[PATCH v6 06/14] mm: introduce CONFIG_ARCH_HAS_LAZY_MMU_MODE
From: Kevin Brodsky <hidden>
Date: 2025-12-15 15:04:11
Also in:
linux-arm-kernel, linux-mm, lkml, sparclinux, xen-devel
Subsystem:
arm64 port (aarch64 architecture), linux for powerpc (32-bit and 64-bit), memory management, memory management - core, paravirt_ops interface, sparc + ultrasparc (sparc/sparc64), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Catalin Marinas, Will Deacon, Madhavan Srinivasan, Michael Ellerman, Andrew Morton, David Hildenbrand, Juergen Gross, "David S. Miller", Andreas Larsson, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Architectures currently opt in for implementing lazy_mmu helpers by defining __HAVE_ARCH_ENTER_LAZY_MMU_MODE. In preparation for introducing a generic lazy_mmu layer that will require storage in task_struct, let's switch to a cleaner approach: instead of defining a macro, select a CONFIG option. This patch introduces CONFIG_ARCH_HAS_LAZY_MMU_MODE and has each arch select it when it implements lazy_mmu helpers. __HAVE_ARCH_ENTER_LAZY_MMU_MODE is removed and <linux/pgtable.h> relies on the new CONFIG instead. On x86, lazy_mmu helpers are only implemented if PARAVIRT_XXL is selected. This creates some complications in arch/x86/boot/, because a few files manually undefine PARAVIRT* options. As a result <asm/paravirt.h> does not define the lazy_mmu helpers, but this breaks the build as <linux/pgtable.h> only defines them if !CONFIG_ARCH_HAS_LAZY_MMU_MODE. There does not seem to be a clean way out of this - let's just undefine that new CONFIG too. Acked-by: David Hildenbrand <redacted> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Signed-off-by: Kevin Brodsky <redacted> --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/pgtable.h | 1 - arch/powerpc/include/asm/book3s/64/tlbflush-hash.h | 2 -- arch/powerpc/platforms/Kconfig.cputype | 1 + arch/sparc/Kconfig | 1 + arch/sparc/include/asm/tlbflush_64.h | 2 -- arch/x86/Kconfig | 1 + arch/x86/boot/compressed/misc.h | 1 + arch/x86/boot/startup/sme.c | 1 + arch/x86/include/asm/paravirt.h | 1 - include/linux/pgtable.h | 2 +- mm/Kconfig | 7 +++++++ 12 files changed, 14 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 93173f0a09c7..3fb4603c0e16 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig@@ -35,6 +35,7 @@ config ARM64 select ARCH_HAS_KCOV select ARCH_HAS_KERNEL_FPU_SUPPORT if KERNEL_MODE_NEON select ARCH_HAS_KEEPINITRD + select ARCH_HAS_LAZY_MMU_MODE select ARCH_HAS_MEMBARRIER_SYNC_CORE select ARCH_HAS_MEM_ENCRYPT select ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 64d5f1d9cce9..f7d66c261347 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h@@ -80,7 +80,6 @@ static inline void queue_pte_barriers(void) } } -#define __HAVE_ARCH_ENTER_LAZY_MMU_MODE static inline void arch_enter_lazy_mmu_mode(void) { /*
diff --git a/arch/powerpc/include/asm/book3s/64/tlbflush-hash.h b/arch/powerpc/include/asm/book3s/64/tlbflush-hash.h
index 2d45f57df169..565c1b7c3eae 100644
--- a/arch/powerpc/include/asm/book3s/64/tlbflush-hash.h
+++ b/arch/powerpc/include/asm/book3s/64/tlbflush-hash.h@@ -24,8 +24,6 @@ DECLARE_PER_CPU(struct ppc64_tlb_batch, ppc64_tlb_batch); extern void __flush_tlb_pending(struct ppc64_tlb_batch *batch); -#define __HAVE_ARCH_ENTER_LAZY_MMU_MODE - static inline void arch_enter_lazy_mmu_mode(void) { struct ppc64_tlb_batch *batch;
