From: Arjan van de Ven <arjan@linux.intel.com>
Date: Mon, 18 Feb 2008 17:58:45 +0000 (-0800)
Subject: x86: fix page_is_ram() thinko
X-Git-Tag: v2.6.25-rc3~109^2
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=156fbc3fbe4ab640297b1ae2092821363840aeb6;p=linux-2.6

x86: fix page_is_ram() thinko

page_is_ram() has a special case for the 640k-1M bios area, however
due to a thinko the special case checks the e820 table entry and
not the memory the user has asked for. This patch fixes the bug.

[ mingo@elte.hu: this too is better solved in the e820 space, but those
  fixes are too intrusive for v2.6.25. ]

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 7fb6eff644..f4c95aec5a 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -50,6 +50,13 @@ int page_is_ram(unsigned long pagenr)
 	if (pagenr == 0)
 		return 0;
 
+	/*
+	 * Second special case: Some BIOSen report the PC BIOS
+	 * area (640->1Mb) as ram even though it is not.
+	 */
+	if (pagenr >= (BIOS_BEGIN >> PAGE_SHIFT) &&
+		    pagenr < (BIOS_END >> PAGE_SHIFT))
+		return 0;
 
 	for (i = 0; i < e820.nr_map; i++) {
 		/*
@@ -60,14 +67,6 @@ int page_is_ram(unsigned long pagenr)
 		addr = (e820.map[i].addr + PAGE_SIZE-1) >> PAGE_SHIFT;
 		end = (e820.map[i].addr + e820.map[i].size) >> PAGE_SHIFT;
 
-		/*
-		 * Sanity check: Some BIOSen report areas as RAM that
-		 * are not. Notably the 640->1Mb area, which is the
-		 * PCI BIOS area.
-		 */
-		if (addr >= (BIOS_BEGIN >> PAGE_SHIFT) &&
-		    end < (BIOS_END >> PAGE_SHIFT))
-			continue;
 
 		if ((pagenr >= addr) && (pagenr < end))
 			return 1;