Commit ac1bea85 (Make cond_resched() report RCU quiescent states)
fixed a problem where a CPU looping in the kernel with but one runnable
task would give RCU CPU stall warnings, even if the in-kernel loop
contained cond_resched() calls.  Unfortunately, in so doing, it introduced
performance regressions in Anton Blanchard's will-it-scale "open1" test.
The problem appears to be not so much the increased cond_resched() path
length as an increase in the rate at which grace periods complete, which
increased per-update grace-period overhead.

This commit takes a different approach to fixing this bug, mainly by
moving the RCU-visible quiescent state from cond_resched() to
rcu_note_context_switch(), and by further reducing the check to a
simple non-zero test of a single per-CPU variable.  However, this
approach requires that the force-quiescent-state processing send
resched IPIs to the offending CPUs.  These will be sent only once
the grace period has reached an age specified by the boot/sysfs
parameter rcutree.jiffies_till_sched_qs, or once the grace period
reaches an age halfway to the point at which RCU CPU stall warnings
will be emitted, whichever comes first.
Reported-by: NDave Hansen <dave.hansen@intel.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Lameter <cl@gentwo.org>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
[ paulmck: Made rcu_momentary_dyntick_idle() as suggested by the
  ktest build robot.  Also fixed smp_mb() comment as noted by
  Oleg Nesterov. ]

Merge with e552592e (Reduce overhead of cond_resched() checks for RCU)
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

Add a "crash_kexec_post_notifiers" boot option to run kdump after
running panic_notifiers and dump kmsg.  This can help rare situations
where kdump fails because of unstable crashed kernel or hardware failure
(memory corruption on critical data/code), or the 2nd kernel is already
broken by the 1st kernel (it's a broken behavior, but who can guarantee
that the "crashed" kernel works correctly?).

Usage: add "crash_kexec_post_notifiers" to kernel boot option.

Note that this actually increases risks of the failure of kdump.  This
option should be set only if you worry about the rare case of kdump
failure rather than increasing the chance of success.
Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: NMotohiro Kosaki <Motohiro.Kosaki@us.fujitsu.com>
Acked-by: NVivek Goyal <vgoyal@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Cc: Satoru MORIYA <satoru.moriya.br@hitachi.com>
Cc: Tomoki Sekiyama <tomoki.sekiyama@hds.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When a module is built into the kernel the module_init() function
becomes an initcall.  Sometimes debugging through dynamic debug can
help, however, debugging built in kernel modules is typically done by
changing the .config, recompiling, and booting the new kernel in an
effort to determine exactly which module caused a problem.

This patchset can be useful stand-alone or combined with initcall_debug.
There are cases where some initcalls can hang the machine before the
console can be flushed, which can make initcall_debug output inaccurate.
Having the ability to skip initcalls can help further debugging of these
scenarios.

Usage: initcall_blacklist=<list of comma separated initcalls>

ex) added "initcall_blacklist=sgi_uv_sysfs_init" as a kernel parameter and
the log contains:

	blacklisting initcall sgi_uv_sysfs_init
	...
	...
	initcall sgi_uv_sysfs_init blacklisted

ex) added "initcall_blacklist=foo_bar,sgi_uv_sysfs_init" as a kernel parameter
and the log contains:

	blacklisting initcall foo_bar
	blacklisting initcall sgi_uv_sysfs_init
	...
	...
	initcall sgi_uv_sysfs_init blacklisted

[akpm@linux-foundation.org: tweak printk text]
Signed-off-by: NPrarit Bhargava <prarit@redhat.com>
Cc: Richard Weinberger <richard.weinberger@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Josh Boyer <jwboyer@fedoraproject.org>
Cc: Rob Landley <rob@landley.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently, "cma=" kernel parameter is used to specify the size of CMA,
but we can't specify where it is located.  We want to locate CMA below
4GB for devices only supporting 32-bit addressing on 64-bit systems
without iommu.

This enables to specify the placement of CMA by extending "cma=" kernel
parameter.

