pm24.git/arch/riscv/mm/fault.c, branch rust-6.8

riscv: handle VM_FAULT_[HWPOISON|HWPOISON_LARGE] faults instead of panicking

2023-10-06T21:11:38Z

Patch series "Fix set_huge_pte_at()". A recent report [1] from Ryan for arm64 revealed that we do not handle swap entries when setting a hugepage backed by a NAPOT region (the contpte riscv equivalent). As explained in [1], the issue was discovered by a new test in kselftest which uses poison entries, but the symptoms are different from arm64 though: - the riscv kernel bugs because we do not handle VM_FAULT_HWPOISON*, this is fixed by patch 1, - after that, the test passes because the first pte_napot() fails (the poison entry does not have the N bit set), and then we only set the first page table entry covering the NAPOT hugepage, which is enough for hugetlb_fault() to correctly raise a VM_FAULT_HWPOISON wherever we write in this mapping since only this first page table entry is checked (see https://elixir.bootlin.com/linux/v6.6-rc3/source/mm/hugetlb.c#L6071). But this seems fragile so patch 2 sets all page table entries of a NAPOT mapping. [1]: https://lore.kernel.org/linux-arm-kernel/20230922115804.2043771-1-ryan.roberts@arm.com/ This patch (of 2): We used to panic when such faults were encountered but we should handle those faults gracefully for userspace by sending a SIGBUS to the process, like most architectures do. Link: https://lkml.kernel.org/r/20230928151846.8229-1-alexghiti@rivosinc.com Link: https://lkml.kernel.org/r/20230928151846.8229-2-alexghiti@rivosinc.com Signed-off-by: Alexandre Ghiti Acked-by: Palmer Dabbelt Cc: Albert Ou Cc: Andrew Jones Cc: Conor Dooley Cc: Paul Walmsley Cc: Qinglin Pan Signed-off-by: Andrew Morton

mm: drop per-VMA lock when returning VM_FAULT_RETRY or VM_FAULT_COMPLETED

2023-08-24T23:20:17Z

handle_mm_fault returning VM_FAULT_RETRY or VM_FAULT_COMPLETED means mmap_lock has been released. However with per-VMA locks behavior is different and the caller should still release it. To make the rules consistent for the caller, drop the per-VMA lock when returning VM_FAULT_RETRY or VM_FAULT_COMPLETED. Currently the only path returning VM_FAULT_RETRY under per-VMA locks is do_swap_page and no path returns VM_FAULT_COMPLETED for now. [willy@infradead.org: fix riscv] Link: https://lkml.kernel.org/r/CAJuCfpE6GWEx1rPBmNpUfoD5o-gNFz9-UFywzCE2PbEGBiVz7g@mail.gmail.com Link: https://lkml.kernel.org/r/20230630211957.1341547-4-surenb@google.com Signed-off-by: Suren Baghdasaryan Acked-by: Peter Xu Tested-by: Conor Dooley Cc: Alistair Popple Cc: Al Viro Cc: Christian Brauner Cc: Christoph Hellwig Cc: David Hildenbrand Cc: David Howells Cc: Davidlohr Bueso Cc: Hillf Danton Cc: "Huang, Ying" Cc: Hugh Dickins Cc: Jan Kara Cc: Johannes Weiner Cc: Josef Bacik Cc: Laurent Dufour Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Matthew Wilcox Cc: Michal Hocko Cc: Michel Lespinasse Cc: Minchan Kim Cc: Pavel Tatashin Cc: Punit Agrawal Cc: Vlastimil Babka Cc: Yu Zhao Signed-off-by: Andrew Morton

mm: remove CONFIG_PER_VMA_LOCK ifdefs

2023-08-18T17:12:50Z

Patch series "Handle most file-backed faults under the VMA lock", v3. This patchset adds the ability to handle page faults on parts of files which are already in the page cache without taking the mmap lock. This patch (of 10): Provide lock_vma_under_rcu() when CONFIG_PER_VMA_LOCK is not defined to eliminate ifdefs in the users. Link: https://lkml.kernel.org/r/20230724185410.1124082-1-willy@infradead.org Link: https://lkml.kernel.org/r/20230724185410.1124082-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Suren Baghdasaryan Cc: Punit Agrawal Cc: Arjun Roy Cc: Eric Dumazet Signed-off-by: Andrew Morton

Merge tag 'riscv-for-linus-6.5-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

2023-06-30T16:37:26Z

Pull RISC-V updates from Palmer Dabbelt: - Support for ACPI - Various cleanups to the ISA string parsing, including making them case-insensitive - Support for the vector extension - Support for independent irq/softirq stacks - Our CPU DT binding now has "unevaluatedProperties: false" * tag 'riscv-for-linus-6.5-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (78 commits) riscv: hibernate: remove WARN_ON in save_processor_state dt-bindings: riscv: cpus: switch to unevaluatedProperties: false dt-bindings: riscv: cpus: add a ref the common cpu schema riscv: stack: Add config of thread stack size riscv: stack: Support HAVE_SOFTIRQ_ON_OWN_STACK riscv: stack: Support HAVE_IRQ_EXIT_ON_IRQ_STACK RISC-V: always report presence of extensions formerly part of the base ISA dt-bindings: riscv: explicitly mention assumption of Zicntr & Zihpm support RISC-V: remove decrement/increment dance in ISA string parser RISC-V: rework comments in ISA string parser RISC-V: validate riscv,isa at boot, not during ISA string parsing RISC-V: split early & late of_node to hartid mapping RISC-V: simplify register width check in ISA string parsing perf: RISC-V: Limit the number of counters returned from SBI riscv: replace deprecated scall with ecall riscv: uprobes: Restore thread.bad_cause riscv: mm: try VMA lock-based page fault handling first riscv: mm: Pre-allocate PGD entries for vmalloc/modules area RISC-V: hwprobe: Expose Zba, Zbb, and Zbs RISC-V: Track ISA extensions per hart ...

