ACPI 5.2.9.3 IA-PC Boot Architecture flag ACPI_FADT_LEGACY_DEVICES
can be used to determine if a system has legacy devices LPC or
ISA devices. The x86 platform already has a struct which lists
known associated legacy devices, we start off careful only
by disabling root devices we should not regress with. The struct
and device list can be expanded with time to cover more root
legacy components.
Signed-off-by: NLuis R. Rodriguez <mcgrof@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: andrew.cooper3@citrix.com
Cc: andriy.shevchenko@linux.intel.com
Cc: bigeasy@linutronix.de
Cc: boris.ostrovsky@oracle.com
Cc: david.vrabel@citrix.com
Cc: ffainelli@freebox.fr
Cc: george.dunlap@citrix.com
Cc: glin@suse.com
Cc: jgross@suse.com
Cc: jlee@suse.com
Cc: josh@joshtriplett.org
Cc: julien.grall@linaro.org
Cc: konrad.wilk@oracle.com
Cc: kozerkov@parallels.com
Cc: lenb@kernel.org
Cc: lguest@lists.ozlabs.org
Cc: linux-acpi@vger.kernel.org
Cc: lv.zheng@intel.com
Cc: matt@codeblueprint.co.uk
Cc: mbizon@freebox.fr
Cc: rjw@rjwysocki.net
Cc: robert.moore@intel.com
Cc: rusty@rustcorp.com.au
Cc: tiwai@suse.de
Cc: toshi.kani@hp.com
Cc: xen-devel@lists.xensource.com
Link: http://lkml.kernel.org/r/1460592286-300-13-git-send-email-mcgrof@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Since we are removing paravirt_enabled() replace it with a
logical equivalent. Even though PNPBIOS is x86 specific we
add an arch-specific type call, which can be implemented by
any architecture to show how other legacy attribute devices
can later be also checked for with other ACPI legacy attribute
flags.

This implicates the first ACPI 5.2.9.3 IA-PC Boot Architecture
ACPI_FADT_LEGACY_DEVICES flag device, and shows how to add more.

The reason pnpbios gets a defined structure and as such uses
a different approach than the RTC legacy quirk is that ACPI
has a respective RTC flag, while pnpbios does not. We fold
the pnpbios quirk under ACPI_FADT_LEGACY_DEVICES ACPI flag
use case, and use a struct of possible devices to enable
future extensions of this.

As per 0-day, this bumps the vmlinux size using i386-tinyconfig as
follows:

TOTAL   TEXT   init.text   x86_early_init_platform_quirks()
+32     +28    +28         +28

That's 4 byte overhead total, the rest is cleared out on init
as its all __init text.

v2: split out subarch handlng on switch to make it easier
    later to add other subarchs. The 'fall-through' switch
    handling can be confusing and we'll remove it later
    when we add handling for X86_SUBARCH_CE4100.
v3: document vmlinux size impact as per 0-day, and also
    explain why pnpbios is treated differently than the
    RTC legacy feature.
Signed-off-by: NLuis R. Rodriguez <mcgrof@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: andrew.cooper3@citrix.com
Cc: andriy.shevchenko@linux.intel.com
Cc: bigeasy@linutronix.de
Cc: boris.ostrovsky@oracle.com
Cc: david.vrabel@citrix.com
Cc: ffainelli@freebox.fr
Cc: george.dunlap@citrix.com
Cc: glin@suse.com
Cc: jgross@suse.com
Cc: jlee@suse.com
Cc: josh@joshtriplett.org
Cc: julien.grall@linaro.org
Cc: konrad.wilk@oracle.com
Cc: kozerkov@parallels.com
Cc: lenb@kernel.org
Cc: lguest@lists.ozlabs.org
Cc: linux-acpi@vger.kernel.org
Cc: lv.zheng@intel.com
Cc: matt@codeblueprint.co.uk
Cc: mbizon@freebox.fr
Cc: rjw@rjwysocki.net
Cc: robert.moore@intel.com
Cc: rusty@rustcorp.com.au
Cc: tiwai@suse.de
Cc: toshi.kani@hp.com
Cc: xen-devel@lists.xensource.com
Link: http://lkml.kernel.org/r/1460592286-300-12-git-send-email-mcgrof@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

The X86_BUG_F00F work around is responsible for fixing up the error
generated on attempted F00F exploitation from an OOPS to a SIGILL.

