[ACPI] reserve EBDA for Dell BIOS that neglects to. (David Shaohua Li)

http://bugme.osdl.org/show_bug.cgi?id=2990

arch/i386/kernel/setup.c

@@ -49,6 +49,7 @@
 #include <asm/ist.h>
 #include <asm/std_resources.h>
 #include "setup_arch_pre.h"
+#include <bios_ebda.h>
 
 /* This value is set up by the early boot code to point to the value
    immediately after the boot time page tables.  It contains a *physical*
@@ -808,6 +809,17 @@ static void __init register_bootmem_low_pages(unsigned long max_low_pfn)
 	}
 }
 
+/*
+ * workaround for Dell systems that neglect to reserve EBDA
+ */
+static void __init reserve_ebda_region(void)
+{
+	unsigned int addr;
+	addr = get_bios_ebda();
+	if (addr)
+		reserve_bootmem(addr, PAGE_SIZE);	
+}
+
 static unsigned long __init setup_memory(void)
 {
 	unsigned long bootmap_size, start_pfn, max_low_pfn;
@@ -854,6 +866,9 @@ static unsigned long __init setup_memory(void)
 	 */
 	reserve_bootmem(0, PAGE_SIZE);
 
+	/* reserve EBDA region, it's a 4K region */
+	reserve_ebda_region();
+
     /* could be an AMD 768MPX chipset. Reserve a page  before VGA to prevent
        PCI prefetch into it (errata #56). Usually the page is reserved anyways,
        unless you have no PS/2 mouse plugged in. */

arch/i386/mm/discontig.c

@@ -31,6 +31,7 @@
 #include <asm/e820.h>
 #include <asm/setup.h>
 #include <asm/mmzone.h>
+#include <bios_ebda.h>
 
 struct pglist_data *node_data[MAX_NUMNODES];
 bootmem_data_t node0_bdata;
@@ -227,6 +228,17 @@ static unsigned long calculate_numa_remap_pages(void)
 	return reserve_pages;
 }
 
+/*
+ * workaround for Dell systems that neglect to reserve EBDA
+ */
+static void __init reserve_ebda_region_node(void)
+{
+	unsigned int addr;
+	addr = get_bios_ebda();
+	if (addr)
+		reserve_bootmem_node(NODE_DATA(0), addr, PAGE_SIZE);
+}
+
 unsigned long __init setup_memory(void)
 {
 	int nid;
@@ -301,6 +313,9 @@ unsigned long __init setup_memory(void)
 	 */
 	reserve_bootmem_node(NODE_DATA(0), PAGE_SIZE, PAGE_SIZE);
 
+	/* reserve EBDA region, it's a 4K region */
+	reserve_ebda_region_node();
+
 #ifdef CONFIG_ACPI_SLEEP
 	/*
 	 * Reserve low memory region for sleep support.

arch/x86_64/kernel/setup.c

@@ -422,6 +422,20 @@ static inline void copy_edd(void)
 #define copy_edd() do {} while (0)
 #endif
 
+#define EBDA_ADDR_POINTER 0x40E
+static void __init reserve_ebda_region(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);
+}
+
 void __init setup_arch(char **cmdline_p)
 {
 	unsigned long low_mem_size;
@@ -486,6 +500,9 @@ void __init setup_arch(char **cmdline_p)
 	 */
 	reserve_bootmem_generic(0, PAGE_SIZE);
 
+	/* reserve ebda region */
+	reserve_ebda_region();
+
 #ifdef CONFIG_SMP
 	/*
 	 * But first pinch a few for the stack/trampoline stuff