linux-kernel - Re: [PATCH] x86: call machine_shutdown and stop all CPUs in native_machine

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Message-ID: <20081020143948.GA13856@hmsendeavour.rdu.redhat.com>
Date:	Mon, 20 Oct 2008 10:39:48 -0400
From:	Neil Horman <nhorman@...hat.com>
To:	Ivan Vecera <ivecera@...hat.com>
Cc:	linux-kernel@...r.kernel.org, tglx@...utronix.de, mingo@...hat.com,
	hpa@...or.com, nhorman@...hat.com, jmarchan@...hat.com
Subject: Re: [PATCH] x86: call machine_shutdown and stop all CPUs in native_machine_halt

On Mon, Oct 20, 2008 at 02:13:07PM +0200, Ivan Vecera wrote:
> Function machine_halt (resp. native_machine_halt) is empty for x86
> architectures. When command 'halt -f' is invoked, the message
> "System halted." is displayed but this is not really true because
> all CPUs are still running.
> There are also similar inconsistencies for other arches (some uses
> power-off for halt or forever-loop with IRQs enabled/disabled).
> IMO there should be used the same approach for all architectures
> OR what does the message "System halted" really mean?
> 
> Signed-off-by: Ivan Vecera <ivecera@...hat.com>
> ---
>  arch/x86/kernel/reboot.c |    8 ++++++++
>  1 files changed, 8 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
> index f4c93f1..15ad949 100644
> --- a/arch/x86/kernel/reboot.c
> +++ b/arch/x86/kernel/reboot.c
> @@ -465,6 +465,14 @@ static void native_machine_restart(char *__unused)
>  
>  static void native_machine_halt(void)
>  {
> +	/* stop other cpus and apics */
> +	machine_shutdown();
> +
> +	/* stop this cpu */
> +	local_irq_disable();
> +	if (hlt_works(smp_processor_id()))
> +		for (;;) halt();
> +	for (;;);
>  }
>  
>  static void native_machine_power_off(void)
> -- 
> 1.5.6.3
> 

Acked-by: Neil Horman <nhorman@...driver.com>

-- 
/***************************************************
 *Neil Horman
 *Senior Software Engineer
 *Red Hat, Inc.
 *nhorman@...hat.com
 *gpg keyid: 1024D / 0x92A74FA1
 *http://pgp.mit.edu
 ***************************************************/
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