[PATCH 00/30] mm/mmap: Drop protection_map[] and platform's SXXX/PXXX requirements

From: Anshuman Khandual
Date: Sun Feb 13 2022 - 21:31:14 EST

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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@xxxxxxx/

This series applies on 5.17-rc3 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: linux-mm@xxxxxxxxx
Cc: linux-arch@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx

Changes in V1:

- 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 (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
extensa/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 | 18 ----
arch/arm/mm/mmu.c | 44 +++++++--
arch/arm64/Kconfig | 1 -
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 | 22 -----
arch/m68k/include/asm/sun3_pgtable.h | 22 -----
arch/m68k/mm/init.c | 104 ++++++++++++++++++++++
arch/m68k/mm/motorola.c | 48 +++++++++-
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 | 16 ----
arch/nios2/mm/init.c | 45 ++++++++++
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 | 4 -
arch/x86/mm/pgprot.c | 71 +++++++++++++++
arch/xtensa/include/asm/pgtable.h | 18 ----
arch/xtensa/mm/init.c | 35 ++++++++
include/linux/mm.h | 6 --
include/linux/mman.h | 4 -
mm/Kconfig | 3 -
mm/debug_vm_pgtable.c | 31 ++++---
mm/mmap.c | 22 -----
64 files changed, 1140 insertions(+), 683 deletions(-)
create mode 100644 arch/x86/mm/pgprot.c

--
2.25.1

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

[PATCH 00/30] mm/mmap: Drop protection_map[] and platform's SXXX/PXXX requirements