Here comes version 2 of the disable built-in patch.
This patch makes it possible to disable built-in code from the kernel
command line. The patch is rather simple - it extends the compiled-in case
of module_init() to include __setup() with a name based on KBUILD_MODNAME.
As an example, if you want to disable built-in firewire support then you
could pass "force_ohci1394=off" on the kernel command line. The feature added
by this patch comes handy when you want to boot a precompiled kernel from a
live cd on som exotic hardware that makes built-in drivers crash.
Changes since last release:
- Upgraded and tested with 2.6.12-rc2
- Added "force_"-prefix to cope with namespace pollution
Signed-off-by: Magnus Damm <[email protected]>
diff -urNp linux-2.6.12-rc2/include/linux/init.h linux-2.6.12-rc2-disable_builtin/include/linux/init.h
--- linux-2.6.12-rc2/include/linux/init.h 2005-04-05 16:57:29.000000000 +0200
+++ linux-2.6.12-rc2-disable_builtin/include/linux/init.h 2005-04-06 00:26:07.000000000 +0200
@@ -143,6 +143,16 @@ struct obs_kernel_param {
/* Relies on saved_command_line being set */
void __init parse_early_param(void);
+
+void __init disable_initcall(void *fn);
+#define __module_init_disable(x) \
+static int __init x##_disable_module(char *str) \
+{ \
+ disable_initcall(x); \
+ return 1; \
+} \
+__setup("force_" __stringify(KBUILD_MODNAME) "=off", x##_disable_module)
+
#endif /* __ASSEMBLY__ */
/**
@@ -153,7 +163,7 @@ void __init parse_early_param(void);
* builtin) or at module insertion time (if a module). There can only
* be one per module.
*/
-#define module_init(x) __initcall(x);
+#define module_init(x) __initcall(x); __module_init_disable(x);
/**
* module_exit() - driver exit entry point
diff -urNp linux-2.6.12-rc2/init/main.c linux-2.6.12-rc2-disable_builtin/init/main.c
--- linux-2.6.12-rc2/init/main.c 2005-04-05 16:59:55.000000000 +0200
+++ linux-2.6.12-rc2-disable_builtin/init/main.c 2005-04-05 21:07:05.000000000 +0200
@@ -539,6 +539,17 @@ struct task_struct *child_reaper = &init
extern initcall_t __initcall_start[], __initcall_end[];
+void __init disable_initcall(void *fn)
+{
+ initcall_t *call;
+
+ for (call = __initcall_start; call < __initcall_end; call++) {
+
+ if (*call == fn)
+ *call = NULL;
+ }
+}
+
static void __init do_initcalls(void)
{
initcall_t *call;
@@ -553,7 +564,8 @@ static void __init do_initcalls(void)
printk("\n");
}
- (*call)();
+ if (*call)
+ (*call)();
msg = NULL;
if (preempt_count() != count) {
-
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