kernel/linux.git/drivers/of/fdt.c, branch v6.18.21

arm64: kdump: Fix elfcorehdr overlap caused by reserved memory processing reorder

2026-01-02T11:56:53+00:00

[ Upstream commit 3e8ade58b71b48913d21b647b2089e03e81f117e ] Commit 8a6e02d0c00e ("of: reserved_mem: Restructure how the reserved memory regions are processed") changed the processing order of reserved memory regions, causing elfcorehdr to overlap with dynamically allocated reserved memory regions during kdump kernel boot. The issue occurs because: 1. kexec-tools allocates elfcorehdr in the last crashkernel reserved memory region and passes it to the second kernel 2. The problematic commit moved dynamic reserved memory allocation (like bman-fbpr) to occur during fdt_scan_reserved_mem(), before elfcorehdr reservation in fdt_reserve_elfcorehdr() 3. bman-fbpr with 16MB alignment requirement can get allocated at addresses that overlap with the elfcorehdr location 4. When fdt_reserve_elfcorehdr() tries to reserve elfcorehdr memory, overlap detection identifies the conflict and skips reservation 5. kdump kernel fails with "Unable to handle kernel paging request" because elfcorehdr memory is not properly reserved The boot log: Before 8a6e02d0c00e: OF: fdt: Reserving 1 KiB of memory at 0xf4fff000 for elfcorehdr OF: reserved mem: 0xf3000000..0xf3ffffff bman-fbpr After 8a6e02d0c00e: OF: reserved mem: 0xf4000000..0xf4ffffff bman-fbpr OF: fdt: elfcorehdr is overlapped Fix this by ensuring elfcorehdr reservation occurs before dynamic reserved memory allocation. Fixes: 8a6e02d0c00e ("of: reserved_mem: Restructure how the reserved memory regions are processed") Signed-off-by: Jianpeng Chang Link: https://patch.msgid.link/20251205015934.700016-1-jianpeng.chang.cn@windriver.com Signed-off-by: Rob Herring (Arm) Signed-off-by: Sasha Levin

of/fdt: Fix incorrect use of dt_root_addr_cells in early_init_dt_check_kho()

2025-12-18T13:03:08+00:00

[ Upstream commit c85da64ce2c36bba469f6feede9ca768f0361741 ] When reading the fdt_size value, the argument passed to dt_mem_next_cell() is dt_root_addr_cells, but it should be dt_root_size_cells. The same issue occurs when reading the scratch_size value. Use a helper function to simplify the code and fix these issues. Fixes: 274cdcb1c004 ("arm64: add KHO support") Signed-off-by: Yuntao Wang Link: https://patch.msgid.link/20251115134753.179931-5-yuntao.wang@linux.dev Signed-off-by: Rob Herring (Arm) Signed-off-by: Sasha Levin

of/fdt: Fix the len check in early_init_dt_check_for_usable_mem_range()

2025-12-18T13:03:07+00:00

[ Upstream commit 463942de13cd30fad5dba709f708483eab7efc2c ] The len value is in bytes, while `dt_root_addr_cells + dt_root_size_cells` is in cells (4 bytes per cell). Modulo calculation between them is incorrect, the units must be converted first. Use helper functions to simplify the code and fix this issue. Fixes: fb319e77a0e7 ("of: fdt: Add memory for devices by DT property "linux,usable-memory-range"") Fixes: 2af2b50acf9b9c38 ("of: fdt: Add generic support for handling usable memory range property") Fixes: 8f579b1c4e347b23 ("arm64: limit memory regions based on DT property, usable-memory-range") Signed-off-by: Yuntao Wang Link: https://patch.msgid.link/20251115134753.179931-4-yuntao.wang@linux.dev Signed-off-by: Rob Herring (Arm) Signed-off-by: Sasha Levin

of/fdt: Fix the len check in early_init_dt_check_for_elfcorehdr()