There is no reason why this code should not be allowed to run on
PV guest on a F00F-affected CPU -- it would simply never trigger.
The pv_enabled() check was there only to avoid printing the f00f
workaround, so removing the check is purely a cosmetic change.
Suggested-by: NAndy Lutomirski <luto@amacapital.net>
Signed-off-by: NLuis R. Rodriguez <mcgrof@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: andrew.cooper3@citrix.com
Cc: andriy.shevchenko@linux.intel.com
Cc: bigeasy@linutronix.de
Cc: boris.ostrovsky@oracle.com
Cc: david.vrabel@citrix.com
Cc: ffainelli@freebox.fr
Cc: george.dunlap@citrix.com
Cc: glin@suse.com
Cc: jgross@suse.com
Cc: jlee@suse.com
Cc: josh@joshtriplett.org
Cc: julien.grall@linaro.org
Cc: konrad.wilk@oracle.com
Cc: kozerkov@parallels.com
Cc: lenb@kernel.org
Cc: lguest@lists.ozlabs.org
Cc: linux-acpi@vger.kernel.org
Cc: lv.zheng@intel.com
Cc: matt@codeblueprint.co.uk
Cc: mbizon@freebox.fr
Cc: rjw@rjwysocki.net
Cc: robert.moore@intel.com
Cc: rusty@rustcorp.com.au
Cc: tiwai@suse.de
Cc: toshi.kani@hp.com
Cc: xen-devel@lists.xensource.com
Link: http://lkml.kernel.org/r/1460592286-300-11-git-send-email-mcgrof@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

There is already a check for boot_params.tboot_addr prior
to paravirt_enabled(). Both Xen and lguest, which are also the
only ones that set paravirt_enabled to true, never set the
boot_params.tboot_addr. The Xen folks are sure a force disable
to 0 is not needed, we recently forced disabled this on lguest.
With this in place this check is no longer needed.

Xen folks are sure force disable to 0 is not needed because
apm_info lives in .bss, we recently forced disabled this on
lguest, and on the Xen side just to be sure Boris zeroed out
the .bss for PV guests through commit 04b6b4a5
("xen/x86: Zero out .bss for PV guests"). With this care taken
into consideration the paravirt_enabled() check is simply not
needed anymore.
Signed-off-by: NLuis R. Rodriguez <mcgrof@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: andrew.cooper3@citrix.com
Cc: andriy.shevchenko@linux.intel.com
Cc: bigeasy@linutronix.de
Cc: boris.ostrovsky@oracle.com
Cc: david.vrabel@citrix.com
Cc: ffainelli@freebox.fr
Cc: george.dunlap@citrix.com
Cc: glin@suse.com
Cc: jgross@suse.com
Cc: jlee@suse.com
Cc: josh@joshtriplett.org
Cc: julien.grall@linaro.org
Cc: konrad.wilk@oracle.com
Cc: kozerkov@parallels.com
Cc: lenb@kernel.org
Cc: lguest@lists.ozlabs.org
Cc: linux-acpi@vger.kernel.org
Cc: lv.zheng@intel.com
Cc: matt@codeblueprint.co.uk
Cc: mbizon@freebox.fr
Cc: rjw@rjwysocki.net
Cc: robert.moore@intel.com
Cc: rusty@rustcorp.com.au
Cc: tiwai@suse.de
Cc: toshi.kani@hp.com
Cc: xen-devel@lists.xensource.com
Link: http://lkml.kernel.org/r/1460592286-300-10-git-send-email-mcgrof@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

There is already a check for apm_info.bios == 0, the
apm_info.bios is set from the boot_params.apm_bios_info.
Both Xen and lguest, which are also the only ones that set
paravirt_enabled to true, never set the apm_bios.info. The

