The patch titled Subject: sparc/mm: avoid calling arch_enter/leave_lazy_mmu() in set_ptes has been added to the -mm mm-unstable branch. Its filename is sparc-mm-avoid-calling-arch_enter-leave_lazy_mmu-in-set_ptes.patch
This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...
This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------ From: Ryan Roberts ryan.roberts@arm.com Subject: sparc/mm: avoid calling arch_enter/leave_lazy_mmu() in set_ptes Date: Mon, 3 Mar 2025 14:15:38 +0000
With commit 1a10a44dfc1d ("sparc64: implement the new page table range API") set_ptes was added to the sparc architecture. The implementation included calling arch_enter/leave_lazy_mmu() calls.
The patch removes the usage of arch_enter/leave_lazy_mmu() since this implies nesting of lazy mmu regions which is not supported. Without this fix, lazy mmu mode is effectively disabled because we exit the mode after the first set_ptes:
remap_pte_range() -> arch_enter_lazy_mmu() -> set_ptes() -> arch_enter_lazy_mmu() -> arch_leave_lazy_mmu() -> arch_leave_lazy_mmu()
Powerpc suffered the same problem and fixed it in a corresponding way with commit 47b8def9358c ("powerpc/mm: Avoid calling arch_enter/leave_lazy_mmu() in set_ptes").
Link: https://lkml.kernel.org/r/20250303141542.3371656-5-ryan.roberts@arm.com Fixes: 1a10a44dfc1d ("sparc64: implement the new page table range API") Signed-off-by: Ryan Roberts ryan.roberts@arm.com Acked-by: David Hildenbrand david@redhat.com Acked-by: Andreas Larsson andreas@gaisler.com Cc: stable@vger.kernel.org Cc: Borislav Betkov bp@alien8.de Cc: Boris Ostrovsky boris.ostrovsky@oracle.com Cc: Catalin Marinas catalin.marinas@arm.com Cc: Dave Hansen dave.hansen@linux.intel.com Cc: David S. Miller davem@davemloft.net Cc: "H. Peter Anvin" hpa@zytor.com Cc: Ingo Molnar mingo@redhat.com Cc: Juegren Gross jgross@suse.com Cc: Matthew Wilcow (Oracle) willy@infradead.org Cc: Thomas Gleinxer tglx@linutronix.de Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
arch/sparc/include/asm/pgtable_64.h | 2 -- 1 file changed, 2 deletions(-)
--- a/arch/sparc/include/asm/pgtable_64.h~sparc-mm-avoid-calling-arch_enter-leave_lazy_mmu-in-set_ptes +++ a/arch/sparc/include/asm/pgtable_64.h @@ -936,7 +936,6 @@ static inline void __set_pte_at(struct m static inline void set_ptes(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte, unsigned int nr) { - arch_enter_lazy_mmu_mode(); for (;;) { __set_pte_at(mm, addr, ptep, pte, 0); if (--nr == 0) @@ -945,7 +944,6 @@ static inline void set_ptes(struct mm_st pte_val(pte) += PAGE_SIZE; addr += PAGE_SIZE; } - arch_leave_lazy_mmu_mode(); } #define set_ptes set_ptes
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Patches currently in -mm which might be from ryan.roberts@arm.com are
mm-dont-skip-arch_sync_kernel_mappings-in-error-paths.patch mm-ioremap-pass-pgprot_t-to-ioremap_prot-instead-of-unsigned-long.patch mm-fix-lazy-mmu-docs-and-usage.patch fs-proc-task_mmu-reduce-scope-of-lazy-mmu-region.patch sparc-mm-disable-preemption-in-lazy-mmu-mode.patch sparc-mm-avoid-calling-arch_enter-leave_lazy_mmu-in-set_ptes.patch revert-x86-xen-allow-nesting-of-same-lazy-mode.patch