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Author SHA1 Message Date
Terry Bowman 27c196c7b7 kernel/resource: Introduce request_mem_region_muxed() 
Support for requesting muxed memory region is implemented but not
currently callable as a macro. Add the request muxed memory
region macro.

MMIO memory accesses can be synchronized using request_mem_region() which
is already available. This call will return failure if the resource is
busy. The 'muxed' version of this macro will handle a busy resource by
using a wait queue to retry until the resource is available.

Signed-off-by: Terry Bowman <terry.bowman@amd.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
 2022-02-10 22:40:00 +01:00
Linus Torvalds d8f9176b4e Merge tag 'acpi-5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm 
Pull ACPI updates from Rafael Wysocki:
 "These update the ACPICA code in the kernel to the most recent upstream
  revision including (but not limited to) new material introduced in the
  6.4 version of the spec, update message printing in the ACPI-related
  code, address a few issues and clean up code in a number of places.

  Specifics:

   - Update ACPICA code in the kernel to upstream revision 20210331
     including the following changes:

      * Add parsing for IVRS IVHD 40h and device entry F0h (Alexander
        Monakov).

      * Add new CEDT table for CXL 2.0 and iASL support for it (Ben
        Widawsky, Bob Moore).

      * NFIT: add Location Cookie field (Bob Moore).

      * HMAT: add new fields/flags (Bob Moore).

      * Add new flags in SRAT (Bob Moore).

      * PMTT: add new fields/structures (Bob Moore).

      * Add CSI2Bus resource template (Bob Moore).

      * iASL: Decode subtable type field for VIOT (Bob Moore).

      * Fix various typos and spelling mistakes (Colin Ian King).

      * Add new predefined objects _BPC, _BPS, and _BPT (Erik Kaneda).

      * Add USB4 capabilities UUID (Erik Kaneda).

      * Add CXL ACPI device ID and _CBR object (Erik Kaneda).

      * MADT: add Multiprocessor Wakeup Structure (Erik Kaneda).

      * PCCT: add support for subtable type 5 (Erik Kaneda).

      * PPTT: add new version of subtable type 1 (Erik Kaneda).

      * Add SDEV secure access components (Erik Kaneda).

      * Add support for PHAT table (Erik Kaneda).

      * iASL: Add definitions for the VIOT table (Jean-Philippe
        Brucker).

      * acpisrc: Add missing conversion for VIOT support (Jean-Philippe
        Brucker).

      * IORT: Updates for revision E.b (Shameer Kolothum).

   - Rearrange message printing in ACPI-related code to avoid using the
     ACPICA's internal message printing macros outside ACPICA and do
     some related code cleanups (Rafael Wysocki).

   - Modify the device enumeration code to turn off all of the unused
     ACPI power resources at the end (Rafael Wysocki).

   - Change the ACPI power resources handling code to turn off unused
     ACPI power resources without checking their status which should not
     be necessary by the spec (Rafael Wysocki).

   - Add empty stubs for CPPC-related functions to be used when
     CONFIG_ACPI_CPPC_LIB is not set (Rafael Wysocki).

   - Simplify device enumeration code (Rafael Wysocki).

   - Change device enumeration code to use match_string() for string
     matching (Andy Shevchenko).

   - Modify irqresource_disabled() to retain the resouce flags that have
     been set already (Angela Czubak).

   - Add native backlight whitelist entry for GA401/GA502/GA503 (Luke
     Jones).

   - Modify the ACPI backlight driver to let the native backlight
     handling take over on hardware-reduced systems (Hans de Goede).

   - Introduce acpi_dev_get() and switch over the ACPI core code to
     using it (Andy Shevchenko).

   - Use kobj_attribute as callback argument instead of a local struct
     type in the CPPC linrary code (Nathan Chancellor).

   - Drop unneeded initializatio of a static variable from the ACPI
     processor driver (Tian Tao).

   - Drop unnecessary local variable assignment from the ACPI APEI code
     (Colin Ian King).

   - Document for_each_acpi_dev_match() macro (Andy Shevchenko).

   - Address assorted coding style issues in multiple places (Xiaofei
     Tan).

   - Capitalize TLAs in a few comments (Andy Shevchenko).

