From patchwork Mon Feb 12 22:30:47 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 13554124 X-Patchwork-Delegate: snitzer@redhat.com Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8001D1FD7; Mon, 12 Feb 2024 22:30:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707777048; cv=none; b=F/lUGZ4mgb+NiXeul8j1pATN7+TKVKAdFVePulRmZZtBP9ie7qKT17Q0NhWRENFS0WLh6QMY9v7WEYU54IxWMGWQ5juOPtbGScB5mPXz8jtU/E8s7FxfWyyOc+scqQDxkqxhdlbyBZgqntZTomsQL7Veqcwd3d2VhTnAaWDvXu4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707777048; c=relaxed/simple; bh=arNrNdq1U2jRMGMoLLjHgljDP1l349QDh1b2d/xif58=; h=Date:To:From:Subject:Message-Id; b=p6GIXDomTS7eSFlnWT/572W9y9Axaw28tsJ6DF9n85ZYHA24cNrxNzmy048b1tiO7Y62h09YsZgTEIaGylbNQ68gli3eLejZjXjLXKUF8AgpjPCXuGNQVNCIpIXRos/DhHqnlYnCXZyt5tV22sFWV+cielyvDV/edPfryJVqXcg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=2fPYtyx9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="2fPYtyx9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3DBBAC433F1; Mon, 12 Feb 2024 22:30:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1707777048; bh=arNrNdq1U2jRMGMoLLjHgljDP1l349QDh1b2d/xif58=; h=Date:To:From:Subject:From; b=2fPYtyx9RzSL4FIhRJuRCRhLXW7YC/nVC/M5RF07icgu9U/IyTjIe8TGwzpNEY5ub +VEbEE+8KGZR8asUUeexsJRZT6tisBtLM/HFuF4WCK8SankNan0RnAag92+momBYNY imZ/Cb8E5BydV6hoQIT/PQ3BonGTlfX8LhmlT4a0= Date: Mon, 12 Feb 2024 14:30:47 -0800 To: mm-commits@vger.kernel.org,willy@infradead.org,vishal.l.verma@intel.com,torvalds@linux-foundation.org,snitzer@kernel.org,mpatocka@redhat.com,linux@armlinux.org.uk,dm-devel@lists.linux.dev,david@fromorbit.com,dave.jiang@intel.com,dan.j.williams@intel.com,arnd@arndb.de,agk@redhat.com,mathieu.desnoyers@efficios.com,akpm@linux-foundation.org From: Andrew Morton Subject: + introduce-cpu_dcache_is_aliasing-across-all-architectures.patch added to mm-unstable branch Message-Id: <20240212223048.3DBBAC433F1@smtp.kernel.org> Precedence: bulk X-Mailing-List: dm-devel@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: Introduce cpu_dcache_is_aliasing() across all architectures has been added to the -mm mm-unstable branch. Its filename is introduce-cpu_dcache_is_aliasing-across-all-architectures.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/introduce-cpu_dcache_is_aliasing-across-all-architectures.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Mathieu Desnoyers Subject: Introduce cpu_dcache_is_aliasing() across all architectures Date: Mon, 12 Feb 2024 11:31:00 -0500 Introduce a generic way to query whether the data cache is virtually aliased on all architectures. Its purpose is to ensure that subsystems which are incompatible with virtually aliased data caches (e.g. FS_DAX) can reliably query this. For data cache aliasing, there are three scenarios dependending on the architecture. Here is a breakdown based on my understanding: A) The data cache is always aliasing: * arc * csky * m68k (note: shared memory mappings are incoherent ? SHMLBA is missing there.) * sh * parisc B) The data cache aliasing is statically known or depends on querying CPU state at runtime: * arm (cache_is_vivt() || cache_is_vipt_aliasing()) * mips (cpu_has_dc_aliases) * nios2 (NIOS2_DCACHE_SIZE > PAGE_SIZE) * sparc32 (vac_cache_size > PAGE_SIZE) * sparc64 (L1DCACHE_SIZE > PAGE_SIZE) * xtensa (DCACHE_WAY_SIZE > PAGE_SIZE) C) The data cache is never aliasing: * alpha * arm64 (aarch64) * hexagon * loongarch (but with incoherent write buffers, which are disabled since commit d23b7795 ("LoongArch: Change SHMLBA from SZ_64K to PAGE_SIZE")) * microblaze * openrisc * powerpc * riscv * s390 * um * x86 Require architectures in A) and B) to select ARCH_HAS_CPU_CACHE_ALIASING and implement "cpu_dcache_is_aliasing()". Architectures in C) don't select ARCH_HAS_CPU_CACHE_ALIASING, and thus cpu_dcache_is_aliasing() simply evaluates to "false". Note that this leaves "cpu_icache_is_aliasing()" to be implemented as future work. This would be useful to gate features like XIP on architectures which have aliasing CPU dcache-icache but not CPU dcache-dcache. Use "cpu_dcache" and "cpu_cache" rather than just "dcache" and "cache" to clarify that we really mean "CPU data cache" and "CPU cache" to eliminate any possible confusion with VFS "dentry cache" and "page cache". Link: https://lore.kernel.org/lkml/20030910210416.GA24258@mail.jlokier.co.uk/ Link: https://lkml.kernel.org/r/20240212163101.19614-8-mathieu.desnoyers@efficios.com Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing caches") Signed-off-by: Mathieu Desnoyers Cc: Linus Torvalds Cc: Dan Williams Cc: Vishal Verma Cc: Dave Jiang Cc: Matthew Wilcox Cc: Arnd Bergmann Cc: Russell King Cc: Alasdair Kergon Cc: Dave Chinner Cc: Michael Sclafani Cc: Mike Snitzer Cc: Mikulas Patocka Signed-off-by: Andrew Morton --- arch/arc/Kconfig | 1 + arch/arc/include/asm/cachetype.h | 9 +++++++++ arch/arm/Kconfig | 1 + arch/arm/include/asm/cachetype.h | 2 ++ arch/csky/Kconfig | 1 + arch/csky/include/asm/cachetype.h | 9 +++++++++ arch/m68k/Kconfig | 1 + arch/m68k/include/asm/cachetype.h | 9 +++++++++ arch/mips/Kconfig | 1 + arch/mips/include/asm/cachetype.h | 9 +++++++++ arch/nios2/Kconfig | 1 + arch/nios2/include/asm/cachetype.h | 10 ++++++++++ arch/parisc/Kconfig | 1 + arch/parisc/include/asm/cachetype.h | 9 +++++++++ arch/sh/Kconfig | 1 + arch/sh/include/asm/cachetype.h | 9 +++++++++ arch/sparc/Kconfig | 1 + arch/sparc/include/asm/cachetype.h | 14 ++++++++++++++ arch/xtensa/Kconfig | 1 + arch/xtensa/include/asm/cachetype.h | 10 ++++++++++ include/linux/cacheinfo.h | 6 ++++++ mm/Kconfig | 6 ++++++ 22 files changed, 112 insertions(+) --- /dev/null +++ a/arch/arc/include/asm/cachetype.h @@ -0,0 +1,9 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_ARC_CACHETYPE_H +#define __ASM_ARC_CACHETYPE_H + +#include + +#define cpu_dcache_is_aliasing() true + +#endif --- a/arch/arc/Kconfig~introduce-cpu_dcache_is_aliasing-across-all-architectures +++ a/arch/arc/Kconfig @@ -6,6 +6,7 @@ config ARC def_bool y select ARC_TIMERS + select ARCH_HAS_CPU_CACHE_ALIASING select ARCH_HAS_CACHE_LINE_SIZE select ARCH_HAS_DEBUG_VM_PGTABLE select ARCH_HAS_DMA_PREP_COHERENT --- a/arch/arm/include/asm/cachetype.h~introduce-cpu_dcache_is_aliasing-across-all-architectures +++ a/arch/arm/include/asm/cachetype.h @@ -20,6 +20,8 @@ extern unsigned int cacheid; #define icache_is_vipt_aliasing() cacheid_is(CACHEID_VIPT_I_ALIASING) #define