Pull memblock updates from Mike Rapoport:

 - 'reserve_mem' command line parameter to allow creation of named
   memory reservation at boot time.

   The driving use-case is to improve the ability of pstore to retain
   ramoops data across reboots.

 - cleanups and small improvements in memblock and mm_init

 - new tests cases in memblock test suite

* tag 'memblock-v6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
  memblock tests: fix implicit declaration of function 'numa_valid_node'
  memblock: Move late alloc warning down to phys alloc
  pstore/ramoops: Add ramoops.mem_name= command line option
  mm/memblock: Add "reserve_mem" to reserved named memory at boot up
  mm/mm_init.c: don't initialize page->lru again
  mm/mm_init.c: not always search next deferred_init_pfn from very beginning
  mm/mm_init.c: use deferred_init_mem_pfn_range_in_zone() to decide loop condition
  mm/mm_init.c: get the highest zone directly
  mm/mm_init.c: move nr_initialised reset down a bit
  mm/memblock: fix a typo in description of for_each_mem_region()
  mm/mm_init.c: use memblock_region_memory_base_pfn() to get startpfn
  mm/memblock: use PAGE_ALIGN_DOWN to get pgend in free_memmap
  mm/memblock: return true directly on finding overlap region
  memblock tests: add memblock_overlaps_region_checks
  mm/memblock: fix comment for memblock_isolate_range()
  memblock tests: add memblock_reserve_many_may_conflict_check()
  memblock tests: add memblock_reserve_all_locations_check()
  mm/memblock: remove empty dummy entry

If a driver/subsystem tries to do an allocation after the memblock
allocations have been freed and the memory handed to the buddy
allocator, it will not actually be legal to use that allocation: the
buddy allocator owns the memory. Currently this mis-use is handled by
the memblock function which does allocations and returns virtual
addresses by printing a warning and doing a kmalloc instead. However
the physical allocation function does not to do this check - callers of
the physical alloc function are unprotected against mis-use.

Improve the error catching here by moving the check into the physical
allocation function which is used by the virtual addr allocation
function.

Signed-off-by: James Gowans <jgowans@amazon.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Alex Graf <graf@amazon.de>
Link: https://lore.kernel.org/r/20240619095555.85980-1-jgowans@amazon.com
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>

In order to allow for requesting a memory region that can be used for
things like pstore on multiple machines where the memory layout is not the
same, add a new option to the kernel command line called "reserve_mem".

The format is:  reserve_mem=nn:align:name

Where it will find nn amount of memory at the given alignment of align.
The name field is to allow another subsystem to retrieve where the memory
was found. For example:

  reserve_mem=12M:4096:oops ramoops.mem_name=oops

Where ramoops.mem_name will tell ramoops that memory was reserved for it
via the reserve_mem option and it can find it by calling:

  if (reserve_mem_find_by_name("oops", &start, &size)) {
	// start holds the start address and size holds the size given

This is typically used for systems that do not wipe the RAM, and this
command line will try to reserve the same physical memory on soft reboots.
Note, it is not guaranteed to be the same location. For example, if KASLR
places the kernel at the location of where the RAM reservation was from a
previous boot, the new reservation will be at a different location.  Any
subsystem using this feature must add a way to verify that the contents of
the physical memory is from a previous boot, as there may be cases where
the memory will not be located at the same location.

Not all systems may work either. There could be bit flips if the reboot
goes through the BIOS. Using kexec to reboot the machine is likely to
have better results in such cases.

Link: https://lore.kernel.org/all/ZjJVnZUX3NZiGW6q@kernel.org/

Suggested-by: Mike Rapoport <rppt@kernel.org>
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20240613155527.437020271@goodmis.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>

Introduce numa_valid_node(nid) that verifies that nid is a valid node ID
and use that instead of comparing nid parameter with either NUMA_NO_NODE
or MAX_NUMNODES.

This makes the checks for valid node IDs consistent and more robust and
allows to get rid of multiple WARNings.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>

Leverage the macro PAGE_ALIGN_DOWN to get pgend.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Link: https://lore.kernel.org/r/20240507075833.6346-7-richard.weiyang@gmail.com
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>

Not necessary to break and check i against type->cnt again.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Link: https://lore.kernel.org/r/20240507075833.6346-6-richard.weiyang@gmail.com
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>

The isolated range is [*@start_rgn, *@end_rgn - 1], while the comment says
"the end region inside the range" is *@end_rgn.

Let's correct it.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Link: https://lore.kernel.org/r/20240507075833.6346-4-richard.weiyang@gmail.com
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>

The dummy entry is introduced in the initial implementation of lmb in
commit 7c8c6b9776fb ("powerpc: Merge lmb.c and make MM initialization
use it.").

