linux-stable.git/arch/x86/include/asm, branch linux-4.3.y

x86/mm: Improve switch_mm() barrier comments

2016-01-31T19:25:43+00:00

commit 4eaffdd5a5fe6ff9f95e1ab4de1ac904d5e0fa8b upstream.

My previous comments were still a bit confusing and there was a
typo. Fix it up.

Reported-by: Peter Zijlstra 
Signed-off-by: Andy Lutomirski 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Dave Hansen 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Rik van Riel 
Cc: Thomas Gleixner 
Fixes: 71b3c126e611 ("x86/mm: Add barriers and document switch_mm()-vs-flush synchronization")
Link: http://lkml.kernel.org/r/0a0b43cdcdd241c5faaaecfbcc91a155ddedc9a1.1452631609.git.luto@kernel.org
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

x86/mm: Add barriers and document switch_mm()-vs-flush synchronization

2016-01-31T19:25:43+00:00

commit 71b3c126e61177eb693423f2e18a1914205b165e upstream.

When switch_mm() activates a new PGD, it also sets a bit that
tells other CPUs that the PGD is in use so that TLB flush IPIs
will be sent.  In order for that to work correctly, the bit
needs to be visible prior to loading the PGD and therefore
starting to fill the local TLB.

Document all the barriers that make this work correctly and add
a couple that were missing.

Signed-off-by: Andy Lutomirski 
Cc: Andrew Morton 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Dave Hansen 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Rik van Riel 
Cc: Thomas Gleixner 
Cc: linux-mm@kvack.org
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

x86/boot: Double BOOT_HEAP_SIZE to 64KB

2016-01-31T19:25:43+00:00

commit 8c31902cffc4d716450be549c66a67a8a3dd479c upstream.

When decompressing kernel image during x86 bootup, malloc memory
for ELF program headers may run out of heap space, which leads
to system halt.  This patch doubles BOOT_HEAP_SIZE to 64KB.

Tested with 32-bit kernel which failed to boot without this patch.

Signed-off-by: H.J. Lu 
Acked-by: H. Peter Anvin 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

x86/paravirt: Prevent rtc_cmos platform device init on PV guests

2016-01-31T19:25:42+00:00

commit d8c98a1d1488747625ad6044d423406e17e99b7a upstream.

Adding the rtc platform device in non-privileged Xen PV guests causes
an IRQ conflict because these guests do not have legacy PIC and may
allocate irqs in the legacy range.

In a single VCPU Xen PV guest we should have:

/proc/interrupts:
           CPU0
  0:       4934  xen-percpu-virq      timer0
  1:          0  xen-percpu-ipi       spinlock0
  2:          0  xen-percpu-ipi       resched0
  3:          0  xen-percpu-ipi       callfunc0
  4:          0  xen-percpu-virq      debug0
  5:          0  xen-percpu-ipi       callfuncsingle0
  6:          0  xen-percpu-ipi       irqwork0
  7:        321   xen-dyn-event     xenbus
  8:         90   xen-dyn-event     hvc_console
  ...

But hvc_console cannot get its interrupt because it is already in use
by rtc0 and the console does not work.

  genirq: Flags mismatch irq 8. 00000000 (hvc_console) vs. 00000000 (rtc0)

We can avoid this problem by realizing that unprivileged PV guests (both
Xen and lguests) are not supposed to have rtc_cmos device and so
adding it is not necessary.

Privileged guests (i.e. Xen's dom0) do use it but they should not have
irq conflicts since they allocate irqs above legacy range (above
gsi_top, in fact).

Instead of explicitly testing whether the guest is privileged we can
extend pv_info structure to include information about guest's RTC
support.

Reported-and-tested-by: Sander Eikelenboom 
Signed-off-by: David Vrabel 
Signed-off-by: Boris Ostrovsky 
Cc: vkuznets@redhat.com
Cc: xen-devel@lists.xenproject.org
Cc: konrad.wilk@oracle.com
Link: http://lkml.kernel.org/r/1449842873-2613-1-git-send-email-boris.ostrovsky@oracle.com
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

x86/irq: Probe for PIC presence before allocating descs for legacy IRQs

2015-12-09T19:34:18+00:00

commit 8c058b0b9c34d8c8d7912880956543769323e2d8 upstream.

Commit d32932d02e18 ("x86/irq: Convert IOAPIC to use hierarchical irqdomain
interfaces") brought a regression for Hyper-V Gen2 instances. These
instances don't have i8259 legacy PIC but they use legacy IRQs for serial
port, rtc, and acpi. With this commit included we end up with these IRQs
not initialized. Earlier, there was a special workaround for legacy IRQs
in mp_map_pin_to_irq() doing mp_irqdomain_map() without looking at
nr_legacy_irqs() and now we fail in __irq_domain_alloc_irqs() when
irq_domain_alloc_descs() returns -EEXIST.