Examples:
 1. locate 64MB CMA below 4GB by "cma=64M@0-4G"
 2. locate 64MB CMA exact at 512MB by "cma=64M@512M"

Note that the DMA contiguous memory allocator on x86 assumes that
page_address() works for the pages to allocate.  So this change requires
to limit end address of contiguous memory area upto max_pfn_mapped to
prevent from locating it on highmem area by the argument of
dma_contiguous_reserve().
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The following warning message is triggered:
 WARNING: CPU: 0 PID: 0 at mm/early_ioremap.c:136 __early_ioremap+0x11f/0x1f2()
 Modules linked in:
 CPU: 0 PID: 0 Comm: swapper Not tainted 3.15.0-rc1-00017-g86dfc6f3-dirty #298
 Hardware name: Intel Corporation S2600CP/S2600CP, BIOS SE5C600.86B.99.99.x036.091920111209 09/19/2011
  0000000000000009 ffffffff81b75c40 ffffffff817c627b 0000000000000000
  ffffffff81b75c78 ffffffff81067b5d 000000000000007b 8000000000000563
  00000000b96b20dc 0000000000000001 ffffffffff300e0c ffffffff81b75c88
 Call Trace:
  [<ffffffff817c627b>] dump_stack+0x45/0x56
  [<ffffffff81067b5d>] warn_slowpath_common+0x7d/0xa0
  [<ffffffff81067c3a>] warn_slowpath_null+0x1a/0x20
  [<ffffffff81d4b9d5>] __early_ioremap+0x11f/0x1f2
  [<ffffffff81d4bc5b>] early_ioremap+0x13/0x15
  [<ffffffff81d2b8f3>] __acpi_map_table+0x13/0x18
  [<ffffffff817b8d1a>] acpi_os_map_memory+0x26/0x14e
  [<ffffffff813ff018>] acpi_tb_acquire_table+0x42/0x70
  [<ffffffff813ff086>] acpi_tb_validate_table+0x27/0x37
  [<ffffffff813ff0e5>] acpi_tb_verify_table+0x22/0xd8
  [<ffffffff813ff6a8>] acpi_tb_install_non_fixed_table+0x60/0x1c9
  [<ffffffff81d61024>] acpi_tb_parse_root_table+0x218/0x26a
  [<ffffffff81d1b120>] ? early_idt_handlers+0x120/0x120
  [<ffffffff81d610cd>] acpi_initialize_tables+0x57/0x59
  [<ffffffff81d5f25d>] acpi_table_init+0x1b/0x99
  [<ffffffff81d2bca0>] acpi_boot_table_init+0x1e/0x85
  [<ffffffff81d23043>] setup_arch+0x99d/0xcc6
  [<ffffffff81d1b120>] ? early_idt_handlers+0x120/0x120
  [<ffffffff81d1bbbe>] start_kernel+0x8b/0x415
  [<ffffffff81d1b120>] ? early_idt_handlers+0x120/0x120
  [<ffffffff81d1b5ee>] x86_64_start_reservations+0x2a/0x2c
  [<ffffffff81d1b72e>] x86_64_start_kernel+0x13e/0x14d
 ---[ end trace 11ae599a1898f4e7 ]---
when installing the following table during early stage:
 ACPI: SSDT 0x00000000B9638018 07A0C4 (v02 INTEL  S2600CP  00004000 INTL 20100331)
The regression is caused by the size limitation of the x86 early IO mapping.

The root cause is:
 1. ACPICA doesn't split IO memory mapping and table mapping;
 2. Linux x86 OSL implements acpi_os_map_memory() using a size limited fix-map
    mechanism during early boot stage, which is more suitable for only IO
    mappings.

This patch fixes this issue by utilizing acpi_gbl_verify_table_checksum to
disable the table mapping during early stage and enabling it again for the
late stage. In this way, the normal code path is not affected. Then after
the code related to the root cause is cleaned up, the early checksum
verification can be easily re-enabled.

A new boot parameter - acpi_force_table_verification is introduced for
the platforms that require the checksum verification to stop loading bad
tables.

This fix also covers the checksum verification for the table overrides. Now
large tables can also be overridden using the initrd override mechanism.
Signed-off-by: NLv Zheng <lv.zheng@intel.com>
Reported-and-tested-by: NYuanhan Liu <yuanhan.liu@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Make the boot console available to more m68k platforms by leveraging
the head.S debug console.

The boot console is enabled by the "earlyprintk" command line argument
which is how most other architectures do this.

This is a change of behaviour for the Mac but does not negatively impact
the common use-case which is not debugging.

