[PATCH] kdump: x86_64: add memmmap command line option

)

From: Vivek Goyal <vgoyal@in.ibm.com>

- This patch introduces the memmap option for x86_64 similar to i386.

- memmap=exactmap enables setting of an exact E820 memory map, as specified
  by the user.

Changes in this version:

- Used e820_end_of_ram() to find the max_pfn as suggested by Andi kleen.

- removed PFN_UP & PFN_DOWN macros

- Printing the user defined map also.

Signed-off-by: Murali M Chakravarthy <muralim@in.ibm.com>
Signed-off-by: Hariprasad Nellitheertha <nharipra@gmail.com>
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 48 insertions, 0 deletions

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;
 }