Re: [PATCH v2 4/4] x86/kernel/common.c: Disable SMEP by kernel optionnosmep
From: Thomas Gleixner
Date: Mon May 16 2011 - 18:02:18 EST
On Mon, 16 May 2011, Fenghua Yu wrote:
> +/*
> + * If SMEP is supported by the processor, SMEP has been enabled in CR4 earlier.
> + * But if kernel option "nosmep" is given, we disable SMEP here.
> + */
> +static __init void config_smep(struct cpuinfo_x86 *c)
> +{
> + if (cpu_has(c, X86_FEATURE_SMEP) && unlikely(disable_smep)) {
That unlikely() is completely pointless. This is init code and inside
of a if() already. Where is the point ?
> + setup_clear_cpu_cap(X86_FEATURE_SMEP);
> + clear_in_cr4(X86_CR4_SMEP);
> + }
> +}
Thanks,
tglx
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