Added early initcall (pre-SMP) support, using an identical interface to

that of regular initcalls. Functions called from do_pre_smp_initcalls()

could be converted to use this cleaner interface.
This is required by CPU hotplug, because early users have to register

notifiers before going SMP. One such CPU hotplug user is the relay

interface with buffer-only channels, which needs to register such a

notifier, to be usable in early code. This in turn is used by kmemtrace.
Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>

---

 include/asm-generic/vmlinux.lds.h |    2 ++

 include/linux/init.h              |    7 +++++++

 init/main.c                       |   13 +++++++++++--

 3 files changed, 20 insertions(+), 2 deletions(-)
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h

index f054778..4a318e5 100644

--- a/include/asm-generic/vmlinux.lds.h

+++ b/include/asm-generic/vmlinux.lds.h

@@ -326,6 +326,8 @@

 	}
 #define INITCALLS							\

+	*(.initcallearly.init)						\

+	__early_initcall_end = .;					\

   	*(.initcall0.init)						\

   	*(.initcall0s.init)						\

   	*(.initcall1.init)						\

diff --git a/include/linux/init.h b/include/linux/init.h

index 21d658c..bd12a4c 100644

--- a/include/linux/init.h

+++ b/include/linux/init.h

@@ -170,6 +170,13 @@ extern void (*late_time_init)(void);

 	__attribute__((__section__(".initcall" level ".init"))) = fn
 /*

+ * Early initcalls run before initializing SMP.

+ *

+ * Only for built-in code, not modules.

+ */

+#define early_initcall(fn)		__define_initcall("early",fn,early)

+

+/*

  * A "pure" initcall has no dependencies on anything else, and purely

  * initializes variables that couldn't be statically initialized.

  *

diff --git a/init/main.c b/init/main.c

index f7fb200..c5397f6 100644

--- a/init/main.c

+++ b/init/main.c

@@ -736,13 +736,13 @@ static void __init do_one_initcall(initcall_t fn)

 }
-extern initcall_t __initcall_start[], __initcall_end[];

+extern in...
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