init: add arch_call_rest_init to allow stack switching (53c99bd6) · Commits · 戴 / test

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 −0

Original line number	Diff line number	Diff line
		@@ -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 */

init/main.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -394,7 +394,7 @@ static void __init setup_command_line(char *command_line)

		static __initdata DECLARE_COMPLETION(kthreadd_done);

		static noinline void __ref rest_init(void)
		noinline void __ref rest_init(void)
		{
		struct task_struct *tsk;
		int pid;
		@@ -528,6 +528,11 @@ static void __init mm_init(void)
		pti_init();
		}

		void __init __weak arch_call_rest_init(void)
		{
		rest_init();
		}

		asmlinkage __visible void __init start_kernel(void)
		{
		char *command_line;
		@@ -736,7 +741,7 @@ asmlinkage __visible void __init start_kernel(void)
		}

		/* Do the rest non-__init'ed, we're now alive */
		rest_init();
		arch_call_rest_init();
		}

		/* Call all constructor functions linked into the kernel. */

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