1 files changed, 97 insertions, 28 deletions

diff --git a/arch/arm/mm/idmap.c b/arch/arm/mm/idmap.c
index 57299446f78..c447ec70e86 100644
--- a/arch/arm/mm/idmap.c
+++ b/arch/arm/mm/idmap.c
@@ -1,13 +1,58 @@
+#include <linux/module.h>
 #include <linux/kernel.h>
+#include <linux/slab.h>
 
 #include <asm/cputype.h>
+#include <asm/idmap.h>
 #include <asm/pgalloc.h>
 #include <asm/pgtable.h>
+#include <asm/sections.h>
+#include <asm/system_info.h>
 
-static void idmap_add_pmd(pgd_t *pgd, unsigned long addr, unsigned long end,
+/*
+ * Note: accesses outside of the kernel image and the identity map area
+ * are not supported on any CPU using the idmap tables as its current
+ * page tables.
+ */
+pgd_t *idmap_pgd;
+phys_addr_t (*arch_virt_to_idmap) (unsigned long x);
+
+#ifdef CONFIG_ARM_LPAE
+static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end,
+	unsigned long prot)
+{
+	pmd_t *pmd;
+	unsigned long next;
+
+	if (pud_none_or_clear_bad(pud) || (pud_val(*pud) & L_PGD_SWAPPER)) {
+		pmd = pmd_alloc_one(&init_mm, addr);
+		if (!pmd) {
+			pr_warning("Failed to allocate identity pmd.\n");
+			return;
+		}
+		/*
+		 * Copy the original PMD to ensure that the PMD entries for
+		 * the kernel image are preserved.
+		 */
+		if (!pud_none(*pud))
+			memcpy(pmd, pmd_offset(pud, 0),
+			       PTRS_PER_PMD * sizeof(pmd_t));
+		pud_populate(&init_mm, pud, pmd);
+		pmd += pmd_index(addr);
+	} else
+		pmd = pmd_offset(pud, addr);
+
+	do {
+		next = pmd_addr_end(addr, end);
+		*pmd = __pmd((addr & PMD_MASK) | prot);
+		flush_pmd_entry(pmd);
+	} while (pmd++, addr = next, addr != end);
+}
+#else	/* !CONFIG_ARM_LPAE */
+static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end,
 	unsigned long prot)
 {
-	pmd_t *pmd = pmd_offset(pgd, addr);
+	pmd_t *pmd = pmd_offset(pud, addr);
 
 	addr = (addr & PMD_MASK) | prot;
 	pmd[0] = __pmd(addr);
@@ -15,53 +60,77 @@ static void idmap_add_pmd(pgd_t *pgd, unsigned long addr, unsigned long end,
 	pmd[1] = __pmd(addr);
 	flush_pmd_entry(pmd);
 }
+#endif	/* CONFIG_ARM_LPAE */
+
+static void idmap_add_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
+	unsigned long prot)
+{
+	pud_t *pud = pud_offset(pgd, addr);
+	unsigned long next;
+
+	do {
+		next = pud_addr_end(addr, end);
+		idmap_add_pmd(pud, addr, next, prot);
+	} while (pud++, addr = next, addr != end);
+}
 
-void identity_mapping_add(pgd_t *pgd, unsigned long addr, unsigned long end)
+static void identity_mapping_add(pgd_t *pgd, const char *text_start,
+				 const char *text_end, unsigned long prot)
 {
-	unsigned long prot, next;
+	unsigned long addr, end;
+	unsigned long next;
+
+	addr = virt_to_idmap(text_start);
+	end = virt_to_idmap(text_end);
+	pr_info("Setting up static identity map for 0x%lx - 0x%lx\n", addr, end);
+
+	prot |= PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_AF;
 
-	prot = PMD_TYPE_SECT | PMD_SECT_AP_WRITE;
 	if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale())
 		prot |= PMD_BIT4;
 
 	pgd += pgd_index(addr);
 	do {
 		next = pgd_addr_end(addr, end);
-		idmap_add_pmd(pgd, addr, next, prot);
+		idmap_add_pud(pgd, addr, next, prot);
 	} while (pgd++, addr = next, addr != end);
 }
 
-#ifdef CONFIG_SMP
-static void idmap_del_pmd(pgd_t *pgd, unsigned long addr, unsigned long end)
-{
-	pmd_t *pmd = pmd_offset(pgd, addr);
-	pmd_clear(pmd);
-}
+extern char  __idmap_text_start[], __idmap_text_end[];
 
-void identity_mapping_del(pgd_t *pgd, unsigned long addr, unsigned long end)
+static int __init init_static_idmap(void)
 {
-	unsigned long next;
+	idmap_pgd = pgd_alloc(&init_mm);
+	if (!idmap_pgd)
+		return -ENOMEM;
 
-	pgd += pgd_index(addr);
-	do {
-		next = pgd_addr_end(addr, end);
-		idmap_del_pmd(pgd, addr, next);
-	} while (pgd++, addr = next, addr != end);
+	identity_mapping_add(idmap_pgd, __idmap_text_start,
+			     __idmap_text_end, 0);
+
+	/* Flush L1 for the hardware to see this page table content */
+	flush_cache_louis();
+
+	return 0;
 }
-#endif
+early_initcall(init_static_idmap);
 
 /*
- * 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
+ * In order to soft-boot, we need to switch to a 1:1 mapping for the
+ * cpu_reset functions. This will then ensure that we have predictable
+ * results when turning off the mmu.
  */
-void setup_mm_for_reboot(char mode)
+void setup_mm_for_reboot(void)
 {
+	/* Switch to the identity mapping. */
+	cpu_switch_mm(idmap_pgd, &init_mm);
+	local_flush_bp_all();
+
+#ifdef CONFIG_CPU_HAS_ASID
 	/*
-	 * 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".
+	 * We don't have a clean ASID for the identity mapping, which
+	 * may clash with virtual addresses of the previous page tables
+	 * and therefore potentially in the TLB.
 	 */
-	identity_mapping_add(current->active_mm->pgd, 0, TASK_SIZE);
 	local_flush_tlb_all();
+#endif
 }