This is also a change of behaviour for other platforms because it means
the serial port stays quiet when CONFIG_EARLY_PRINTK is not enabled. This
is also an improvement for the common use-case.
Signed-off-by: NFinn Thain <fthain@telegraphics.com.au>
Tested-by: NStephen N Chivers <schivers@csc.com.au>
[Geert: CONSOLE_DEBUG should depend on CONFIG_FONT_SUPPORT]
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>

On some systems the platform doesn't support neither
PM_SUSPEND_MEM nor PM_SUSPEND_STANDBY, so PM_SUSPEND_FREEZE is the
only available system sleep state.  However, some user space frameworks
only use the "mem" and (sometimes) "standby" sleep state labels, so
the users of those systems need to modify user space in order to be
able to use system suspend at all and that is not always possible.

For this reason, add a new kernel command line argument,
relative_sleep_states, allowing the users of those systems to change
the way in which the kernel assigns labels to system sleep states.
Namely, for relative_sleep_states=1, the "mem", "standby" and "freeze"
labels will enumerate the available system sleem states from the
deepest to the shallowest, respectively, so that "mem" is always
present in /sys/power/state and the other state strings may or may
not be presend depending on what is supported by the platform.

Update system sleep states documentation to reflect this change.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

1) __setup() is messy, prefer module_param and core_param.
2) Document --
3) Document modprobe scraping /proc/cmdline.
4) Document handing of leftover parameters to init.
5) Document use of quotes to protect whitespace.
Reported-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

One can logically expect that when the user has specified "nordrand",
the user doesn't want any use of the CPU random number generator,
neither RDRAND nor RDSEED, so disable both.
Reported-by: NStephan Mueller <smueller@chronox.de>
Cc: Theodore Ts'o <tytso@mit.edu>
Link: http://lkml.kernel.org/r/21542339.0lFnPSyGRS@myon.chronox.deSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>

acpi-video is unique in that it not only generates brightness up/down
keypresses, but also (sometimes) actively changes the brightness itself.

This presents an inconsistent kernel interface to userspace, basically there
are 2 different scenarios, depending on the laptop model:

 1) On some laptops a brightness up/down keypress means: show a brightness osd
 with the current brightness, iow it is a brightness has changed notification.

 2) Where as on (a lot of) other laptops it means a brightness up/down key was
 pressed, deal with it.

Most of the desktop environments interpret any press as in scenario 2, and
change the brightness up / down as a response to the key events, causing it
to be changed twice, once by acpi-video and once by the DE.

With the new default for video.use_native_backlight we will be moving even
more laptops over to behaving as in scenario 2. Making the remaining laptops
even more of a weird exception. Also note that it is hard to detect scenario
1 properly in userspace, and AFAIK none of the DE-s deals with it.

Therefor this commit changes the default of brightness_switch_enabled to 0
making its behavior consistent with all the other backlight drivers.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Reviewed-by: NAaron Lu <aaron.lu@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Add earlycon support for the arm/arm64 semihosting debug serial
interface. This allows enabling a debug console when early_params are
processed. This is based on the arm64 earlyprintk smh support and is
intended to replace it.
Signed-off-by: NRob Herring <robh@kernel.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add earlycon support for the pl011 serial port. This allows enabling
the pl011 for console when early_params are processed. This is based
on the arm64 earlyprintk support and is intended to replace it.
Signed-off-by: NRob Herring <robh@kernel.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

It is reported that when acpi_gbl_disable_ssdt_table_load is specified, user
still can see it installed into /sys/firmware/acpi/tables on Linux boxes.
This is because the option only stops table "loading", but doesn't stop
table "installing", thus it is still in the acpi_gbl_root_table_list. With
previous cleanups, it is possible to prevent SSDT installations to make
it not such confusing.  The global variable is also renamed.  Lv Zheng.
Signed-off-by: NLv Zheng <lv.zheng@intel.com>
[rjw: Subject]
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

These serial drivers were removed in kernel v3.1, so we can drop their
documentation files and references to their magic numbers and
parameters.

There are still references to these old drivers in
Documentation/devices.txt but I'm afraid they can't be removed.
Signed-off-by: NJean Delvare <jdelvare@suse.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Rob Landley <rob@landley.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add description of early_ioremap_debug kernel parameter.
Signed-off-by: NMark Salter <msalter@redhat.com>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Keep all power-domains already enabled by bootloader on, even if no
driver has claimed them. This is useful for debug and development, but
should not be needed on a platform with proper driver support.
Signed-off-by: NTushar Behera <tushar.behera@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The previous commit "ACPICA: Add auto-serialization support for ill-behaved
control methods" introduced the auto-serialization facility as a workaround
that can be enabled by "acpi_auto_serialize":

This feature marks control methods that create named objects as "serialized"
to avoid unwanted AE_ALREADY_EXISTS control method evaluation failures.