   - Correct assorted typos in comments (Tom Saeger)"

* tag 'acpi-5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (68 commits)
  ACPI: video: use native backlight for GA401/GA502/GA503
  ACPI: APEI: remove redundant assignment to variable rc
  ACPI: utils: Capitalize abbreviations in the comments
  ACPI: utils: Document for_each_acpi_dev_match() macro
  ACPI: bus: Introduce acpi_dev_get() and reuse it in ACPI code
  ACPI: scan: Utilize match_string() API
  resource: Prevent irqresource_disabled() from erasing flags
  ACPI: CPPC: Replace cppc_attr with kobj_attribute
  ACPI: scan: Call acpi_get_object_info() from acpi_set_pnp_ids()
  ACPI: scan: Drop sta argument from acpi_init_device_object()
  ACPI: scan: Drop sta argument from acpi_add_single_object()
  ACPI: scan: Rearrange checks in acpi_bus_check_add()
  ACPI: scan: Fold acpi_bus_type_and_status() into its caller
  ACPI: video: Check LCD flag on ACPI-reduced-hardware devices
  ACPI: utils: Add acpi_reduced_hardware() helper
  ACPI: dock: fix some coding style issues
  ACPI: sysfs: fix some coding style issues
  ACPI: PM: add a missed blank line after declarations
  ACPI: custom_method: fix a coding style issue
  ACPI: CPPC: fix some coding style issues
  ...
 2021-04-26 15:03:23 -07:00
Angela Czubak d08a745729 resource: Prevent irqresource_disabled() from erasing flags 
Some Chromebooks use hard-coded interrupts in their ACPI tables.
This is an excerpt as dumped on Relm:

...
            Name (_HID, "ELAN0001")  // _HID: Hardware ID
            Name (_DDN, "Elan Touchscreen ")  // _DDN: DOS Device Name
            Name (_UID, 0x05)  // _UID: Unique ID
            Name (ISTP, Zero)
            Method (_CRS, 0, NotSerialized)  // _CRS: Current Resource Settings
            {
                Name (BUF0, ResourceTemplate ()
                {
                    I2cSerialBusV2 (0x0010, ControllerInitiated, 0x00061A80,
                        AddressingMode7Bit, "\\_SB.I2C1",
                        0x00, ResourceConsumer, , Exclusive,
                        )
                    Interrupt (ResourceConsumer, Edge, ActiveLow, Exclusive, ,, )
                    {
                        0x000000B8,
                    }
                })
                Return (BUF0) /* \_SB_.I2C1.ETSA._CRS.BUF0 */
            }
...

This interrupt is hard-coded to 0xB8 = 184 which is too high to be mapped
to IO-APIC, so no triggering information is propagated as acpi_register_gsi()
fails and irqresource_disabled() is issued, which leads to erasing triggering
and polarity information.

Do not overwrite flags as it leads to erasing triggering and polarity
information which might be useful in case of hard-coded interrupts.
This way the information can be read later on even though mapping to
APIC domain failed.

Signed-off-by: Angela Czubak <acz@semihalf.com>
[ rjw: Changelog rearrangement ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 2021-04-08 20:01:54 +02:00
Hector Martin 7c566bb5e4 asm-generic/io.h: Add a non-posted variant of ioremap() 
ARM64 currently defaults to posted MMIO (nGnRE), but some devices
require the use of non-posted MMIO (nGnRnE). Introduce a new ioremap()
variant to handle this case. ioremap_np() returns NULL on arches that
do not implement this variant.

sparc64 is the only architecture that needs to be touched directly,
because it includes neither of the generic io.h or iomap.h headers.

This adds the IORESOURCE_MEM_NONPOSTED flag, which maps to this
variant and marks a given resource as requiring non-posted mappings.
This is implemented in the resource system because it is a SoC-level
requirement, so existing drivers do not need special-case code to pick
this ioremap variant.

Then this is implemented in devres by introducing devm_ioremap_np(),
and making devm_ioremap_resource() automatically select this variant
when the resource has the IORESOURCE_MEM_NONPOSTED flag set.

Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Hector Martin <marcan@marcan.st>
 2021-04-08 20:18:38 +09:00
Daniel Vetter 71a1d8ed90 resource: Move devmem revoke code to resource framework 
We want all iomem mmaps to consistently revoke ptes when the kernel
takes over and CONFIG_IO_STRICT_DEVMEM is enabled. This includes the
pci bar mmaps available through procfs and sysfs, which currently do
not revoke mappings.

