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

mm: call ctor/dtor for kernel PTEs

2025-05-12T00:48:21+00:00

Since [1], constructors/destructors are expected to be called for all page table pages, at all levels and for both user and kernel pgtables. There is however one glaring exception: kernel PTEs are managed via separate helpers (pte_alloc_kernel/pte_free_kernel), which do not call the [cd]tor, at least not in the generic implementation. The most obvious reason for this anomaly is that init_mm is special-cased not to use split page table locks. As a result calling ptlock_init() for PTEs associated with init_mm would be wasteful, potentially resulting in dynamic memory allocation. However, pgtable [cd]tors perform other actions - currently related to accounting/statistics, and potentially more functionally significant in the future. Now that pagetable_pte_ctor() is passed the associated mm, we can make it skip the call to ptlock_init() for init_mm; this allows us to call the ctor from pte_alloc_one_kernel() too. This is matched by a call to the pgtable destructor in pte_free_kernel(); no special-casing is needed on that path, as ptlock_free() is already called unconditionally. (ptlock_free() is a no-op unless a ptlock was allocated for the given PTP.) This patch ensures that all architectures that rely on call the [cd]tor for kernel PTEs. pte_free_kernel() cannot be overridden so changing the generic implementation is sufficient. pte_alloc_one_kernel() can be overridden using __HAVE_ARCH_PTE_ALLOC_ONE_KERNEL, and a few architectures implement it by calling the page allocator directly. We amend those so that they call the generic __pte_alloc_one_kernel() instead, if possible, ensuring that the ctor is called. A few architectures do not use ; those will be taken care of separately. [1] https://lore.kernel.org/linux-mm/20250103184415.2744423-1-kevin.brodsky@arm.com/ Link: https://lkml.kernel.org/r/20250408095222.860601-4-kevin.brodsky@arm.com Signed-off-by: Kevin Brodsky Reviewed-by: Alexander Gordeev # s390 Cc: Albert Ou Cc: Andreas Larsson Cc: Catalin Marinas Cc: David S. Miller Cc: Geert Uytterhoeven Cc: Linus Waleij Cc: Madhavan Srinivasan Cc: Mark Rutland Cc: Matthew Wilcox (Oracle) Cc: Michael Ellerman Cc: Mike Rapoport Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Zijlstra Cc: Qi Zheng Cc: Ryan Roberts Cc: Will Deacon Cc: Cc: Yang Shi Cc: Dave Hansen Signed-off-by: Andrew Morton

mm: pgtable: convert some architectures to use tlb_remove_ptdesc()

2025-04-01T22:17:13+00:00

Now, the nine architectures of csky, hexagon, loongarch, m68k, mips, nios2, openrisc, sh and um do not select CONFIG_MMU_GATHER_RCU_TABLE_FREE, and just call pagetable_dtor() + tlb_remove_page_ptdesc() (the wrapper of tlb_remove_page()). This is the same as the implementation of tlb_remove_{ptdesc|table}() under !CONFIG_MMU_GATHER_TABLE_FREE, so convert these architectures to use tlb_remove_ptdesc(). The ultimate goal is to make the architecture only use tlb_remove_ptdesc() or tlb_remove_table() for page table pages. [zhengqi.arch@bytedance.com: v2] Link: https://lkml.kernel.org/r/20250303072603.45423-1-zhengqi.arch@bytedance.com [akpm@linux-foundation.org: remove trailing semi in arch/loongarch/include/asm/pgalloc.h] Link: https://lkml.kernel.org/r/19db3e8673b67bad2f1df1ab37f1c89d99eacfea.1740454179.git.zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng Suggested-by: Peter Zijlstra (Intel) Reviewed-by: Kevin Brodsky Acked-by: Geert Uytterhoeven [m68k] Cc: Alexandre Ghiti Cc: "Aneesh Kumar K.V" Cc: Arnd Bergmann Cc: Dave Hansen Cc: David Hildenbrand Cc: Hugh Dickens Cc: Jann Horn Cc: Matthew Wilcow (Oracle) Cc: "Mike Rapoport (IBM)" Cc: Muchun Song Cc: Nicholas Piggin Cc: Rik van Riel Cc: Vishal Moola (Oracle) Cc: Will Deacon Cc: Yu Zhao Signed-off-by: Andrew Morton

