ARM: pgtable: collect up identity mapping functions

We have two places where we create identity mappings - one when we bring
secondary CPUs online, and one where we setup some mappings for soft-
reboot.  Combine these two into a single implementation.  Also collect
the identity mapping deletion function.

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

3 files changed, 53 insertions, 37 deletions

diff --git a/arch/arm/mm/Makefile b/arch/arm/mm/Makefile
index d63b6c41375..00d74a04af3 100644
--- a/arch/arm/mm/Makefile
+++ b/arch/arm/mm/Makefile
@@ -5,8 +5,8 @@
 obj-y				:= dma-mapping.o extable.o fault.o init.o \
 				   iomap.o
 
-obj-$(CONFIG_MMU)		+= fault-armv.o flush.o ioremap.o mmap.o \
-				   pgd.o mmu.o vmregion.o
+obj-$(CONFIG_MMU)		+= fault-armv.o flush.o idmap.o ioremap.o \
+				   mmap.o pgd.o mmu.o vmregion.o
 
 ifneq ($(CONFIG_MMU),y)
 obj-y				+= nommu.o
diff --git a/arch/arm/mm/idmap.c b/arch/arm/mm/idmap.c
new file mode 100644
index 00000000000..034124d1272
--- /dev/null
+++ b/arch/arm/mm/idmap.c
@@ -0,0 +1,51 @@
+#include <linux/kernel.h>
+
+#include <asm/cputype.h>
+#include <asm/pgalloc.h>
+#include <asm/pgtable.h>
+
+void identity_mapping_add(pgd_t *pgd, unsigned long addr, unsigned long end)
+{
+	unsigned long prot;
+
+	prot = PMD_TYPE_SECT | PMD_SECT_AP_WRITE;
+	if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale())
+		prot |= PMD_BIT4;
+
+	for (addr &= PGDIR_MASK; addr < end;) {
+		pmd_t *pmd = pmd_offset(pgd + pgd_index(addr), addr);
+		pmd[0] = __pmd(addr | prot);
+		addr += SECTION_SIZE;
+		pmd[1] = __pmd(addr | prot);
+		addr += SECTION_SIZE;
+		flush_pmd_entry(pmd);
+	}
+}
+
+#ifdef CONFIG_SMP
+void identity_mapping_del(pgd_t *pgd, unsigned long addr, unsigned long end)
+{
+	for (addr &= PGDIR_MASK; addr < end; addr += PGDIR_SIZE) {
+		pmd_t *pmd = pmd_offset(pgd + pgd_index(addr), addr);
+		pmd[0] = __pmd(0);
+		pmd[1] = __pmd(0);
+		clean_pmd_entry(pmd);
+	}
+}
+#endif
+
+/*
+ * In order to soft-boot, we need to insert a 1:1 mapping in place of
+ * the user-mode pages.  This will then ensure that we have predictable
+ * results when turning the mmu off
+ */
+void setup_mm_for_reboot(char mode)
+{
+	/*
+	 * We need to access to user-mode page tables here. For kernel threads
+	 * we don't have any user-mode mappings so we use the context that we
+	 * "borrowed".
+	 */
+	identity_mapping_add(current->active_mm->pgd, 0, TASK_SIZE);
+	local_flush_tlb_all();
+}
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 94ee0930d69..bd1a11e62f4 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -1045,38 +1045,3 @@ void __init paging_init(struct machine_desc *mdesc)
 	empty_zero_page = virt_to_page(zero_page);
 	__flush_dcache_page(NULL, empty_zero_page);
 }
-
-/*
- * In order to soft-boot, we need to insert a 1:1 mapping in place of
- * the user-mode pages.  This will then ensure that we have predictable
- * results when turning the mmu off
- */
-void setup_mm_for_reboot(char mode)
-{
-	unsigned long base_pmdval;
-	pgd_t *pgd;
-	int i;
-
-	/*
-	 * We need to access to user-mode page tables here. For kernel threads
-	 * we don't have any user-mode mappings so we use the context that we
-	 * "borrowed".
-	 */
-	pgd = current->active_mm->pgd;
-
-	base_pmdval = PMD_SECT_AP_WRITE | PMD_SECT_AP_READ | PMD_TYPE_SECT;
-	if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale())
-		base_pmdval |= PMD_BIT4;
-
-	for (i = 0; i < FIRST_USER_PGD_NR + USER_PTRS_PER_PGD; i++, pgd++) {
-		unsigned long pmdval = (i << PGDIR_SHIFT) | base_pmdval;
-		pmd_t *pmd;
-
-		pmd = pmd_off(pgd, i << PGDIR_SHIFT);
-		pmd[0] = __pmd(pmdval);
-		pmd[1] = __pmd(pmdval + (1 << (PGDIR_SHIFT - 1)));
-		flush_pmd_entry(pmd);
-	}
-
-	local_flush_tlb_all();
-}