To prepare for this, move the code from the /dev/kmem driver to
kernel/resource.c.

During review Jason spotted that barriers are used somewhat
inconsistently. Fix that up while we shuffle this code, since it
doesn't have an actual impact at runtime. Otherwise no semantic and
behavioural changes intended, just code extraction and adjusting
comments and names.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kees Cook <keescook@chromium.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: linux-mm@kvack.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: linux-media@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20201127164131.2244124-11-daniel.vetter@ffwll.ch
 2021-01-12 14:26:31 +01:00
Linus Torvalds aab7ce2b09 Merge tag 'acpi-5.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm 
Pull ACPI updates from Rafael Wysocki:
 "These update the ACPICA code in the kernel to upstream revision
  20201113, fix and clean up some resources manipulation code, extend
  the enumeration and gpio-line-names property documentation, clean up
  the handling of _DEP during device enumeration, add a new backlight
  DMI quirk, clean up transaction handling in the EC driver and make
  some assorted janitorial changes.

  Specifics:

   - Update ACPICA code in the kernel to upstream revision 20201113 with
     changes as follows:
       * Add 5 new UUIDs to the known UUID table (Bob Moore)
       * Remove extreaneous "the" in comments (Colin Ian King)
       * Add function trace macros to improve debugging (Erik Kaneda)
       * Fix interpreter memory leak (Erik Kaneda)
       * Handle "orphan" _REG for GPIO OpRegions (Hans de Goede)

   - Introduce resource_union() and resource_intersection() helpers and
     clean up some resource-manipulation code with the help of them
     (Andy Shevchenko)

   - Revert problematic commit related to the handling of resources in
     the ACPI core (Daniel Scally)

   - Extend the ACPI device enumeration documentation and the
     gpio-line-names _DSD property documentation, clean up the latter
     (Flavio Suligoi)

   - Clean up _DEP handling during device enumeration, modify the list
     of _DEP exceptions and the handling of it and fix up terminology
     related to _DEP (Hans de Goede, Rafael Wysocki)

   - Eliminate in_interrupt() usage from the ACPI EC driver (Sebastian
     Andrzej Siewior)

   - Clean up the advance_transaction() routine and related code in the
     ACPI EC driver (Rafael Wysocki)

   - Add new backlight quirk for GIGABYTE GB-BXBT-2807 (Jasper St
     Pierre)

   - Make assorted janitorial changes in several ACPI-related pieces of
     code (Hanjun Guo, Jason Yan, Punit Agrawal)"

* tag 'acpi-5.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (40 commits)
  ACPI: scan: Fix up _DEP-related terminology with supplier/consumer
  ACPI: scan: Drop INT3396 from acpi_ignore_dep_ids[]
  ACPI: video: Add DMI quirk for GIGABYTE GB-BXBT-2807
  Revert "ACPI / resources: Use AE_CTRL_TERMINATE to terminate resources walks"
  ACPI: scan: Add PNP0D80 to the _DEP exceptions list
  ACPI: scan: Call acpi_get_object_info() from acpi_add_single_object()
  ACPI: scan: Add acpi_info_matches_hids() helper
  ACPICA: Update version to 20201113
  ACPICA: Interpreter: fix memory leak by using existing buffer
  ACPICA: Add function trace macros to improve debugging
  ACPICA: Also handle "orphan" _REG methods for GPIO OpRegions
  ACPICA: Remove extreaneous "the" in comments
  ACPICA: Add 5 new UUIDs to the known UUID table
  resource: provide meaningful MODULE_LICENSE() in test suite
  ASoC: Intel: catpt: Replace open coded variant of resource_intersection()
  ACPI: processor: Drop duplicate setting of shared_cpu_map
  ACPI: EC: Clean up status flags checks in advance_transaction()
  ACPI: EC: Untangle error handling in advance_transaction()
  ACPI: EC: Simplify error handling in advance_transaction()
  ACPI: EC: Rename acpi_ec_is_gpe_raised()
  ...
 2020-12-15 16:39:06 -08:00
John Garry 9806731db6 resource: Add irqresource_disabled() 
Add a common function to set the fields for a irq resource to disabled,
which mimics what is done in acpi_dev_irqresource_disabled(), with a view
to replace that function.

Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/1606905417-183214-3-git-send-email-john.garry@huawei.com
 2020-12-11 14:47:50 +00:00
Andy Shevchenko f65674df1b resource: Introduce resource_intersection() for overlapping resources 
There will be at least one user that can utilize new helper.
Provide the helper for future user and for wider use.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 2020-11-17 18:06:28 +01:00
Andy Shevchenko 5562f35d7f resource: Introduce resource_union() for overlapping resources 
Some already present users may utilize resource_union() helper.
Provide it for them and for wider use in the future.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Tested-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 2020-11-17 18:06:28 +01:00
Andy Shevchenko 1f90f6a835 resource: Group resource_overlaps() with other inline helpers 
For better maintenance group resource_overlaps() with other inline helpers.
While at it, drop extra parentheses.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Tested-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 2020-11-17 18:06:28 +01:00
David Hildenbrand cb8e3c8b4f kernel/resource: make iomem_resource implicit in release_mem_region_adjustable() 
"mem" in the name already indicates the root, similar to
release_mem_region() and devm_request_mem_region().  Make it implicit.
The only single caller always passes iomem_resource, other parents are not
applicable.

Suggested-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kees Cook <keescook@chromium.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Link: https://lkml.kernel.org/r/20200916073041.10355-1-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-10-16 11:11:18 -07:00
David Hildenbrand 9ca6551ee2 mm/memory_hotplug: MEMHP_MERGE_RESOURCE to specify merging of System RAM resources 
Some add_memory*() users add memory in small, contiguous memory blocks.
Examples include virtio-mem, hyper-v balloon, and the XEN balloon.

This can quickly result in a lot of memory resources, whereby the actual
resource boundaries are not of interest (e.g., it might be relevant for
DIMMs, exposed via /proc/iomem to user space).  We really want to merge
added resources in this scenario where possible.

Let's provide a flag (MEMHP_MERGE_RESOURCE) to specify that a resource
either created within add_memory*() or passed via add_memory_resource()
shall be marked mergeable and merged with applicable siblings.

To implement that, we need a kernel/resource interface to mark selected
System RAM resources mergeable (IORESOURCE_SYSRAM_MERGEABLE) and trigger
merging.

Note: We really want to merge after the whole operation succeeded, not
directly when adding a resource to the resource tree (it would break
add_memory_resource() and require splitting resources again when the
operation failed - e.g., due to -ENOMEM).

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kees Cook <keescook@chromium.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Roger Pau Monné <roger.pau@citrix.com>
Cc: Julien Grall <julien@xen.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Wei Yang <richardw.yang@linux.intel.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Leonardo Bras <leobras.c@gmail.com>
Cc: Libor Pechacek <lpechacek@suse.cz>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: "Oliver O'Halloran" <oohall@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Pingfan Liu <kernelfans@gmail.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Link: https://lkml.kernel.org/r/20200911103459.10306-6-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-10-16 11:11:18 -07:00
David Hildenbrand 7cf603d17d kernel/resource: move and rename IORESOURCE_MEM_DRIVER_MANAGED 
IORESOURCE_MEM_DRIVER_MANAGED currently uses an unused PnP bit, which is
always set to 0 by hardware.  This is far from beautiful (and confusing),
and the bit only applies to SYSRAM.  So let's move it out of the
bus-specific (PnP) defined bits.

We'll add another SYSRAM specific bit soon.  If we ever need more bits for
other purposes, we can steal some from "desc", or reshuffle/regroup what
we have.

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kees Cook <keescook@chromium.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Wei Yang <richardw.yang@linux.intel.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Julien Grall <julien@xen.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Leonardo Bras <leobras.c@gmail.com>
Cc: Libor Pechacek <lpechacek@suse.cz>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: "Oliver O'Halloran" <oohall@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Pingfan Liu <kernelfans@gmail.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Roger Pau Monné <roger.pau@citrix.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Wei Liu <wei.liu@kernel.org>
Link: https://lkml.kernel.org/r/20200911103459.10306-3-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-10-16 11:11:18 -07:00
David Hildenbrand ec62d04e3f kernel/resource: make release_mem_region_adjustable() never fail 
Patch series "selective merging of system ram resources", v4.

Some add_memory*() users add memory in small, contiguous memory blocks.
Examples include virtio-mem, hyper-v balloon, and the XEN balloon.

