Merge branches 'x86/asm', 'x86/cleanups', 'x86/cpudetect', 'x86/debug', 'x86/doc...

[linux-2.6-omap-h63xx.git] / arch / x86 / mm / pat.c

diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 8b08fb955274148454a2acaa538c78215322e655..9127e31c726866d462d0da61d03ceade383ced4e 100644 (file)
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -30,7 +30,7 @@
 #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);
@@ -42,6 +42,11 @@ static int __init nopat(char *str)
        return 0;
 }
 early_param("nopat", nopat);
+#else
+static inline void pat_disable(const char *reason)
+{
+       (void)reason;
+}
 #endif
 
 
@@ -78,16 +83,20 @@ 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 */
@@ -333,11 +342,23 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
                                              req_type & _PAGE_CACHE_MASK);
        }
 
-       is_range_ram = pagerange_is_ram(start, end);
-       if (is_range_ram == 1)
-               return reserve_ram_pages_type(start, end, req_type, new_type);
-       else if (is_range_ram < 0)
-               return -EINVAL;
+       if (new_type)
+               *new_type = actual_type;
+
+       /*
+        * For legacy reasons, some parts of the physical address range in the
+        * legacy 1MB region is treated as non-RAM (even when listed as RAM in
+        * the e820 tables).  So we will track the memory attributes of this
+        * legacy 1MB region using the linear memtype_list always.
+        */
+       if (end >= ISA_END_ADDRESS) {
+               is_range_ram = pagerange_is_ram(start, end);
+               if (is_range_ram == 1)
+                       return reserve_ram_pages_type(start, end, req_type,
+                                                     new_type);
+               else if (is_range_ram < 0)
+                       return -EINVAL;
+       }
 
        new  = kmalloc(sizeof(struct memtype), GFP_KERNEL);
        if (!new)
@@ -347,9 +368,6 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
        new->end        = end;
        new->type       = actual_type;
 
-       if (new_type)
-               *new_type = actual_type;
-
        spin_lock(&memtype_lock);
 
        if (cached_entry && start >= cached_start)
@@ -437,11 +455,19 @@ int free_memtype(u64 start, u64 end)
        if (is_ISA_range(start, end - 1))
                return 0;
 
-       is_range_ram = pagerange_is_ram(start, end);
-       if (is_range_ram == 1)
-               return free_ram_pages_type(start, end);
-       else if (is_range_ram < 0)
-               return -EINVAL;
+       /*
+        * For legacy reasons, some parts of the physical address range in the
+        * legacy 1MB region is treated as non-RAM (even when listed as RAM in
+        * the e820 tables).  So we will track the memory attributes of this
+        * legacy 1MB region using the linear memtype_list always.
+        */
+       if (end >= ISA_END_ADDRESS) {
+               is_range_ram = pagerange_is_ram(start, end);
+               if (is_range_ram == 1)
+                       return free_ram_pages_type(start, end);
+               else if (is_range_ram < 0)
+                       return -EINVAL;
+       }
 
        spin_lock(&memtype_lock);
        list_for_each_entry(entry, &memtype_list, nd) {