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Subject[v2 PATCH 2/2] powerpc/8xx: use _PAGE_RO instead of _PAGE_RW
Date
On powerpc 8xx, in TLB entries, 0x400 bit is set to 1 for read-only pages
and is set to 0 for RW pages. So we should use _PAGE_RO instead of _PAGE_RW

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>

---
v2 is a complete rework compared to v1

arch/powerpc/include/asm/pte-8xx.h | 7 +++----
arch/powerpc/kernel/head_8xx.S | 3 ---
2 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/include/asm/pte-8xx.h b/arch/powerpc/include/asm/pte-8xx.h
index daa4616..4f5583e 100644
--- a/arch/powerpc/include/asm/pte-8xx.h
+++ b/arch/powerpc/include/asm/pte-8xx.h
@@ -46,7 +46,7 @@
* require a TLB exception handler change. It is assumed unused bits
* are always zero.
*/
-#define _PAGE_RW 0x0400 /* lsb PP bits, inverted in HW */
+#define _PAGE_RO 0x0400 /* lsb PP bits */
#define _PAGE_USER 0x0800 /* msb PP bits */
/* set when neither _PAGE_USER nor _PAGE_RW are set */
#define _PAGE_KNLRO 0x0200
@@ -62,9 +62,8 @@
#define PTE_ATOMIC_UPDATES 1

/* We need to add _PAGE_SHARED to kernel pages */
-#define _PAGE_KERNEL_RO (_PAGE_SHARED | _PAGE_KNLRO)
-#define _PAGE_KERNEL_ROX (_PAGE_EXEC | _PAGE_KNLRO)
-#define _PAGE_KERNEL_RW (_PAGE_DIRTY | _PAGE_RW | _PAGE_HWWRITE)
+#define _PAGE_KERNEL_RO (_PAGE_SHARED | _PAGE_RO | _PAGE_KNLRO)
+#define _PAGE_KERNEL_ROX (_PAGE_EXEC | _PAGE_RO | _PAGE_KNLRO)

#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_PTE_8xx_H */
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 3d4b8ee..807b0db 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -441,9 +441,6 @@ DataStoreTLBMiss:
and r11, r11, r10
rlwimi r10, r11, 0, _PAGE_PRESENT
#endif
- /* invert RW */
- xori r10, r10, _PAGE_RW
-
/* The Linux PTE won't go exactly into the MMU TLB.
* Software indicator bits 22 and 28 must be clear.
* Software indicator bits 24, 25, 26, and 27 must be
--
2.1.0


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