As the comment says the empty dummy entry is to simplify the code.

	/* Create a dummy zero size LMB which will get coalesced away later.
         * This simplifies the lmb_add() code below...
         */

While current code is reimplemented by Tejun in commit 784656f9c680
("memblock: Reimplement memblock_add_region()"). This empty dummy entry
seems not benefit the code any more.

Let's remove it.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
CC: Paul Mackerras <paulus@ozlabs.org>
CC: Tejun Heo <tj@kernel.org>
CC: Mike Rapoport <rppt@kernel.org>
Link: https://lore.kernel.org/r/20240405015821.13411-1-richard.weiyang@gmail.com
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>

On an (old) x86 system with SRAT just covering space above 4Gb:

    ACPI: SRAT: Node 0 PXM 0 [mem 0x100000000-0xfffffffff] hotplug

the commit referenced below leads to this NUMA configuration no longer
being refused by a CONFIG_NUMA=y kernel (previously

    NUMA: nodes only cover 6144MB of your 8185MB e820 RAM. Not used.
    No NUMA configuration found
    Faking a node at [mem 0x0000000000000000-0x000000027fffffff]

was seen in the log directly after the message quoted above), because of
memblock_validate_numa_coverage() checking for NUMA_NO_NODE (only). This
in turn led to memblock_alloc_range_nid()'s warning about MAX_NUMNODES
triggering, followed by a NULL deref in memmap_init() when trying to
access node 64's (NODE_SHIFT=6) node data.

To compensate said change, make memblock_set_node() warn on and adjust
a passed in value of MAX_NUMNODES, just like various other functions
already do.

Fixes: ff6c3d81f2e8 ("NUMA: optimize detection of memory with no node id assigned by firmware")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/1c8a058c-5365-4f27-a9f1-3aeb7fb3e7b2@suse.com
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>

Pull cxl fixes from Dan Williams:
 "A collection of significant fixes for the CXL subsystem.

  The largest change in this set, that bordered on "new development", is
  the fix for the fact that the location of the new qos_class attribute
  did not match the Documentation. The fix ends up deleting more code
  than it added, and it has a new unit test to backstop basic errors in
  this interface going forward. So the "red-diff" and unit test saved
  the "rip it out and try again" response.

  In contrast, the new notification path for firmware reported CXL
  errors (CXL CPER notifications) has a locking context bug that can not
  be fixed with a red-diff. Given where the release cycle stands, it is
  not comfortable to squeeze in that fix in these waning days. So, that
  receives the "back it out and try again later" treatment.

  There is a regression fix in the code that establishes memory NUMA
  nodes for platform CXL regions. That has an ack from x86 folks. There
  are a couple more fixups for Linux to understand (reassemble) CXL
  regions instantiated by platform firmware. The policy around platforms
  that do not match host-physical-address with system-physical-address
  (i.e. systems that have an address translation mechanism between the
  address range reported in the ACPI CEDT.CFMWS and endpoint decoders)
  has been softened to abort driver load rather than teardown the memory
  range (can cause system hangs). Lastly, there is a robustness /
  regression fix for cases where the driver would previously continue in
  the face of error, and a fixup for PCI error notification handling.

  Summary:

   - Fix NUMA initialization from ACPI CEDT.CFMWS

   - Fix region assembly failures due to async init order

   - Fix / simplify export of qos_class information

   - Fix cxl_acpi initialization vs single-window-init failures

   - Fix handling of repeated 'pci_channel_io_frozen' notifications

   - Workaround platforms that violate host-physical-address ==
     system-physical address assumptions

   - Defer CXL CPER notification handling to v6.9"

* tag 'cxl-fixes-6.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl:
  cxl/acpi: Fix load failures due to single window creation failure
  acpi/ghes: Remove CXL CPER notifications
  cxl/pci: Fix disabling memory if DVSEC CXL Range does not match a CFMWS window
  cxl/test: Add support for qos_class checking
  cxl: Fix sysfs export of qos_class for memdev
  cxl: Remove unnecessary type cast in cxl_qos_class_verify()
  cxl: Change 'struct cxl_memdev_state' *_perf_list to single 'struct cxl_dpa_perf'
  cxl/region: Allow out of order assembly of autodiscovered regions
  cxl/region: Handle endpoint decoders in cxl_region_find_decoder()
  x86/numa: Fix the sort compare func used in numa_fill_memblks()
  x86/numa: Fix the address overlap check in numa_fill_memblks()
  cxl/pci: Skip to handle RAS errors if CXL.mem device is detached