Enable method auto-serialization as the default kernel behavior.  The new kernel
parameter is also changed from "acpi_auto_serialize" to "acpi_no_auto_serialize"
to reflect the default behavior.

References: https://bugzilla.kernel.org/show_bug.cgi?id=52191
References: http://www.spinics.net/lists/linux-acpi/msg49496.htmlSigned-off-by: NLv Zheng <lv.zheng@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This change adds support to automatically mark a control method as
"serialized" if the method creates any named objects. This will
positively prevent the method from being entered by more than one
thread and thus preventing a possible abort when an attempt is
made to create an object twice.

Implemented by parsing all non-serialize control methods at table
load time.

This feature is disabled by default and this patch also adds a new
Linux kernel parameter "acpi_auto_serialize" to allow this feature
to be turned on for a specific boot.

References: https://bugzilla.kernel.org/show_bug.cgi?id=52191Signed-off-by: NBob Moore <robert.moore@intel.com>
Signed-off-by: NLv Zheng <lv.zheng@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

According to the reports, the "acpi_serialize" mechanism is broken as:

 A. The parallel method calls can still happen when the interpreter lock is
    released under the following conditions:
    1. External callbacks are invoked, for example, by the region handlers,
       the exception handlers, etc.;
    2. Module level execution is performed when Load/LoadTable opcodes are
       executed, and
    3. The _REG control methods are invoked to complete the region
       registrations.
 B. For the following situations, the interpreter lock need to be released
    even for a serialized method while currently, the lock-releasing
    operation is marked as a no-op by
    acpi_ex_relinquish/reacquire_interpreter() when this mechanism is
    enabled:
    1. Wait opcode is executed,
    2. Acquire opcode is executed, and
    3. Sleep opcode is executed.

This patch removes this mechanism and the internal
acpi_ex_relinquish/reacquire_interpreter() APIs.  Lv Zheng.

References: https://bugzilla.kernel.org/show_bug.cgi?id=52191Signed-off-by: NLv Zheng <lv.zheng@intel.com>
Signed-off-by: NBob Moore <robert.moore@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Many Pentium M systems disable PAE but may have a functionally usable PAE
implementation. This adds the "forcepae" parameter which bypasses the boot
check for PAE, and sets the CPU as being PAE capable. Using this parameter
will taint the kernel with TAINT_CPU_OUT_OF_SPEC.
Signed-off-by: NChris Bainbridge <chris.bainbridge@gmail.com>
Link: http://lkml.kernel.org/r/20140307114040.GA4997@localhostAcked-by: NBorislav Petkov <bp@suse.de>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

The compat vDSO is a complicated hack that's needed to maintain
compatibility with a small range of glibc versions.

This removes it and replaces it with a much simpler hack: a config
option to disable the 32-bit vDSO by default.

This also changes the default value of CONFIG_COMPAT_VDSO to n --
users configuring kernels from scratch almost certainly want that
choice.
Signed-off-by: NAndy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/4bb4690899106eb11430b1186d5cc66ca9d1660c.1394751608.git.luto@amacapital.netSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Randomize the load address of modules in the kernel to make kASLR
effective for modules.  Modules can only be loaded within a particular
range of virtual address space.  This patch adds 10 bits of entropy to
the load address by adding 1-1024 * PAGE_SIZE to the beginning range
where modules are loaded.

The single base offset was chosen because randomizing each module
load ends up wasting/fragmenting memory too much. Prior approaches to
minimizing fragmentation while doing randomization tend to result in
worse entropy than just doing a single base address offset.

