The usbfs_snoop facility can be very useful for debugging problems
involving usbfs.  However, it always prints out the entire contents of
every URB.  When dealing with large quantities of data, this can be
less than helpful.

This patch ameliorates the situation by adding a module parameter to
usbcore for controlling the maximum number of bytes to print when
snooping an URB.  This makes debugging much easier.  For backward
compatibility, the default value is set unreasonably high.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert commit 053f56de (Documentation: kernel_parameters for Intel P
state driver) as the code documented by it has been reverted already.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

In many cases of hardlockup reports, it's actually not possible to know
why it triggered, because the CPU that got stuck is usually waiting on a
resource (with IRQs disabled) in posession of some other CPU is holding.

IOW, we are often looking at the stacktrace of the victim and not the
actual offender.

Introduce sysctl / cmdline parameter that makes it possible to have
hardlockup detector perform all-CPU backtrace.
Signed-off-by: NJiri Kosina <jkosina@suse.cz>
Reviewed-by: NAaron Tomlin <atomlin@redhat.com>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Acked-by: NDon Zickus <dzickus@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

commit aa2110cb (ACPI: add boot option acpi=copy_dsdt to fix corrupt
DSDT) added copy_dsdt as an ACPI boot option, but did not add it to ACPI
format options in Documentation/kernel-parameters.txt.  Fix that.
Signed-off-by: NRami Rosen <ramirose@gmail.com>
[ rjw: Subject & changelog ]
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Add support for DT and command line based earlycon support for
lpuart and lpuart32 used on Freescale Vybrid and and QorIQ LS1021A
processors.
Signed-off-by: NStefan Agner <stefan@agner.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Added new option "no_acpi" for not using ACPI processor performance
control objects in Intel P state driver.
Signed-off-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch introduces new boot option named "efi_fake_mem".
By specifying this parameter, you can add arbitrary attribute
to specific memory range.
This is useful for debugging of Address Range Mirroring feature.

For example, if "efi_fake_mem=2G@4G:0x10000,2G@0x10a0000000:0x10000"
is specified, the original (firmware provided) EFI memmap will be
updated so that the specified memory regions have
EFI_MEMORY_MORE_RELIABLE attribute (0x10000):

 <original>
   efi: mem36: [Conventional Memory|  |  |  |  |  |   |WB|WT|WC|UC] range=[0x0000000100000000-0x00000020a0000000) (129536MB)

 <updated>
   efi: mem36: [Conventional Memory|  |MR|  |  |  |   |WB|WT|WC|UC] range=[0x0000000100000000-0x0000000180000000) (2048MB)
   efi: mem37: [Conventional Memory|  |  |  |  |  |   |WB|WT|WC|UC] range=[0x0000000180000000-0x00000010a0000000) (61952MB)
   efi: mem38: [Conventional Memory|  |MR|  |  |  |   |WB|WT|WC|UC] range=[0x00000010a0000000-0x0000001120000000) (2048MB)
   efi: mem39: [Conventional Memory|  |  |  |  |  |   |WB|WT|WC|UC] range=[0x0000001120000000-0x00000020a0000000) (63488MB)

And you will find that the following message is output:

   efi: Memory: 4096M/131455M mirrored memory
Signed-off-by: NTaku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>

The kernel NMI watchdog acts as both a hardlockup and softlockup detector.
However, the kernel parameter nmi_watchdog can only enable or disable the
hardlockup detector. Clarify that in the documentation.
Signed-off-by: NPranith Kumar <bobby.prani@gmail.com>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

This commit loosens rcutree.rcu_fanout_leaf range checks
and replaces a panic() with a fallback to compile-time values.
This fallback is accompanied by a WARN_ON(), and both occur when the
rcutree.rcu_fanout_leaf value is too small to accommodate the number of
CPUs.  For example, given the current four-level limit for the rcu_node
tree, a system with more than 16 CPUs built with CONFIG_FANOUT=2 must
have rcutree.rcu_fanout_leaf larger than 2.
Reported-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

Enable VT-d Posted-Interrtups and add a command line
parameter for it.
Signed-off-by: NFeng Wu <feng.wu@intel.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NAlex Williamson <alex.williamson@redhat.com>
Acked-by: NJoerg Roedel <joro@8bytes.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This form of the earlycon parameter was added by commit fb11ffe7
("of/fdt: add FDT serial scanning for earlycon") without documentation.
Signed-off-by: NScott Wood <scottwood@freescale.com>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

In commit 94fb9334 ("x86/crash: Allocate enough low memory when
crashkernel=high") the default value of crashkernel low memory
is changed to 256M. In this patch update it accordingly.
Signed-off-by: NBaoquan He <bhe@redhat.com>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

Allow comma separated filenames in the edid_firmware parameter.

