1 files changed, 12 insertions, 0 deletions

diff --git a/arch/arm/mm/idmap.c b/arch/arm/mm/idmap.c
index 8e0e52eb76b5..c447ec70e868 100644
--- a/arch/arm/mm/idmap.c
+++ b/arch/arm/mm/idmap.c
@@ -9,6 +9,11 @@
 #include <asm/sections.h>
 #include <asm/system_info.h>
 
+/*
+ * 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);
 
@@ -25,6 +30,13 @@ static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end,
                         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