| Message ID | 1646045273-9343-1-git-send-email-anshuman.khandual@arm.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | mm/mmap: Drop protection_map[] and platform's __SXXX/__PXXX requirements | expand |
On 2/28/22 16:17, Anshuman Khandual wrote: > 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 Hello Andrew, I am planning to rework this series later, as it is already some what late for the next merge window. I am wondering if you could consider just these above two independent patches for v5.18-rc1 ? - Anshuman