For example:

edid_firmware=eDP-1:edid/1280x480.bin,DP-2:edid/1920x1080.bin

v2: Use strsep() to simplify parsing of comma seperated string. (Matt)
    Move initial bail before strdup. (Matt)
v3: Changed conditionals after while loop to make more readable (Jani)
    Updated kernel-parameters.txt to reflect changes (Jani)
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Signed-off-by: NBob Paauwe <bob.j.paauwe@intel.com>
[danvet: Flatten else control flow and appease checkpatch.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

dis_ucode_ldr was introduced in 65cef131 ("x86, microcode: Add a disable
chicken bit") and will disable microcode loading on x86.  This kernel
parameter is buried in the code and should be added to the Documentation.
Signed-off-by: NPrarit Bhargava <prarit@redhat.com>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

Allow advanced users to set the layoutstats timer in order to lengthen
or shorten the period between layoutstat transmissions to the server.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

64 bit pv-domains under Xen are limited to 512 GB of RAM today. The
main reason has been the 3 level p2m tree, which was replaced by the
virtual mapped linear p2m list. Parallel to the p2m list which is
being used by the kernel itself there is a 3 level mfn tree for usage
by the Xen tools and eventually for crash dump analysis. For this tree
the linear p2m list can serve as a replacement, too. As the kernel
can't know whether the tools are capable of dealing with the p2m list
instead of the mfn tree, the limit of 512 GB can't be dropped in all
cases.

This patch replaces the hard limit by a kernel parameter which tells
the kernel to obey the 512 GB limit or not. The default is selected by
a configuration parameter which specifies whether the 512 GB limit
should be active per default for domUs (domain save/restore/migration
and crash dump analysis are affected).

Memory above the domain limit is returned to the hypervisor instead of
being identity mapped, which was wrong anyway.

The kernel configuration parameter to specify the maximum size of a
domain can be deleted, as it is not relevant any more.
Signed-off-by: NJuergen Gross <jgross@suse.com>
Acked-by: NKonrad Rzeszutek Wilk <Konrad.wilk@oracle.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>

A big problem with the current i8042 debugging option is that it outputs
data going to and from the keyboard by default. As a result, many dmesg
logs uploaded by users will unintentionally contain sensitive information
such as their password, as such it's probably a good idea not to output
data coming from the keyboard unless specifically enabled by the user.
Signed-off-by: NStephen Chandler Paul <cpaul@redhat.com>
Reviewed-by: NAndreas Mohr <andim2@users.sf.net>
Reviewed-by: NBenjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>

This commit changes the documentation of the rcutorture parameters to
better match reality.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

The platform firmware on some systems expects Linux to return "5" as
the supported ACPI revision which makes it expose system configuration
information in a special way.

For example, based on what ACPI exports as the supported revision,
Dell XPS 13 (2015) configures its audio device to either work in HDA
mode or in I2S mode, where the former is supposed to be used on Linux
until the latter is fully supported (in the kernel as well as in user
space).

Since ACPI 6 mandates that _REV should return "2" if ACPI 2 or later
is supported by the OS, a subsequent change will make that happen, so
make it possible to override that on systems where "5" is expected to
be returned for Linux to work correctly one them (such as the Dell
machine mentioned above).
Original-by: NDominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The PCI based UART can be specified for earlyprintk with the 'pciserial'
parameter from the ea9e9d80. This patch adds missing information about
this parameter.
Signed-off-by: NAlexander Kuleshov <kuleshovmail@gmail.com>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

This patch defines a builtin measurement policy "tcb", similar to the
existing "ima_tcb", but with additional rules to also measure files
based on the effective uid and to measure files opened with the "read"
mode bit set (eg. read, read-write).

Changing the builtin "ima_tcb" policy could potentially break existing
users.  Instead of defining a new separate boot command line option each
time the builtin measurement policy is modified, this patch defines a
single generic boot command line option "ima_policy=" to specify the
builtin policy and deprecates the use of the builtin ima_tcb policy.