This can quickly result in a lot of memory resources, whereby the actual
resource boundaries are not of interest (e.g., it might be relevant for
DIMMs, exposed via /proc/iomem to user space).  We really want to merge
added resources in this scenario where possible.

Resources are effectively stored in a list-based tree.  Having a lot of
resources not only wastes memory, it also makes traversing that tree more
expensive, and makes /proc/iomem explode in size (e.g., requiring
kexec-tools to manually merge resources when creating a kdump header.  The
current kexec-tools resource count limit does not allow for more than
~100GB of memory with a memory block size of 128MB on x86-64).

Let's allow to selectively merge system ram resources by specifying a new
flag for add_memory*().  Patch #5 contains a /proc/iomem example.  Only
tested with virtio-mem.

This patch (of 8):

Let's make sure splitting a resource on memory hotunplug will never fail.
This will become more relevant once we merge selected System RAM resources
- then, we'll trigger that case more often on memory hotunplug.

In general, this function is already unlikely to fail.  When we remove
memory, we free up quite a lot of metadata (memmap, page tables, memory
block device, etc.).  The only reason it could really fail would be when
injecting allocation errors.

All other error cases inside release_mem_region_adjustable() seem to be
sanity checks if the function would be abused in different context - let's
add WARN_ON_ONCE() in these cases so we can catch them.

[natechancellor@gmail.com: fix use of ternary condition in release_mem_region_adjustable]
  Link: https://lkml.kernel.org/r/20200922060748.2452056-1-natechancellor@gmail.com
  Link: https://github.com/ClangBuiltLinux/linux/issues/1159

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kees Cook <keescook@chromium.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Wei Yang <richardw.yang@linux.intel.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Julien Grall <julien@xen.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Leonardo Bras <leobras.c@gmail.com>
Cc: Libor Pechacek <lpechacek@suse.cz>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: "Oliver O'Halloran" <oohall@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Pingfan Liu <kernelfans@gmail.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Roger Pau Monn <roger.pau@citrix.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Wei Liu <wei.liu@kernel.org>
Link: https://lkml.kernel.org/r/20200911103459.10306-2-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-10-16 11:11:17 -07:00
Linus Torvalds 9aa900c809 Merge tag 'char-misc-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc 
Pull char/misc driver updates from Greg KH:
 "Here is the large set of char/misc driver patches for 5.8-rc1

  Included in here are:

   - habanalabs driver updates, loads

   - mhi bus driver updates

   - extcon driver updates

   - clk driver updates (approved by the clock maintainer)

   - firmware driver updates

   - fpga driver updates

   - gnss driver updates

   - coresight driver updates

   - interconnect driver updates

   - parport driver updates (it's still alive!)

   - nvmem driver updates

   - soundwire driver updates

   - visorbus driver updates

   - w1 driver updates

   - various misc driver updates

  In short, loads of different driver subsystem updates along with the
  drivers as well.

  All have been in linux-next for a while with no reported issues"

* tag 'char-misc-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (233 commits)
  habanalabs: correctly cast u64 to void*
  habanalabs: initialize variable to default value
  extcon: arizona: Fix runtime PM imbalance on error
  extcon: max14577: Add proper dt-compatible strings
  extcon: adc-jack: Fix an error handling path in 'adc_jack_probe()'
  extcon: remove redundant assignment to variable idx
  w1: omap-hdq: print dev_err if irq flags are not cleared
  w1: omap-hdq: fix interrupt handling which did show spurious timeouts
  w1: omap-hdq: fix return value to be -1 if there is a timeout
  w1: omap-hdq: cleanup to add missing newline for some dev_dbg
  /dev/mem: Revoke mappings when a driver claims the region
  misc: xilinx-sdfec: convert get_user_pages() --> pin_user_pages()
  misc: xilinx-sdfec: cleanup return value in xsdfec_table_write()
  misc: xilinx-sdfec: improve get_user_pages_fast() error handling
  nvmem: qfprom: remove incorrect write support
  habanalabs: handle MMU cache invalidation timeout
  habanalabs: don't allow hard reset with open processes
  habanalabs: GAUDI does not support soft-reset
  habanalabs: add print for soft reset due to event
  habanalabs: improve MMU cache invalidation code
  ...
 2020-06-07 10:59:32 -07:00
David Hildenbrand 7b7b27214b mm/memory_hotplug: introduce add_memory_driver_managed() 
Patch series "mm/memory_hotplug: Interface to add driver-managed system
ram", v4.

kexec (via kexec_load()) can currently not properly handle memory added
via dax/kmem, and will have similar issues with virtio-mem.  kexec-tools
will currently add all memory to the fixed-up initial firmware memmap.  In
case of dax/kmem, this means that - in contrast to a proper reboot - how
that persistent memory will be used can no longer be configured by the
kexec'd kernel.  In case of virtio-mem it will be harmful, because that
memory might contain inaccessible pieces that require coordination with
hypervisor first.

