Re: [PATCH] Fix booting pentium+ with dodgy TSC

[Pavel Machek]

On Sun 2008-04-06 17:23:38, Rusty Russell wrote:
> Linus please apply.  Almost by definition this patch can't make things worse.
> 
> We handle a broken tsc these days, so no need to panic.  We clear the TSC bit
> when tsc_init decides it's unreliable (eg. under lguest w/ bad host TSC),
> leading to bogus panic.
> 
> Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
> 
> diff -r 5e0a39f4d07b arch/x86/kernel/cpu/bugs.c
> --- a/arch/x86/kernel/cpu/bugs.c	Sun Apr 06 13:40:39 2008 +1000
> +++ b/arch/x86/kernel/cpu/bugs.c	Sun Apr 06 17:14:12 2008 +1000
> @@ -143,14 +143,6 @@ static void __init check_config(void)
>  #endif
>  
>  /*
> - * If we configured ourselves for a TSC, we'd better have one!
> - */
> -#ifdef CONFIG_X86_TSC
> -	if (!cpu_has_tsc)
> -		panic("Kernel compiled for Pentium+, requires TSC feature!");
> -#endif
> -

CONFIG_X86_TSC means 'cpu has _some_ tsc, rdmsr will work'. If you are
confident noone will read broken tsc, please also remove the config
option. It is meaningless after your patch.
							Pavel
-- 
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