From 8690bbcf3b7010b31fdbf3851e1add6ae19b8624 Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Thu, 15 Feb 2024 09:46:32 -0500 Subject: [PATCH] Introduce cpu_dcache_is_aliasing() across all architectures 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/20240215144633.96437-9-mathieu.desnoyers@efficios.com Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing caches") Signed-off-by: Mathieu Desnoyers Cc: Dan Williams Cc: Vishal Verma Cc: Dave Jiang Cc: Matthew Wilcox Cc: Arnd Bergmann Cc: Russell King Cc: Alasdair Kergon Cc: Christoph Hellwig Cc: Dave Chinner Cc: Heiko Carstens Cc: kernel test robot 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(+) create mode 100644 arch/arc/include/asm/cachetype.h create mode 100644 arch/csky/include/asm/cachetype.h create mode 100644 arch/m68k/include/asm/cachetype.h create mode 100644 arch/mips/include/asm/cachetype.h create mode 100644 arch/nios2/include/asm/cachetype.h create mode 100644 arch/parisc/include/asm/cachetype.h create mode 100644 arch/sh/include/asm/cachetype.h create mode 100644 arch/sparc/include/asm/cachetype.h create mode 100644 arch/xtensa/include/asm/cachetype.h diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig index 1b0483c51cc1..7d294a3242a4 100644 --- a/arch/arc/Kconfig +++ b/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 diff --git a/arch/arc/include/asm/cachetype.h b/arch/arc/include/asm/cachetype.h new file mode 100644 index 000000000000..05fc7ed59712 --- /dev/null +++ b/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 diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 0af6709570d1..66a8e64b226e 100644 --- a/arch/arm/Kconfig +++ b/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 diff --git a/arch/arm/include/asm/cachetype.h b/arch/arm/include/asm/cachetype.h index e8c30430be33..b9dbe1d4c8fe 100644 --- a/arch/arm/include/asm/cachetype.h +++ b/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. diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig index cf2a6fd7dff8..8a91eccf76dc 100644 --- a/arch/csky/Kconfig +++ b/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 diff --git a/arch/csky/include/asm/cachetype.h b/arch/csky/include/asm/cachetype.h new file mode 100644 index 000000000000..98cbe3af662f --- /dev/null +++ b/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 diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig index 4b3e93cac723..a9c3e3de0c6d 100644 --- a/arch/m68k/Kconfig +++ b/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 diff --git a/arch/m68k/include/asm/cachetype.h b/arch/m68k/include/asm/cachetype.h new file mode 100644 index 000000000000..7fad5d9ab8fe --- /dev/null +++ b/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 diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index 797ae590ebdb..ab1c8bd96666 100644 --- a/arch/mips/Kconfig +++ b/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 diff --git a/arch/mips/include/asm/cachetype.h b/arch/mips/include/asm/cachetype.h new file mode 100644 index 000000000000..9f4ba2fe1155 --- /dev/null +++ b/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 diff --git a/arch/nios2/Kconfig b/arch/nios2/Kconfig index 58d9565dc2c7..6b3a14633d2f 100644 --- a/arch/nios2/Kconfig +++ b/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 diff --git a/arch/nios2/include/asm/cachetype.h b/arch/nios2/include/asm/cachetype.h new file mode 100644 index 000000000000..eb9c416b8a1c --- /dev/null +++ b/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 diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig index 5c845e8d59d9..da6e97ba46a6 100644 --- a/arch/parisc/Kconfig +++ b/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 diff --git a/arch/parisc/include/asm/cachetype.h b/arch/parisc/include/asm/cachetype.h new file mode 100644 index 000000000000..e0868a1d3c47 --- /dev/null +++ b/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 diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig index 7500521b2b98..2ad3e29f0ebe 100644 --- a/arch/sh/Kconfig +++ b/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) diff --git a/arch/sh/include/asm/cachetype.h b/arch/sh/include/asm/cachetype.h new file mode 100644 index 000000000000..a5fffe536068 --- /dev/null +++ b/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 diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig index 204c43cb3d43..cbec48219d9e 100644 --- a/arch/sparc/Kconfig +++ b/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 diff --git a/arch/sparc/include/asm/cachetype.h b/arch/sparc/include/asm/cachetype.h new file mode 100644 index 000000000000..caf1c0045892 --- /dev/null +++ b/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 diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig index 6f248d87e496..6689a8547346 100644 --- a/arch/xtensa/Kconfig +++ b/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 diff --git a/arch/xtensa/include/asm/cachetype.h b/arch/xtensa/include/asm/cachetype.h new file mode 100644 index 000000000000..51bd49e2a1c5 --- /dev/null +++ b/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 diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h index d504eb4b49ab..2cb15fe4fe12 100644 --- a/include/linux/cacheinfo.h +++ b/include/linux/cacheinfo.h @@ -138,4 +138,10 @@ static inline int get_cpu_cacheinfo_id(int cpu, int level) #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 */ diff --git a/mm/Kconfig b/mm/Kconfig index 2b267553f793..b924f4a5a3ef 100644 --- a/mm/Kconfig +++ b/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