Xen folks are sure force disable to 0 is not needed because
apm_info lives in .bss, we recently forced disabled this on
lguest, and on the Xen side just to be sure Boris zeroed out
the .bss for PV guests through commit 04b6b4a5
("xen/x86: Zero out .bss for PV guests"). With this care taken
into consideration the paravirt_enabled() check is simply not
needed anymore.
Signed-off-by: NLuis R. Rodriguez <mcgrof@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: andrew.cooper3@citrix.com
Cc: andriy.shevchenko@linux.intel.com
Cc: bigeasy@linutronix.de
Cc: boris.ostrovsky@oracle.com
Cc: david.vrabel@citrix.com
Cc: ffainelli@freebox.fr
Cc: george.dunlap@citrix.com
Cc: glin@suse.com
Cc: jgross@suse.com
Cc: jlee@suse.com
Cc: josh@joshtriplett.org
Cc: julien.grall@linaro.org
Cc: konrad.wilk@oracle.com
Cc: kozerkov@parallels.com
Cc: lenb@kernel.org
Cc: lguest@lists.ozlabs.org
Cc: linux-acpi@vger.kernel.org
Cc: lv.zheng@intel.com
Cc: matt@codeblueprint.co.uk
Cc: mbizon@freebox.fr
Cc: rjw@rjwysocki.net
Cc: robert.moore@intel.com
Cc: rusty@rustcorp.com.au
Cc: tiwai@suse.de
Cc: toshi.kani@hp.com
Cc: xen-devel@lists.xensource.com
Link: http://lkml.kernel.org/r/1460592286-300-9-git-send-email-mcgrof@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

This replaces the paravirt_enabled() check with a
proper x86 legacy platform quirk.

As per 0-day, this bumps the vmlinux size using i386-tinyconfig as
follows:

TOTAL   TEXT   init.text   x86_early_init_platform_quirks()
+39     +35    +35         +25

That's a 4 byte total overhead, the rest is all cleared out
upon init as its all __init text.

v2: document 0-day vmlinux size impact
Signed-off-by: NLuis R. Rodriguez <mcgrof@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: andrew.cooper3@citrix.com
Cc: andriy.shevchenko@linux.intel.com
Cc: bigeasy@linutronix.de
Cc: boris.ostrovsky@oracle.com
Cc: david.vrabel@citrix.com
Cc: ffainelli@freebox.fr
Cc: george.dunlap@citrix.com
Cc: glin@suse.com
Cc: jgross@suse.com
Cc: jlee@suse.com
Cc: josh@joshtriplett.org
Cc: julien.grall@linaro.org
Cc: konrad.wilk@oracle.com
Cc: kozerkov@parallels.com
Cc: lenb@kernel.org
Cc: lguest@lists.ozlabs.org
Cc: linux-acpi@vger.kernel.org
Cc: lv.zheng@intel.com
Cc: matt@codeblueprint.co.uk
Cc: mbizon@freebox.fr
Cc: rjw@rjwysocki.net
Cc: robert.moore@intel.com
Cc: rusty@rustcorp.com.au
Cc: tiwai@suse.de
Cc: toshi.kani@hp.com
Cc: xen-devel@lists.xensource.com
Link: http://lkml.kernel.org/r/1460592286-300-7-git-send-email-mcgrof@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

This moves the ACPI specific check into the ACPI boot code,
it also takes advantage of the x86_platform.legacy.rtc which
is checked for already on the RTC initialization code. This
lets us remove the nasty #ifdefery and consolidate the checks
to use only one toggle to disable the RTC init code.

The works as RTC is initialized by device_initcall(add_rtc_cmos),
this will run late in boot on start_kernel() during rest_init(),
acpi_parse_fadt() gets called earlier during setup_arch().
Signed-off-by: NLuis R. Rodriguez <mcgrof@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: andrew.cooper3@citrix.com
Cc: andriy.shevchenko@linux.intel.com
Cc: bigeasy@linutronix.de
Cc: boris.ostrovsky@oracle.com
Cc: david.vrabel@citrix.com
Cc: ffainelli@freebox.fr
Cc: george.dunlap@citrix.com
Cc: glin@suse.com
Cc: jgross@suse.com
Cc: jlee@suse.com
Cc: josh@joshtriplett.org
Cc: julien.grall@linaro.org
Cc: konrad.wilk@oracle.com
Cc: kozerkov@parallels.com
Cc: lenb@kernel.org
Cc: lguest@lists.ozlabs.org
Cc: linux-acpi@vger.kernel.org
Cc: lv.zheng@intel.com
Cc: matt@codeblueprint.co.uk
Cc: mbizon@freebox.fr
Cc: rjw@rjwysocki.net
Cc: robert.moore@intel.com
Cc: rusty@rustcorp.com.au
Cc: tiwai@suse.de
Cc: toshi.kani@hp.com
Cc: xen-devel@lists.xensource.com
Link: http://lkml.kernel.org/r/1460592286-300-6-git-send-email-mcgrof@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

We have 4 types of x86 platforms that disable RTC:

  * Intel MID
  * Lguest - uses paravirt
  * Xen dom-U - uses paravirt
  * x86 on legacy systems annotated with an ACPI legacy flag

We can consolidate all of these into a platform specific legacy
quirk set early in boot through i386_start_kernel() and through
x86_64_start_reservations(). This deals with the RTC quirks which
we can rely on through the hardware subarch, the ACPI check can
be dealt with separately.