icache_is_pipt() cacheid_is(CACHEID_PIPT) +#define cpu_dcache_is_aliasing() (cache_is_vivt() || cache_is_vipt_aliasing()) + /* * __LINUX_ARM_ARCH__ is the minimum supported CPU architecture * Mask out support which will never be present on newer CPUs. --- a/arch/arm/Kconfig~introduce-cpu_dcache_is_aliasing-across-all-architectures +++ a/arch/arm/Kconfig @@ -5,6 +5,7 @@ config ARM select ARCH_32BIT_OFF_T select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE if HAVE_KRETPROBES && FRAME_POINTER && !ARM_UNWIND select ARCH_HAS_BINFMT_FLAT + select ARCH_HAS_CPU_CACHE_ALIASING select ARCH_HAS_CPU_FINALIZE_INIT if MMU select ARCH_HAS_CURRENT_STACK_POINTER select ARCH_HAS_DEBUG_VIRTUAL if MMU --- /dev/null +++ a/arch/csky/include/asm/cachetype.h @@ -0,0 +1,9 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_CSKY_CACHETYPE_H +#define __ASM_CSKY_CACHETYPE_H + +#include + +#define cpu_dcache_is_aliasing() true + +#endif --- a/arch/csky/Kconfig~introduce-cpu_dcache_is_aliasing-across-all-architectures +++ a/arch/csky/Kconfig @@ -2,6 +2,7 @@ config CSKY def_bool y select ARCH_32BIT_OFF_T + select ARCH_HAS_CPU_CACHE_ALIASING select ARCH_HAS_DMA_PREP_COHERENT select ARCH_HAS_GCOV_PROFILE_ALL select ARCH_HAS_SYNC_DMA_FOR_CPU --- /dev/null +++ a/arch/m68k/include/asm/cachetype.h @@ -0,0 +1,9 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_M68K_CACHETYPE_H +#define __ASM_M68K_CACHETYPE_H + +#include + +#define cpu_dcache_is_aliasing() true + +#endif --- a/arch/m68k/Kconfig~introduce-cpu_dcache_is_aliasing-across-all-architectures +++ a/arch/m68k/Kconfig @@ -3,6 +3,7 @@ config M68K bool default y select ARCH_32BIT_OFF_T + select ARCH_HAS_CPU_CACHE_ALIASING select ARCH_HAS_BINFMT_FLAT select ARCH_HAS_CPU_FINALIZE_INIT if MMU select ARCH_HAS_CURRENT_STACK_POINTER --- /dev/null +++ a/arch/mips/include/asm/cachetype.h @@ -0,0 +1,9 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_MIPS_CACHETYPE_H +#define __ASM_MIPS_CACHETYPE_H + +#include + +#define cpu_dcache_is_aliasing() cpu_has_dc_aliases + +#endif --- a/arch/mips/Kconfig~introduce-cpu_dcache_is_aliasing-across-all-architectures +++ a/arch/mips/Kconfig @@ -4,6 +4,7 @@ config MIPS default y select ARCH_32BIT_OFF_T if !64BIT select ARCH_BINFMT_ELF_STATE if MIPS_FP_SUPPORT + select ARCH_HAS_CPU_CACHE_ALIASING select ARCH_HAS_CPU_FINALIZE_INIT select ARCH_HAS_CURRENT_STACK_POINTER if !CC_IS_CLANG || CLANG_VERSION >= 140000 select ARCH_HAS_DEBUG_VIRTUAL if !64BIT --- /dev/null +++ a/arch/nios2/include/asm/cachetype.h @@ -0,0 +1,10 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_NIOS2_CACHETYPE_H +#define __ASM_NIOS2_CACHETYPE_H + +#include +#include + +#define cpu_dcache_is_aliasing() (NIOS2_DCACHE_SIZE > PAGE_SIZE) + +#endif --- a/arch/nios2/Kconfig~introduce-cpu_dcache_is_aliasing-across-all-architectures +++ a/arch/nios2/Kconfig @@ -2,6 +2,7 @@ config NIOS2 def_bool y select ARCH_32BIT_OFF_T + select ARCH_HAS_CPU_CACHE_ALIASING select ARCH_HAS_DMA_PREP_COHERENT select ARCH_HAS_SYNC_DMA_FOR_CPU select ARCH_HAS_SYNC_DMA_FOR_DEVICE --- /dev/null +++ a/arch/parisc/include/asm/cachetype.h @@ -0,0 +1,9 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_PARISC_CACHETYPE_H +#define __ASM_PARISC_CACHETYPE_H + +#include + +#define cpu_dcache_is_aliasing() true + +#endif --- a/arch/parisc/Kconfig~introduce-cpu_dcache_is_aliasing-across-all-architectures +++ a/arch/parisc/Kconfig @@ -8,6 +8,7 @@ config PARISC select HAVE_FUNCTION_GRAPH_TRACER select HAVE_SYSCALL_TRACEPOINTS select ARCH_WANT_FRAME_POINTERS + select ARCH_HAS_CPU_CACHE_ALIASING select ARCH_HAS_DMA_ALLOC if PA11 select ARCH_HAS_ELF_RANDOMIZE select ARCH_HAS_STRICT_KERNEL_RWX --- /dev/null +++ a/arch/sh/include/asm/cachetype.h @@ -0,0 +1,9 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_SH_CACHETYPE_H +#define __ASM_SH_CACHETYPE_H + +#include + +#define cpu_dcache_is_aliasing() true + +#endif --- a/arch/sh/Kconfig~introduce-cpu_dcache_is_aliasing-across-all-architectures +++ a/arch/sh/Kconfig @@ -2,6 +2,7 @@ config SUPERH def_bool y select ARCH_32BIT_OFF_T + select ARCH_HAS_CPU_CACHE_ALIASING select ARCH_ENABLE_MEMORY_HOTPLUG if SPARSEMEM && MMU select ARCH_ENABLE_MEMORY_HOTREMOVE if SPARSEMEM && MMU select ARCH_HAVE_NMI_SAFE_CMPXCHG if (GUSA_RB || CPU_SH4A) --- /dev/null +++ a/arch/sparc/include/asm/cachetype.h @@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_SPARC_CACHETYPE_H +#define __ASM_SPARC_CACHETYPE_H + +#include + +#ifdef CONFIG_SPARC32 +extern int vac_cache_size; +#define cpu_dcache_is_aliasing() (vac_cache_size > PAGE_SIZE) +#else +#define cpu_dcache_is_aliasing() (L1DCACHE_SIZE > PAGE_SIZE) +#endif + +#endif --- a/arch/sparc/Kconfig~introduce-cpu_dcache_is_aliasing-across-all-architectures +++ a/arch/sparc/Kconfig @@ -13,6 +13,7 @@ config 64BIT config SPARC bool default y + select ARCH_HAS_CPU_CACHE_ALIASING select ARCH_MIGHT_HAVE_PC_PARPORT if SPARC64 && PCI select ARCH_MIGHT_HAVE_PC_SERIO select DMA_OPS --- /dev/null +++ a/arch/xtensa/include/asm/cachetype.h @@ -0,0 +1,10 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_XTENSA_CACHETYPE_H +#define __ASM_XTENSA_CACHETYPE_H + +#include +#include + +#define cpu_dcache_is_aliasing() (DCACHE_WAY_SIZE > PAGE_SIZE) + +#endif --- a/arch/xtensa/Kconfig~introduce-cpu_dcache_is_aliasing-across-all-architectures +++ a/arch/xtensa/Kconfig @@ -2,6 +2,7 @@ config XTENSA def_bool y select ARCH_32BIT_OFF_T + select ARCH_HAS_CPU_CACHE_ALIASING select ARCH_HAS_BINFMT_FLAT if !MMU select ARCH_HAS_CURRENT_STACK_POINTER select ARCH_HAS_DEBUG_VM_PGTABLE --- a/include/linux/cacheinfo.h~introduce-cpu_dcache_is_aliasing-across-all-architectures +++ a/include/linux/cacheinfo.h @@ -138,4 +138,10 @@ static inline int get_cpu_cacheinfo_id(i #define use_arch_cache_info() (false) #endif +#ifndef CONFIG_ARCH_HAS_CPU_CACHE_ALIASING +#define cpu_dcache_is_aliasing() false +#else +#include +#endif + #endif /* _LINUX_CACHEINFO_H */ --- a/mm/Kconfig~introduce-cpu_dcache_is_aliasing-across-all-architectures +++ a/mm/Kconfig @@ -973,6 +973,12 @@ config IDLE_PAGE_TRACKING See Documentation/admin-guide/mm/idle_page_tracking.rst for more details. +# Architectures which implement cpu_dcache_is_aliasing() to query +# whether the data caches are aliased (VIVT or VIPT with dcache +# aliasing) need to select this. +config ARCH_HAS_CPU_CACHE_ALIASING + bool + config ARCH_HAS_CACHE_LINE_SIZE bool