1 files changed, 52 insertions, 0 deletions
diff --git a/arch/i386/kernel/e820.c b/arch/i386/kernel/e820.c
index 0db9576..be4934f 100644
--- a/arch/i386/kernel/e820.c
+++ b/arch/i386/kernel/e820.c
@@ -8,6 +8,7 @@
 #include <linux/module.h>
 #include <linux/mm.h>
 #include <linux/efi.h>
+#include <linux/pfn.h>
 
 #include <asm/pgtable.h>
 #include <asm/page.h>
@@ -539,3 +540,54 @@ int __init copy_e820_map(struct e820entry * biosmap, int nr_map)
 	return 0;
 }
 
+/*
+ * Callback for efi_memory_walk.
+ */
+static int __init
+efi_find_max_pfn(unsigned long start, unsigned long end, void *arg)
+{
+	unsigned long *max_pfn = arg, pfn;
+
+	if (start < end) {
+		pfn = PFN_UP(end -1);
+		if (pfn > *max_pfn)
+			*max_pfn = pfn;
+	}
+	return 0;
+}
+
+static int __init
+efi_memory_present_wrapper(unsigned long start, unsigned long end, void *arg)
+{
+	memory_present(0, PFN_UP(start), PFN_DOWN(end));
+	return 0;
+}
+
+/*
+ * Find the highest page frame number we have available
+ */
+void __init find_max_pfn(void)
+{
+	int i;
+
+	max_pfn = 0;
+	if (efi_enabled) {
+		efi_memmap_walk(efi_find_max_pfn, &max_pfn);
+		efi_memmap_walk(efi_memory_present_wrapper, NULL);
+		return;
+	}
+
+	for (i = 0; i < e820.nr_map; i++) {
+		unsigned long start, end;
+		/* RAM? */
+		if (e820.map[i].type != E820_RAM)
+			continue;
+		start = PFN_UP(e820.map[i].addr);
+		end = PFN_DOWN(e820.map[i].addr + e820.map[i].size);
+		if (start >= end)
+			continue;
+		if (end > max_pfn)
+			max_pfn = end;
+		memory_present(0, start, end);
+	}
+}