[The "ima_policy=" boot command line option is based on Roberto Sassu's
"ima: added new policy type exec" patch.]
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: NDr. Greg Wettstein <gw@idfusion.org>
Cc: stable@vger.kernel.org

Although the extended tables are theoretically a completely orthogonal
feature to PASID and anything else that *uses* the newly-available bits,
some of the early hardware has problems even when all we do is enable
them and use only the same bits that were in the old context tables.

For now, there's no motivation to support extended tables unless we're
going to use PASID support to do SVM. So just don't use them unless
PASID support is advertised too. Also add a command-line bailout just in
case later chips also have issues.

The equivalent problem for PASID support has already been fixed with the
upcoming VT-d spec update and commit bd00c606 ("iommu/vt-d: Change
PASID support to bit 40 of Extended Capability Register"), because the
problematic platforms use the old definition of the PASID-capable bit,
which is now marked as reserved and meaningless.

So with this change, we'll magically start using ECS again only when we
see the new hardware advertising "hey, we have PASID support and we
actually tested it this time" on bit 40.

The VT-d hardware architect has promised that we are not going to have
any reason to support ECS *without* PASID any time soon, and he'll make
sure he checks with us before changing that.

In the future, if hypothetical new features also use new bits in the
context tables and can be seen on implementations *without* PASID support,
we might need to add their feature bits to the ecs_enabled() macro.
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

MPX has the _potential_ to cause some issues.  Say part of your
init system tried to protect one of its components from buffer
overflows with MPX.  If there were a false positive, it's
possible that MPX could keep a system from booting.

MPX could also potentially cause performance issues since it is
present in hot paths like the unmap path.

Allow it to be disabled at boot time.
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave@sr71.net>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150607183702.2E8B77AB@viggo.jf.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Support command line parameters of the form:
earlycon=<name>,io|mmio|mmio32|mmio32be,<addr>,<options>

This commit seem to be needed even after commit:
serial: 8250: Add support for big-endian MMIO accesses
c627f2ceSigned-off-by: NNoam Camus <noamc@ezchip.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

By default, with rcutorture.nreaders equal to -1, rcutorture provisions
N-1 reader kthreads, where N is the number of CPUs.  This avoids
rcutorture-induced stalls, but also avoids heavier levels of torture.
This commit therefore allows negative values of rcutorture.nreaders
to specify larger numbers of reader kthreads, so that for example
rcutorture.nreaders=-2 provisions N kthreads and rcutorture.nreaders=-5
provisions N+3 kthreads.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: Update documentation, as suggested by Josh Triplett. ]

The purpose of this commit is to make it easier to verify that RCU's
combining tree is set up correctly, which is useful to have when making
changes in how that tree is initialized.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NPranith Kumar <bobby.prani@gmail.com>
[ paulmck: Fold fix found by Fengguang's 0-day test robot. ]

The CONFIG_RCU_FANOUT_EXACT Kconfig parameter is used primarily (and
perhaps only) by rcutorture to verify that RCU works correctly in specific
rcu_node combining-tree configurations.  It therefore does not make
much sense have this as a question to people attempting to configure
their kernels.  So this commit creates an rcutree.rcu_fanout_exact=
boot parameter that rcutorture can use, and eliminates the original
CONFIG_RCU_FANOUT_EXACT Kconfig parameter.
Reported-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NPranith Kumar <bobby.prani@gmail.com>

Grace-period scans of the rcu_node combining tree normally
proceed quite quickly, so that it is very difficult to reproduce
races against them.  This commit therefore allows grace-period
pre-initialization and cleanup to be artificially slowed down,
increasing race-reproduction probability.  A pair of pairs of new
Kconfig parameters are provided, RCU_TORTURE_TEST_SLOW_PREINIT to
enable the slowing down of propagating CPU-hotplug changes up the
combining tree along with RCU_TORTURE_TEST_SLOW_PREINIT_DELAY to
specify the delay in jiffies, and RCU_TORTURE_TEST_SLOW_CLEANUP
to enable the slowing down of the end-of-grace-period cleanup scan
along with RCU_TORTURE_TEST_SLOW_CLEANUP_DELAY to specify the delay
in jiffies.  Boot-time parameters named rcutree.gp_preinit_delay and
rcutree.gp_cleanup_delay allow these delays to be specified at boot time.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

Some init systems may wish to express the desire to have device drivers
run their probe() code asynchronously. This implements support for this
and allows userspace to request async probe as a preference through a
generic shared device driver module parameter, async_probe.

