x86, kdump: Change crashkernel_high/low= to crashkernel=,high/low

Per hpa, use crashkernel=X,high crashkernel=Y,low instead of
crashkernel_hign=X crashkernel_low=Y. As that could be extensible.

-v2: according to Vivek, change delimiter to ;
-v3: let hign and low only handle simple form and it conforms to
	description in kernel-parameters.txt
     still keep crashkernel=X override any crashkernel=X,high
        crashkernel=Y,low
-v4: update get_last_crashkernel returning and add more strict
     checking in parse_crashkernel_simple() found by HATAYAMA.
-v5: Change delimiter back to , according to HPA.
     also separate parse_suffix from parse_simper according to vivek.
	so we can avoid @pos in that path.
-v6: Tight the checking about crashkernel=X,highblahblah,high
     found by HTYAYAMA.

Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1366089828-19692-5-git-send-email-yinghai@kernel.org
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 96 insertions, 13 deletions

diff --git a/kernel/kexec.c b/kernel/kexec.c
index 1b2f73f5f9b9..401fdb041f35 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -1368,35 +1368,114 @@ static int __init parse_crashkernel_simple(char 		*cmdline,
         return 0;
 }
 
+#define SUFFIX_HIGH 0
+#define SUFFIX_LOW  1
+#define SUFFIX_NULL 2
+static __initdata char *suffix_tbl[] = {
+        [SUFFIX_HIGH] = ",high",
+        [SUFFIX_LOW]  = ",low",
+        [SUFFIX_NULL] = NULL,
+};
+
 /*
- * That function is the entry point for command line parsing and should be
- * called from the arch-specific code.
+ * That function parses "suffix"  crashkernel command lines like
+ *
+ *      crashkernel=size,[high|low]
+ *
+ * It returns 0 on success and -EINVAL on failure.
  */
+static int __init parse_crashkernel_suffix(char *cmdline,
+                                           unsigned long long   *crash_size,
+                                           unsigned long long   *crash_base,
+                                           const char *suffix)
+{
+        char *cur = cmdline;
+
+        *crash_size = memparse(cmdline, &cur);
+        if (cmdline == cur) {
+                pr_warn("crashkernel: memory value expected\n");
+                return -EINVAL;
+        }
+
+        /* check with suffix */
+        if (strncmp(cur, suffix, strlen(suffix))) {
+                pr_warn("crashkernel: unrecognized char\n");
+                return -EINVAL;
+        }
+        cur += strlen(suffix);
+        if (*cur != ' ' && *cur != '\0') {
+                pr_warn("crashkernel: unrecognized char\n");
+                return -EINVAL;
+        }
+
+        return 0;
+}
+
+static __init char *get_last_crashkernel(char *cmdline,
+                             const char *name,
+                             const char *suffix)
+{
+        char *p = cmdline, *ck_cmdline = NULL;
+
+        /* find crashkernel and use the last one if there are more */
+        p = strstr(p, name);
+        while (p) {
+                char *end_p = strchr(p, ' ');
+                char *q;
+
+                if (!end_p)
+                        end_p = p + strlen(p);
+
+                if (!suffix) {
+                        int i;
+
+                        /* skip the one with any known suffix */
+                        for (i = 0; suffix_tbl[i]; i++) {
+                                q = end_p - strlen(suffix_tbl[i]);
+                                if (!strncmp(q, suffix_tbl[i],
+                                             strlen(suffix_tbl[i])))
+                                        goto next;
+                        }
+                        ck_cmdline = p;
+                } else {
+                        q = end_p - strlen(suffix);
+                        if (!strncmp(q, suffix, strlen(suffix)))
+                                ck_cmdline = p;
+                }
+next:
+                p = strstr(p+1, name);
+        }
+
+        if (!ck_cmdline)
+                return NULL;
+
+        return ck_cmdline;
+}
+
 static int __init __parse_crashkernel(char *cmdline,
                              unsigned long long system_ram,
                              unsigned long long *crash_size,
                              unsigned long long *crash_base,
-                                const char *name)
+                             const char *name,
+                             const char *suffix)
 {
-        char    *p = cmdline, *ck_cmdline = NULL;
         char    *first_colon, *first_space;
+        char    *ck_cmdline;
 
         BUG_ON(!crash_size || !crash_base);
         *crash_size = 0;
         *crash_base = 0;
 
-        /* find crashkernel and use the last one if there are more */
-        p = strstr(p, name);
-        while (p) {
-                ck_cmdline = p;
-                p = strstr(p+1, name);
-        }
+        ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
 
         if (!ck_cmdline)
                 return -EINVAL;
 
         ck_cmdline += strlen(name);
 
+        if (suffix)
+                return parse_crashkernel_suffix(ck_cmdline, crash_size,
+                                crash_base, suffix);
         /*
          * if the commandline contains a ':', then that's the extended
          * syntax -- if not, it must be the classic syntax
@@ -1413,13 +1492,17 @@ static int __init __parse_crashkernel(char *cmdline,
         return 0;
 }
 
+/*
+ * That function is the entry point for command line parsing and should be
+ * called from the arch-specific code.
+ */
 int __init parse_crashkernel(char *cmdline,
                              unsigned long long system_ram,
                              unsigned long long *crash_size,
                              unsigned long long *crash_base)
 {
         return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
-                                        "crashkernel=");
+                                        "crashkernel=", NULL);
 }
 
 int __init parse_crashkernel_high(char *cmdline,
@@ -1428,7 +1511,7 @@ int __init parse_crashkernel_high(char *cmdline,
                              unsigned long long *crash_base)
 {
         return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
-                                        "crashkernel_high=");
+                                "crashkernel=", suffix_tbl[SUFFIX_HIGH]);
 }
 
 int __init parse_crashkernel_low(char *cmdline,
@@ -1437,7 +1520,7 @@ int __init parse_crashkernel_low(char *cmdline,
                              unsigned long long *crash_base)
 {
         return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
-                                        "crashkernel_low=");
+                                "crashkernel=", suffix_tbl[SUFFIX_LOW]);
 }
 
 static void update_vmcoreinfo_note(void)