1 files changed, 27 insertions, 0 deletions

diff --git a/arch/x86_64/kernel/setup.c b/arch/x86_64/kernel/setup.c
index 64c4534b930..ff9620b800c 100644
--- a/arch/x86_64/kernel/setup.c
+++ b/arch/x86_64/kernel/setup.c
@@ -275,6 +275,7 @@ static __init void parse_cmdline_early (char ** cmdline_p)
 {
         char c = ' ', *to = command_line, *from = COMMAND_LINE;
         int len = 0;
+        int userdef = 0;
 
         /* Save unparsed command line copy for /proc/cmdline */
         memcpy(saved_command_line, COMMAND_LINE, COMMAND_LINE_SIZE);
@@ -357,6 +358,28 @@ static __init void parse_cmdline_early (char ** cmdline_p)
                 if (!memcmp(from, "mem=", 4))
                         parse_memopt(from+4, &from); 
 
+                if (!memcmp(from, "memmap=", 7)) {
+                        /* exactmap option is for used defined memory */
+                        if (!memcmp(from+7, "exactmap", 8)) {
+#ifdef CONFIG_CRASH_DUMP
+                                /* If we are doing a crash dump, we
+                                 * still need to know the real mem
+                                 * size before original memory map is
+                                 * reset.
+                                 */
+                                saved_max_pfn = e820_end_of_ram();
+#endif
+                                from += 8+7;
+                                end_pfn_map = 0;
+                                e820.nr_map = 0;
+                                userdef = 1;
+                        }
+                        else {
+                                parse_memmapopt(from+7, &from);
+                                userdef = 1;
+                        }
+                }
+
 #ifdef CONFIG_NUMA
                 if (!memcmp(from, "numa=", 5))
                         numa_setup(from+5); 
@@ -403,6 +426,10 @@ static __init void parse_cmdline_early (char ** cmdline_p)
                         break;
                 *(to++) = c;
         }
+        if (userdef) {
+                printk(KERN_INFO "user-defined physical RAM map:\n");
+                e820_print_map("user");
+        }
         *to = '\0';
         *cmdline_p = command_line;
 }