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From: Ira Weiny <ira.weiny@intel.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Andy Lutomirski <luto@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	x86@kernel.org, Dave Hansen <dave.hansen@linux.intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Fenghua Yu <fenghua.yu@intel.com>,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-nvdimm@lists.01.org, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org, linux-kselftest@vger.kernel.org
Subject: Re: [PATCH RFC V3 1/9] x86/pkeys: Create pkeys_common.h
Date: Tue, 13 Oct 2020 12:44:05 -0700	[thread overview]
Message-ID: <20201013194405.GG2046448@iweiny-DESK2.sc.intel.com> (raw)
In-Reply-To: <0305912d-891f-839a-e861-49f5fada62b1@intel.com>

On Tue, Oct 13, 2020 at 10:46:16AM -0700, Dave Hansen wrote:
> On 10/9/20 12:42 PM, ira.weiny@intel.com wrote:
> > Protection Keys User (PKU) and Protection Keys Supervisor (PKS) work
> > in similar fashions and can share common defines.
> 
> Could we be a bit less abstract?  PKS and PKU each have:
> 1. A single control register
> 2. The same number of keys
> 3. The same number of bits in the register per key
> 4. Access and Write disable in the same bit locations
> 
> That means that we can share all the macros that synthesize and
> manipulate register values between the two features.

Sure.  Done.

> 
> > +++ b/arch/x86/include/asm/pkeys_common.h
> > @@ -0,0 +1,11 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef _ASM_X86_PKEYS_INTERNAL_H
> > +#define _ASM_X86_PKEYS_INTERNAL_H
> > +
> > +#define PKR_AD_BIT 0x1
> > +#define PKR_WD_BIT 0x2
> > +#define PKR_BITS_PER_PKEY 2
> > +
> > +#define PKR_AD_KEY(pkey)	(PKR_AD_BIT << ((pkey) * PKR_BITS_PER_PKEY))
> 
> Now that this has moved away from its use-site, it's a bit less
> self-documenting.  Let's add a comment:
> 
> /*
>  * Generate an Access-Disable mask for the given pkey.  Several of these
>  * can be OR'd together to generate pkey register values.
>  */

Fair enough. done.

> 
> Once that's in place, along with the updated changelog:
> 
> Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>

Thanks,
Ira


  reply	other threads:[~2020-10-13 19:44 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-09 19:42 [PATCH RFC V3 0/9] PKS: Add Protection Keys Supervisor (PKS) support RFC v3 ira.weiny
2020-10-09 19:42 ` [PATCH RFC V3 1/9] x86/pkeys: Create pkeys_common.h ira.weiny
2020-10-13 17:46   ` Dave Hansen
2020-10-13 19:44     ` Ira Weiny [this message]
2020-10-09 19:42 ` [PATCH RFC V3 2/9] x86/fpu: Refactor arch_set_user_pkey_access() for PKS support ira.weiny
2020-10-13 17:50   ` Dave Hansen
2020-10-13 23:56     ` Ira Weiny
2020-10-16 10:57   ` Peter Zijlstra
2020-10-17  3:32     ` Ira Weiny
2020-10-19  9:35       ` Peter Zijlstra
2020-10-09 19:42 ` [PATCH RFC V3 3/9] x86/pks: Enable Protection Keys Supervisor (PKS) ira.weiny
2020-10-13 18:23   ` Dave Hansen
2020-10-14  2:08     ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 4/9] x86/pks: Preserve the PKRS MSR on context switch ira.weiny
2020-10-13 18:31   ` Dave Hansen
2020-10-14 22:36     ` Ira Weiny
2020-10-16 11:12     ` Peter Zijlstra
2020-10-17  5:14       ` Ira Weiny
2020-10-19  9:37         ` Peter Zijlstra
2020-10-19 18:48           ` Ira Weiny
2020-10-16 11:06   ` Peter Zijlstra
2020-10-17  5:37     ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 5/9] x86/pks: Add PKS kernel API ira.weiny
2020-10-13 18:43   ` Dave Hansen
2020-10-15  1:08     ` Ira Weiny
2020-10-16 11:07   ` Peter Zijlstra
2020-10-17  5:42     ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 6/9] x86/entry: Pass irqentry_state_t by reference ira.weiny
2020-10-16 11:45   ` Peter Zijlstra
2020-10-16 12:55     ` Thomas Gleixner
2020-10-19  5:37       ` Ira Weiny
2020-10-19  9:32         ` Thomas Gleixner
2020-10-19 20:26           ` Ira Weiny
2020-10-19 21:12             ` Thomas Gleixner
2020-10-20 14:10               ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 7/9] x86/entry: Preserve PKRS MSR across exceptions ira.weiny
2020-10-13 18:52   ` Dave Hansen
2020-10-15  3:46     ` Ira Weiny
2020-10-15  4:06       ` Dave Hansen
2020-10-15  4:18         ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 8/9] x86/fault: Report the PKRS state on fault ira.weiny
2020-10-13 18:56   ` Dave Hansen
2020-10-15  4:13     ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 9/9] x86/pks: Add PKS test code ira.weiny
2020-10-13 19:02   ` Dave Hansen
2020-10-15  4:46     ` Ira Weiny
2020-10-09 20:18 ` [PATCH RFC V3 0/9] PKS: Add Protection Keys Supervisor (PKS) support RFC v3 Ira Weiny

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