x86: make max_pfn cover acpi table below 4g

When system have 4g less ram installed, and acpi table sit
near end of ram, make max_pfn cover them too,
so 64bit kernel don't need to mess up fixmap.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: "Suresh Siddha" <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 12 insertions, 6 deletions

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index e07d4019e266..2e08619a9c5c 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1056,12 +1056,20 @@ unsigned long __initdata end_user_pfn = MAX_ARCH_PFN;
 /*
  * Find the highest page frame number we have available
  */
-unsigned long __init e820_end_of_ram(void)
+unsigned long __init e820_end(void)
 {
-        unsigned long last_pfn;
+        int i;
+        unsigned long last_pfn = 0;
         unsigned long max_arch_pfn = MAX_ARCH_PFN;
 
-        last_pfn = find_max_pfn_with_active_regions();
+        for (i = 0; i < e820.nr_map; i++) {
+                struct e820entry *ei = &e820.map[i];
+                unsigned long end_pfn;
+
+                end_pfn = (ei->addr + ei->size) >> PAGE_SHIFT;
+                if (end_pfn > last_pfn)
+                        last_pfn = end_pfn;
+        }
 
         if (last_pfn > max_arch_pfn)
                 last_pfn = max_arch_pfn;
@@ -1192,9 +1200,7 @@ static int __init parse_memmap_opt(char *p)
                  * the real mem size before original memory map is
                  * reset.
                  */
-                e820_register_active_regions(0, 0, -1UL);
-                saved_max_pfn = e820_end_of_ram();
-                remove_all_active_ranges();
+                saved_max_pfn = e820_end();
 #endif
                 e820.nr_map = 0;
                 userdef = 1;