From 3ae54d6d9b447b3aae4cdfc1b64b59c791cc2102 Mon Sep 17 00:00:00 2001
From: Bjorn Helgaas <bjorn.helgaas@hp.com>
Date: Thu, 16 Dec 2010 10:38:56 -0700
Subject: [PATCH] --- yaml --- r: 223417 b: refs/heads/master c:
 4dc2287c1805e7fe8a7cb90bbcd44abee8cdb914 h: refs/heads/master i:   223415:
 67c96ed15d2f89c76c0d4f0f6da83c1e779d6eeb v: v3

---
 [refs]                           |  2 +-
 trunk/arch/x86/kernel/resource.c | 38 +++++++++++++++++++++++++++++++-
 2 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 0425e93662fc..d75fa2655f46 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 30919b0bf356a8ee0ef4f7d38ca8ad99b96820b2
+refs/heads/master: 4dc2287c1805e7fe8a7cb90bbcd44abee8cdb914
diff --git a/trunk/arch/x86/kernel/resource.c b/trunk/arch/x86/kernel/resource.c
index 407a900da9df..89638af2ff19 100644
--- a/trunk/arch/x86/kernel/resource.c
+++ b/trunk/arch/x86/kernel/resource.c
@@ -1,11 +1,47 @@
 #include <linux/ioport.h>
 #include <asm/e820.h>
 
+static void resource_clip(struct resource *res, resource_size_t start,
+			  resource_size_t end)
+{
+	resource_size_t low = 0, high = 0;
+
+	if (res->end < start || res->start > end)
+		return;		/* no conflict */
+
+	if (res->start < start)
+		low = start - res->start;
+
+	if (res->end > end)
+		high = res->end - end;
+
+	/* Keep the area above or below the conflict, whichever is larger */
+	if (low > high)
+		res->end = start - 1;
+	else
+		res->start = end + 1;
+}
+
+static void remove_e820_regions(struct resource *avail)
+{
+	int i;
+	struct e820entry *entry;
+
+	for (i = 0; i < e820.nr_map; i++) {
+		entry = &e820.map[i];
+
+		resource_clip(avail, entry->addr,
+			      entry->addr + entry->size - 1);
+	}
+}
+
 void arch_remove_reservations(struct resource *avail)
 {
-	/* Trim out BIOS area (low 1MB) */
+	/* Trim out BIOS area (low 1MB) and E820 regions */
 	if (avail->flags & IORESOURCE_MEM) {
 		if (avail->start < BIOS_END)
 			avail->start = BIOS_END;
+
+		remove_e820_regions(avail);
 	}
 }