[PATCH x86 for review II] [2/39] x86_64: Break init() in two parts to avoid MODPOST warnings

Andi Kleen
2007-02-12T07:37:50Z

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

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>

---

init/main.c | 81 +++++++++++++++++++++++++++++++++---------------------------
1 file changed, 45 insertions(+), 36 deletions(-)

Index: linux/init/main.c
===================================================================
--- linux.orig/init/main.c
+++ linux/init/main.c
@@ -713,7 +713,49 @@ static void run_init_process(char *init_
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();
/*
@@ -761,39 +803,6 @@ 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;
}