile' qualifier from pointer target type [-Wdiscarded-qualifiers]
      return test_bit(PG_waiters, mem);
				  ^~~
    In file included from include/linux/bitops.h:38,
		     from include/linux/kernel.h:11,
		     from include/linux/list.h:9,
		     from include/linux/wait.h:7,
		     from include/linux/wait_bit.h:8,
		     from include/linux/fs.h:6,
		     from include/linux/dax.h:5,
		     from mm/filemap.c:14:
    arch/h8300/include/asm/bitops.h:69:57: note: expected 'const long unsigned int *' but argument is of type 'volatile void *'
     static inline int test_bit(int nr, const unsigned long *addr)
					~~~~~~~~~~~~~~~~~~~~~^~~~

Make the bitmask pointed to by the "addr" parameter volatile to fix
this, like is done on other architectures.
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NYoshinori Sato <ysato@users.sourceforge.jp>
      5743ee22