For Xen things are bit more complex given that the @X86_SUBARCH_XEN
x86_hardware_subarch is shared on for Xen which uses the PV path for
both domU and dom0. Since the semantics for differentiating between
the two are Xen specific we provide a platform helper to help override
default legacy features -- x86_platform.set_legacy_features(). Use
of this helper is highly discouraged, its only purpose should be
to account for the lack of semantics available within your given
x86_hardware_subarch.

As per 0-day, this bumps the vmlinux size using i386-tinyconfig as
follows:

TOTAL   TEXT   init.text    x86_early_init_platform_quirks()
+70     +62    +62          +43

Only 8 bytes overhead total, as the main increase in size is
all removed via __init.
Suggested-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NLuis R. Rodriguez <mcgrof@kernel.org>
Reviewed-by: NJuergen Gross <jgross@suse.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: andrew.cooper3@citrix.com
Cc: andriy.shevchenko@linux.intel.com
Cc: bigeasy@linutronix.de
Cc: boris.ostrovsky@oracle.com
Cc: david.vrabel@citrix.com
Cc: ffainelli@freebox.fr
Cc: george.dunlap@citrix.com
Cc: glin@suse.com
Cc: jlee@suse.com
Cc: josh@joshtriplett.org
Cc: julien.grall@linaro.org
Cc: konrad.wilk@oracle.com
Cc: kozerkov@parallels.com
Cc: lenb@kernel.org
Cc: lguest@lists.ozlabs.org
Cc: linux-acpi@vger.kernel.org
Cc: lv.zheng@intel.com
Cc: matt@codeblueprint.co.uk
Cc: mbizon@freebox.fr
Cc: rjw@rjwysocki.net
Cc: robert.moore@intel.com
Cc: rusty@rustcorp.com.au
Cc: tiwai@suse.de
Cc: toshi.kani@hp.com
Cc: xen-devel@lists.xensource.com
Link: http://lkml.kernel.org/r/1460592286-300-5-git-send-email-mcgrof@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

The use of subarch should have no current effect on Xen
PV guests, as such this should have no current functional
effects.
Signed-off-by: NLuis R. Rodriguez <mcgrof@kernel.org>
Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: andrew.cooper3@citrix.com
Cc: andriy.shevchenko@linux.intel.com
Cc: bigeasy@linutronix.de
Cc: boris.ostrovsky@oracle.com
Cc: ffainelli@freebox.fr
Cc: george.dunlap@citrix.com
Cc: glin@suse.com
Cc: jgross@suse.com
Cc: jlee@suse.com
Cc: josh@joshtriplett.org
Cc: julien.grall@linaro.org
Cc: konrad.wilk@oracle.com
Cc: kozerkov@parallels.com
Cc: lenb@kernel.org
Cc: lguest@lists.ozlabs.org
Cc: linux-acpi@vger.kernel.org
Cc: lv.zheng@intel.com
Cc: matt@codeblueprint.co.uk
Cc: mbizon@freebox.fr
Cc: rjw@rjwysocki.net
Cc: robert.moore@intel.com
Cc: rusty@rustcorp.com.au
Cc: tiwai@suse.de
Cc: toshi.kani@hp.com
Cc: xen-devel@lists.xensource.com
Link: http://lkml.kernel.org/r/1460592286-300-3-git-send-email-mcgrof@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Although hardware_subarch has been in place since the x86 boot
protocol 2.07 it hasn't been used much. Enumerate current possible
values to avoid misuses and help with semantics later at boot
time should this be used further.

