kernel/linux.git/arch/arm64/include/asm/pgalloc.h, branch v6.18.21

arm64: pgtable: use mmu gather to free p4d level page table

2025-01-26T04:22:21+00:00

Like other levels of page tables, also use mmu gather mechanism to free p4d level page table. Link: https://lkml.kernel.org/r/3fd48525397b34a64f7c0eb76746da30814dc941.1736317725.git.zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng Originally-by: Peter Zijlstra (Intel) Reviewed-by: Kevin Brodsky Cc: Alexander Gordeev Cc: Alexandre Ghiti Cc: Alexandre Ghiti Cc: Andreas Larsson Cc: Aneesh Kumar K.V (Arm) Cc: Arnd Bergmann Cc: Dave Hansen Cc: David Hildenbrand Cc: David Rientjes Cc: Hugh Dickins Cc: Jann Horn Cc: Lorenzo Stoakes Cc: Matthew Wilcox (Oracle) Cc: Mike Rapoport (Microsoft) Cc: Muchun Song Cc: Nicholas Piggin Cc: Palmer Dabbelt Cc: Ryan Roberts Cc: Thomas Gleixner Cc: Vishal Moola (Oracle) Cc: Will Deacon Cc: Yu Zhao Signed-off-by: Andrew Morton

asm-generic: pgalloc: provide generic p4d_{alloc_one,free}

2025-01-26T04:22:21+00:00

Four architectures currently implement 5-level pgtables: arm64, riscv, x86 and s390. The first three have essentially the same implementation for p4d_alloc_one() and p4d_free(), so we've got an opportunity to reduce duplication like at the lower levels. Provide a generic version of p4d_alloc_one() and p4d_free(), and make use of it on those architectures. Their implementation is the same as at PUD level, except that p4d_free() performs a runtime check by calling mm_p4d_folded(). 5-level pgtables depend on a runtime-detected hardware feature on all supported architectures, so we might as well include this check in the generic implementation. No runtime check is required in p4d_alloc_one() as the top-level p4d_alloc() already does the required check. Link: https://lkml.kernel.org/r/26d69c74a29183ecc335b9b407040d8e4cd70c6a.1736317725.git.zhengqi.arch@bytedance.com Signed-off-by: Kevin Brodsky Signed-off-by: Qi Zheng Acked-by: Dave Hansen Acked-by: Arnd Bergmann [asm-generic] Cc: Alexander Gordeev Cc: Alexandre Ghiti Cc: Alexandre Ghiti Cc: Andreas Larsson Cc: Aneesh Kumar K.V (Arm) Cc: David Hildenbrand Cc: David Rientjes Cc: Hugh Dickins Cc: Jann Horn Cc: Lorenzo Stoakes Cc: Matthew Wilcox (Oracle) Cc: Mike Rapoport (Microsoft) Cc: Muchun Song Cc: Nicholas Piggin Cc: Palmer Dabbelt Cc: Peter Zijlstra (Intel) Cc: Ryan Roberts Cc: Thomas Gleixner Cc: Vishal Moola (Oracle) Cc: Will Deacon Cc: Yu Zhao Signed-off-by: Andrew Morton

arm64: Add support for FEAT_HAFT

2024-11-05T13:18:35+00:00

Armv8.9/v9.4 introduces the feature Hardware managed Access Flag for Table descriptors (FEAT_HAFT). The feature is indicated by ID_AA64MMFR1_EL1.HAFDBS == 0b0011 and can be enabled by TCR2_EL1.HAFT so it has a dependency on FEAT_TCR2. Adds the Kconfig for FEAT_HAFT and support detecting and enabling the feature. The feature is enabled in __cpu_setup() before MMU on just like HA. A CPU capability is added to notify the user of the feature. Add definition of P{G,4,U,M}D_TABLE_AF bit and set the AF bit when creating the page table, which will save the hardware from having to update them at runtime. This will be ignored if FEAT_HAFT is not enabled. The AF bit of table descriptors cannot be managed by the software per spec, unlike the HA. So this should be used only if it's supported system wide by system_supports_haft(). Signed-off-by: Yicong Yang Link: https://lore.kernel.org/r/20241102104235.62560-4-yangyicong@huawei.com Reviewed-by: Catalin Marinas [catalin.marinas@arm.com: added the ID check back to __cpu_setup in case of future CPU errata] Signed-off-by: Catalin Marinas

arm64/mm: Use generic __pud_free() helper in pud_free() implementation

2024-03-01T15:25:45+00:00

Commit 0dd4f60a2c76 ("arm64: mm: Add support for folding PUDs at runtime") implements specialized PUD alloc/free helpers to allow the decision whether or not to fold PUDs to be made at runtime when the number of paging levels is 4 or higher. Its implementation of pud_free() is based on the generic version that existed when the patch was first written, but in the meantime, the freeing of a PUD has become a bit more involved, and so instead of simply freeing the page, we should invoke the generic __pud_free() that encapsulates whatever needs doing at this point. This fixes a reported warning emitted by the page flags self-diagnostics. Reported-by: Ryan Roberts Signed-off-by: Ard Biesheuvel Tested-by: Ryan Roberts Link: https://lore.kernel.org/r/20240301104046.1234309-5-ardb+git@google.com Signed-off-by: Catalin Marinas