Example kASLR boot without this change, with a single module loaded:
---[ Modules ]---
0xffffffffc0000000-0xffffffffc0001000           4K     ro     GLB x  pte
0xffffffffc0001000-0xffffffffc0002000           4K     ro     GLB NX pte
0xffffffffc0002000-0xffffffffc0004000           8K     RW     GLB NX pte
0xffffffffc0004000-0xffffffffc0200000        2032K                   pte
0xffffffffc0200000-0xffffffffff000000        1006M                   pmd
---[ End Modules ]---

Example kASLR boot after this change, same module loaded:
---[ Modules ]---
0xffffffffc0000000-0xffffffffc0200000           2M                   pmd
0xffffffffc0200000-0xffffffffc03bf000        1788K                   pte
0xffffffffc03bf000-0xffffffffc03c0000           4K     ro     GLB x  pte
0xffffffffc03c0000-0xffffffffc03c1000           4K     ro     GLB NX pte
0xffffffffc03c1000-0xffffffffc03c3000           8K     RW     GLB NX pte
0xffffffffc03c3000-0xffffffffc0400000         244K                   pte
0xffffffffc0400000-0xffffffffff000000        1004M                   pmd
---[ End Modules ]---
Signed-off-by: NAndy Honig <ahonig@google.com>
Link: http://lkml.kernel.org/r/20140226005916.GA27083@www.outflux.netSigned-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Sometimes, there might be bugs caused by unexpected AML which is compliant
to the Windows but not compliant to the Linux implementation.

There is a predefined validation mechanism implemented in ACPICA to repair
the unexpected AML evaluation results that are caused by the unexpected
AMLs.  For example, BIOS may return misorder _CST result and the repair
mechanism can make an ascending order on the returned _CST package object
based on the C-state type.
This mechanism is quite useful to implement an AML interpreter with better
compliance with the real world where Windows is the de-facto standard and
BIOS codes are only tested on one platform thus not compliant to the
ACPI specification.

But if a compliance issue hasn't been figured out yet, it will be
difficult for developers to identify if the unexpected evaluation result
is caused by this mechanism or by the AML interpreter.
For example, _PR0 is expected to be a control method, but BIOS may use
Package: "Name(_PR0, Package(1) {P1PR})".
This boot option can disable the predefined validation mechanism so that
developers can make sure the root cause comes from the parser/executer.

This patch adds a new kernel parameter to disable this feature.

A build test has been made on a Dell Inspiron mini 1100 (i386 z530)
machine when this patch is applied and the corresponding boot test is
performed w/ or w/o the new kernel parameter specified.

References: https://bugzilla.kernel.org/show_bug.cgi?id=67901Tested-by: NFabian Wehning <fabian.wehning@googlemail.com>
Signed-off-by: NLv Zheng <lv.zheng@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Clean up descriptions of memmap= boot options.

Add periods (full stops), drop commas, change "used" to "reserved" or
"marked".
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Andiry Xu <andiry.xu@gmail.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The usage of the 'gpt' kernel parameter is twofold: (i) skip any mbr
integrity checks and (ii) enable the backup GPT header to be used in
situations where the primary one is corrupted.  This last "feature" is not
obvious and needs to be properly documented in the kernel-parameters
document.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=63591Signed-off-by: NDavidlohr Bueso <davidlohr@hp.com>
Cc: Matt Domsch <Matt_Domsch@dell.com>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: "Chandramouleeswaran,Aswin" <aswin@hp.com>
Cc: Chris Murphy <bugzilla@colorremedies.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add "kmemcheck=xx" to Documentation/kernel-parameters.txt.
Signed-off-by: NXishi Qiu <qiuxishi@huawei.com>
Cc: Vegard Nossum <vegardno@ifi.uio.no>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Rob Landley <rob@landley.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fixup caught by checkpatch.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

When booting a kexec/kdump kernel on a system that has specific memory
hotplug regions the boot will fail with warnings like:

