Re: [PATCH 6/6] kexec jump: fix for ftrace

[Pavel Machek <pavel@suse.cz>]

> Restore ftrace after jumping back from kexeced kernel.
> 
> Signed-off-by: Huang Ying <ying.huang@intel.com>
> 
> ---
>  arch/x86/kernel/machine_kexec_32.c |   19 +++++++++++++++++++
>  kernel/kexec.c                     |    2 --
>  2 files changed, 19 insertions(+), 2 deletions(-)
> 
> @@ -124,7 +126,15 @@ void machine_kexec(struct kimage *image)
>  				       unsigned int has_pae,
>  				       unsigned int preserve_context);
>  
> +#ifdef CONFIG_KEXEC_JUMP
> +	if (kexec_image->preserve_context)
> +		save_processor_state();
> +#endif
> +
> +#ifdef CONFIG_FTRACE
> +	save_ftrace_enabled = ftrace_enabled;
>  	tracer_disable();
> +#endif
>  
>  	/* Interrupts aren't acceptable while we reboot */
>  	raw_local_irq_disable();

The patch does way more than its changelog says...
									Pavel


> @@ -182,6 +192,15 @@ void machine_kexec(struct kimage *image)
>  					   (unsigned long)page_list,
>  					   image->start, cpu_has_pae,
>  					   image->preserve_context);
> +
> +#ifdef CONFIG_KEXEC_JUMP
> +	if (kexec_image->preserve_context)
> +		restore_processor_state();
> +#endif
> +
> +#ifdef CONFIG_FTRACE
> +	ftrace_enabled = save_ftrace_enabled;
> +#endif
>  }
>  
>  void arch_crash_save_vmcoreinfo(void)
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -1469,7 +1469,6 @@ int kernel_kexec(void)
>  		error = device_power_down(PMSG_FREEZE);
>  		if (error)
>  			goto Enable_irqs;
> -		save_processor_state();
>  	} else
>  #endif
>  	{
> @@ -1482,7 +1481,6 @@ int kernel_kexec(void)
>  
>  #ifdef CONFIG_KEXEC_JUMP
>  	if (kexec_image->preserve_context) {
> -		restore_processor_state();
>  		device_power_up(PMSG_RESTORE);
>   Enable_irqs:
>  		local_irq_enable();
> 

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html