protection_map[] is an array based construct that translates given vm_flags combination. This array contains page protection map, which is populated by the platform via [__S000 .. __S111] and [__P000 .. __P111] exported macros. Primary usage for protection_map[] is for vm_get_page_prot(), which is used to determine page protection value for a given vm_flags. vm_get_page_prot() implementation, could again call platform overrides arch_vm_get_page_prot() and arch_filter_pgprot(). Some platforms override protection_map[] that was originally built with __SXXX/__PXXX with different runtime values. Currently there are multiple layers of abstraction i.e __SXXX/__PXXX macros , protection_map[], arch_vm_get_page_prot() and arch_filter_pgprot() built between the platform and generic MM, finally defining vm_get_page_prot(). Hence this series proposes to drop later two abstraction levels and instead just move the responsibility of defining vm_get_page_prot() to the platform (still utilizing generic protection_map[] array) itself making it clean and simple. This first introduces ARCH_HAS_VM_GET_PAGE_PROT which enables the platforms to define custom vm_get_page_prot(). This starts converting platforms that define the overrides arch_filter_pgprot() or arch_vm_get_page_prot() which enables for those constructs to be dropped off completely. The series has been inspired from an earlier discuss with Christoph Hellwig https://lore.kernel.org/all/1632712920-8171-1-git-send-email-anshuman.khandual@xxxxxxx/ This series applies on 5.18-rc1 after the following patch. https://lore.kernel.org/all/1643004823-16441-1-git-send-email-anshuman.khandual@xxxxxxx/ This series has been cross built for multiple platforms. - Anshuman Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: linuxppc-dev@xxxxxxxxxxxxxxxx Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx Cc: sparclinux@xxxxxxxxxxxxxxx Cc: linux-mm@xxxxxxxxx Cc: linux-arch@xxxxxxxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Changes in V4: - ARCH_HAS_VM_GET_PAGE_PROT now excludes generic protection_map[] - Changed platform's vm_get_page_prot() to use generic protection_map[] - Dropped all platform changes not enabling either arch_vm_get_page_prot() or arch_filter_pgprot() - Dropped all previous tags as code base has changed Changes in V3: https://lore.kernel.org/all/1646045273-9343-1-git-send-email-anshuman.khandual@xxxxxxx/ - Dropped variable 'i' from sme_early_init() on x86 platform - Moved CONFIG_COLDFIRE vm_get_page_prot() inside arch/m68k/mm/mcfmmu.c - Moved CONFIG_SUN3 vm_get_page_prot() inside arch/m68k/mm/sun3mmu.c - Dropped cachebits for vm_get_page_prot() inside arch/m68k/mm/motorola.c - Dropped PAGE_XXX_C definitions from arch/m68k/include/asm/motorola_pgtable.h - Used PAGE_XXX instead for vm_get_page_prot() inside arch/m68k/mm/motorola.c - Dropped all references to protection_map[] in the tree - Replaced s/extensa/xtensa/ on the patch title - Moved left over comments from pgtable.h into init.c on nios2 platform Changes in V2: https://lore.kernel.org/all/1645425519-9034-1-git-send-email-anshuman.khandual@xxxxxxx/ - Dropped the entire comment block in [PATCH 30/30] per Geert - Replaced __P010 (although commented) with __PAGE_COPY on arm platform - Replaced __P101 with PAGE_READONLY on um platform Changes in V1: https://lore.kernel.org/all/1644805853-21338-1-git-send-email-anshuman.khandual@xxxxxxx/ - Add white spaces around the | operators - Moved powerpc_vm_get_page_prot() near vm_get_page_prot() on powerpc - Moved arm64_vm_get_page_prot() near vm_get_page_prot() on arm64 - Moved sparc_vm_get_page_prot() near vm_get_page_prot() on sparc - Compacted vm_get_page_prot() switch cases on all platforms - _PAGE_CACHE040 inclusion is dependent on CPU_IS_040_OR_060 - VM_SHARED case should return PAGE_NONE (not PAGE_COPY) on SH platform - Reorganized VM_SHARED, VM_EXEC, VM_WRITE, VM_READ - Dropped the last patch [RFC V1 31/31] which added macros for vm_flags combinations https://lore.kernel.org/all/1643029028-12710-32-git-send-email-anshuman.khandual@xxxxxxx/ Changes in RFC: https://lore.kernel.org/all/1643029028-12710-1-git-send-email-anshuman.khandual@xxxxxxx/ Anshuman Khandual (6): mm/mmap: Add new config ARCH_HAS_VM_GET_PAGE_PROT powerpc/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT arm64/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT sparc/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT mm/mmap: Drop arch_filter_pgprot() mm/mmap: Drop arch_vm_get_page_pgprot() Christoph Hellwig (1): x86/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT arch/arm64/Kconfig | 1 + arch/arm64/include/asm/mman.h | 24 ---------------------- arch/arm64/mm/mmap.c | 33 ++++++++++++++++++++++++++++++ arch/powerpc/Kconfig | 1 + arch/powerpc/include/asm/mman.h | 12 ----------- arch/powerpc/mm/mmap.c | 26 ++++++++++++++++++++++++ arch/sparc/Kconfig | 1 + arch/sparc/include/asm/mman.h | 6 ------ arch/sparc/mm/init_64.c | 13 ++++++++++++ arch/x86/Kconfig | 2 +- arch/x86/include/asm/pgtable.h | 5 ----- arch/x86/include/uapi/asm/mman.h | 14 ------------- arch/x86/mm/Makefile | 2 +- arch/x86/mm/pgprot.c | 35 ++++++++++++++++++++++++++++++++ include/linux/mman.h | 4 ---- mm/Kconfig | 2 +- mm/mmap.c | 14 ++++--------- 17 files changed, 117 insertions(+), 78 deletions(-) create mode 100644 arch/x86/mm/pgprot.c -- 2.25.1