2025-12-18T13:03:07+00:00

[ Upstream commit bec5f6092bc1328895992ff02b862ba34b45a0b7 ] The len value is in bytes, while `dt_root_addr_cells + dt_root_size_cells` is in cells (4 bytes per cell). Comparing them directly is incorrect. Use a helper function to simplify the code and address this issue. Fixes: f7e7ce93aac1 ("of: fdt: Add generic support for handling elf core headers property") Fixes: e62aaeac426ab1dd ("arm64: kdump: provide /proc/vmcore file") Signed-off-by: Yuntao Wang Link: https://patch.msgid.link/20251115134753.179931-3-yuntao.wang@linux.dev Signed-off-by: Rob Herring (Arm) Signed-off-by: Sasha Levin

of/fdt: Consolidate duplicate code into helper functions

2025-12-18T13:03:07+00:00

[ Upstream commit 8278cb72c60399f6dc6300c409879fb4c7291513 ] Currently, there are many pieces of nearly identical code scattered across different places. Consolidate the duplicate code into helper functions to improve maintainability and reduce the likelihood of errors. Signed-off-by: Yuntao Wang Link: https://patch.msgid.link/20251115134753.179931-2-yuntao.wang@linux.dev Signed-off-by: Rob Herring (Arm) Stable-dep-of: bec5f6092bc1 ("of/fdt: Fix the len check in early_init_dt_check_for_elfcorehdr()") Signed-off-by: Sasha Levin

arm64: add KHO support

2025-05-13T06:50:41+00:00

We now have all bits in place to support KHO kexecs. Add awareness of KHO in the kexec file as well as boot path for arm64 and adds the respective kconfig option to the architecture so that it can use KHO successfully. Changes to the "chosen" node have been sent to https://github.com/devicetree-org/dt-schema/pull/158. Link: https://lkml.kernel.org/r/20250509074635.3187114-10-changyuanl@google.com Signed-off-by: Alexander Graf Co-developed-by: Mike Rapoport (Microsoft) Signed-off-by: Mike Rapoport (Microsoft) Co-developed-by: Changyuan Lyu Signed-off-by: Changyuan Lyu Cc: Andy Lutomirski Cc: Anthony Yznaga Cc: Arnd Bergmann Cc: Ashish Kalra Cc: Ben Herrenschmidt Cc: Borislav Betkov Cc: Catalin Marinas Cc: Dave Hansen Cc: David Woodhouse Cc: Eric Biederman Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: James Gowans Cc: Jason Gunthorpe Cc: Jonathan Corbet Cc: Krzysztof Kozlowski Cc: Marc Rutland Cc: Paolo Bonzini Cc: Pasha Tatashin Cc: Peter Zijlstra Cc: Pratyush Yadav Cc: Rob Herring Cc: Saravana Kannan Cc: Stanislav Kinsburskii Cc: Steven Rostedt Cc: Thomas Gleinxer Cc: Thomas Lendacky Cc: Will Deacon Signed-off-by: Andrew Morton

Merge tag 'mm-stable-2025-01-26-14-59' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-01-27T02:36:23+00:00

