[ARM] Control v6 'global' bit via Linux PTE entries

Unfortunately, we can't use the "user" bit in the page tables to
control whether a page table entry is "global" or "asid" specific,
since the vector page is mapped as "user" accessible but is not
process specific.

Therefore, give direct control of the ARMv6 "nG" (not global)
bit to the mm layers.

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

3 files changed, 18 insertions, 5 deletions

diff --git a/arch/arm/mm/mm-armv.c b/arch/arm/mm/mm-armv.c
index e33fe4229d05..3c655c54e231 100644
--- a/arch/arm/mm/mm-armv.c
+++ b/arch/arm/mm/mm-armv.c
@@ -383,6 +383,7 @@ static void __init build_mem_type_table(void)
 {
         struct cachepolicy *cp;
         unsigned int cr = get_cr();
+        unsigned int user_pgprot;
         int cpu_arch = cpu_architecture();
         int i;
 
@@ -408,6 +409,9 @@ static void __init build_mem_type_table(void)
                 }
         }
 
+        cp = &cache_policies[cachepolicy];
+        user_pgprot = cp->pte;
+
         /*
          * ARMv6 and above have extended page tables.
          */
@@ -426,11 +430,18 @@ static void __init build_mem_type_table(void)
                 mem_types[MT_MINICLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
                 mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
 
+                /*
+                 * Mark the device area as "shared device"
+                 */
                 mem_types[MT_DEVICE].prot_pte |= L_PTE_BUFFERABLE;
                 mem_types[MT_DEVICE].prot_sect |= PMD_SECT_BUFFERED;
-        }
 
-        cp = &cache_policies[cachepolicy];
+                /*
+                 * User pages need to be mapped with the ASID
+                 * (iow, non-global)
+                 */
+                user_pgprot |= L_PTE_ASID;
+        }
 
         if (cpu_arch >= CPU_ARCH_ARMv5) {
                 mem_types[MT_LOW_VECTORS].prot_pte |= cp->pte & PTE_CACHEABLE;
@@ -448,7 +459,7 @@ static void __init build_mem_type_table(void)
 
         for (i = 0; i < 16; i++) {
                 unsigned long v = pgprot_val(protection_map[i]);
-                v &= (~(PTE_BUFFERABLE|PTE_CACHEABLE)) | cp->pte;
+                v &= (~(PTE_BUFFERABLE|PTE_CACHEABLE)) | user_pgprot;
                 protection_map[i] = __pgprot(v);
         }
 
diff --git a/arch/arm/mm/proc-v6.S b/arch/arm/mm/proc-v6.S
index 75e65522c8d2..3429ddcf65d1 100644
--- a/arch/arm/mm/proc-v6.S
+++ b/arch/arm/mm/proc-v6.S
@@ -133,7 +133,7 @@ ENTRY(cpu_v6_switch_mm)
 ENTRY(cpu_v6_set_pte)
         str     r1, [r0], #-2048                @ linux version
 
-        bic     r2, r1, #0x00000ff0
+        bic     r2, r1, #0x000007f0
         bic     r2, r2, #0x00000003
         orr     r2, r2, #PTE_EXT_AP0 | 2
 
@@ -142,7 +142,7 @@ ENTRY(cpu_v6_set_pte)
         orreq   r2, r2, #PTE_EXT_APX
 
         tst     r1, #L_PTE_USER
-        orrne   r2, r2, #PTE_EXT_AP1 | PTE_EXT_NG
+        orrne   r2, r2, #PTE_EXT_AP1
         tstne   r2, #PTE_EXT_APX
         bicne   r2, r2, #PTE_EXT_APX | PTE_EXT_AP0
 
diff --git a/include/asm-arm/pgtable.h b/include/asm-arm/pgtable.h
index 8bd4c0faf230..478c49b56e18 100644
--- a/include/asm-arm/pgtable.h
+++ b/include/asm-arm/pgtable.h
@@ -230,6 +230,8 @@ extern void __pgd_error(const char *file, int line, unsigned long val);
 #define L_PTE_WRITE             (1 << 5)
 #define L_PTE_EXEC              (1 << 6)
 #define L_PTE_DIRTY             (1 << 7)
+#define L_PTE_SHARED            (1 << 10)       /* shared between CPUs (v6) */
+#define L_PTE_ASID              (1 << 11)       /* non-global (use ASID, v6) */
 
 #ifndef __ASSEMBLY__