Re: [PATCH v3 2/7] x86/jump_label: Use text_poke_early() during early_init

From: Peter Zijlstra <peterz@infradead.org>
To: Nadav Amit <namit@vmware.com>
Cc: Ingo Molnar <mingo@redhat.com>,
	linux-kernel@vger.kernel.org, x86@kernel.org,
	"H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Kees Cook <keescook@chromium.org>,
	Dave Hansen <dave.hansen@intel.com>,
	Masami Hiramatsu <mhiramat@kernel.org>
Subject: Re: [PATCH v3 2/7] x86/jump_label: Use text_poke_early() during early_init
Date: Mon, 5 Nov 2018 14:33:47 +0100	[thread overview]
Message-ID: <20181105133347.GA22485@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20181105123953.GA22467@hirez.programming.kicks-ass.net>

On Mon, Nov 05, 2018 at 01:39:53PM +0100, Peter Zijlstra wrote:
> On Fri, Nov 02, 2018 at 04:29:41PM -0700, Nadav Amit wrote:
> > diff --git a/init/main.c b/init/main.c
> > index a664246450d1..b0fa26637496 100644
> > --- a/init/main.c
> > +++ b/init/main.c
> > @@ -117,6 +117,8 @@ extern void radix_tree_init(void);
> >   */
> >  bool early_boot_irqs_disabled __read_mostly;
> >  
> > +u8 early_boot_done __read_mostly;
> > +
> >  enum system_states system_state __read_mostly;
> >  EXPORT_SYMBOL(system_state);
> 
> Should this not be using system_state ^ ? The site is very close to
> SYSTEM_SCHEDULING, can we use that or should we add another state ?

We must be before kernel_init() -> kernel_init_freeable() -> smp_init().

So we need another state, something like SYSTEM_BOOTING_SMP I suppose ?

> > @@ -735,6 +737,8 @@ asmlinkage __visible void __init start_kernel(void)
> >  		efi_free_boot_services();
> >  	}
> >  
> > +	early_boot_done = true;
> > +
> >  	/* Do the rest non-__init'ed, we're now alive */
> >  	rest_init();
> >  }
> > -- 
> > 2.17.1
> > 