1 files changed, 61 insertions, 28 deletions

diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 8b08fb955274..05f9aef6818a 100644
--- 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 */
@@ -211,6 +220,33 @@ chk_conflict(struct memtype *new, struct memtype *entry, unsigned long *type)
 static struct memtype *cached_entry;
 static u64 cached_start;
 
+static int pat_pagerange_is_ram(unsigned long start, unsigned long end)
+{
+	int ram_page = 0, not_rampage = 0;
+	unsigned long page_nr;
+
+	for (page_nr = (start >> PAGE_SHIFT); page_nr < (end >> PAGE_SHIFT);
+	     ++page_nr) {
+		/*
+		 * For legacy reasons, physical address range in the legacy ISA
+		 * region is tracked as non-RAM. This will allow users of
+		 * /dev/mem to map portions of legacy ISA region, even when
+		 * some of those portions are listed(or not even listed) with
+		 * different e820 types(RAM/reserved/..)
+		 */
+		if (page_nr >= (ISA_END_ADDRESS >> PAGE_SHIFT) &&
+		    page_is_ram(page_nr))
+			ram_page = 1;
+		else
+			not_rampage = 1;
+
+		if (ram_page == not_rampage)
+			return -1;
+	}
+
+	return ram_page;
+}
+
 /*
  * For RAM pages, mark the pages as non WB memory type using
  * PageNonWB (PG_arch_1). We allow only one set_memory_uc() or
@@ -333,9 +369,13 @@ 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 (new_type)
+		*new_type = actual_type;
+
+	is_range_ram = pat_pagerange_is_ram(start, end);
 	if (is_range_ram == 1)
-		return reserve_ram_pages_type(start, end, req_type, new_type);
+		return reserve_ram_pages_type(start, end, req_type,
+					      new_type);
 	else if (is_range_ram < 0)
 		return -EINVAL;
 
@@ -347,9 +387,6 @@ 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)
@@ -437,7 +474,7 @@ int free_memtype(u64 start, u64 end)
 	if (is_ISA_range(start, end - 1))
 		return 0;
 
-	is_range_ram = pagerange_is_ram(start, end);
+	is_range_ram = pat_pagerange_is_ram(start, end);
 	if (is_range_ram == 1)
 		return free_ram_pages_type(start, end);
 	else if (is_range_ram < 0)
@@ -609,17 +646,13 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
 	unsigned long flags;
 	unsigned long want_flags = (pgprot_val(*vma_prot) & _PAGE_CACHE_MASK);
 
-	is_ram = pagerange_is_ram(paddr, paddr + size);
+	is_ram = pat_pagerange_is_ram(paddr, paddr + size);
 
-	if (is_ram != 0) {
-		/*
-		 * For mapping RAM pages, drivers need to call
-		 * set_memory_[uc|wc|wb] directly, for reserve and free, before
-		 * setting up the PTE.
-		 */
-		WARN_ON_ONCE(1);
-		return 0;
-	}
+	/*
+	 * reserve_pfn_range() doesn't support RAM pages.
+	 */
+	if (is_ram != 0)
+		return -EINVAL;
 
 	ret = reserve_memtype(paddr, paddr + size, want_flags, &flags);
 	if (ret)
@@ -676,7 +709,7 @@ static void free_pfn_range(u64 paddr, unsigned long size)
 {
 	int is_ram;
 
-	is_ram = pagerange_is_ram(paddr, paddr + size);
+	is_ram = pat_pagerange_is_ram(paddr, paddr + size);
 	if (is_ram == 0)
 		free_memtype(paddr, paddr + size);
 }