[PATCH] generic: Break init() in two parts to avoid MODPOST warnings

o init() is a non __init function in .text section but it calls many
  functions which are in .init.text section. Hence MODPOST generates lots
  of cross reference warnings on i386 if compiled with CONFIG_RELOCATABLE=y

WARNING: vmlinux - Section mismatch: reference to .init.text:smp_prepare_cpus from .text between 'init' (at offset 0xc0101049) and 'rest_init'
WARNING: vmlinux - Section mismatch: reference to .init.text:migration_init from .text between 'init' (at offset 0xc010104e) and 'rest_init'
WARNING: vmlinux - Section mismatch: reference to .init.text:spawn_ksoftirqd from .text between 'init' (at offset 0xc0101053) and 'rest_init'

o This patch breaks down init() in two parts. One part which can go
  in .init.text section and can be freed and other part which has to
  be non __init(init_post()). Now init() calls init_post() and init_post()
  does not call any functions present in .init sections. Hence getting
  rid of warnings.

Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Andi Kleen <ak@suse.de>

diff --git a/init/main.c b/init/main.c
index 4e9e92b..62ded9f 100644 (file)
--- a/init/main.c
+++ b/init/main.c
@@ -727,7 +727,49 @@ static void run_init_process(char *init_filename)
        kernel_execve(init_filename, argv_init, envp_init);
 }
 
-static int init(void * unused)
+/* This is a non __init function. Force it to be noinline otherwise gcc
+ * makes it inline to init() and it becomes part of init.text section
+ */
+static int noinline init_post(void)
+{
+       free_initmem();
+       unlock_kernel();
+       mark_rodata_ro();
+       system_state = SYSTEM_RUNNING;
+       numa_default_policy();
+
+       if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
+               printk(KERN_WARNING "Warning: unable to open an initial console.\n");
+
+       (void) sys_dup(0);
+       (void) sys_dup(0);
+
+       if (ramdisk_execute_command) {
+               run_init_process(ramdisk_execute_command);
+               printk(KERN_WARNING "Failed to execute %s\n",
+                               ramdisk_execute_command);
+       }
+
+       /*
+        * We try each of these until one succeeds.
+        *
+        * The Bourne shell can be used instead of init if we are
+        * trying to recover a really broken machine.
+        */
+       if (execute_command) {
+               run_init_process(execute_command);
+               printk(KERN_WARNING "Failed to execute %s.  Attempting "
+                                       "defaults...\n", execute_command);
+       }
+       run_init_process("/sbin/init");
+       run_init_process("/etc/init");
+       run_init_process("/bin/init");
+       run_init_process("/bin/sh");
+
+       panic("No init found.  Try passing init= option to kernel.");
+}
+
+static int __init init(void * unused)
 {
        lock_kernel();
        /*
@@ -775,39 +817,6 @@ static int init(void * unused)
         * we're essentially up and running. Get rid of the
         * initmem segments and start the user-mode stuff..
         */
-       free_initmem();
-       unlock_kernel();
-       mark_rodata_ro();
-       system_state = SYSTEM_RUNNING;
-       numa_default_policy();
-
-       if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
-               printk(KERN_WARNING "Warning: unable to open an initial console.\n");
-
-       (void) sys_dup(0);
-       (void) sys_dup(0);
-
-       if (ramdisk_execute_command) {
-               run_init_process(ramdisk_execute_command);
-               printk(KERN_WARNING "Failed to execute %s\n",
-                               ramdisk_execute_command);
-       }
-
-       /*
-        * We try each of these until one succeeds.
-        *
-        * The Bourne shell can be used instead of init if we are 
-        * trying to recover a really broken machine.
-        */
-       if (execute_command) {
-               run_init_process(execute_command);
-               printk(KERN_WARNING "Failed to execute %s.  Attempting "
-                                       "defaults...\n", execute_command);
-       }
-       run_init_process("/sbin/init");
-       run_init_process("/etc/init");
-       run_init_process("/bin/init");
-       run_init_process("/bin/sh");
-
-       panic("No init found.  Try passing init= option to kernel.");
+       init_post();
+       return 0;
 }