From: Eduard - Gabriel Munteanu 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 Cc: Tom Zanussi Signed-off-by: Andrew Morton --- include/asm-generic/vmlinux.lds.h | 2 ++ include/linux/init.h | 7 +++++++ init/main.c | 13 +++++++++++-- 3 files changed, 20 insertions(+), 2 deletions(-) diff -puN include/asm-generic/vmlinux.lds.h~better-interface-for-hooking-early-initcalls include/asm-generic/vmlinux.lds.h --- a/include/asm-generic/vmlinux.lds.h~better-interface-for-hooking-early-initcalls +++ a/include/asm-generic/vmlinux.lds.h @@ -361,6 +361,8 @@ } #define INITCALLS \ + *(.initcallearly.init) \ + __early_initcall_end = .; \ *(.initcall0.init) \ *(.initcall0s.init) \ *(.initcall1.init) \ diff -puN include/linux/init.h~better-interface-for-hooking-early-initcalls include/linux/init.h --- a/include/linux/init.h~better-interface-for-hooking-early-initcalls +++ a/include/linux/init.h @@ -171,6 +171,13 @@ 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 -puN init/main.c~better-interface-for-hooking-early-initcalls init/main.c --- a/init/main.c~better-interface-for-hooking-early-initcalls +++ a/init/main.c @@ -742,13 +742,13 @@ static void __init do_one_initcall(initc } -extern initcall_t __initcall_start[], __initcall_end[]; +extern initcall_t __initcall_start[], __initcall_end[], __early_initcall_end[]; static void __init do_initcalls(void) { initcall_t *call; - for (call = __initcall_start; call < __initcall_end; call++) + for (call = __early_initcall_end; call < __initcall_end; call++) do_one_initcall(*call); /* Make sure there is no pending stuff from the initcall sequence */ @@ -782,6 +782,14 @@ static int __init nosoftlockup_setup(cha } __setup("nosoftlockup", nosoftlockup_setup); +static void __init __do_pre_smp_initcalls(void) +{ + initcall_t *call; + + for (call = __initcall_start; call < __early_initcall_end; call++) + do_one_initcall(*call); +} + static void __init do_pre_smp_initcalls(void) { extern int spawn_ksoftirqd(void); @@ -872,6 +880,7 @@ static int __init kernel_init(void * unu smp_prepare_cpus(setup_max_cpus); + __do_pre_smp_initcalls(); do_pre_smp_initcalls(); smp_init(); _