x86/PCI: never allocate PCI space from the last 1M below 4G

Commit Message

Bjorn Helgaas Nov. 29, 2010, 6:30 p.m. UTC

None

Patch

diff --git a/arch/x86/include/asm/e820.h b/arch/x86/include/asm/e820.h
index 5be1542..c1e908f 100644
--- a/arch/x86/include/asm/e820.h
+++ b/arch/x86/include/asm/e820.h
@@ -72,6 +72,9 @@  struct e820map {
 #define BIOS_BEGIN		0x000a0000
 #define BIOS_END		0x00100000
 
+#define BIOS_ROM_BASE		0xfff00000
+#define BIOS_ROM_END		0x100000000ULL
+
 #ifdef __KERNEL__
 /* see comment in arch/x86/kernel/e820.c */
 extern struct e820map e820;
diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c
index c4bb261..6890241 100644
--- a/arch/x86/pci/i386.c
+++ b/arch/x86/pci/i386.c
@@ -65,8 +65,14 @@  pcibios_align_resource(void *data, const struct resource *res,
 			resource_size_t size, resource_size_t align)
 {
 	struct pci_dev *dev = data;
-	resource_size_t start = round_down(res->end - size + 1, align);
+	resource_size_t start, end = res->end;
 
+	/* Make sure we don't allocate from the last 1M before 4G */
+	if (res->flags & IORESOURCE_MEM) {
+		if (end >= BIOS_ROM_BASE && end < BIOS_ROM_END)
+			end = BIOS_ROM_BASE - 1;
+	}
+	start = round_down(end - size + 1, align);
 	if (res->flags & IORESOURCE_IO) {
 
 		/*
@@ -80,6 +86,8 @@  pcibios_align_resource(void *data, const struct resource *res,
 	} else if (res->flags & IORESOURCE_MEM) {
 		if (start < BIOS_END)
 			start = res->end;	/* fail; no space */
+		if (start >= BIOS_ROM_BASE && start < BIOS_ROM_END)
+			start = ALIGN(BIOS_ROM_END, align);
 	}
 	return start;
 }