The essence of the issue seems to be that early_irq_init() calls
arch_probe_nr_irqs() to figure out the number of legacy IRQs before
we probe for i8259 and gets 16. Later when init_8259A() is called we switch
to NULL legacy PIC and nr_legacy_irqs() starts to return 0 but we already
have 16 descs allocated.

Solve the issue by separating i8259 probe from init and calling it in
arch_probe_nr_irqs() before we actually use nr_legacy_irqs() information.

Fixes: d32932d02e18 ("x86/irq: Convert IOAPIC to use hierarchical irqdomain interfaces")
Signed-off-by: Vitaly Kuznetsov 
Cc: Jiang Liu 
Cc: K. Y. Srinivasan 
Link: http://lkml.kernel.org/r/1446543614-3621-1-git-send-email-vkuznets@redhat.com
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

KVM: x86: add read_phys to x86_emulate_ops

2015-12-09T19:34:16+00:00

commit 7a036a6f670f63b32c5ee126425f9109271ca13f upstream.

We want to read the physical memory when emulating RSM.

X86EMUL_IO_NEEDED is returned on all errors for consistency with other
helpers.

Signed-off-by: Radim Krčmář 
Tested-by: Laszlo Ersek 
Signed-off-by: Paolo Bonzini 
Signed-off-by: Greg Kroah-Hartman

Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2015-10-23T13:34:32+00:00

Pull x86 fixes from Ingo Molnar:
 "Misc fixes: two KASAN fixes, two EFI boot fixes, two boot-delay
  optimization fixes, and a fix for a IRQ handling hang observed on
  virtual platforms"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm, kasan: Silence KASAN warnings in get_wchan()
  compiler, atomics, kasan: Provide READ_ONCE_NOCHECK()
  x86, kasan: Fix build failure on KASAN=y && KMEMCHECK=y kernels
  x86/smpboot: Fix CPU #1 boot timeout
  x86/smpboot: Fix cpu_init_udelay=10000 corner case boot parameter misbehavior
  x86/ioapic: Disable interrupts when re-routing legacy IRQs
  x86/setup: Extend low identity map to cover whole kernel range
  x86/efi: Fix multiple GOP device support

x86, kasan: Fix build failure on KASAN=y && KMEMCHECK=y kernels

2015-10-19T08:07:23+00:00

Declaration of memcpy() is hidden under #ifndef CONFIG_KMEMCHECK.
In asm/efi.h under #ifdef CONFIG_KASAN we #undef memcpy(), due to
which the following happens:

  In file included from arch/x86/kernel/setup.c:96:0:
  ./arch/x86/include/asm/desc.h: In function ‘native_write_idt_entry’:
  ./arch/x86/include/asm/desc.h:122:2: error: implicit declaration of function ‘memcpy’ [-Werror=implicit-function-declaration]   memcpy(&idt[entry], gate, sizeof(*gate));
    ^
    cc1: some warnings being treated as errors
    make[2]: *** [arch/x86/kernel/setup.o] Error 1

We will get rid of that #undef in asm/efi.h eventually.
But in the meanwhile move memcpy() declaration out of #ifdefs
to fix the build.

Reported-by: Borislav Petkov 
Signed-off-by: Andrey Ryabinin 
Cc: Andy Lutomirski 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/1444994933-28328-1-git-send-email-aryabinin@virtuozzo.com
Signed-off-by: Ingo Molnar

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2015-10-14T17:01:32+00:00

Pull KVM fixes from Paolo Bonzini:
 "Bug fixes for system management mode emulation.

  The first two patches fix SMM emulation on Nehalem processors.  The
  others fix some cases that became apparent as work progressed on the
  firmware side"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86: fix RSM into 64-bit protected mode
  KVM: x86: fix previous commit for 32-bit
  KVM: x86: fix SMI to halted VCPU
  KVM: x86: clean up kvm_arch_vcpu_runnable
  KVM: x86: map/unmap private slots in __x86_set_memory_region
  KVM: x86: build kvm_userspace_memory_region in x86_set_memory_region

KVM: x86: build kvm_userspace_memory_region in x86_set_memory_region

2015-10-13T16:28:46+00:00

The next patch will make x86_set_memory_region fill the
userspace_addr.  Since the struct is not used untouched
anymore, it makes sense to build it in x86_set_memory_region
directly; it also simplifies the callers.

Reported-by: Alexandre DERUMIER 
Cc: stable@vger.kernel.org
Fixes: 9da0e4d5ac969909f6b435ce28ea28135a9cbd69
Reviewed-by: Radim Krčmář 
Signed-off-by: Paolo Bonzini