 swapper/0: page allocation failure: order:9, mode:0x84d0
 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.10.0-65.el7.x86_64 #1
 Hardware name: QCI QSSC-S4R/QSSC-S4R, BIOS QSSC-S4R.QCI.01.00.S013.032920111005 03/29/2011
  0000000000000000 ffff8800341bd8c8 ffffffff815bcc67 ffff8800341bd950
  ffffffff8113b1a0 ffff880036339b00 0000000000000009 00000000000084d0
  ffff8800341bd950 ffffffff815b87ee 0000000000000000 0000000000000200
 Call Trace:
  [<ffffffff815bcc67>] dump_stack+0x19/0x1b
  [<ffffffff8113b1a0>] warn_alloc_failed+0xf0/0x160
  [<ffffffff815b87ee>] ?  __alloc_pages_direct_compact+0xac/0x196
  [<ffffffff8113f14f>] __alloc_pages_nodemask+0x7ff/0xa00
  [<ffffffff815b417c>] vmemmap_alloc_block+0x62/0xba
  [<ffffffff815b41e9>] vmemmap_alloc_block_buf+0x15/0x3b
  [<ffffffff815b1ff6>] vmemmap_populate+0xb4/0x21b
  [<ffffffff815b461d>] sparse_mem_map_populate+0x27/0x35
  [<ffffffff815b400f>] sparse_add_one_section+0x7a/0x185
  [<ffffffff815a1e9f>] __add_pages+0xaf/0x240
  [<ffffffff81047359>] arch_add_memory+0x59/0xd0
  [<ffffffff815a21d9>] add_memory+0xb9/0x1b0
  [<ffffffff81333b9c>] acpi_memory_device_add+0x18d/0x26d
  [<ffffffff81309a01>] acpi_bus_device_attach+0x7d/0xcd
  [<ffffffff8132379d>] acpi_ns_walk_namespace+0xc8/0x17f
  [<ffffffff81309984>] ? acpi_bus_type_and_status+0x90/0x90
  [<ffffffff81309984>] ? acpi_bus_type_and_status+0x90/0x90
  [<ffffffff81323c8c>] acpi_walk_namespace+0x95/0xc5
  [<ffffffff8130a6d6>] acpi_bus_scan+0x8b/0x9d
  [<ffffffff81a2019a>] acpi_scan_init+0x63/0x160
  [<ffffffff81a1ffb5>] acpi_init+0x25d/0x2a6
  [<ffffffff81a1fd58>] ? acpi_sleep_proc_init+0x2a/0x2a
  [<ffffffff810020e2>] do_one_initcall+0xe2/0x190
  [<ffffffff819e20c4>] kernel_init_freeable+0x17c/0x207
  [<ffffffff819e18d0>] ? do_early_param+0x88/0x88
  [<ffffffff8159fea0>] ? rest_init+0x80/0x80
  [<ffffffff8159feae>] kernel_init+0xe/0x180
  [<ffffffff815cca2c>] ret_from_fork+0x7c/0xb0
  [<ffffffff8159fea0>] ? rest_init+0x80/0x80
 Mem-Info:
 Node 0 DMA per-cpu:
 CPU    0: hi:    0, btch:   1 usd:   0
 Node 0 DMA32 per-cpu:
 CPU    0: hi:   42, btch:   7 usd:   0
 active_anon:0 inactive_anon:0 isolated_anon:0
  active_file:0 inactive_file:0 isolated_file:0
  unevictable:0 dirty:0 writeback:0 unstable:0
  free:872 slab_reclaimable:13 slab_unreclaimable:1880
  mapped:0 shmem:0 pagetables:0 bounce:0
  free_cma:0

because the system has run out of memory at boot time.  This occurs
because of the following sequence in the boot:

Main kernel boots and sets E820 map.  The second kernel is booted with a
map generated by the kdump service using memmap= and memmap=exactmap.
These parameters are added to the kernel parameters of the kexec/kdump
kernel.   The kexec/kdump kernel has limited memory resources so as not
to severely impact the main kernel.

The system then panics and the kdump/kexec kernel boots (which is a
completely new kernel boot).  During this boot ACPI is initialized and the
kernel (as can be seen above) traverses the ACPI namespace and finds an
entry for a memory device to be hotadded.

ie)

  [<ffffffff815a1e9f>] __add_pages+0xaf/0x240
  [<ffffffff81047359>] arch_add_memory+0x59/0xd0
  [<ffffffff815a21d9>] add_memory+0xb9/0x1b0
  [<ffffffff81333b9c>] acpi_memory_device_add+0x18d/0x26d
  [<ffffffff81309a01>] acpi_bus_device_attach+0x7d/0xcd
  [<ffffffff8132379d>] acpi_ns_walk_namespace+0xc8/0x17f
  [<ffffffff81309984>] ? acpi_bus_type_and_status+0x90/0x90
  [<ffffffff81309984>] ? acpi_bus_type_and_status+0x90/0x90
  [<ffffffff81323c8c>] acpi_walk_namespace+0x95/0xc5
  [<ffffffff8130a6d6>] acpi_bus_scan+0x8b/0x9d
  [<ffffffff81a2019a>] acpi_scan_init+0x63/0x160
  [<ffffffff81a1ffb5>] acpi_init+0x25d/0x2a6

At this point the kernel adds page table information and the the kexec/kdump
kernel runs out of memory.

