1 files changed, 12 insertions, 0 deletions

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 7791eef95b91..d1c636bf31a7 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -112,6 +112,14 @@
 #define ARCH_SETUP
 #endif
 
+/*
+ * end_pfn only includes RAM, while max_pfn_mapped includes all e820 entries.
+ * The direct mapping extends to max_pfn_mapped, so that we can directly access
+ * apertures, ACPI and other tables without having to play with fixmaps.
+ */
+unsigned long max_low_pfn_mapped;
+unsigned long max_pfn_mapped;
+
 RESERVE_BRK(dmi_alloc, 65536);
 
 unsigned int boot_cpu_id __read_mostly;
@@ -860,12 +868,16 @@ void __init setup_arch(char **cmdline_p)
                 max_low_pfn = max_pfn;
 
         high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1;
+        max_pfn_mapped = KERNEL_IMAGE_SIZE >> PAGE_SHIFT;
 #endif
 
 #ifdef CONFIG_X86_CHECK_BIOS_CORRUPTION
         setup_bios_corruption_check();
 #endif
 
+        printk(KERN_DEBUG "initial memory mapped : 0 - %08lx\n",
+                        max_pfn_mapped<<PAGE_SHIFT);
+
         reserve_brk();
 
         /* max_pfn_mapped is updated here */