[ARM] Introduce new PTE memory type bits

Provide L_PTE_MT_xxx definitions to describe the memory types that we
use in Linux/ARM.  These definitions are carefully picked such that:

1. their LSBs match what is required for pre-ARMv6 CPUs.
2. they all have a unique encoding, including after modification
   by build_mem_type_table() (the result being that some have more
   than one combination.)

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 6 insertions, 5 deletions

diff --git a/arch/arm/mm/fault-armv.c b/arch/arm/mm/fault-armv.c
index a8ec97b4752e..6f92904a81e9 100644
--- a/arch/arm/mm/fault-armv.c
+++ b/arch/arm/mm/fault-armv.c
@@ -21,7 +21,7 @@
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
 
-static unsigned long shared_pte_mask = L_PTE_CACHEABLE;
+static unsigned long shared_pte_mask = L_PTE_MT_BUFFERABLE;
 
 /*
  * We take the easy way out of this problem - we make the
@@ -63,9 +63,10 @@ static int adjust_pte(struct vm_area_struct *vma, unsigned long address)
          * If this page isn't present, or is already setup to
          * fault (ie, is old), we can safely ignore any issues.
          */
-        if (ret && pte_val(entry) & shared_pte_mask) {
+        if (ret && (pte_val(entry) & L_PTE_MT_MASK) != shared_pte_mask) {
                 flush_cache_page(vma, address, pte_pfn(entry));
-                pte_val(entry) &= ~shared_pte_mask;
+                pte_val(entry) &= ~L_PTE_MT_MASK;
+                pte_val(entry) |= shared_pte_mask;
                 set_pte_at(vma->vm_mm, address, pte, entry);
                 flush_tlb_page(vma, address);
         }
@@ -197,7 +198,7 @@ void __init check_writebuffer_bugs(void)
                 unsigned long *p1, *p2;
                 pgprot_t prot = __pgprot(L_PTE_PRESENT|L_PTE_YOUNG|
                                          L_PTE_DIRTY|L_PTE_WRITE|
-                                         L_PTE_BUFFERABLE);
+                                         L_PTE_MT_BUFFERABLE);
 
                 p1 = vmap(&page, 1, VM_IOREMAP, prot);
                 p2 = vmap(&page, 1, VM_IOREMAP, prot);
@@ -218,7 +219,7 @@ void __init check_writebuffer_bugs(void)
 
         if (v) {
                 printk("failed, %s\n", reason);
-                shared_pte_mask |= L_PTE_BUFFERABLE;
+                shared_pte_mask = L_PTE_MT_UNCACHED;
         } else {
                 printk("ok\n");
         }