Implementation for async probe is supported through a module parameter
given that since synchronous probe has been prevalent for years some
userspace might exist which relies on the fact that the device driver
will probe synchronously and the assumption that devices it provides
will be immediately available after this.
Signed-off-by: NLuis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Description of nomce tells opposite.
Signed-off-by: NMasanari Iida <standby24x7@gmail.com>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

Signed-off-by: NDominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch adds the template 'ima-sig' among choices for the kernel
parameter 'ima_template'.
Signed-off-by: NRoberto Sassu <rsassu@suse.de>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

No change to default behavior.

Replace the hard-coded mdelay(10) in cpu_up() with a variable
udelay, that is set to a defined default -- rather than a magic
number.

Add a boot-time override, "cpu_init_udelay=N"
Signed-off-by: NLen Brown <len.brown@intel.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jan H. Schönherr <jschoenh@amazon.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/2fe8e6c798e8def271122f62df9bbf58dc283e2a.1431379433.git.len.brown@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

We have started seeing SSD firmware updates introduce support for queued
TRIM. Sadly, in most cases this support is completely untested and can
lead to either errors or data corruption.

Add two libata force flags that can be used to either enable or disable
queued TRIM support.
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NTejun Heo <tj@kernel.org>

The usb-storage driver sets max_sectors = 240 in its scsi-host template,
for uas we do not want to do that for all devices, but testing has shown
that some devices need it.

This commit adds a US_FL_MAX_SECTORS_240 flag for such devices, and
implements support for it in uas.c, while at it it also adds support
for US_FL_MAX_SECTORS_64 to uas.c.

Cc: stable@vger.kernel.org # 3.16
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since arm64/arm support memtest command line option update the "memtest"
entry.
Signed-off-by: NVladimir Murzin <vladimir.murzin@arm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add ioremap_pud_enabled() and ioremap_pmd_enabled(), which return 1 when
I/O mappings with pud/pmd are enabled on the kernel.

ioremap_huge_init() calls arch_ioremap_pud_supported() and
arch_ioremap_pmd_supported() to initialize the capabilities at boot-time.

A new kernel option "nohugeiomap" is also added, so that user can disable
the huge I/O map capabilities when necessary.
Signed-off-by: NToshi Kani <toshi.kani@hp.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Robert Elliott <Elliott@hp.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With the current user interface of the watchdog mechanism it is only
possible to disable or enable both lockup detectors at the same time.
This series introduces new kernel parameters and changes the semantics of
some existing kernel parameters, so that the hard lockup detector and the
soft lockup detector can be disabled or enabled individually.  With this
series applied, the user interface is as follows.

- parameters in /proc/sys/kernel

  . soft_watchdog
    This is a new parameter to control and examine the run state of
    the soft lockup detector.

  . nmi_watchdog
    The semantics of this parameter have changed. It can now be used
    to control and examine the run state of the hard lockup detector.

  . watchdog
    This parameter is still available to control the run state of both
    lockup detectors at the same time. If this parameter is examined,
    it shows the logical OR of soft_watchdog and nmi_watchdog.

  . watchdog_thresh
    The semantics of this parameter are not affected by the patch.

- kernel command line parameters

  . nosoftlockup
    The semantics of this parameter have changed. It can now be used
    to disable the soft lockup detector at boot time.

  . nmi_watchdog=0 or nmi_watchdog=1
    Disable or enable the hard lockup detector at boot time. The patch
    introduces '=1' as a new option.

  . nowatchdog
    The semantics of this parameter are not affected by the patch. It
    is still available to disable both lockup detectors at boot time.

Also, remove the proc_dowatchdog() function which is no longer needed.

[dzickus@redhat.com: wrote changelog]
[dzickus@redhat.com: update documentation for kernel params and sysctl]
Signed-off-by: NUlrich Obergfell <uobergfe@redhat.com>
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Document the expected behavior of kernel command lines of the forms:
    console=uart[8250],io|mmio|mmio32,<addr>[,options]
    console=uart[8250],<addr>[,options]
and
    earlycon=uart[8250],io|mmio|mmio32,<addr>[,options]
    earlycon=uart[8250],<addr>[,options]
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The MIPS port has supported this option since forever, long before SH
was even in plans.
Signed-off-by: NMaciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9665/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>