Re: [PATCH v10 10/12] x86, mm, pat: Cleanup init flags in pat_init()

[Borislav Petkov]

On Wed, May 27, 2015 at 09:19:02AM -0600, Toshi Kani wrote:
> pat_init() uses two flags, 'boot_cpu' and 'boot_pat_state', for
> tracking the boot CPU's initialization status.  'boot_pat_state'
> is also overloaded to carry the boot PAT value.
> 
> This patch cleans this up by replacing them with a new single
> flag, 'boot_cpu_done', to track the boot CPU's initialization
> status.  'boot_pat_state' is only used to carry the boot PAT
> value as a result.
> 
> Suggested-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Signed-off-by: Toshi Kani <toshi.kani@xxxxxx>
> ---
>  arch/x86/mm/pat.c |   42 ++++++++++++++++++++----------------------
>  1 file changed, 20 insertions(+), 22 deletions(-)

...

> +		rdmsrl(MSR_IA32_CR_PAT, boot_pat_state);
> +		if (!boot_pat_state) {
> +			pat_disable("PAT read returns always zero, disabled.");
> +			return;
> +		}
> +	} else if (!cpu_has_pat) {
> +		/*
> +		 * If this happens we are on a secondary CPU, but
> +		 * switched to PAT on the boot CPU. We have no way to
> +		 * undo PAT.
> +		 */
> +		pr_err("PAT enabled, but not supported by secondary CPU\n");
> +		BUG();

These could be replaced with a panic().

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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