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index 4c321a8ea896..f399917c17bd 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype@@ -93,6 +93,7 @@ config PPC_BOOK3S_64 select IRQ_WORK select PPC_64S_HASH_MMU if !PPC_RADIX_MMU select KASAN_VMALLOC if KASAN + select ARCH_HAS_LAZY_MMU_MODE config PPC_BOOK3E_64 bool "Embedded processors"
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index a630d373e645..2bad14744ca4 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig@@ -112,6 +112,7 @@ config SPARC64 select NEED_PER_CPU_PAGE_FIRST_CHUNK select ARCH_SUPPORTS_SCHED_SMT if SMP select ARCH_SUPPORTS_SCHED_MC if SMP + select ARCH_HAS_LAZY_MMU_MODE config ARCH_PROC_KCORE_TEXT def_bool y
diff --git a/arch/sparc/include/asm/tlbflush_64.h b/arch/sparc/include/asm/tlbflush_64.h
index 925bb5d7a4e1..4e1036728e2f 100644
--- a/arch/sparc/include/asm/tlbflush_64.h
+++ b/arch/sparc/include/asm/tlbflush_64.h@@ -39,8 +39,6 @@ static inline void flush_tlb_range(struct vm_area_struct *vma, void flush_tlb_kernel_range(unsigned long start, unsigned long end); -#define __HAVE_ARCH_ENTER_LAZY_MMU_MODE - void flush_tlb_pending(void); void arch_enter_lazy_mmu_mode(void); void arch_flush_lazy_mmu_mode(void);
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 80527299f859..2427a66cb0fe 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig@@ -808,6 +808,7 @@ config PARAVIRT config PARAVIRT_XXL bool depends on X86_64 + select ARCH_HAS_LAZY_MMU_MODE config PARAVIRT_DEBUG bool "paravirt-ops debugging"
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index fd855e32c9b9..4f86c5903e03 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h@@ -11,6 +11,7 @@ #undef CONFIG_PARAVIRT #undef CONFIG_PARAVIRT_XXL #undef CONFIG_PARAVIRT_SPINLOCKS +#undef CONFIG_ARCH_HAS_LAZY_MMU_MODE #undef CONFIG_KASAN #undef CONFIG_KASAN_GENERIC
diff --git a/arch/x86/boot/startup/sme.c b/arch/x86/boot/startup/sme.c
index e7ea65f3f1d6..b76a7c95dfe1 100644
--- a/arch/x86/boot/startup/sme.c
+++ b/arch/x86/boot/startup/sme.c@@ -24,6 +24,7 @@ #undef CONFIG_PARAVIRT #undef CONFIG_PARAVIRT_XXL #undef CONFIG_PARAVIRT_SPINLOCKS +#undef CONFIG_ARCH_HAS_LAZY_MMU_MODE /* * This code runs before CPU feature bits are set. By default, the
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index b5e59a7ba0d0..13f9cd31c8f8 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h@@ -526,7 +526,6 @@ static inline void arch_end_context_switch(struct task_struct *next) PVOP_VCALL1(cpu.end_context_switch, next); } -#define __HAVE_ARCH_ENTER_LAZY_MMU_MODE static inline void arch_enter_lazy_mmu_mode(void) { PVOP_VCALL0(mmu.lazy_mode.enter);
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 1abc4a1c3d72..d46d86959bd6 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h@@ -235,7 +235,7 @@ static inline int pmd_dirty(pmd_t pmd) * * Nesting is not permitted and the mode cannot be used in interrupt context. */ -#ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE +#ifndef CONFIG_ARCH_HAS_LAZY_MMU_MODE static inline void arch_enter_lazy_mmu_mode(void) {} static inline void arch_leave_lazy_mmu_mode(void) {} static inline void arch_flush_lazy_mmu_mode(void) {}
diff --git a/mm/Kconfig b/mm/Kconfig
index bd0ea5454af8..62073bd61544 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig@@ -1464,6 +1464,13 @@ config PT_RECLAIM config FIND_NORMAL_PAGE def_bool n +config ARCH_HAS_LAZY_MMU_MODE + bool + help + The architecture uses the lazy MMU mode. This allows changes to + MMU-related architectural state to be deferred until the mode is + exited. See <linux/pgtable.h> for details. + source "mm/damon/Kconfig" endmenu
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2.51.2