linux-kernel - Re: [PATCH 4/9] x86, pkeys: override pkey when moving away from PROT

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Message-ID: <6e3f8e1c-afed-64de-9815-8478e18532aa@intel.com>
Date:   Fri, 6 Apr 2018 17:47:29 -0700
From:   Dave Hansen <dave.hansen@...el.com>
To:     Ram Pai <linuxram@...ibm.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>
Cc:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        shakeelb@...gle.com, stable@...nel.org, tglx@...utronix.de,
        mpe@...erman.id.au, mingo@...nel.org, akpm@...ux-foundation.org,
        shuah@...nel.org
Subject: Re: [PATCH 4/9] x86, pkeys: override pkey when moving away from
 PROT_EXEC

On 04/06/2018 05:09 PM, Ram Pai wrote:
>> -	/*
>> -	 * Look for a protection-key-drive execute-only mapping
>> -	 * which is now being given permissions that are not
>> -	 * execute-only.  Move it back to the default pkey.
>> -	 */
>> -	if (vma_is_pkey_exec_only(vma) &&
>> -	    (prot & (PROT_READ|PROT_WRITE))) {
>> -		return 0;
>> -	}
>> +
> Dave,
> 	this can be simply:
> 
> 	if ((vma_is_pkey_exec_only(vma) && (prot != PROT_EXEC))
> 		return ARCH_DEFAULT_PKEY;

Yes, but we're removing that code entirely. :)