From 53c99bd665a2649341ed6aed358ab56a3eedcd00 Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Fri, 31 Aug 2018 10:42:24 +0200
Subject: init: add arch_call_rest_init to allow stack switching

With CONFIG_VMAP_STACK=y the kernel stack of all tasks should be
allocated in the vmalloc space. The initial stack used for all
the early init code is in the init_thread_union. To be able to
switch from this early stack to a properly allocated stack
from vmalloc the architecture needs a switch-over point.

Introduce the arch_call_rest_init() function with a weak definition
in init/main.c with the only purpose to call rest_init() from the
end of start_kernel(). The architecture override can then do the
necessary magic to switch to the new vmalloc'ed stack.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
 include/linux/start_kernel.h | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'include/linux/start_kernel.h')

diff --git a/include/linux/start_kernel.h b/include/linux/start_kernel.h
index 4b268d86a784..8b369a41c03c 100644
--- a/include/linux/start_kernel.h
+++ b/include/linux/start_kernel.h
@@ -9,5 +9,7 @@
    up something else. */
 
 extern asmlinkage void __init start_kernel(void);
+extern void __init arch_call_rest_init(void);
+extern void __ref rest_init(void);
 
 #endif /* _LINUX_START_KERNEL_H */
-- 
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