In both cases, we want to let the driver in the kexec'd kernel handle
detecting and adding the memory, like during an ordinary reboot.
Introduce add_memory_driver_managed().  More on the samentics are in patch
#1.

In the future, we might want to make this behavior configurable for
dax/kmem- either by configuring it in the kernel (which would then also
allow to configure kexec_file_load()) or in kexec-tools by also adding
"System RAM (kmem)" memory from /proc/iomem to the fixed-up initial
firmware memmap.

More on the motivation can be found in [1] and [2].

[1] https://lkml.kernel.org/r/20200429160803.109056-1-david@redhat.com
[2] https://lkml.kernel.org/r/20200430102908.10107-1-david@redhat.com

This patch (of 3):

Some device drivers rely on memory they managed to not get added to the
initial (firmware) memmap as system RAM - so it's not used as initial
system RAM by the kernel and the driver is under control.  While this is
the case during cold boot and after a reboot, kexec is not aware of that
and might add such memory to the initial (firmware) memmap of the kexec
kernel.  We need ways to teach kernel and userspace that this system ram
is different.

For example, dax/kmem allows to decide at runtime if persistent memory is
to be used as system ram.  Another future user is virtio-mem, which has to
coordinate with its hypervisor to deal with inaccessible parts within
memory resources.

We want to let users in the kernel (esp. kexec) but also user space
(esp. kexec-tools) know that this memory has different semantics and
needs to be handled differently:
1. Don't create entries in /sys/firmware/memmap/
2. Name the memory resource "System RAM ($DRIVER)" (exposed via
   /proc/iomem) ($DRIVER might be "kmem", "virtio_mem").
3. Flag the memory resource IORESOURCE_MEM_DRIVER_MANAGED

/sys/firmware/memmap/ [1] represents the "raw firmware-provided memory
map" because "on most architectures that firmware-provided memory map is
modified afterwards by the kernel itself".  The primary user is kexec on
x86-64.  Since commit d96ae53091 ("memory-hotplug: create
/sys/firmware/memmap entry for new memory"), we add all hotplugged memory
to that firmware memmap - which makes perfect sense for traditional memory
hotplug on x86-64, where real HW will also add hotplugged DIMMs to the
firmware memmap.  We replicate what the "raw firmware-provided memory map"
looks like after hot(un)plug.

To keep things simple, let the user provide the full resource name instead
of only the driver name - this way, we don't have to manually
allocate/craft strings for memory resources.  Also use the resource name
to make decisions, to avoid passing additional flags.  In case the name
isn't "System RAM", it's special.

We don't have to worry about firmware_map_remove() on the removal path.
If there is no entry, it will simply return with -EINVAL.

We'll adapt dax/kmem in a follow-up patch.

[1] https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-firmware-memmap

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Link: http://lkml.kernel.org/r/20200508084217.9160-1-david@redhat.com
Link: http://lkml.kernel.org/r/20200508084217.9160-3-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-04 19:06:23 -07:00
Dan Williams 3234ac664a /dev/mem: Revoke mappings when a driver claims the region 
Close the hole of holding a mapping over kernel driver takeover event of
a given address range.

Commit 90a545e981 ("restrict /dev/mem to idle io memory ranges")
introduced CONFIG_IO_STRICT_DEVMEM with the goal of protecting the
kernel against scenarios where a /dev/mem user tramples memory that a
kernel driver owns. However, this protection only prevents *new* read(),
write() and mmap() requests. Established mappings prior to the driver
calling request_mem_region() are left alone.

Especially with persistent memory, and the core kernel metadata that is
stored there, there are plentiful scenarios for a /dev/mem user to
violate the expectations of the driver and cause amplified damage.

