From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 70B892F7AC4; Fri, 7 Nov 2025 13:56:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762523789; cv=none; b=I4l0Piaic6gN7GXhtMfx5ZSbuSlcfZ/pTjSTMK4lenOB/PJ9Z446RqYfT8bVAH8IWqDVq1th6i/SqOrzW6XHA4OBiD7ug8h/E/zG1vHlnrnbhTEDd3twxSpCLe83lFEga6Dj5XGbFqDG7dpKw21Q7Pi2yW24mOPu7i0fKuDQfDY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762523789; c=relaxed/simple; bh=Va4qQyTeB2jj6UdT1RZ8AmuEGlHP9zV/bkngcJuvx+g=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=QWWwZlvDpLLsuJ2lsGfjHv1riblFMctRFmTg53qDZ90F7emjrrsGpWM8nR7S2PCq6PUiN1r5wluzI2RHLtoJSkmObXbARhwjGUG3rKgAMRvVNVN6qqHWeQI1X1PGdj+Qn/nvnWTVyYlC7fbf3rKln3k3tsTIyNvEaoh7DwGJ+2M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id F05461515; Fri, 7 Nov 2025 05:56:18 -0800 (PST) Received: from [10.57.86.134] (unknown [10.57.86.134]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 235F03F66E; Fri, 7 Nov 2025 05:56:22 -0800 (PST) Message-ID: <6a9c846f-22b6-4d5f-81dc-6cdcd4905952@arm.com> Date: Fri, 7 Nov 2025 13:56:20 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 05/12] mm: introduce CONFIG_ARCH_HAS_LAZY_MMU_MODE Content-Language: en-GB To: Kevin Brodsky , linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, Alexander Gordeev , Andreas Larsson , Andrew Morton , Boris Ostrovsky , Borislav Petkov , Catalin Marinas , Christophe Leroy , Dave Hansen , David Hildenbrand , "David S. Miller" , David Woodhouse , "H. Peter Anvin" , Ingo Molnar , Jann Horn , Juergen Gross , "Liam R. Howlett" , Lorenzo Stoakes , Madhavan Srinivasan , Michael Ellerman , Michal Hocko , Mike Rapoport , Nicholas Piggin , Peter Zijlstra , Suren Baghdasaryan , Thomas Gleixner , Vlastimil Babka , Will Deacon , Yeoreum Yun , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org References: <20251029100909.3381140-1-kevin.brodsky@arm.com> <20251029100909.3381140-6-kevin.brodsky@arm.com> From: Ryan Roberts In-Reply-To: <20251029100909.3381140-6-kevin.brodsky@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 29/10/2025 10:09, Kevin Brodsky wrote: > 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 > 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 > does not define the lazy_mmu helpers, but this > breaks the build as 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. > > Signed-off-by: Kevin Brodsky > --- > 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 | 3 +++ > 12 files changed, 10 insertions(+), 7 deletions(-) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 6663ffd23f25..e6bf5c7311b5 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -122,6 +122,7 @@ config ARM64 > select ARCH_WANTS_NO_INSTR > select ARCH_WANTS_THP_SWAP if ARM64_4K_PAGES > select ARCH_HAS_UBSAN > + select ARCH_HAS_LAZY_MMU_MODE nit: This list is mostly in alphabetical order. Further up the list there are a lot of ARCH_HAS_* entries. Perhaps move it to the correct position in that lot? Then ARCH_HAS_UBSAN stays out of order on its own. Otherwise, all looks reasonable to me: Reviewed-by: Ryan Roberts > select ARM_AMBA > select ARM_ARCH_TIMER > select ARM_GIC > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index 0944e296dd4a..54f8d6bb6f22 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 7704dbe8e88d..623a8a8b2d0e 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 7b527d18aa5e..2942d57cf59c 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 fa3b616af03a..ef4332d720ab 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -804,6 +804,7 @@ 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 db1048621ea2..cdd7f692d9ee 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 32e8457ad535..9894366e768b 100644 > --- a/include/linux/pgtable.h > +++ b/include/linux/pgtable.h > @@ -231,7 +231,7 @@ static inline int pmd_dirty(pmd_t pmd) > * held, but for kernel PTE updates, no lock is held). 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 0e26f4fc8717..5480c9a1bfb2 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -1372,6 +1372,9 @@ config PT_RECLAIM > config FIND_NORMAL_PAGE > def_bool n > > +config ARCH_HAS_LAZY_MMU_MODE > + bool > + > source "mm/damon/Kconfig" > > endmenu