asm-generic: pgalloc: provide generic __pgd_{alloc,free}

2025-01-26T04:22:24+00:00

We already have a generic implementation of alloc/free up to P4D level, as well as pgd_free(). Let's finish the work and add a generic PGD-level alloc helper as well. Unlike at lower levels, almost all architectures need some specific magic at PGD level (typically initialising PGD entries), so introducing a generic pgd_alloc() isn't worth it. Instead we introduce two new helpers, __pgd_alloc() and __pgd_free(), and make use of them in the arch-specific pgd_alloc() and pgd_free() wherever possible. To accommodate as many arch as possible, __pgd_alloc() takes a page allocation order. Because pagetable_alloc() allocates zeroed pages, explicit zeroing in pgd_alloc() becomes redundant and we can get rid of it. Some trivial implementations of pgd_free() also become unnecessary once __pgd_alloc() is used; remove them. Another small improvement is consistent accounting of PGD pages by using GFP_PGTABLE_{USER,KERNEL} as appropriate. Not all PGD allocations can be handled by the generic helpers. In particular, multiple architectures allocate PGDs from a kmem_cache, and those PGDs may not be page-sized. Link: https://lkml.kernel.org/r/20250103184415.2744423-6-kevin.brodsky@arm.com Signed-off-by: Kevin Brodsky Acked-by: Dave Hansen Acked-by: Qi Zheng Cc: Andy Lutomirski Cc: Catalin Marinas Cc: Ingo Molnar Cc: Linus Walleij Cc: Matthew Wilcox (Oracle) Cc: Mike Rapoport (Microsoft) Cc: Peter Zijlstra Cc: Ryan Roberts Cc: Thomas Gleixner Cc: Will Deacon Signed-off-by: Andrew Morton

mm: pgtable: introduce pagetable_dtor()

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

The pagetable_p*_dtor() are exactly the same except for the handling of ptlock. If we make ptlock_free() handle the case where ptdesc->ptl is NULL and remove VM_BUG_ON_PAGE() from pmd_ptlock_free(), we can unify pagetable_p*_dtor() into one function. Let's introduce pagetable_dtor() to do this. Later, pagetable_dtor() will be moved to tlb_remove_ptdesc(), so that ptlock and page table pages can be freed together (regardless of whether RCU is used). This prevents the use-after-free problem where the ptlock is freed immediately but the page table pages is freed later via RCU. Link: https://lkml.kernel.org/r/47f44fff9dc68d9d9e9a0d6c036df275f820598a.1736317725.git.zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng Originally-by: Peter Zijlstra (Intel) Reviewed-by: Kevin Brodsky Acked-by: Alexander Gordeev [s390] 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

csky: convert __pte_free_tlb() to use ptdescs

2023-08-21T20:37:55+00:00

Part of the conversions to replace pgtable constructor/destructors with ptdesc equivalents. Link: https://lkml.kernel.org/r/20230807230513.102486-20-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) Acked-by: Guo Ren Acked-by: Mike Rapoport (IBM) Cc: Arnd Bergmann Cc: Catalin Marinas Cc: Christophe Leroy Cc: Claudio Imbrenda Cc: Dave Hansen Cc: David Hildenbrand Cc: "David S. Miller" Cc: Dinh Nguyen Cc: Geert Uytterhoeven Cc: Geert Uytterhoeven Cc: Huacai Chen Cc: Hugh Dickins Cc: John Paul Adrian Glaubitz Cc: Jonas Bonn Cc: Matthew Wilcox Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Richard Weinberger Cc: Thomas Bogendoerfer Cc: Yoshinori Sato Signed-off-by: Andrew Morton

csky: drop definition of PGD_ORDER

2022-07-18T00:14:42+00:00

This is the order of the page table allocation, not the order of a PGD. Since its always hardwired to 0, simply drop it. Link: https://lkml.kernel.org/r/20220703141203.147893-3-rppt@kernel.org Signed-off-by: Mike Rapoport Cc: Arnd Bergmann Cc: Dinh Nguyen Cc: Guo Ren Cc: Helge Deller Cc: Huacai Chen Cc: James Bottomley Cc: "Matthew Wilcox (Oracle)" Cc: Max Filippov Cc: Thomas Bogendoerfer Cc: Xuerui Wang Signed-off-by: Andrew Morton

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

csky: Fixup compile error

2021-02-27T14:04:14+00:00

csky: Add memory layout 2.5G(user):1.5G(kernel)

2021-01-12T01:52:40+00:00

There are two ways for translating va to pa for csky: - Use TLB(Translate Lookup Buffer) and PTW (Page Table Walk) - Use SSEG0/1 (Simple Segment Mapping) We use tlb mapping 0-2G and 3G-4G virtual address area and SSEG0/1 are for 2G-2.5G and 2.5G-3G translation. We could disable SSEG0 to use 2G-2.5G as TLB user mapping. Signed-off-by: Guo Ren

asm-generic: pgalloc: provide generic pgd_free()

2020-08-07T18:33:26+00:00

Most architectures define pgd_free() as a wrapper for free_page(). Provide a generic version in asm-generic/pgalloc.h and enable its use for most architectures. Signed-off-by: Mike Rapoport Signed-off-by: Andrew Morton Reviewed-by: Pekka Enberg Acked-by: Geert Uytterhoeven [m68k] Cc: Abdul Haleem Cc: Andy Lutomirski Cc: Arnd Bergmann Cc: Christophe Leroy Cc: Joerg Roedel Cc: Joerg Roedel Cc: Max Filippov Cc: Peter Zijlstra (Intel) Cc: Satheesh Rajendran Cc: Stafford Horne Cc: Stephen Rothwell Cc: Steven Rostedt Cc: Matthew Wilcox Link: http://lkml.kernel.org/r/20200627143453.31835-7-rppt@kernel.org Signed-off-by: Linus Torvalds