4 files changed, 50 insertions, 1 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 0dc848bf0b56..12b7d938a897 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -832,7 +832,7 @@ running once the system is up.
         mem=nopentium   [BUGS=IA-32] Disable usage of 4MB pages for kernel
                         memory.
 
-        memmap=exactmap [KNL,IA-32] Enable setting of an exact
+        memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
                         E820 memory map, as specified by the user.
                         Such memmap=exactmap lines can be constructed based on
                         BIOS output or other requirements. See the memmap=nn@ss
diff --git a/arch/x86_64/kernel/e820.c b/arch/x86_64/kernel/e820.c
index 17579a1a174b..293cd71a266a 100644
--- a/arch/x86_64/kernel/e820.c
+++ b/arch/x86_64/kernel/e820.c
@@ -559,6 +559,27 @@ void __init parse_memopt(char *p, char **from)
         end_user_pfn >>= PAGE_SHIFT;    
 } 
 
+void __init parse_memmapopt(char *p, char **from)
+{
+        unsigned long long start_at, mem_size;
+
+        mem_size = memparse(p, from);
+        p = *from;
+        if (*p == '@') {
+                start_at = memparse(p+1, from);
+                add_memory_region(start_at, mem_size, E820_RAM);
+        } else if (*p == '#') {
+                start_at = memparse(p+1, from);
+                add_memory_region(start_at, mem_size, E820_ACPI);
+        } else if (*p == '$') {
+                start_at = memparse(p+1, from);
+                add_memory_region(start_at, mem_size, E820_RESERVED);
+        } else {
+                end_user_pfn = (mem_size >> PAGE_SHIFT);
+        }
+        p = *from;
+}
+
 unsigned long pci_mem_start = 0xaeedbabe;
 
 /*
diff --git a/arch/x86_64/kernel/setup.c b/arch/x86_64/kernel/setup.c
index 64c4534b930c..ff9620b800c0 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;
 }
diff --git a/include/asm-x86_64/e820.h b/include/asm-x86_64/e820.h
index e682edc24a68..8dcc32665240 100644
--- a/include/asm-x86_64/e820.h
+++ b/include/asm-x86_64/e820.h
@@ -55,6 +55,7 @@ extern unsigned long e820_hole_size(unsigned long start_pfn,
                                     unsigned long end_pfn);
 
 extern void __init parse_memopt(char *p, char **end);
+extern void __init parse_memmapopt(char *p, char **end);
 
 extern struct e820map e820;
 #endif/*!__ASSEMBLY__*/