Merge tag 'acpi-5.5-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
  20191018, add support for EFI specific purpose memory, update the ACPI
  EC driver to make it work on systems with hardware-reduced ACPI,
  improve ACPI-based device enumeration for some platforms, rework the
  lid blacklist handling in the button driver and add more lid quirks to
  it, unify ACPI _HID/_UID matching, fix assorted issues and clean up
  the code and documentation.

  Specifics:

   - Update the ACPICA code in the kernel to upstream revision 20191018
     including:
      * Fixes for Clang warnings (Bob Moore)
      * Fix for possible overflow in get_tick_count() (Bob Moore)
      * Introduction of acpi_unload_table() (Bob Moore)
      * Debugger and utilities updates (Erik Schmauss)
      * Fix for unloading tables loaded via configfs (Nikolaus Voss)

   - Add support for EFI specific purpose memory to optionally allow
     either application-exclusive or core-kernel-mm managed access to
     differentiated memory (Dan Williams)

   - Fix and clean up processing of the HMAT table (Brice Goglin, Qian
     Cai, Tao Xu)

   - Update the ACPI EC driver to make it work on systems with
     hardware-reduced ACPI (Daniel Drake)

   - Always build in support for the Generic Event Device (GED) to allow
     one kernel binary to work both on systems with full hardware ACPI
     and hardware-reduced ACPI (Arjan van de Ven)

   - Fix the table unload mechanism to unregister platform devices
     created when the given table was loaded (Andy Shevchenko)

   - Rework the lid blacklist handling in the button driver and add more
     lid quirks to it (Hans de Goede)

   - Improve ACPI-based device enumeration for some platforms based on
     Intel BayTrail SoCs (Hans de Goede)

   - Add an OpRegion driver for the Cherry Trail Crystal Cove PMIC and
     prevent handlers from being registered for unhandled PMIC OpRegions
     (Hans de Goede)

   - Unify ACPI _HID/_UID matching (Andy Shevchenko)

   - Clean up documentation and comments (Cao jin, James Pack, Kacper
     Piwiński)"

* tag 'acpi-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (52 commits)
  ACPI: OSI: Shoot duplicate word
  ACPI: HMAT: use %u instead of %d to print u32 values
  ACPI: NUMA: HMAT: fix a section mismatch
  ACPI: HMAT: don't mix pxm and nid when setting memory target processor_pxm
  ACPI: NUMA: HMAT: Register "soft reserved" memory as an "hmem" device
  ACPI: NUMA: HMAT: Register HMAT at device_initcall level
  device-dax: Add a driver for "hmem" devices
  dax: Fix alloc_dax_region() compile warning
  lib: Uplevel the pmem "region" ida to a global allocator
  x86/efi: Add efi_fake_mem support for EFI_MEMORY_SP
  arm/efi: EFI soft reservation to memblock
  x86/efi: EFI soft reservation to E820 enumeration
  efi: Common enable/disable infrastructure for EFI soft reservation
  x86/efi: Push EFI_MEMMAP check into leaf routines
  efi: Enumerate EFI_MEMORY_SP
  ACPI: NUMA: Establish a new drivers/acpi/numa/ directory
  ACPICA: Update version to 20191018
  ACPICA: debugger: remove leading whitespaces when converting a string to a buffer
  ACPICA: acpiexec: initialize all simple types and field units from user input
  ACPICA: debugger: add field unit support for acpi_db_get_next_token
  ...

1 files changed, 22 insertions, 5 deletions

diff --git a/drivers/dax/Kconfig b/drivers/dax/Kconfig
index f33c73e4af41..3b6c06f07326 100644
--- a/drivers/dax/Kconfig
+++ b/drivers/dax/Kconfig
@@ -32,19 +32,36 @@ config DEV_DAX_PMEM
 
 	  Say M if unsure
 
+config DEV_DAX_HMEM
+	tristate "HMEM DAX: direct access to 'specific purpose' memory"
+	depends on EFI_SOFT_RESERVE
+	default DEV_DAX
+	help
+	  EFI 2.8 platforms, and others, may advertise 'specific purpose'
+	  memory. For example, a high bandwidth memory pool. The
+	  indication from platform firmware is meant to reserve the
+	  memory from typical usage by default. This driver creates
+	  device-dax instances for these memory ranges, and that also
+	  enables the possibility to assign them to the DEV_DAX_KMEM
+	  driver to override the reservation and add them to kernel
+	  "System RAM" pool.
+
+	  Say M if unsure.
+
 config DEV_DAX_KMEM
 	tristate "KMEM DAX: volatile-use of persistent memory"
 	default DEV_DAX
 	depends on DEV_DAX
 	depends on MEMORY_HOTPLUG # for add_memory() and friends
 	help
-	  Support access to persistent memory as if it were RAM.  This
-	  allows easier use of persistent memory by unmodified
-	  applications.
+	  Support access to persistent, or other performance
+	  differentiated memory as if it were System RAM. This allows
+	  easier use of persistent memory by unmodified applications, or
+	  adds core kernel memory services to heterogeneous memory types
+	  (HMEM) marked "reserved" by platform firmware.
 
 	  To use this feature, a DAX device must be unbound from the
-	  device_dax driver (PMEM DAX) and bound to this kmem driver
-	  on each boot.
+	  device_dax driver and bound to this kmem driver on each boot.
 
 	  Say N if unsure.