1 files changed, 22 insertions, 8 deletions

diff --git a/arch/x86_64/kernel/setup.c b/arch/x86_64/kernel/setup.c
index ebc3c33b1c6c..f0870bef24d1 100644
--- a/arch/x86_64/kernel/setup.c
+++ b/arch/x86_64/kernel/setup.c
@@ -571,17 +571,28 @@ static inline void copy_edd(void)
 #endif
 
 #define EBDA_ADDR_POINTER 0x40E
-static void __init reserve_ebda_region(void)
+
+unsigned __initdata ebda_addr;
+unsigned __initdata ebda_size;
+
+static void discover_ebda(void)
 {
-        unsigned int addr;
-        /** 
+        /*
          * there is a real-mode segmented pointer pointing to the 
          * 4K EBDA area at 0x40E
          */
-        addr = *(unsigned short *)phys_to_virt(EBDA_ADDR_POINTER);
-        addr <<= 4;
-        if (addr)
-                reserve_bootmem_generic(addr, PAGE_SIZE);
+        ebda_addr = *(unsigned short *)EBDA_ADDR_POINTER;
+        ebda_addr <<= 4;
+
+        ebda_size = *(unsigned short *)(unsigned long)ebda_addr;
+
+        /* Round EBDA up to pages */
+        if (ebda_size == 0)
+                ebda_size = 1;
+        ebda_size <<= 10;
+        ebda_size = round_up(ebda_size + (ebda_addr & ~PAGE_MASK), PAGE_SIZE);
+        if (ebda_size > 64*1024)
+                ebda_size = 64*1024;
 }
 
 void __init setup_arch(char **cmdline_p)
@@ -627,6 +638,8 @@ void __init setup_arch(char **cmdline_p)
 
         check_efer();
 
+        discover_ebda();
+
         init_memory_mapping(0, (end_pfn_map << PAGE_SHIFT));
 
         dmi_scan_machine();
@@ -669,7 +682,8 @@ void __init setup_arch(char **cmdline_p)
         reserve_bootmem_generic(0, PAGE_SIZE);
 
         /* reserve ebda region */
-        reserve_ebda_region();
+        if (ebda_addr)
+                reserve_bootmem_generic(ebda_addr, ebda_size);
 
 #ifdef CONFIG_SMP
         /*