[PATCH V3 00/30] mm/mmap: Drop protection_map[] and platform's __SXXX/__PXXX requirements

Anshuman Khandual
2022-02-28T10:59:23Z

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 all these abstraction levels and instead
just move the responsibility of defining vm_get_page_prot() to the platform
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
either change protection_map[] or define the overrides arch_filter_pgprot()
or arch_vm_get_page_prot() which enables for those constructs to be dropped
off completely. This series then converts remaining platforms which enables
for __SXXX/__PXXX constructs to be dropped off completely. Finally it drops
the generic vm_get_page_prot() and then ARCH_HAS_VM_GET_PAGE_PROT as every
platform now defines their own vm_get_page_prot().

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@arm.com/

This series applies on 5.17-rc6 after the following patch.

https://lore.kernel.org/all/1643004823-16441-1-git-send-email-anshuman.khandual@arm.com/

This series has been cross built for multiple platforms.

- Anshuman

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: sparclinux@vger.kernel.org
Cc: linux-mips@vger.kernel.org
Cc: linux-m68k@lists.linux-m68k.org
Cc: linux-s390@vger.kernel.org
Cc: linux-riscv@lists.infradead.org
Cc: linux-alpha@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-csky@vger.kernel.org
Cc: linux-xtensa@linux-xtensa.org
Cc: linux-parisc@vger.kernel.org
Cc: openrisc@lists.librecores.org
Cc: linux-um@lists.infradead.org
Cc: linux-hexagon@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

Changes in V3:

- 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@arm.com/

- 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@arm.com/

- 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@arm.com/

Changes in RFC:

https://lore.kernel.org/all/1643029028-12710-1-git-send-email-anshuman.khandual@arm.com/

Anshuman Khandual (29):
mm/debug_vm_pgtable: Drop protection_map[] usage
mm/mmap: Clarify protection_map[] indices
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
mips/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
m68k/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
arm/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
mm/mmap: Drop protection_map[]
mm/mmap: Drop arch_filter_pgprot()
mm/mmap: Drop arch_vm_get_page_pgprot()
s390/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
riscv/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
alpha/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
sh/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
arc/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
csky/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
xtensa/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
parisc/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
openrisc/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
um/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
microblaze/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
nios2/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
hexagon/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
nds32/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
ia64/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
mm/mmap: Drop generic vm_get_page_prot()
mm/mmap: Drop ARCH_HAS_VM_GET_PAGE_PROT

Christoph Hellwig (1):
x86/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

arch/alpha/include/asm/pgtable.h | 17 -----
arch/alpha/mm/init.c | 37 +++++++++++
arch/arc/include/asm/pgtable-bits-arcv2.h | 17 -----
arch/arc/mm/mmap.c | 41 ++++++++++++
arch/arm/include/asm/pgtable.h | 20 +-----
arch/arm/lib/uaccess_with_memcpy.c | 2 +-
arch/arm/mm/mmu.c | 44 +++++++++++--
arch/arm64/Kconfig | 1 -
arch/arm64/include/asm/memory.h | 3 +-
arch/arm64/include/asm/mman.h | 24 -------
arch/arm64/include/asm/pgtable-prot.h | 18 ------
arch/arm64/include/asm/pgtable.h | 11 ----
arch/arm64/mm/mmap.c | 78 +++++++++++++++++++++++
arch/csky/include/asm/pgtable.h | 18 ------
arch/csky/mm/init.c | 32 ++++++++++
arch/hexagon/include/asm/pgtable.h | 24 -------
arch/hexagon/mm/init.c | 67 +++++++++++++++++++
arch/ia64/include/asm/pgtable.h | 17 -----
arch/ia64/mm/init.c | 41 +++++++++++-
arch/m68k/include/asm/mcf_pgtable.h | 59 -----------------
arch/m68k/include/asm/motorola_pgtable.h | 29 ---------
arch/m68k/include/asm/sun3_pgtable.h | 22 -------
arch/m68k/mm/mcfmmu.c | 59 +++++++++++++++++
arch/m68k/mm/motorola.c | 43 ++++++++++++-
arch/m68k/mm/sun3mmu.c | 39 ++++++++++++
arch/microblaze/include/asm/pgtable.h | 17 -----
arch/microblaze/mm/init.c | 41 ++++++++++++
arch/mips/include/asm/pgtable.h | 22 -------
arch/mips/mm/cache.c | 60 +++++++++--------
arch/nds32/include/asm/pgtable.h | 17 -----
arch/nds32/mm/mmap.c | 37 +++++++++++
arch/nios2/include/asm/pgtable.h | 24 -------
arch/nios2/mm/init.c | 47 ++++++++++++++
arch/openrisc/include/asm/pgtable.h | 18 ------
arch/openrisc/mm/init.c | 41 ++++++++++++
arch/parisc/include/asm/pgtable.h | 20 ------
arch/parisc/mm/init.c | 40 ++++++++++++
arch/powerpc/include/asm/mman.h | 12 ----
arch/powerpc/include/asm/pgtable.h | 19 ------
arch/powerpc/mm/mmap.c | 59 +++++++++++++++++
arch/riscv/include/asm/pgtable.h | 16 -----
arch/riscv/mm/init.c | 42 ++++++++++++
arch/s390/include/asm/pgtable.h | 17 -----
arch/s390/mm/mmap.c | 33 ++++++++++
arch/sh/include/asm/pgtable.h | 17 -----
arch/sh/mm/mmap.c | 38 +++++++++++
arch/sparc/include/asm/mman.h | 6 --
arch/sparc/include/asm/pgtable_32.h | 19 ------
arch/sparc/include/asm/pgtable_64.h | 19 ------
arch/sparc/mm/init_32.c | 35 ++++++++++
arch/sparc/mm/init_64.c | 70 ++++++++++++++------
arch/um/include/asm/pgtable.h | 17 -----
arch/um/kernel/mem.c | 35 ++++++++++
arch/x86/Kconfig | 1 -
arch/x86/include/asm/pgtable.h | 5 --
arch/x86/include/asm/pgtable_types.h | 19 ------
arch/x86/include/uapi/asm/mman.h | 14 ----
arch/x86/mm/Makefile | 2 +-
arch/x86/mm/mem_encrypt_amd.c | 6 --
arch/x86/mm/pgprot.c | 71 +++++++++++++++++++++
arch/x86/um/mem_32.c | 2 +-
arch/xtensa/include/asm/pgtable.h | 19 ------
arch/xtensa/mm/init.c | 35 ++++++++++
drivers/gpu/drm/drm_vm.c | 4 +-
include/linux/mm.h | 6 --
include/linux/mman.h | 4 --
mm/Kconfig | 3 -
mm/debug_vm_pgtable.c | 31 +++++----
mm/mmap.c | 44 +------------
69 files changed, 1138 insertions(+), 729 deletions(-)
create mode 100644 arch/x86/mm/pgprot.c

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2.25.1