riscv/mm: Convert to using lock_mm_and_find_vma()

2023-06-24T21:12:58Z

Signed-off-by: Ben Hutchings Signed-off-by: Linus Torvalds

riscv: mm: try VMA lock-based page fault handling first

2023-06-20T15:10:13Z

Attempt VMA lock-based page fault handling first, and fall back to the existing mmap_lock-based handling if that fails. A simple running the ebizzy benchmark on Lichee Pi 4A shows that PER_VMA_LOCK can improve the ebizzy benchmark by about 32.68%. In theory, the more CPUs, the bigger improvement, but I don't have any HW platform which has more than 4 CPUs. This is the riscv variant of "x86/mm: try VMA lock-based page fault handling first". Signed-off-by: Jisheng Zhang Reviewed-by: Guo Ren Reviewed-by: Suren Baghdasaryan Link: https://lore.kernel.org/r/20230523165942.2630-1-jszhang@kernel.org Signed-off-by: Palmer Dabbelt

riscv: mm: Pre-allocate PGD entries for vmalloc/modules area

2023-06-20T00:58:01Z

The RISC-V port requires that kernel PGD entries are to be synchronized between MMs. This is done via the vmalloc_fault() function, that simply copies the PGD entries from init_mm to the faulting one. Historically, faulting in PGD entries have been a source for both bugs [1], and poor performance. One way to get rid of vmalloc faults is by pre-allocating the PGD entries. Pre-allocating the entries potientially wastes 64 * 4K (65 on SV39). The pre-allocation function is pulled from Jörg Rödel's x86 work, with the addition of 3-level page tables (PMD allocations). The pmd_alloc() function needs the ptlock cache to be initialized (when split page locks is enabled), so the pre-allocation is done in a RISC-V specific pgtable_cache_init() implementation. Pre-allocate the kernel PGD entries for the vmalloc/modules area, but only for 64b platforms. Link: https://lore.kernel.org/lkml/20200508144043.13893-1-joro@8bytes.org/ # [1] Signed-off-by: Björn Töpel Reviewed-by: Alexandre Ghiti Link: https://lore.kernel.org/r/20230531093817.665799-1-bjorn@kernel.org Signed-off-by: Palmer Dabbelt

Merge tag 'riscv-for-linus-6.4-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

2023-04-28T23:55:39Z

Pull RISC-V updates from Palmer Dabbelt: - Support for runtime detection of the Svnapot extension - Support for Zicboz when clearing pages - We've moved to GENERIC_ENTRY - Support for !MMU on rv32 systems - The linear region is now mapped via huge pages - Support for building relocatable kernels - Support for the hwprobe interface - Various fixes and cleanups throughout the tree * tag 'riscv-for-linus-6.4-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (57 commits) RISC-V: hwprobe: Explicity check for -1 in vdso init RISC-V: hwprobe: There can only be one first riscv: Allow to downgrade paging mode from the command line dt-bindings: riscv: add sv57 mmu-type RISC-V: hwprobe: Remove __init on probe_vendor_features() riscv: Use --emit-relocs in order to move .rela.dyn in init riscv: Check relocations at compile time powerpc: Move script to check relocations at compile time in scripts/ riscv: Introduce CONFIG_RELOCATABLE riscv: Move .rela.dyn outside of init to avoid empty relocations riscv: Prepare EFI header for relocatable kernels riscv: Unconditionnally select KASAN_VMALLOC if KASAN riscv: Fix ptdump when KASAN is enabled riscv: Fix EFI stub usage of KASAN instrumented strcmp function riscv: Move DTB_EARLY_BASE_VA to the kernel address space riscv: Rework kasan population functions riscv: Split early and final KASAN population functions riscv: Use PUD/P4D/PGD pages for the linear mapping riscv: Move the linear mapping creation in its own function riscv: Get rid of riscv_pfn_base variable ...

riscv: entry: Convert to generic entry

2023-03-23T15:47:00Z

This patch converts riscv to use the generic entry infrastructure from kernel/entry/*. The generic entry makes maintainers' work easier and codes more elegant. Here are the changes: - More clear entry.S with handle_exception and ret_from_exception - Get rid of complex custom signal implementation - Move syscall procedure from assembly to C, which is much more readable. - Connect ret_from_fork & ret_from_kernel_thread to generic entry. - Wrap with irqentry_enter/exit and syscall_enter/exit_from_user_mode - Use the standard preemption code instead of custom Suggested-by: Huacai Chen Reviewed-by: Björn Töpel Tested-by: Yipeng Zou Tested-by: Jisheng Zhang Signed-off-by: Guo Ren Signed-off-by: Guo Ren Cc: Ben Hutchings Link: https://lore.kernel.org/r/20230222033021.983168-5-guoren@kernel.org Signed-off-by: Palmer Dabbelt

RISC-V: mm: Support huge page in vmalloc_fault()

2023-03-15T02:15:34Z

Since RISC-V supports ioremap() with huge page (pud/pmd) mapping, However, vmalloc_fault() assumes that the vmalloc range is limited to pte mappings. To complete the vmalloc_fault() function by adding huge page support. Fixes: 310f541a027b ("riscv: Enable HAVE_ARCH_HUGE_VMAP for 64BIT") Cc: stable@vger.kernel.org Signed-off-by: Dylan Jhong Reviewed-by: Alexandre Ghiti Link: https://lore.kernel.org/r/20230310075021.3919290-1-dylan@andestech.com Signed-off-by: Palmer Dabbelt