Re: [RFC PATCH -v2.1] x86: Kill notsc

From: H. Peter Anvin
Date: Tue Nov 17 2015 - 00:03:28 EST


On 11/16/15 13:25, Thomas Gleixner wrote:
> On Mon, 16 Nov 2015, Borislav Petkov wrote:
>> -/*
>> - * disable flag for tsc. Takes effect by clearing the TSC cpu flag
>> - * in cpu/common.c
>> - */
>> -int __init notsc_setup(char *str)
>> +/* Disable the TSC feature flag to avoid further TSC use. */
>> +int __init notsc_setup(void)
>> {
>> +#ifndef CONFIG_X86_TSC
>> setup_clear_cpu_cap(X86_FEATURE_TSC);
>
> This is silly, really.
>
> If CONFIG_X86_TSC is disabled then we should just not compile tsc.c at
> all and map cpu_has_tsc and stuff depending on it to false.
>

CONFIG_X86_TSC means TSC is obligatory, not that it is supported.

-hpa


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/