Pull MM updates from Andrew Morton: "The various patchsets are summarized below. Plus of course many indivudual patches which are described in their changelogs. - "Allocate and free frozen pages" from Matthew Wilcox reorganizes the page allocator so we end up with the ability to allocate and free zero-refcount pages. So that callers (ie, slab) can avoid a refcount inc & dec - "Support large folios for tmpfs" from Baolin Wang teaches tmpfs to use large folios other than PMD-sized ones - "Fix mm/rodata_test" from Petr Tesarik performs some maintenance and fixes for this small built-in kernel selftest - "mas_anode_descend() related cleanup" from Wei Yang tidies up part of the mapletree code - "mm: fix format issues and param types" from Keren Sun implements a few minor code cleanups - "simplify split calculation" from Wei Yang provides a few fixes and a test for the mapletree code - "mm/vma: make more mmap logic userland testable" from Lorenzo Stoakes continues the work of moving vma-related code into the (relatively) new mm/vma.c - "mm/page_alloc: gfp flags cleanups for alloc_contig_*()" from David Hildenbrand cleans up and rationalizes handling of gfp flags in the page allocator - "readahead: Reintroduce fix for improper RA window sizing" from Jan Kara is a second attempt at fixing a readahead window sizing issue. It should reduce the amount of unnecessary reading - "synchronously scan and reclaim empty user PTE pages" from Qi Zheng addresses an issue where "huge" amounts of pte pagetables are accumulated: https://lore.kernel.org/lkml/cover.1718267194.git.zhengqi.arch@bytedance.com/ Qi's series addresses this windup by synchronously freeing PTE memory within the context of madvise(MADV_DONTNEED) - "selftest/mm: Remove warnings found by adding compiler flags" from Muhammad Usama Anjum fixes some build warnings in the selftests code when optional compiler warnings are enabled - "mm: don't use __GFP_HARDWALL when migrating remote pages" from David Hildenbrand tightens the allocator's observance of __GFP_HARDWALL - "pkeys kselftests improvements" from Kevin Brodsky implements various fixes and cleanups in the MM selftests code, mainly pertaining to the pkeys tests - "mm/damon: add sample modules" from SeongJae Park enhances DAMON to estimate application working set size - "memcg/hugetlb: Rework memcg hugetlb charging" from Joshua Hahn provides some cleanups to memcg's hugetlb charging logic - "mm/swap_cgroup: remove global swap cgroup lock" from Kairui Song removes the global swap cgroup lock. A speedup of 10% for a tmpfs-based kernel build was demonstrated - "zram: split page type read/write handling" from Sergey Senozhatsky has several fixes and cleaups for zram in the area of zram_write_page(). A watchdog softlockup warning was eliminated - "move pagetable_*_dtor() to __tlb_remove_table()" from Kevin Brodsky cleans up the pagetable destructor implementations. A rare use-after-free race is fixed - "mm/debug: introduce and use VM_WARN_ON_VMG()" from Lorenzo Stoakes simplifies and cleans up the debugging code in the VMA merging logic - "Account page tables at all levels" from Kevin Brodsky cleans up and regularizes the pagetable ctor/dtor handling. This results in improvements in accounting accuracy - "mm/damon: replace most damon_callback usages in sysfs with new core functions" from SeongJae Park cleans up and generalizes DAMON's sysfs file interface logic - "mm/damon: enable page level properties based monitoring" from SeongJae Park increases the amount of information which is presented in response to DAMOS actions - "mm/damon: remove DAMON debugfs interface" from SeongJae Park removes DAMON's long-deprecated debugfs interfaces. Thus the migration to sysfs is completed - "mm/hugetlb: Refactor hugetlb allocation resv accounting" from Peter Xu cleans up and generalizes the hugetlb reservation accounting - "mm: alloc_pages_bulk: small API refactor" from Luiz Capitulino removes a never-used feature of the alloc_pages_bulk() interface - "mm/damon: extend DAMOS filters for inclusion" from SeongJae Park extends DAMOS filters to support not only exclusion (rejecting), but also inclusion (allowing) behavior - "Add zpdesc memory descriptor for zswap.zpool" from Alex Shi introduces a new memory descriptor for zswap.zpool that currently overlaps with struct page for now. This is part of the effort to reduce the size of struct page and to enable dynamic allocation of memory descriptors - "mm, swap: rework of swap allocator locks" from Kairui Song redoes and simplifies the swap allocator locking. A speedup of 400% was demonstrated for one workload. As was a 35% reduction for kernel build time with swap-on-zram - "mm: update mips to use do_mmap(), make mmap_region() internal" from Lorenzo Stoakes reworks MIPS's use of mmap_region() so that mmap_region() can be made MM-internal - "mm/mglru: performance optimizations" from Yu Zhao fixes a few MGLRU regressions and otherwise improves MGLRU performance - "Docs/mm/damon: add tuning guide and misc updates" from SeongJae Park updates DAMON documentation - "Cleanup for memfd_create()" from Isaac Manjarres does that thing - "mm: hugetlb+THP folio and migration cleanups" from David Hildenbrand provides various cleanups in the areas of hugetlb folios, THP folios and migration - "Uncached buffered IO" from Jens Axboe implements the new RWF_DONTCACHE flag which provides synchronous dropbehind for pagecache reading and writing. To permite userspace to address issues with massive buildup of useless pagecache when reading/writing fast devices - "selftests/mm: virtual_address_range: Reduce memory" from Thomas Weißschuh fixes and optimizes some of the MM selftests" * tag 'mm-stable-2025-01-26-14-59' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits) mm/compaction: fix UBSAN shift-out-of-bounds warning s390/mm: add missing ctor/dtor on page table upgrade kasan: sw_tags: use str_on_off() helper in kasan_init_sw_tags() tools: add VM_WARN_ON_VMG definition mm/damon/core: use str_high_low() helper in damos_wmark_wait_us() seqlock: add missing parameter documentation for raw_seqcount_try_begin() mm/page-writeback: consolidate wb_thresh bumping logic into __wb_calc_thresh mm/page_alloc: remove the incorrect and misleading comment zram: remove zcomp_stream_put() from write_incompressible_page() mm: separate move/undo parts from migrate_pages_batch() mm/kfence: use str_write_read() helper in get_access_type() selftests/mm/mkdirty: fix memory leak in test_uffdio_copy() kasan: hw_tags: Use str_on_off() helper in kasan_init_hw_tags() selftests/mm: virtual_address_range: avoid reading from VM_IO mappings selftests/mm: vm_util: split up /proc/self/smaps parsing selftests/mm: virtual_address_range: unmap chunks after validation selftests/mm: virtual_address_range: mmap() without PROT_WRITE selftests/memfd/memfd_test: fix possible NULL pointer dereference mm: add FGP_DONTCACHE folio creation flag mm: call filemap_fdatawrite_range_kick() after IOCB_DONTCACHE issue ...

