[RFC PATCH 7/9] powerpc/mm/book3s-64: Shuffle read, write, execute and user bits in PTE
From: Paul Mackerras <hidden>
Date: 2016-02-20 06:13:17
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
This moves the _PAGE_EXEC, _PAGE_RW and _PAGE_USER bits around in the Linux PTE on 64-bit Book 3S systems to correspond with the bit positions used in radix mode by PowerISA v3.0 CPUs. This also adds a _PAGE_READ bit corresponding to the read permission bit in the radix PTE. _PAGE_READ is currently unused but could possibly be used in future to improve pte_protnone(). Signed-off-by: Paul Mackerras <redacted> --- arch/powerpc/include/asm/book3s/64/hash.h | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h
index c8eba0e..0fc750c 100644
--- a/arch/powerpc/include/asm/book3s/64/hash.h
+++ b/arch/powerpc/include/asm/book3s/64/hash.h@@ -13,9 +13,12 @@ * We could create separate kernel read-only if we used the 3 PP bits * combinations that newer processors provide but we currently don't. */ -#define _PAGE_BIT_SWAP_TYPE 2 -#define _PAGE_USER 0x00004 /* page may be accessed by userspace */ -#define _PAGE_EXEC 0x00008 /* execute permission */ +#define _PAGE_BIT_SWAP_TYPE 0 + +#define _PAGE_EXEC 0x00001 /* execute permission */ +#define _PAGE_RW 0x00002 /* read & write access allowed */ +#define _PAGE_READ 0x00004 /* read access allowed */ +#define _PAGE_USER 0x00008 /* page may be accessed by userspace */ #define _PAGE_GUARDED 0x00010 /* G: guarded (side-effect) page */ /* M (memory coherence) is always set in the HPTE, so we don't need it here */ #define _PAGE_COHERENT 0x0
@@ -23,7 +26,6 @@ #define _PAGE_WRITETHRU 0x00040 /* W: cache write-through */ #define _PAGE_DIRTY 0x00080 /* C: page changed */ #define _PAGE_ACCESSED 0x00100 /* R: page referenced */ -#define _PAGE_RW 0x00200 /* software: user write access allowed */ #define _PAGE_BUSY 0x00800 /* software: PTE & hash are busy */ #define _PAGE_SPECIAL 0x10000 /* software: special page */
--
2.5.0