3 files changed, 75 insertions, 2 deletions

diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index ea48b82a3707..b4ca38a21158 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -96,6 +96,14 @@ basename_flags = -D"KBUILD_BASENAME=KBUILD_STR($(call name-fix,$(basetarget)))"
 modname_flags  = $(if $(filter 1,$(words $(modname))),\
                  -D"KBUILD_MODNAME=KBUILD_STR($(call name-fix,$(modname)))")
 
+#hash values
+ifdef CONFIG_DYNAMIC_PRINTK_DEBUG
+debug_flags = -D"DEBUG_HASH=$(shell ./scripts/basic/hash djb2 $(@D)$(modname))"\
+              -D"DEBUG_HASH2=$(shell ./scripts/basic/hash r5 $(@D)$(modname))"
+else
+debug_flags =
+endif
+
 orig_c_flags   = $(KBUILD_CFLAGS) $(ccflags-y) $(CFLAGS_$(basetarget).o)
 _c_flags       = $(filter-out $(CFLAGS_REMOVE_$(basetarget).o), $(orig_c_flags))
 _a_flags       = $(KBUILD_AFLAGS) $(asflags-y) $(AFLAGS_$(basetarget).o)
@@ -121,7 +129,8 @@ endif
 
 c_flags        = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(KBUILD_CPPFLAGS) \
                  $(__c_flags) $(modkern_cflags) \
-                 -D"KBUILD_STR(s)=\#s" $(basename_flags) $(modname_flags)
+                 -D"KBUILD_STR(s)=\#s" $(basename_flags) $(modname_flags) \
+                  $(debug_flags)
 
 a_flags        = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(KBUILD_CPPFLAGS) \
                  $(__a_flags) $(modkern_aflags)
diff --git a/scripts/basic/Makefile b/scripts/basic/Makefile
index 4c324a1f1e0e..09559951df12 100644
--- a/scripts/basic/Makefile
+++ b/scripts/basic/Makefile
@@ -9,7 +9,7 @@
 # fixdep:        Used to generate dependency information during build process
 # docproc:       Used in Documentation/DocBook
 
-hostprogs-y     := fixdep docproc
+hostprogs-y     := fixdep docproc hash
 always          := $(hostprogs-y)
 
 # fixdep is needed to compile other host programs
diff --git a/scripts/basic/hash.c b/scripts/basic/hash.c
new file mode 100644
index 000000000000..3299ad7fc8c0
--- /dev/null
+++ b/scripts/basic/hash.c
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2008 Red Hat, Inc., Jason Baron <jbaron@redhat.com>
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define DYNAMIC_DEBUG_HASH_BITS 6
+
+static const char *program;
+
+static void usage(void)
+{
+        printf("Usage: %s <djb2|r5> <modname>\n", program);
+        exit(1);
+}
+
+/* djb2 hashing algorithm by Dan Bernstein. From:
+ * http://www.cse.yorku.ca/~oz/hash.html
+ */
+
+unsigned int djb2_hash(char *str)
+{
+        unsigned long hash = 5381;
+        int c;
+
+        c = *str;
+        while (c) {
+                hash = ((hash << 5) + hash) + c;
+                c = *++str;
+        }
+        return (unsigned int)(hash & ((1 << DYNAMIC_DEBUG_HASH_BITS) - 1));
+}
+
+unsigned int r5_hash(char *str)
+{
+        unsigned long hash = 0;
+        int c;
+
+        c = *str;
+        while (c) {
+                hash = (hash + (c << 4) + (c >> 4)) * 11;
+                c = *++str;
+        }
+        return (unsigned int)(hash & ((1 << DYNAMIC_DEBUG_HASH_BITS) - 1));
+}
+
+int main(int argc, char *argv[])
+{
+        program = argv[0];
+
+        if (argc != 3)
+                usage();
+        if (!strcmp(argv[1], "djb2"))
+                printf("%d\n", djb2_hash(argv[2]));
+        else if (!strcmp(argv[1], "r5"))
+                printf("%d\n", r5_hash(argv[2]));
+        else
+                usage();
+        exit(0);
+}
+