Teach request_mem_region() to find and shoot down active /dev/mem
mappings that it believes it has successfully claimed for the exclusive
use of the driver. Effectively a driver call to request_mem_region()
becomes a hole-punch on the /dev/mem device.

The typical usage of unmap_mapping_range() is part of
truncate_pagecache() to punch a hole in a file, but in this case the
implementation is only doing the "first half" of a hole punch. Namely it
is just evacuating current established mappings of the "hole", and it
relies on the fact that /dev/mem establishes mappings in terms of
absolute physical address offsets. Once existing mmap users are
invalidated they can attempt to re-establish the mapping, or attempt to
continue issuing read(2) / write(2) to the invalidated extent, but they
will then be subject to the CONFIG_IO_STRICT_DEVMEM checking that can
block those subsequent accesses.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes: 90a545e981 ("restrict /dev/mem to idle io memory ranges")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/159009507306.847224.8502634072429766747.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 2020-05-27 11:10:05 +02:00
Dan Williams 262b45ae3a x86/efi: EFI soft reservation to E820 enumeration 
UEFI 2.8 defines an EFI_MEMORY_SP attribute bit to augment the
interpretation of the EFI Memory Types as "reserved for a specific
purpose".

The proposed Linux behavior for specific purpose memory is that it is
reserved for direct-access (device-dax) by default and not available for
any kernel usage, not even as an OOM fallback.  Later, through udev
scripts or another init mechanism, these device-dax claimed ranges can
be reconfigured and hot-added to the available System-RAM with a unique
node identifier. This device-dax management scheme implements "soft" in
the "soft reserved" designation by allowing some or all of the
reservation to be recovered as typical memory. This policy can be
disabled at compile-time with CONFIG_EFI_SOFT_RESERVE=n, or runtime with
efi=nosoftreserve.

This patch introduces 2 new concepts at once given the entanglement
between early boot enumeration relative to memory that can optionally be
reserved from the kernel page allocator by default. The new concepts
are:

- E820_TYPE_SOFT_RESERVED: Upon detecting the EFI_MEMORY_SP
  attribute on EFI_CONVENTIONAL memory, update the E820 map with this
  new type. Only perform this classification if the
  CONFIG_EFI_SOFT_RESERVE=y policy is enabled, otherwise treat it as
  typical ram.

- IORES_DESC_SOFT_RESERVED: Add a new I/O resource descriptor for
  a device driver to search iomem resources for application specific
  memory. Teach the iomem code to identify such ranges as "Soft Reserved".

Note that the comment for do_add_efi_memmap() needed refreshing since it
seemed to imply that the efi map might overflow the e820 table, but that
is not an issue as of commit 7b6e4ba3cb "x86/boot/e820: Clean up the
E820_X_MAX definition" that removed the 128 entry limit for
e820__range_add().

A follow-on change integrates parsing of the ACPI HMAT to identify the
node and sub-range boundaries of EFI_MEMORY_SP designated memory. For
now, just identify and reserve memory of this type.

Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reported-by: kbuild test robot <lkp@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 2019-11-07 15:44:14 +01:00
Christoph Hellwig 0c38519039 resource: add a not device managed request_free_mem_region variant 
Factor out the guts of devm_request_free_mem_region so that we can
implement both a device managed and a manually release version as tiny
wrappers around it.

Link: https://lore.kernel.org/r/20190818090557.17853-2-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Bharata B Rao <bharata@linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
 2019-08-20 09:39:41 -03:00
Linus Torvalds fec88ab0af Merge tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma 
Pull HMM updates from Jason Gunthorpe:
 "Improvements and bug fixes for the hmm interface in the kernel:

   - Improve clarity, locking and APIs related to the 'hmm mirror'
     feature merged last cycle. In linux-next we now see AMDGPU and
     nouveau to be using this API.

   - Remove old or transitional hmm APIs. These are hold overs from the
     past with no users, or APIs that existed only to manage cross tree
     conflicts. There are still a few more of these cleanups that didn't
     make the merge window cut off.

