| Message ID | 20230613224545.612182854@linutronix.de |
|---|---|
| State | New |
| Headers | show |
| Series | init, treewide, x86: Cleanup check_bugs() and start sanitizing the x86 boot process | expand |
On Wed, 2023-06-14 at 01:39 +0200, Thomas Gleixner wrote: > Fortunately none of the init calls between calibrate_delay() and > arch_cpu_finalize_init() is relevant for the functionality of > arch_cpu_finalize_init(). > Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com> I did my best to find a counterpoint to this statement. The only thing I found was that lockdep_init_task(&init_task) in fork_init() is now called after the spin_lock() usage in set_memory_4k(). But AFAICT, that whole lockdep_init_task() call is unneeded because the fields it sets are already statically initialized. I mention only because I'm not 100% sure the lockdep_init_task() call is not serving some purpose I'm missing.
On Thu, Jun 15 2023 at 21:44, Rick P. Edgecombe wrote: > On Wed, 2023-06-14 at 01:39 +0200, Thomas Gleixner wrote: >> Fortunately none of the init calls between calibrate_delay() and >> arch_cpu_finalize_init() is relevant for the functionality of >> arch_cpu_finalize_init(). >> > > Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com> > > I did my best to find a counterpoint to this statement. The only thing > I found was that lockdep_init_task(&init_task) in fork_init() is now > called after the spin_lock() usage in set_memory_4k(). > > But AFAICT, that whole lockdep_init_task() call is unneeded because > the fields it sets are already statically initialized. Correct. The call there looks absolute pointless. Peter?
--- a/init/main.c +++ b/init/main.c @@ -1041,6 +1041,8 @@ asmlinkage __visible void __init __no_sa sched_clock_init(); calibrate_delay(); + arch_cpu_finalize_init(); + /* * This needs to be called before any devices perform DMA * operations that might use the SWIOTLB bounce buffers. It will @@ -1077,8 +1079,6 @@ asmlinkage __visible void __init __no_sa taskstats_init_early(); delayacct_init(); - arch_cpu_finalize_init(); - acpi_subsystem_init(); arch_post_acpi_subsys_init(); kcsan_init();
X86 is reworking the boot process so that initializations which are not required during early boot can be moved into the late boot process and out of the fragile and restricted initial boot phase. arch_cpu_finalize_init() is the obvious place to do such initializations, but arch_cpu_finalize_init() is invoked too late in start_kernel() e.g. for initializing the FPU completely. fork_init() requires that the FPU is initialized as the size of task_struct on X86 depends on the size of the required FPU register buffer. Fortunately none of the init calls between calibrate_delay() and arch_cpu_finalize_init() is relevant for the functionality of arch_cpu_finalize_init(). Invoke it right after calibrate_delay() where everything which is relevant for arch_cpu_finalize_init() has been set up already. No functional change intended. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> --- init/main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)