x86: introduce max_low_pfn_mapped for 64-bit
when more than 4g memory is installed, don't map the big hole below 4g.
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>
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 3451e0b..9f5002e 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1056,7 +1056,7 @@
/*
* Find the highest page frame number we have available
*/
-unsigned long __init e820_end(void)
+static unsigned long __init e820_end_pfn(unsigned long limit_pfn, unsigned type)
{
int i;
unsigned long last_pfn = 0;
@@ -1064,12 +1064,21 @@
for (i = 0; i < e820.nr_map; i++) {
struct e820entry *ei = &e820.map[i];
+ unsigned long start_pfn;
unsigned long end_pfn;
- if (ei->type != E820_RAM)
+ if (ei->type != type)
continue;
+ start_pfn = ei->addr >> PAGE_SHIFT;
end_pfn = (ei->addr + ei->size) >> PAGE_SHIFT;
+
+ if (start_pfn >= limit_pfn)
+ continue;
+ if (end_pfn > limit_pfn) {
+ last_pfn = limit_pfn;
+ break;
+ }
if (end_pfn > last_pfn)
last_pfn = end_pfn;
}
@@ -1083,7 +1092,15 @@
last_pfn, max_arch_pfn);
return last_pfn;
}
+unsigned long __init e820_end_of_ram_pfn(void)
+{
+ return e820_end_pfn(MAX_ARCH_PFN, E820_RAM);
+}
+unsigned long __init e820_end_of_low_ram_pfn(void)
+{
+ return e820_end_pfn(1UL<<(32 - PAGE_SHIFT), E820_RAM);
+}
/*
* Finds an active region in the address range from start_pfn to last_pfn and
* returns its range in ei_startpfn and ei_endpfn for the e820 entry.
@@ -1206,7 +1223,7 @@
* the real mem size before original memory map is
* reset.
*/
- saved_max_pfn = e820_end();
+ saved_max_pfn = e820_end_of_ram_pfn();
#endif
e820.nr_map = 0;
userdef = 1;