These enums should only ever be used by architecture x86 code,
and all that code should be well contained and compartamentalized,
clarify that as well.
Signed-off-by: NLuis R. Rodriguez <mcgrof@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: andrew.cooper3@citrix.com
Cc: andriy.shevchenko@linux.intel.com
Cc: bigeasy@linutronix.de
Cc: boris.ostrovsky@oracle.com
Cc: david.vrabel@citrix.com
Cc: ffainelli@freebox.fr
Cc: george.dunlap@citrix.com
Cc: glin@suse.com
Cc: jgross@suse.com
Cc: jlee@suse.com
Cc: josh@joshtriplett.org
Cc: julien.grall@linaro.org
Cc: konrad.wilk@oracle.com
Cc: kozerkov@parallels.com
Cc: lenb@kernel.org
Cc: lguest@lists.ozlabs.org
Cc: linux-acpi@vger.kernel.org
Cc: lv.zheng@intel.com
Cc: matt@codeblueprint.co.uk
Cc: mbizon@freebox.fr
Cc: rjw@rjwysocki.net
Cc: robert.moore@intel.com
Cc: rusty@rustcorp.com.au
Cc: tiwai@suse.de
Cc: toshi.kani@hp.com
Cc: xen-devel@lists.xensource.com
Link: http://lkml.kernel.org/r/1460592286-300-2-git-send-email-mcgrof@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

If KASLR is built in but not available at run-time (either due to the
current conflict with hibernation, command-line request, or e820 parsing
failures), announce the state explicitly. To support this, a new "warn"
function is created, based on the existing "error" function.
Suggested-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: H.J. Lu <hjl.tools@gmail.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1461185746-8017-6-git-send-email-keescook@chromium.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Two uses of memcpy() (screen scrolling and ELF parsing) were handling
overlapping memory areas. While there were no explicitly noticed bugs
here (yet), it is best to fix this so that the copying will always be
safe.

Instead of making a new memmove() function that might collide with other
memmove() definitions in the decompressors, this just makes the compressed
boot code's copy of memcpy() overlap-safe.
Suggested-by: NLasse Collin <lasse.collin@tukaani.org>
Reported-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: H.J. Lu <hjl.tools@gmail.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1461185746-8017-5-git-send-email-keescook@chromium.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

This rearranges the pieces needed to include the decompressor code
in misc.c. It wasn't obvious why things were there, so a comment was
added and definitions consolidated.
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: H.J. Lu <hjl.tools@gmail.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1461185746-8017-4-git-send-email-keescook@chromium.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Currently CONFIG_RANDOMIZE_BASE_MAX_OFFSET is used to limit the maximum
offset for kernel randomization. This limit doesn't need to be a CONFIG
since it is tied completely to KERNEL_IMAGE_SIZE, and will make no sense
once physical and virtual offsets are randomized separately. This patch
removes CONFIG_RANDOMIZE_BASE_MAX_OFFSET and consolidates the Kconfig
help text.

[kees: rewrote changelog, dropped KERNEL_IMAGE_SIZE_DEFAULT, rewrote help]
Signed-off-by: NBaoquan He <bhe@redhat.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: H.J. Lu <hjl.tools@gmail.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1461185746-8017-3-git-send-email-keescook@chromium.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

The comment that describes the analysis for the size of the decompressor
code only took gzip into account (there are currently 6 other decompressors
that could be used). The actual z_extract_offset calculation in code was
already handling the correct maximum size, but this documentation hadn't
been updated. This updates the documentation, fixes several typos, moves
the comment to header.S, updates references, and adds a note at the end
of the decompressor include list to remind us about updating the comment
in the future.

(Instead of moving the comment to mkpiggy.c, where the calculation
is currently happening, it is being moved to header.S because
the calculations in mkpiggy.c will be removed in favor of header.S
calculations in a following patch, and it seemed like overkill to move
the giant comment twice, especially when there's already reference to
z_extract_offset in header.S.)
Signed-off-by: NBaoquan He <bhe@redhat.com>
[ Rewrote changelog, cleaned up comment style, moved comments around. ]
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: H.J. Lu <hjl.tools@gmail.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1461185746-8017-2-git-send-email-keescook@chromium.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

The variable "random" is also the name of a libc function. It's better
coding style to avoid overloading such things, so rename it to the more
accurate "random_addr".
Suggested-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: H.J. Lu <hjl.tools@gmail.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1460997735-24785-7-git-send-email-keescook@chromium.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

The name "choose_kernel_location" isn't specific enough, and doesn't
describe the primary thing it does: choosing a random location. This
patch renames it to "choose_random_location", and clarifies the what
routines are contained in the kaslr.c source file.
Suggested-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: H.J. Lu <hjl.tools@gmail.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1460997735-24785-6-git-send-email-keescook@chromium.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

The function "decompress_kernel" now performs many more duties, so this
patch renames it to "extract_kernel" and updates callers and comments.
Additionally the file header comment for misc.c is improved to actually
describe what is contained.
Suggested-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: H.J. Lu <hjl.tools@gmail.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1460997735-24785-5-git-send-email-keescook@chromium.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

The non-compressed boot code uses the (much more obvious) name
"boot_params" for the global pointer to the x86 boot parameters. The
compressed kernel loader code, though, was using the legacy name
"real_mode". There is no need to have a different name, and changing it
improves readability.
Suggested-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: H.J. Lu <hjl.tools@gmail.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1460997735-24785-4-git-send-email-keescook@chromium.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Since the boot_params can be found using the real_mode global variable,
there is no need to pass around a pointer to it. This slightly simplifies
the choose_kernel_location function and its callers.