arm64: mm: Add support for folding PUDs at runtime

2024-02-16T12:42:41+00:00

In order to support LPA2 on 16k pages in a way that permits non-LPA2 systems to run the same kernel image, we have to be able to fall back to at most 48 bits of virtual addressing. Falling back to 48 bits would result in a level 0 with only 2 entries, which is suboptimal in terms of TLB utilization. So instead, let's fall back to 47 bits in that case. This means we need to be able to fold PUDs dynamically, similar to how we fold P4Ds for 48 bit virtual addressing on LPA2 with 4k pages. Signed-off-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20240214122845.2033971-81-ardb+git@google.com Signed-off-by: Catalin Marinas

arm64: mm: Add definitions to support 5 levels of paging

2024-02-16T12:42:39+00:00

Add the required types and descriptor accessors to support 5 levels of paging in the common code. This is one of the prerequisites for supporting 52-bit virtual addressing with 4k pages. Note that this does not cover the code that handles kernel mappings or the fixmap. Signed-off-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20240214122845.2033971-76-ardb+git@google.com Signed-off-by: Catalin Marinas

arm64: mm: Fix VM_BUG_ON(mm != &init_mm) for trans_pgd

2021-11-16T10:12:57+00:00

trans_pgd_create_copy() can hit "VM_BUG_ON(mm != &init_mm)" in the function pmd_populate_kernel(). This is the combined consequence of commit 5de59884ac0e ("arm64: trans_pgd: pass NULL instead of init_mm to *_populate functions"), which replaced &init_mm with NULL and commit 59511cfd08f3 ("arm64: mm: use XN table mapping attributes for user/kernel mappings"), which introduced the VM_BUG_ON. Since the former sounds reasonable, it is better to work on the later. From the perspective of trans_pgd, two groups of functions are considered in the later one: pmd_populate_kernel() mm == NULL should be fixed, else it hits VM_BUG_ON() p?d_populate() mm == NULL means PXN, that is OK, since trans_pgd only copies a linear map, no execution will happen on the map. So it is good enough to just relax VM_BUG_ON() to disregard mm == NULL Fixes: 59511cfd08f3 ("arm64: mm: use XN table mapping attributes for user/kernel mappings") Signed-off-by: Pingfan Liu Cc: # 5.13.x Cc: Ard Biesheuvel Cc: James Morse Cc: Matthias Brugger Reviewed-by: Catalin Marinas Reviewed-by: Pasha Tatashin Link: https://lore.kernel.org/r/20211112052214.9086-1-kernelfans@gmail.com Signed-off-by: Will Deacon

mm/thp: define default pmd_pgtable()

2021-07-01T18:06:03+00:00

Currently most platforms define pmd_pgtable() as pmd_page() duplicating the same code all over. Instead just define a default value i.e pmd_page() for pmd_pgtable() and let platforms override when required via . All the existing platform that override pmd_pgtable() have been moved into their respective header in order to precede before the new generic definition. This makes it much cleaner with reduced code. Link: https://lkml.kernel.org/r/1623646133-20306-1-git-send-email-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual Acked-by: Geert Uytterhoeven Acked-by: Mike Rapoport Cc: Nick Hu Cc: Richard Henderson Cc: Vineet Gupta Cc: Catalin Marinas Cc: Will Deacon Cc: Guo Ren Cc: Brian Cain Cc: Geert Uytterhoeven Cc: Michal Simek Cc: Thomas Bogendoerfer Cc: Ley Foon Tan Cc: Jonas Bonn Cc: Stefan Kristiansson Cc: Stafford Horne Cc: "James E.J. Bottomley" Cc: Michael Ellerman Cc: Christophe Leroy Cc: Paul Walmsley Cc: Palmer Dabbelt Cc: Heiko Carstens Cc: Yoshinori Sato Cc: "David S. Miller" Cc: Jeff Dike Cc: Thomas Gleixner Cc: Chris Zankel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

arm64: mm: use XN table mapping attributes for user/kernel mappings

2021-03-19T18:50:46+00:00

As the kernel and user space page tables are strictly mutually exclusive when it comes to executable permissions, we can set the UXN table attribute on all table entries that are created while creating kernel mappings in the swapper page tables, and the PXN table attribute on all table entries that are created while creating user space mappings in user space page tables. While at it, get rid of a redundant comment. Reviewed-by: Anshuman Khandual Signed-off-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20210310104942.174584-4-ardb@kernel.org Signed-off-by: Catalin Marinas

arm64: mm: add missing P4D definitions and use them consistently

2021-03-19T18:47:15+00:00

Even though level 0, 1 and 2 descriptors share the same attribute encodings, let's be a bit more consistent about using the right one at the right level. So add new macros for level 0/P4D definitions, and clean up some inconsistencies involving these macros. Acked-by: Mark Rutland Reviewed-by: Anshuman Khandual Signed-off-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20210310104942.174584-2-ardb@kernel.org Signed-off-by: Catalin Marinas