   - Improve some core mm APIs:
       - export alloc_pages_vma() for driver use
       - refactor into devm_request_free_mem_region() to manage
         DEVICE_PRIVATE resource reservations
       - refactor duplicative driver code into the core dev_pagemap
         struct

   - Remove hmm wrappers of improved core mm APIs, instead have drivers
     use the simplified API directly

   - Remove DEVICE_PUBLIC

   - Simplify the kconfig flow for the hmm users and core code"

* tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (42 commits)
  mm: don't select MIGRATE_VMA_HELPER from HMM_MIRROR
  mm: remove the HMM config option
  mm: sort out the DEVICE_PRIVATE Kconfig mess
  mm: simplify ZONE_DEVICE page private data
  mm: remove hmm_devmem_add
  mm: remove hmm_vma_alloc_locked_page
  nouveau: use devm_memremap_pages directly
  nouveau: use alloc_page_vma directly
  PCI/P2PDMA: use the dev_pagemap internal refcount
  device-dax: use the dev_pagemap internal refcount
  memremap: provide an optional internal refcount in struct dev_pagemap
  memremap: replace the altmap_valid field with a PGMAP_ALTMAP_VALID flag
  memremap: remove the data field in struct dev_pagemap
  memremap: add a migrate_to_ram method to struct dev_pagemap_ops
  memremap: lift the devmap_enable manipulation into devm_memremap_pages
  memremap: pass a struct dev_pagemap to ->kill and ->cleanup
  memremap: move dev_pagemap callbacks into a separate structure
  memremap: validate the pagemap type passed to devm_memremap_pages
  mm: factor out a devm_request_free_mem_region helper
  mm: export alloc_pages_vma
  ...
 2019-07-14 19:42:11 -07:00
Christoph Hellwig 0092908d16 mm: factor out a devm_request_free_mem_region helper 
Keep the physical address allocation that hmm_add_device does with the
rest of the resource code, and allow future reuse of it without the hmm
wrapper.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
 2019-07-02 14:32:44 -03:00
Christoph Hellwig 25b2995a35 mm: remove MEMORY_DEVICE_PUBLIC support 
The code hasn't been used since it was added to the tree, and doesn't
appear to actually be usable.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
 2019-07-02 14:32:43 -03:00
Lianbo Jiang 5da04cc86d x86/mm: Rework ioremap resource mapping determination 
On ioremap(), __ioremap_check_mem() does a couple of checks on the
supplied memory range to determine how the range should be mapped and in
particular what protection flags should be used.

Generalize the procedure by introducing IORES_MAP_* flags which control
different aspects of the ioremapping and use them in the respective
helpers which determine which descriptor flags should be set per range.

 [ bp:
   - Rewrite commit message.
   - Add/improve comments.
   - Reflow __ioremap_caller()'s args.
   - s/__ioremap_check_desc/__ioremap_check_encrypted/g;
   - s/__ioremap_res_check/__ioremap_collect_map_flags/g;
   - clarify __ioremap_check_ram()'s purpose. ]

Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
Co-developed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: bhe@redhat.com
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: dyoung@redhat.com
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: kexec@lists.infradead.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190423013007.17838-3-lijiang@redhat.com
 2019-06-20 09:58:07 +02:00
Lianbo Jiang ae9e13d621 x86/e820, ioport: Add a new I/O resource descriptor IORES_DESC_RESERVED 
When executing the kexec_file_load() syscall, the first kernel needs to
pass the e820 reserved ranges to the second kernel because some devices
(PCI, for example) need them present in the kdump kernel for proper
initialization.

But the kernel can not exactly match the e820 reserved ranges when
walking through the iomem resources using the default IORES_DESC_NONE
descriptor, because there are several types of e820 ranges which are
marked IORES_DESC_NONE, see e820_type_to_iores_desc().

Therefore, add a new I/O resource descriptor called IORES_DESC_RESERVED
to mark exactly those ranges. It will be used to match the reserved
resource ranges when walking through iomem resources.

 [ bp: Massage commit message. ]

Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: bhe@redhat.com
Cc: dave.hansen@linux.intel.com
Cc: dyoung@redhat.com
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Huang Zijiang <huang.zijiang@zte.com.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: kexec@lists.infradead.org
Cc: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190423013007.17838-2-lijiang@redhat.com
 2019-06-20 09:54:31 +02:00
Yaowei Bai 9825b451f9 kernel/resource: iomem_is_exclusive can be boolean 
Make iomem_is_exclusive return bool due to this particular function only
using either one or zero as its return value.

No functional change.

Link: http://lkml.kernel.org/r/1513266622-15860-5-git-send-email-baiyaowei@cmss.chinamobile.com
Signed-off-by: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2018-02-06 18:32:47 -08:00