[PATCH V5 02/26] mm/mmap: Define DECLARE_VM_GET_PAGE_PROT
From: Anshuman Khandual <hidden>
Date: 2022-06-27 04:59:21
Also in:
linux-alpha, linux-arm-kernel, linux-m68k, linux-mips, linux-mm, linux-riscv, linux-s390, linux-sh, linux-um, lkml, sparclinux
Subsystem:
memory management, memory management - core, memory mapping, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Liam R. Howlett, Lorenzo Stoakes, Linus Torvalds
This just converts the generic vm_get_page_prot() implementation into a new macro i.e DECLARE_VM_GET_PAGE_PROT which later can be used across platforms when enabling them with ARCH_HAS_VM_GET_PAGE_PROT. This does not create any functional change. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org Suggested-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Anshuman Khandual <redacted> --- include/linux/pgtable.h | 28 ++++++++++++++++++++++++++++ mm/mmap.c | 26 +------------------------- 2 files changed, 29 insertions(+), 25 deletions(-)
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 3cdc16cfd867..014ee8f0fbaa 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h@@ -1689,4 +1689,32 @@ typedef unsigned int pgtbl_mod_mask; #define MAX_PTRS_PER_P4D PTRS_PER_P4D #endif +/* description of effects of mapping type and prot in current implementation. + * this is due to the limited x86 page protection hardware. The expected + * behavior is in parens: + * + * map_type prot + * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC + * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes + * w: (no) no w: (no) no w: (yes) yes w: (no) no + * x: (no) no x: (no) yes x: (no) yes x: (yes) yes + * + * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes + * w: (no) no w: (no) no w: (copy) copy w: (no) no + * x: (no) no x: (no) yes x: (no) yes x: (yes) yes + * + * On arm64, PROT_EXEC has the following behaviour for both MAP_SHARED and + * MAP_PRIVATE (with Enhanced PAN supported): + * r: (no) no + * w: (no) no + * x: (yes) yes + */ +#define DECLARE_VM_GET_PAGE_PROT \ +pgprot_t vm_get_page_prot(unsigned long vm_flags) \ +{ \ + return protection_map[vm_flags & \ + (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)]; \ +} \ +EXPORT_SYMBOL(vm_get_page_prot); + #endif /* _LINUX_PGTABLE_H */
diff --git a/mm/mmap.c b/mm/mmap.c
index b01f0280bda2..b46d5e931bb3 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c@@ -81,26 +81,6 @@ static void unmap_region(struct mm_struct *mm, struct vm_area_struct *vma, struct vm_area_struct *prev, unsigned long start, unsigned long end); -/* description of effects of mapping type and prot in current implementation. - * this is due to the limited x86 page protection hardware. The expected - * behavior is in parens: - * - * map_type prot - * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC - * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes - * w: (no) no w: (no) no w: (yes) yes w: (no) no - * x: (no) no x: (no) yes x: (no) yes x: (yes) yes - * - * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes - * w: (no) no w: (no) no w: (copy) copy w: (no) no - * x: (no) no x: (no) yes x: (no) yes x: (yes) yes - * - * On arm64, PROT_EXEC has the following behaviour for both MAP_SHARED and - * MAP_PRIVATE (with Enhanced PAN supported): - * r: (no) no - * w: (no) no - * x: (yes) yes - */ #ifdef __P000 pgprot_t protection_map[16] __ro_after_init = { [VM_NONE] = __P000,
@@ -123,11 +103,7 @@ pgprot_t protection_map[16] __ro_after_init = { #endif #ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT -pgprot_t vm_get_page_prot(unsigned long vm_flags) -{ - return protection_map[vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]; -} -EXPORT_SYMBOL(vm_get_page_prot); +DECLARE_VM_GET_PAGE_PROT #endif /* CONFIG_ARCH_HAS_VM_GET_PAGE_PROT */ static pgprot_t vm_pgprot_modify(pgprot_t oldprot, unsigned long vm_flags)
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2.25.1