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

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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>

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 0dc848bf0b56bb59b0c69eacfc3fb4d6a593fb7c..12b7d938a897f2ce0564a1a9d9bc6fa388f95afd 100644 (file)
--- 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 17579a1a174bda40da7f3291793ac746b9515cb0..293cd71a266aa221800c6e3246ee768cce5a71cd 100644 (file)
--- 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 64c4534b930c74bc118cf1530a812401456f3d4e..ff9620b800c07d1ba203b118d4175b13878680ab 100644 (file)
--- 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 e682edc24a68072c97da7611be582f92b9000425..8dcc32665240fbaa657029e34c65274f8e234fd4 100644 (file)
--- 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__*/