[kees: rewrote changelog, tracked file rename]
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: H.J. Lu <hjl.tools@gmail.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1460997735-24785-3-git-send-email-keescook@chromium.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

In order to avoid confusion over what this file provides, rename it to
kaslr.c since it is used exclusively for the kernel ASLR, not userspace
ASLR.
Suggested-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: H.J. Lu <hjl.tools@gmail.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1460997735-24785-2-git-send-email-keescook@chromium.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

This reverts commit c4004b02.

Sadly, my hope that nobody would actually use the special kernel entries
in /proc/iomem were dashed by kexec.  Which reads /proc/iomem explicitly
to find the kernel base address.  Nasty.

Anyway, that means we can't do the sane and simple thing and just remove
the entries, and we'll instead have to mask them out based on permissions.
Reported-by: NZhengyu Zhang <zhezhang@redhat.com>
Reported-by: NDave Young <dyoung@redhat.com>
Reported-by: NFreeman Zhang <freeman.zhang1992@gmail.com>
Reported-by: NEmrah Demir <ed@abdsec.com>
Reported-by: NBaoquan He <bhe@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix the FTRACE function tracer for 32- and 64-bit kernel.
The former code was horribly broken.

Reimplement most coding in assembly and utilize optimizations, e.g. put
mcount() and ftrace_stub() into one L1 cacheline.
Signed-off-by: NHelge Deller <deller@gmx.de>

When we loop over all queued machine check error records to pass them
to the registered notifiers we use llist_for_each_entry(). But the loop
calls gen_pool_free() for the entry in the body of the loop - and then
the iterator looks at node->next after the free.

Use llist_for_each_entry_safe() instead.
Signed-off-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org>
Cc: Gong Chen <gong.chen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/0205920@agluck-desk.sc.intel.com
Link: http://lkml.kernel.org/r/1459929916-12852-4-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

The website handhelds.org has been down for a long time and is
likely never coming back online.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NOlof Johansson <olof@lixom.net>

My intention was to ioremap a 4-byte register.  Coincidentally enough,
sizeof(SZ_4) equals to SZ_4, but this code is weird anyway.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NOlof Johansson <olof@lixom.net>

The ColdFire architecture specific gpio support code registers a sysfs
bus device named "gpio". This clashes with the new generic API device
added in commit 3c702e99 ("gpio: add a userspace chardev ABI for GPIOs").

The old ColdFire sysfs gpio device was never used for anything specific,
and no links or other nodes were created under it. The new API sysfs gpio
device has all the same default sysfs links (device, drivers, etc) and
they are properly populated.

Remove the old ColdFire sysfs gpio registration.
Signed-off-by: NGreg Ungerer <gerg@uclinux.org>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>

This ensures that the guest doesn't see XSAVE extensions
(e.g. xgetbv1 or xsavec) that the host lacks.

Cc: stable@vger.kernel.org
Reviewed-by: NRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

An interrupt handler that uses the fpu can kill a KVM VM, if it runs
under the following conditions:
 - the guest's xcr0 register is loaded on the cpu
 - the guest's fpu context is not loaded
 - the host is using eagerfpu

Note that the guest's xcr0 register and fpu context are not loaded as
part of the atomic world switch into "guest mode". They are loaded by
KVM while the cpu is still in "host mode".

