From: Peter Zijlstra <peterz@infradead.org>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Paul Mackerras <paulus@samba.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Ingo Molnar <mingo@redhat.com>, Kees Cook <keescook@chromium.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Erik Bosman <ebn310@few.vu.nl>
Subject: Re: [RFC 1/5] x86: Clean up cr4 manipulation
Date: Thu, 16 Oct 2014 10:16:33 +0200 [thread overview]
Message-ID: <20141016081633.GG7369@worktop.fdxtended.com> (raw)
In-Reply-To: <724658a527c0572dde1a400a5e90b85f45421201.1413323611.git.luto@amacapital.net>
On Tue, Oct 14, 2014 at 03:57:35PM -0700, Andy Lutomirski wrote:
> +/* Set in this cpu's CR4. */
> +static inline void cr4_set(unsigned long mask)
> +{
> + unsigned long cr4;
> +
> + cr4 = read_cr4();
> + cr4 |= mask;
> + write_cr4(cr4);
> +}
> +
> +/* Clear in this cpu's CR4. */
> +static inline void cr4_clear(unsigned long mask)
> +{
> + unsigned long cr4;
> +
> + cr4 = read_cr4();
> + cr4 &= ~mask;
> + write_cr4(cr4);
> +}
I would have called these cr4_or() and cr4_nand(). When first reading
this I expected cr4_set() to be a pure write_cr4() and cr4_clear() to do
write_cr4(0) -- which obviously doesn't make too much sense.
cr4_{set,clear}_mask() might maybe be clearer but is more typing, and
the logical ops as suggested should have unambiguous meaning.
next prev parent reply other threads:[~2014-10-16 8:16 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-14 22:57 [RFC 0/5] CR4 handling improvements Andy Lutomirski
2014-10-14 22:57 ` [RFC 1/5] x86: Clean up cr4 manipulation Andy Lutomirski
2014-10-16 8:16 ` Peter Zijlstra [this message]
2014-10-16 11:18 ` Borislav Petkov
2014-10-16 11:29 ` Borislav Petkov
2014-10-16 15:32 ` Andy Lutomirski
2014-10-16 15:47 ` Borislav Petkov
2014-10-14 22:57 ` [RFC 2/5] x86: Store a per-cpu shadow copy of CR4 Andy Lutomirski
2014-10-16 8:26 ` Peter Zijlstra
2014-10-16 11:49 ` Borislav Petkov
2014-10-16 15:30 ` Andy Lutomirski
2014-10-14 22:57 ` [RFC 3/5] x86: Add a comment clarifying LDT context switching Andy Lutomirski
2014-10-16 15:49 ` Borislav Petkov
2014-10-16 16:21 ` Andy Lutomirski
2014-10-21 5:41 ` Borislav Petkov
2014-10-21 5:44 ` Andy Lutomirski
2014-10-21 6:05 ` Borislav Petkov
2014-10-14 22:57 ` [RFC 4/5] perf: Add pmu callbacks to track event mapping and unmapping Andy Lutomirski
2014-10-14 22:57 ` [RFC 5/5] x86,perf: Only allow rdpmc if a perf_event is mapped Andy Lutomirski
2014-10-16 8:42 ` Peter Zijlstra
2014-10-16 15:37 ` Andy Lutomirski
2014-10-16 15:57 ` Borislav Petkov
2014-10-17 0:00 ` Andy Lutomirski
2014-10-19 20:23 ` Andy Lutomirski
2014-10-19 21:33 ` Peter Zijlstra
2014-10-19 22:05 ` Andy Lutomirski
2014-10-19 22:20 ` Peter Zijlstra
2014-10-19 22:57 ` Andy Lutomirski
2014-10-20 8:33 ` Peter Zijlstra
2014-10-20 16:49 ` Andy Lutomirski
2014-10-20 17:39 ` Andy Lutomirski
2014-10-21 8:59 ` Peter Zijlstra
2014-10-19 21:35 ` Peter Zijlstra
2014-10-20 0:08 ` Andy Lutomirski
2014-10-20 8:48 ` Peter Zijlstra
2014-10-20 9:24 ` Martin Schwidefsky
2014-10-20 10:51 ` Hendrik Brueckner
2014-10-21 9:14 ` Peter Zijlstra
2014-10-21 15:52 ` Andy Lutomirski
2014-10-21 4:06 ` [RFC 0/5] CR4 handling improvements Vince Weaver
2014-10-21 4:28 ` Andy Lutomirski
2014-10-21 15:00 ` Vince Weaver
2014-10-21 16:04 ` Peter Zijlstra
2014-10-21 17:05 ` Vince Weaver
2014-10-23 11:42 ` Peter Zijlstra
2014-10-24 12:41 ` Vince Weaver
2014-10-24 22:14 ` Andy Lutomirski
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