This can also be reproduced by using the memmap=exactmap and mem=X
parameters on the main kernel and booting.

This patchset resolves the problem by adding a kernel parameter,
acpi_no_memhotplug, to disable ACPI memory hotplug.
Signed-off-by: NPrarit Bhargava <prarit@redhat.com>
Acked-by: NVivek Goyal <vgoyal@redhat.com>
Acked-by: NToshi Kani <toshi.kani@hp.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Add disable_cpu_apicid kernel parameter. To use this kernel parameter,
specify an initial APIC ID of the corresponding CPU you want to
disable.

This is mostly used for the kdump 2nd kernel to disable BSP to wake up
multiple CPUs without causing system reset or hang due to sending INIT
from AP to BSP.

Kdump users first figure out initial APIC ID of the BSP, CPU0 in the
1st kernel, for example from /proc/cpuinfo and then set up this kernel
parameter for the 2nd kernel using the obtained APIC ID.

However, doing this procedure at each boot time manually is awkward,
which should be automatically done by user-land service scripts, for
example, kexec-tools on fedora/RHEL distributions.

This design is more flexible than disabling BSP in kernel boot time
automatically in that in kernel boot time we have no choice but
referring to ACPI/MP table to obtain initial APIC ID for BSP, meaning
that the method is not applicable to the systems without such BIOS
tables.

One assumption behind this design is that users get initial APIC ID of
the BSP in still healthy state and so BSP is uniquely kept in
CPU0. Thus, through the kernel parameter, only one initial APIC ID can
be specified.

In a comparison with disabled_cpu_apicid, we use read_apic_id(), not
boot_cpu_physical_apicid, because on some platforms, the variable is
modified to the apicid reported as BSP through MP table and this
function is executed with the temporarily modified
boot_cpu_physical_apicid. As a result, disabled_cpu_apicid kernel
parameter doesn't work well for apicids of APs.

Fixing the wrong handling of boot_cpu_physical_apicid requires some
reviews and tests beyond some platforms and it could take some
time. The fix here is a kind of workaround to focus on the main topic
of this patch.
Signed-off-by: NHATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Link: http://lkml.kernel.org/r/20140115064458.1545.38775.stgit@localhost6.localdomain6Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Further documentation of the 3 possible kernel value of the audit
command line option.
Signed-off-by: NEric Paris <eparis@redhat.com>

The default audit_backlog_limit is 64.  This was a reasonable limit at one time.

systemd causes so much audit queue activity on startup that auditd doesn't
start before the backlog queue has already overflowed by more than a factor of
2.  On a system with audit= not set on the kernel command line, this isn't an
issue since that history isn't kept for auditd when it is available.  On a
system with audit=1 set on the kernel command line, kaudit tries to keep that
history until auditd is able to drain the queue.

This default can be changed by the "-b" option in audit.rules once the system
has booted, but won't help with lost messages on boot.

One way to solve this would be to increase the default backlog queue size to
avoid losing any messages before auditd is able to consume them.  This would
be overkill to the embedded community and insufficient for some servers.

Another way to solve it might be to add a kconfig option to set the default
based on the system type.  An embedded system would get the current (or
smaller) default, while Workstations might get more than now and servers might
get more.

None of these solutions helps if a system's compiled default is too small to
see the lost messages without compiling a new kernel.

This patch adds a kernel set-up parameter (audit already has one to
enable/disable it) "audit_backlog_limit=<n>" that overrides the default to
allow the system administrator to set the backlog limit.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

Add the "audit=" kernel start-up parameter to Documentation/kernel-parameters.txt.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

Documentation/kernel-parameters.txt doesn't contain up-to-date
documentation regarding swiotlb= parameter. Update it.
Signed-off-by: NJiri Kosina <jkosina@suse.cz>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

A user on StackExchange had a failing SSD that's soldered directly
onto the motherboard of his system. The BIOS does not give any option
to disable it at all, so he can't just hide it from the OS via the
BIOS.

The old IDE layer had hdX=noprobe override for situations like this,
but that was never ported to the libata layer.

This patch implements a disable flag for libata.force.

