powerpc/mm: Free up _PAGE_COHERENCE for numa fault use later

Set  memory coherence always on hash64 config. If
a platform cannot have memory coherence always set they
can infer that from _PAGE_NO_CACHE and _PAGE_WRITETHRU
like in lpar. So we dont' really need a separate bit
for tracking _PAGE_COHERENCE.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/include/asm/pte-hash64.h b/arch/powerpc/include/asm/pte-hash64.h
index 0419eeb..55aea0c 100644 (file)
--- a/arch/powerpc/include/asm/pte-hash64.h
+++ b/arch/powerpc/include/asm/pte-hash64.h
@@ -19,7 +19,7 @@
 #define _PAGE_FILE             0x0002 /* (!present only) software: pte holds file offset */
 #define _PAGE_EXEC             0x0004 /* No execute on POWER4 and newer (we invert) */
 #define _PAGE_GUARDED          0x0008
-#define _PAGE_COHERENT         0x0010 /* M: enforce memory coherence (SMP systems) */
+/* We can derive Memory coherence from _PAGE_NO_CACHE */
 #define _PAGE_NO_CACHE         0x0020 /* I: cache inhibit */
 #define _PAGE_WRITETHRU                0x0040 /* W: cache write-through */
 #define _PAGE_DIRTY            0x0080 /* C: page changed */

diff --git a/arch/powerpc/mm/hash_low_64.S b/arch/powerpc/mm/hash_low_64.S
index d3cbda6..1136d26 100644 (file)
--- a/arch/powerpc/mm/hash_low_64.S
+++ b/arch/powerpc/mm/hash_low_64.S
@@ -148,7 +148,10 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
        and     r0,r0,r4                /* _PAGE_RW & _PAGE_DIRTY ->r0 bit 30*/
        andc    r0,r30,r0               /* r0 = pte & ~r0 */
        rlwimi  r3,r0,32-1,31,31        /* Insert result into PP lsb */
-       ori     r3,r3,HPTE_R_C          /* Always add "C" bit for perf. */
+       /*
+        * Always add "C" bit for perf. Memory coherence is always enabled
+        */
+       ori     r3,r3,HPTE_R_C | HPTE_R_M
 
        /* We eventually do the icache sync here (maybe inline that
         * code rather than call a C function...) 
@@ -457,7 +460,10 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
        and     r0,r0,r4                /* _PAGE_RW & _PAGE_DIRTY ->r0 bit 30*/
        andc    r0,r3,r0                /* r0 = pte & ~r0 */
        rlwimi  r3,r0,32-1,31,31        /* Insert result into PP lsb */
-       ori     r3,r3,HPTE_R_C          /* Always add "C" bit for perf. */
+       /*
+        * Always add "C" bit for perf. Memory coherence is always enabled
+        */
+       ori     r3,r3,HPTE_R_C | HPTE_R_M
 
        /* We eventually do the icache sync here (maybe inline that
         * code rather than call a C function...)
@@ -795,7 +801,10 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
        and     r0,r0,r4                /* _PAGE_RW & _PAGE_DIRTY ->r0 bit 30*/
        andc    r0,r30,r0               /* r0 = pte & ~r0 */
        rlwimi  r3,r0,32-1,31,31        /* Insert result into PP lsb */
-       ori     r3,r3,HPTE_R_C          /* Always add "C" bit for perf. */
+       /*
+        * Always add "C" bit for perf. Memory coherence is always enabled
+        */
+       ori     r3,r3,HPTE_R_C | HPTE_R_M
 
        /* We eventually do the icache sync here (maybe inline that
         * code rather than call a C function...)

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 6176b3c..de68812 100644 (file)
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -169,9 +169,10 @@ static unsigned long htab_convert_pte_flags(unsigned long pteflags)
        if ((pteflags & _PAGE_USER) && !((pteflags & _PAGE_RW) &&
                                         (pteflags & _PAGE_DIRTY)))
                rflags |= 1;
-
-       /* Always add C */
-       return rflags | HPTE_R_C;
+       /*
+        * Always add "C" bit for perf. Memory coherence is always enabled
+        */
+       return rflags | HPTE_R_C | HPTE_R_M;
 }
 
 int htab_bolt_mapping(unsigned long vstart, unsigned long vend,

diff --git a/arch/powerpc/mm/hugepage-hash64.c b/arch/powerpc/mm/hugepage-hash64.c
index 34de9e0..826893f 100644 (file)
--- a/arch/powerpc/mm/hugepage-hash64.c
+++ b/arch/powerpc/mm/hugepage-hash64.c
@@ -127,7 +127,11 @@ repeat:
 
                /* Add in WIMG bits */
                rflags |= (new_pmd & (_PAGE_WRITETHRU | _PAGE_NO_CACHE |
-                                     _PAGE_COHERENT | _PAGE_GUARDED));
+                                     _PAGE_GUARDED));
+               /*
+                * enable the memory coherence always
+                */
+               rflags |= HPTE_R_M;
 
                /* Insert into the hash table, primary slot */
                slot = ppc_md.hpte_insert(hpte_group, vpn, pa, rflags, 0,

diff --git a/arch/powerpc/mm/hugetlbpage-hash64.c b/arch/powerpc/mm/hugetlbpage-hash64.c
index 0b7fb67..a5bcf93 100644 (file)
--- a/arch/powerpc/mm/hugetlbpage-hash64.c
+++ b/arch/powerpc/mm/hugetlbpage-hash64.c
@@ -99,6 +99,10 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
                /* Add in WIMG bits */
                rflags |= (new_pte & (_PAGE_WRITETHRU | _PAGE_NO_CACHE |
                                      _PAGE_COHERENT | _PAGE_GUARDED));
+               /*
+                * enable the memory coherence always
+                */
+               rflags |= HPTE_R_M;
 
                slot = hpte_insert_repeating(hash, vpn, pa, rflags, 0,
                                             mmu_psize, ssize);