[PATCH V3 02/30] mm/mmap: Clarify protection_map[] indices
From: Anshuman Khandual <hidden>
Date: 2022-02-28 10:49:28
Also in:
linux-alpha, linux-arch, linux-arm-kernel, linux-m68k, linux-mips, linux-mm, linux-riscv, linux-s390, linux-sh, linux-um, lkml, sparclinux
Subsystem:
memory management, memory mapping, the rest · Maintainers:
Andrew Morton, Liam R. Howlett, Lorenzo Stoakes, Linus Torvalds
protection_map[] maps vm_flags access combinations into page protection value as defined by the platform via __PXXX and __SXXX macros. The array indices in protection_map[], represents vm_flags access combinations but it's not very intuitive to derive. This makes it clear and explicit. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Anshuman Khandual <redacted> --- mm/mmap.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index d445c1b9d606..34000a7d7efa 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c@@ -102,8 +102,22 @@ static void unmap_region(struct mm_struct *mm, * x: (yes) yes */ pgprot_t protection_map[16] __ro_after_init = { - __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111, - __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111 + [VM_NONE] = __P000, + [VM_READ] = __P001, + [VM_WRITE] = __P010, + [VM_WRITE | VM_READ] = __P011, + [VM_EXEC] = __P100, + [VM_EXEC | VM_READ] = __P101, + [VM_EXEC | VM_WRITE] = __P110, + [VM_EXEC | VM_WRITE | VM_READ] = __P111, + [VM_SHARED] = __S000, + [VM_SHARED | VM_READ] = __S001, + [VM_SHARED | VM_WRITE] = __S010, + [VM_SHARED | VM_WRITE | VM_READ] = __S011, + [VM_SHARED | VM_EXEC] = __S100, + [VM_SHARED | VM_EXEC | VM_READ] = __S101, + [VM_SHARED | VM_EXEC | VM_WRITE] = __S110, + [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = __S111 }; #ifndef CONFIG_ARCH_HAS_FILTER_PGPROT
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2.25.1