1 files changed, 49 insertions, 28 deletions

diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index e0ab173b6974..2ed37158012d 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -31,7 +31,7 @@
 #ifdef CONFIG_X86_PAT
 int __read_mostly pat_enabled = 1;
 
-void __cpuinit pat_disable(char *reason)
+void __cpuinit pat_disable(const char *reason)
 {
         pat_enabled = 0;
         printk(KERN_INFO "%s\n", reason);
@@ -43,6 +43,11 @@ static int __init nopat(char *str)
         return 0;
 }
 early_param("nopat", nopat);
+#else
+static inline void pat_disable(const char *reason)
+{
+        (void)reason;
+}
 #endif
 
 
@@ -79,16 +84,20 @@ void pat_init(void)
         if (!pat_enabled)
                 return;
 
-        /* Paranoia check. */
-        if (!cpu_has_pat && boot_pat_state) {
-                /*
-                 * If this happens we are on a secondary CPU, but
-                 * switched to PAT on the boot CPU. We have no way to
-                 * undo PAT.
-                 */
-                printk(KERN_ERR "PAT enabled, "
-                       "but not supported by secondary CPU\n");
-                BUG();
+        if (!cpu_has_pat) {
+                if (!boot_pat_state) {
+                        pat_disable("PAT not supported by CPU.");
+                        return;
+                } else {
+                        /*
+                         * If this happens we are on a secondary CPU, but
+                         * switched to PAT on the boot CPU. We have no way to
+                         * undo PAT.
+                         */
+                        printk(KERN_ERR "PAT enabled, "
+                               "but not supported by secondary CPU\n");
+                        BUG();
+                }
         }
 
         /* Set PWT to Write-Combining. All other bits stay the same */
@@ -626,6 +635,33 @@ void unmap_devmem(unsigned long pfn, unsigned long size, pgprot_t vma_prot)
 }
 
 /*
+ * Change the memory type for the physial address range in kernel identity
+ * mapping space if that range is a part of identity map.
+ */
+int kernel_map_sync_memtype(u64 base, unsigned long size, unsigned long flags)
+{
+        unsigned long id_sz;
+
+        if (!pat_enabled || base >= __pa(high_memory))
+                return 0;
+
+        id_sz = (__pa(high_memory) < base + size) ?
+                                __pa(high_memory) - base :
+                                size;
+
+        if (ioremap_change_attr((unsigned long)__va(base), id_sz, flags) < 0) {
+                printk(KERN_INFO
+                        "%s:%d ioremap_change_attr failed %s "
+                        "for %Lx-%Lx\n",
+                        current->comm, current->pid,
+                        cattr_name(flags),
+                        base, (unsigned long long)(base + size));
+                return -EINVAL;
+        }
+        return 0;
+}
+
+/*
  * Internal interface to reserve a range of physical memory with prot.
  * Reserved non RAM regions only and after successful reserve_memtype,
  * this func also keeps identity mapping (if any) in sync with this new prot.
@@ -634,7 +670,7 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
                                 int strict_prot)
 {
         int is_ram = 0;
-        int id_sz, ret;
+        int ret;
         unsigned long flags;
         unsigned long want_flags = (pgprot_val(*vma_prot) & _PAGE_CACHE_MASK);
 
@@ -671,23 +707,8 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
                                      flags);
         }
 
-        /* Need to keep identity mapping in sync */
-        if (paddr >= __pa(high_memory))
-                return 0;
-
-        id_sz = (__pa(high_memory) < paddr + size) ?
-                                __pa(high_memory) - paddr :
-                                size;
-
-        if (ioremap_change_attr((unsigned long)__va(paddr), id_sz, flags) < 0) {
+        if (kernel_map_sync_memtype(paddr, size, flags) < 0) {
                 free_memtype(paddr, paddr + size);
-                printk(KERN_ERR
-                        "%s:%d reserve_pfn_range ioremap_change_attr failed %s "
-                        "for %Lx-%Lx\n",
-                        current->comm, current->pid,
-                        cattr_name(flags),
-                        (unsigned long long)paddr,
-                        (unsigned long long)(paddr + size));
                 return -EINVAL;
         }
         return 0;