mm/memblock: add memblock_alloc_or_panic interface

2025-01-26T04:22:38+00:00

Before SLUB initialization, various subsystems used memblock_alloc to allocate memory. In most cases, when memory allocation fails, an immediate panic is required. To simplify this behavior and reduce repetitive checks, introduce `memblock_alloc_or_panic`. This function ensures that memory allocation failures result in a panic automatically, improving code readability and consistency across subsystems that require this behavior. [guoweikang.kernel@gmail.com: arch/s390: save_area_alloc default failure behavior changed to panic] Link: https://lkml.kernel.org/r/20250109033136.2845676-1-guoweikang.kernel@gmail.com Link: https://lore.kernel.org/lkml/Z2fknmnNtiZbCc7x@kernel.org/ Link: https://lkml.kernel.org/r/20250102072528.650926-1-guoweikang.kernel@gmail.com Signed-off-by: Guo Weikang Acked-by: Geert Uytterhoeven [m68k] Reviewed-by: Alexander Gordeev [s390] Acked-by: Mike Rapoport (Microsoft) Cc: Alexander Gordeev Signed-off-by: Andrew Morton

of/fdt: Restore possibility to use both ACPI and FDT from bootloader

2025-01-24T21:57:08+00:00

There are cases when the bootloader provides information to the kernel in both ACPI and DTB, not interchangeably. One such use case is virtual machines in Android. When running on x86, the Android Virtualization Framework (AVF) boots VMs with ACPI like it is usually done on x86 (i.e. the virtual LAPIC, IOAPIC, HPET, PCI MMCONFIG etc are described in ACPI) but also passes various AVF-specific boot parameters in DTB. This allows reusing the same implementations of various AVF components on both arm64 and x86. Commit 7b937cc243e5 ("of: Create of_root if no dtb provided by firmware") removed the possibility to do that, since among other things it introduced forcing emptying the bootloader-provided DTB if ACPI is enabled (probably assuming that if ACPI is available, a DTB can only be useful for applying overlays to it afterwards, for testing purposes). So restore this possibility. Instead of completely preventing using ACPI and DT together, rely on arch-specific setup code to prevent using both to set up the same things (see various acpi_disabled checks under arch/). Fixes: 7b937cc243e5 ("of: Create of_root if no dtb provided by firmware") Signed-off-by: Dmytro Maluka Link: https://lore.kernel.org/r/20250105172741.3476758-3-dmaluka@chromium.org Signed-off-by: Rob Herring (Arm)

of/fdt: Check fdt_get_mem_rsv() error in early_init_fdt_scan_reserved_mem()

2025-01-13T23:47:29+00:00

early_init_fdt_scan_reserved_mem() invoks fdt_get_mem_rsv(), and it will use uninitialized variables @base and @size once the callee suffers error. Fix by checking fdt_get_mem_rsv() error as other callers do. Signed-off-by: Zijun Hu Link: https://lore.kernel.org/r/20250109-of_core_fix-v4-13-db8a72415b8c@quicinc.com Signed-off-by: Rob Herring (Arm)