Usage of the fpu in interrupt context is gated by irq_fpu_usable(). The
interrupt handler will look something like this:

if (irq_fpu_usable()) {
        kernel_fpu_begin();

        [... code that uses the fpu ...]

        kernel_fpu_end();
}

As long as the guest's fpu is not loaded and the host is using eager
fpu, irq_fpu_usable() returns true (interrupted_kernel_fpu_idle()
returns true). The interrupt handler proceeds to use the fpu with
the guest's xcr0 live.

kernel_fpu_begin() saves the current fpu context. If this uses
XSAVE[OPT], it may leave the xsave area in an undesirable state.
According to the SDM, during XSAVE bit i of XSTATE_BV is not modified
if bit i is 0 in xcr0. So it's possible that XSTATE_BV[i] == 1 and
xcr0[i] == 0 following an XSAVE.

kernel_fpu_end() restores the fpu context. Now if any bit i in
XSTATE_BV == 1 while xcr0[i] == 0, XRSTOR generates a #GP. The
fault is trapped and SIGSEGV is delivered to the current process.

Only pre-4.2 kernels appear to be vulnerable to this sequence of
events. Commit 653f52c3 ("kvm,x86: load guest FPU context more eagerly")
from 4.2 forces the guest's fpu to always be loaded on eagerfpu hosts.

This patch fixes the bug by keeping the host's xcr0 loaded outside
of the interrupts-disabled region where KVM switches into guest mode.

Cc: stable@vger.kernel.org
Suggested-by: NAndy Lutomirski <luto@amacapital.net>
Signed-off-by: NDavid Matlack <dmatlack@google.com>
[Move load after goto cancel_injection. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

kvm-unit-tests complained about the PFEC is not set properly, e.g,:
test pte.rw pte.d pte.nx pde.p pde.rw pde.pse user fetch: FAIL: error code 15
expected 5
Dump mapping: address: 0x123400000000
------L4: 3e95007
------L3: 3e96007
------L2: 2000083

It's caused by the reason that PFEC returned to guest is copied from the
PFEC triggered by shadow page table

This patch fixes it and makes the logic of updating errcode more clean
Signed-off-by: NXiao Guangrong <guangrong.xiao@linux.intel.com>
[Do not assume pfec.p=1. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Update the comment to reflect the changes of commit 0de79858 (parisc: Use
generic extable search and sort routines).
Signed-off-by: NHelge Deller <deller@gmx.de>

Handling exceptions from modules never worked on parisc.
It was just masked by the fact that exceptions from modules
don't happen during normal use.

When a module triggers an exception in get_user() we need to load the
main kernel dp value before accessing the exception_data structure, and
afterwards restore the original dp value of the module on exit.
Noticed-by: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NHelge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org

The kernel module testcase (lib/test_user_copy.c) exhibited a kernel
crash on parisc if the parameters for copy_from_user were reversed
("illegal reversed copy_to_user" testcase).

Fix this potential crash by checking the fault handler if the faulting
address is in the exception table.
Signed-off-by: NHelge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>

We want to avoid the kernel module loader to create function pointers
for the kernel fixup routines of get_user() and put_user(). Changing
the external reference from function type to int type fixes this.

This unbreaks exception handling for get_user() and put_user() when
called from a kernel module.
Signed-off-by: NHelge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org

Commit 0de79858 (parisc: Use generic extable search and sort routines)
changed the exception tables to use 32bit relative offsets.

This patch now adds support to the kernel module loader to handle such
R_PARISC_PCREL32 relocations for 32- and 64-bit modules.
Signed-off-by: NHelge Deller <deller@gmx.de>

It was reported that a kernel with CONFIG_ARM_PATCH_IDIV=y stopped
booting when compiled with the upcoming gcc 6.  Turns out that turning
a function address into a writable array is undefined and gcc 6 decided
it was OK to omit the store to the first word of the function while
still preserving the store to the second word.

Even though gcc 6 is now fixed to behave more coherently, it is a
mystery that gcc 4 and gcc 5 actually produce wanted code in the kernel.
And in fact the reduced test case to illustrate the issue does indeed
break with gcc < 6 as well.

In any case, let's guard the kernel against undefined compiler behavior
by hiding the nature of the array location as suggested by gcc
developers.

Reference: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70128Signed-off-by: NNicolas Pitre <nico@linaro.org>
Reported-by: NMarcin Juszkiewicz <mjuszkiewicz@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: stable@vger.kernel.org # v4.5
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Wire up the preadv2 and pwritev2 syscalls for ARM.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Some processors use the Interrupt Response Time Limit (IRTL) MSR value
to describe the maximum IRQ response time latency for deep
package C-states.  (Though others have the register, but do not use it)
Lets print it out to give insight into the cases where it is used.

IRTL begain in SNB, with PC3/PC6/PC7, and HSW added PC8/PC9/PC10.
Signed-off-by: NLen Brown <len.brown@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>

Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>