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>
This commit is contained in:
Martin Schwidefsky 2018-08-31 10:42:24 +02:00
parent 00e9e6645a
commit 53c99bd665
2 changed files with 9 additions and 2 deletions

View File

@ -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 */

View File

@ -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. */