Example use:

 libata.force=2.0:disable

[v2 of the patch, removed the nodisable flag per Tejun Heo]
Signed-off-by: NRobin H. Johnson <robbat2@gentoo.org>
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
Link: http://unix.stackexchange.com/questions/102648/how-to-tell-linux-kernel-3-0-to-completely-ignore-a-failing-disk
Link: http://askubuntu.com/questions/352836/how-can-i-tell-linux-kernel-to-completely-ignore-a-disk-as-if-it-was-not-even-co
Link: http://superuser.com/questions/599333/how-to-disable-kernel-probing-for-drive

This new parameter is used to control how to report HW error reporting,
especially for newer Intel platform, like Ivybridge-EX, which contains
an enhanced error decoding functionality in the firmware, i.e. eMCA.
Signed-off-by: NChen, Gong <gong.chen@linux.intel.com>
Acked-by: NTony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/1386310630-12529-2-git-send-email-gong.chen@linux.intel.com
[ Boris: massage commit message. ]
Signed-off-by: NBorislav Petkov <bp@suse.de>

Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

In doc, it said that 'Currently supported controllers - "memory"',
but actually we can use cgroup_disable=cpu,cpuset and all other
controllers, so this is confusing for cgroup users without much
cgroup knowledge. We need to make it clear.

[some comments copied from Paul Menage's original patch 8bab8dde]
Signed-off-by: NQiang Huang <h.huangqiang@huawei.com>
Acked-by: NRob Landley <rob@landley.net>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

The CONFIG_HPET_MMAP Kconfig option exposes the memory map of the HPET
registers to userspace.  The Kconfig help points out that in some cases
this can be a security risk as some systems may erroneously configure the
map such that additional data is exposed to userspace.

This is a problem for distributions -- some users want the MMAP
functionality but it comes with a significant security risk.  In an effort
to mitigate this risk, and due to the low number of users of the MMAP
functionality, I've introduced a kernel parameter, hpet_mmap_enable, that
is required in order to actually have the HPET MMAP exposed.
Signed-off-by: NPrarit Bhargava <prarit@redhat.com>
Acked-by: NMatt Wilson <msw@amazon.com>
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The hot-Pluggable field in SRAT specifies which memory is hotpluggable.
As we mentioned before, if hotpluggable memory is used by the kernel, it
cannot be hot-removed.  So memory hotplug users may want to set all
hotpluggable memory in ZONE_MOVABLE so that the kernel won't use it.

Memory hotplug users may also set a node as movable node, which has
ZONE_MOVABLE only, so that the whole node can be hot-removed.

But the kernel cannot use memory in ZONE_MOVABLE.  By doing this, the
kernel cannot use memory in movable nodes.  This will cause NUMA
performance down.  And other users may be unhappy.

So we need a way to allow users to enable and disable this functionality.
In this patch, we introduce movable_node boot option to allow users to
choose to not to consume hotpluggable memory at early boot time and later
we can set it as ZONE_MOVABLE.

To achieve this, the movable_node boot option will control the memblock
allocation direction.  That said, after memblock is ready, before SRAT is
parsed, we should allocate memory near the kernel image as we explained in
the previous patches.  So if movable_node boot option is set, the kernel
does the following:

1. After memblock is ready, make memblock allocate memory bottom up.
2. After SRAT is parsed, make memblock behave as default, allocate memory
   top down.

Users can specify "movable_node" in kernel commandline to enable this
functionality.  For those who don't use memory hotplug or who don't want
to lose their NUMA performance, just don't specify anything.  The kernel
will work as before.
Signed-off-by: NTang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: NZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Suggested-by: NKamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Suggested-by: NIngo Molnar <mingo@kernel.org>
Acked-by: NTejun Heo <tj@kernel.org>
Acked-by: NToshi Kani <toshi.kani@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Thomas Renninger <trenn@suse.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We map the EFI regions needed for runtime services non-contiguously,
with preserved alignment on virtual addresses starting from -4G down
for a total max space of 64G. This way, we provide for stable runtime
services addresses across kernels so that a kexec'd kernel can still use
them.

Thus, they're mapped in a separate pagetable so that we don't pollute
the kernel namespace.

Add an efi= kernel command line parameter for passing miscellaneous
options and chicken bits from the command line.

While at it, add a chicken bit called "efi=old_map" which can be used as
a fallback to the old runtime services mapping method in case there's
some b0rkage with a particular EFI implementation (haha, it is hard to
hold up the sarcasm here...).

Also, add the UEFI RT VA space to Documentation/x86/x86_64/mm.txt.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>