[ARM SMP] Add support for shared memory attribute

We need to set the shared memory attribute in the page tables
on SMP systems to allow the cache coherency to operate.

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

2 files changed, 39 insertions, 17 deletions

diff --git a/arch/arm/mm/mm-armv.c b/arch/arm/mm/mm-armv.c
index fb5b40289de2..9e50127be635 100644
--- a/arch/arm/mm/mm-armv.c
+++ b/arch/arm/mm/mm-armv.c
@@ -354,7 +354,7 @@ void __init build_mem_type_table(void)
 {
         struct cachepolicy *cp;
         unsigned int cr = get_cr();
-        unsigned int user_pgprot;
+        unsigned int user_pgprot, kern_pgprot;
         int cpu_arch = cpu_architecture();
         int i;
 
@@ -381,7 +381,7 @@ void __init build_mem_type_table(void)
         }
 
         cp = &cache_policies[cachepolicy];
-        user_pgprot = cp->pte;
+        kern_pgprot = user_pgprot = cp->pte;
 
         /*
          * ARMv6 and above have extended page tables.
@@ -393,6 +393,7 @@ void __init build_mem_type_table(void)
                  */
                 mem_types[MT_MEMORY].prot_sect &= ~PMD_BIT4;
                 mem_types[MT_ROM].prot_sect &= ~PMD_BIT4;
+
                 /*
                  * Mark cache clean areas and XIP ROM read only
                  * from SVC mode and no access from userspace.
@@ -412,32 +413,47 @@ void __init build_mem_type_table(void)
                  * (iow, non-global)
                  */
                 user_pgprot |= L_PTE_ASID;
+
+#ifdef CONFIG_SMP
+                /*
+                 * Mark memory with the "shared" attribute for SMP systems
+                 */
+                user_pgprot |= L_PTE_SHARED;
+                kern_pgprot |= L_PTE_SHARED;
+                mem_types[MT_MEMORY].prot_sect |= PMD_SECT_S;
+#endif
         }
 
+        for (i = 0; i < 16; i++) {
+                unsigned long v = pgprot_val(protection_map[i]);
+                v = (v & ~(L_PTE_BUFFERABLE|L_PTE_CACHEABLE)) | user_pgprot;
+                protection_map[i] = __pgprot(v);
+        }
+
+        mem_types[MT_LOW_VECTORS].prot_pte |= kern_pgprot;
+        mem_types[MT_HIGH_VECTORS].prot_pte |= kern_pgprot;
+
         if (cpu_arch >= CPU_ARCH_ARMv5) {
-                mem_types[MT_LOW_VECTORS].prot_pte |= cp->pte & PTE_CACHEABLE;
-                mem_types[MT_HIGH_VECTORS].prot_pte |= cp->pte & PTE_CACHEABLE;
+#ifndef CONFIG_SMP
+                /*
+                 * Only use write-through for non-SMP systems
+                 */
+                mem_types[MT_LOW_VECTORS].prot_pte &= ~L_PTE_BUFFERABLE;
+                mem_types[MT_HIGH_VECTORS].prot_pte &= ~L_PTE_BUFFERABLE;
+#endif
         } else {
-                mem_types[MT_LOW_VECTORS].prot_pte |= cp->pte;
-                mem_types[MT_HIGH_VECTORS].prot_pte |= cp->pte;
                 mem_types[MT_MINICLEAN].prot_sect &= ~PMD_SECT_TEX(1);
         }
 
+        pgprot_kernel = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG |
+                                 L_PTE_DIRTY | L_PTE_WRITE |
+                                 L_PTE_EXEC | kern_pgprot);
+
         mem_types[MT_LOW_VECTORS].prot_l1 |= ecc_mask;
         mem_types[MT_HIGH_VECTORS].prot_l1 |= ecc_mask;
         mem_types[MT_MEMORY].prot_sect |= ecc_mask | cp->pmd;
         mem_types[MT_ROM].prot_sect |= cp->pmd;
 
-        for (i = 0; i < 16; i++) {
-                unsigned long v = pgprot_val(protection_map[i]);
-                v = (v & ~(PTE_BUFFERABLE|PTE_CACHEABLE)) | user_pgprot;
-                protection_map[i] = __pgprot(v);
-        }
-
-        pgprot_kernel = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG |
-                                 L_PTE_DIRTY | L_PTE_WRITE |
-                                 L_PTE_EXEC | cp->pte);
-
         switch (cp->pmd) {
         case PMD_SECT_WT:
                 mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_WT;
diff --git a/arch/arm/mm/proc-v6.S b/arch/arm/mm/proc-v6.S
index 9bb5fff406fb..a39d8fa2ede5 100644
--- a/arch/arm/mm/proc-v6.S
+++ b/arch/arm/mm/proc-v6.S
@@ -112,6 +112,9 @@ ENTRY(cpu_v6_dcache_clean_area)
 ENTRY(cpu_v6_switch_mm)
         mov     r2, #0
         ldr     r1, [r1, #MM_CONTEXT_ID]        @ get mm->context.id
+#ifdef CONFIG_SMP
+        orr     r0, r0, #2                      @ set shared pgtable
+#endif
         mcr     p15, 0, r2, c7, c5, 6           @ flush BTAC/BTB
         mcr     p15, 0, r2, c7, c10, 4          @ drain write buffer
         mcr     p15, 0, r0, c2, c0, 0           @ set TTB 0
@@ -140,7 +143,7 @@ ENTRY(cpu_v6_switch_mm)
 ENTRY(cpu_v6_set_pte)
         str     r1, [r0], #-2048                @ linux version
 
-        bic     r2, r1, #0x000007f0
+        bic     r2, r1, #0x000003f0
         bic     r2, r2, #0x00000003
         orr     r2, r2, #PTE_EXT_AP0 | 2
 
@@ -198,6 +201,9 @@ __v6_setup:
         mcr     p15, 0, r0, c7, c10, 4          @ drain write buffer
         mcr     p15, 0, r0, c8, c7, 0           @ invalidate I + D TLBs
         mcr     p15, 0, r0, c2, c0, 2           @ TTB control register
+#ifdef CONFIG_SMP
+        orr     r4, r4, #2                      @ set shared pgtable
+#endif
         mcr     p15, 0, r4, c2, c0, 1           @ load TTB1
 #ifdef CONFIG_VFP
         mrc     p15, 0, r0, c1, c0, 2