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-rw-r--r--arch/x86/kernel/e820_64.c8
-rw-r--r--arch/x86/kernel/head64.c28
2 files changed, 27 insertions, 9 deletions
diff --git a/arch/x86/kernel/e820_64.c b/arch/x86/kernel/e820_64.c
index 8b914a833ac6..4a0953857cb2 100644
--- a/arch/x86/kernel/e820_64.c
+++ b/arch/x86/kernel/e820_64.c
@@ -621,10 +621,10 @@ static int __init copy_e820_map(struct e820entry *biosmap, int nr_map)
return -1;
do {
- unsigned long start = biosmap->addr;
- unsigned long size = biosmap->size;
- unsigned long end = start + size;
- unsigned long type = biosmap->type;
+ u64 start = biosmap->addr;
+ u64 size = biosmap->size;
+ u64 end = start + size;
+ u32 type = biosmap->type;
/* Overflow in 64 bits? Ignore the memory map. */
if (start > end)
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index b684552347df..269a6b481fe6 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -55,12 +55,30 @@ static void __init copy_bootdata(char *real_mode_data)
/*
* The BIOS places the EBDA/XBDA at the top of conventional
* memory, and usually decreases the reported amount of
- * conventional memory (int 0x12) too.
+ * conventional memory (int 0x12) too. This also contains a
+ * workaround for Dell systems that neglect to reserve EBDA.
+ * The same workaround also avoids a problem with the AMD768MPX
+ * 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.
*/
-static __init void reserve_ebda(void)
+static void __init reserve_ebda_region(void)
{
unsigned int lowmem, ebda_addr;
+ /* To determine the position of the EBDA and the */
+ /* end of conventional memory, we need to look at */
+ /* the BIOS data area. In a paravirtual environment */
+ /* that area is absent. We'll just have to assume */
+ /* that the paravirt case can handle memory setup */
+ /* correctly, without our help. */
+#ifdef CONFIG_PARAVIRT
+ if ((boot_params.hdr.version >= 0x207) &&
+ (boot_params.hdr.hardware_subarch != 0)) {
+ return;
+ }
+#endif
+
/* end of low (conventional) memory */
lowmem = *(unsigned short *)__va(BIOS_LOWMEM_KILOBYTES);
lowmem <<= 10;
@@ -80,8 +98,8 @@ static __init void reserve_ebda(void)
lowmem = 0x9f000;
/* Paranoia: should never happen, but... */
- if (lowmem >= 0x100000)
- lowmem = 0xa0000;
+ if ((lowmem == 0) || (lowmem >= 0x100000))
+ lowmem = 0x9f000;
/* reserve all memory between lowmem and the 1MB mark */
reserve_early(lowmem, 0x100000, "BIOS reserved");
@@ -140,7 +158,7 @@ void __init x86_64_start_kernel(char * real_mode_data)
reserve_early(ramdisk_image, ramdisk_end, "RAMDISK");
}
- reserve_ebda();
+ reserve_ebda_region();
/*
* At this point everything still needed from the boot loader
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