[PATCH 07/10] powerpc/603: let's handle PAGE_DIRTY directly

From: Christophe Leroy
Date: Fri Jan 25 2019 - 07:34:20 EST


PAGE_DIRTY corresponds to the C bit. If writing on
a page for which the C bit is not set, a DataStoreTLBMiss
is generated. No need to check it in DataLoadTLBMiss.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
---
arch/powerpc/kernel/head_32.S | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index 2aec3f91c9f5..abbaf51b6f58 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -597,12 +597,10 @@ DataLoadTLBMiss:
stw r0,0(r2) /* update PTE (accessed bit) */
/* Convert linux-style PTE to low word of PPC-style PTE */
rlwinm r1,r0,32-10,31,31 /* _PAGE_RW -> PP lsb */
- rlwinm r2,r0,32-7,31,31 /* _PAGE_DIRTY -> PP lsb */
- and r1,r1,r2 /* writable if _RW and _DIRTY */
rlwimi r0,r0,32-1,30,30 /* _PAGE_USER -> PP msb */
rlwimi r0,r0,32-1,31,31 /* _PAGE_USER -> PP lsb */
ori r1,r1,0xe04 /* clear out reserved bits */
- andc r1,r0,r1 /* PP = user? (rw&dirty? 2: 3): 0 */
+ andc r1,r0,r1 /* PP = user? rw? 2: 3: 0 */
BEGIN_FTR_SECTION
rlwinm r1,r1,0,~_PAGE_COHERENT /* clear M (coherence not required) */
END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT)
@@ -671,7 +669,7 @@ DataStoreTLBMiss:
lwz r0,0(r2) /* get linux-style pte */
andc. r1,r1,r0 /* check access & ~permission */
bne- DataAddressInvalid /* return if access not permitted */
- ori r0,r0,_PAGE_ACCESSED|_PAGE_DIRTY
+ ori r0,r0,_PAGE_ACCESSED
/*
* NOTE! We are assuming this is not an SMP system, otherwise
* we would need to update the pte atomically with lwarx/stwcx.
--
2.13.3