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From: will.deacon@arm•com (Will Deacon)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH V2 1/4] ARM: perf: Set suniden bit.
Date: Thu, 7 Aug 2014 18:33:16 +0100	[thread overview]
Message-ID: <20140807173316.GH31101@arm.com> (raw)
In-Reply-To: <53E22E0B.7080907@parkeon.com>

On Wed, Aug 06, 2014 at 02:30:51PM +0100, Martin Fuzzey wrote:
> On 06/08/14 12:49, Will Deacon wrote:
> > +	/*
> > +	 * Bits indicating any CPU or platform specific activations that have
> > +	 * been done so we can undo them when stopping
> > +	 */
> > +	struct {
> > +		unsigned int secure_regs_available : 1;
> > +		unsigned int secure_debug_requested : 1;
> > +		unsigned int platform_enabled : 1;
> > +	} activated_flags;
> > This should be a single bool secure_access; field.
> 
> The idea was to only actually modify the security settings while someone 
> actually uses perf rather than just anytime the driver is loaded.
> But I didn't want to disable the bit when exiting perf mode if it had 
> already been enabled elsewhere (eg by the bootloader).
> Hence the first two bits.
> 
> I'm not sure how important this really is but it seemed sensible and not 
> too hard.

I think it's unnecessary complication. We've booted secure, we're not
spawning a non-secure OS and we're not doing any strange
soft-virtualisation. This means that we own the PMU and can configure it
once during probe.

Will

  reply	other threads:[~2014-08-07 17:33 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-05 14:48 [PATCH V2 0/4] ARM: perf: Support i.MX53 Martin Fuzzey
2014-08-05 14:48 ` [PATCH V2 1/4] ARM: perf: Set suniden bit Martin Fuzzey
2014-08-06 10:49   ` Will Deacon
2014-08-06 13:30     ` Martin Fuzzey
2014-08-07 17:33       ` Will Deacon [this message]
2016-01-06 14:55         ` [PATCH V3 1/1] " George G. Davis
2016-01-12 17:11           ` Will Deacon
2016-01-14  4:36             ` [PATCH v4 1/1] ARM: perf: Set ARMv7 SDER SUNIDEN bit George G. Davis
2016-01-15  2:50               ` Rob Herring
2016-01-15 17:46               ` Will Deacon
2014-08-05 14:48 ` [PATCH V2 2/4] ARM: perf: Associate PMU data with driver Martin Fuzzey
2014-08-06 10:50   ` Will Deacon
2014-08-06 13:03     ` Russell King - ARM Linux
2014-08-05 14:48 ` [PATCH V2 3/4] ARM: i.MX53: Add Soc specific PMU setup Martin Fuzzey
2014-08-05 14:48 ` [PATCH V2 4/4] ARM: dts: i.MX53: Add PMU DT entry Martin Fuzzey
2014-08-06 10:50   ` Will Deacon
2014-08-06 13:35     ` Martin Fuzzey
2014-08-07  5:53       ` Shawn Guo
2014-08-07  8:00         ` Martin Fuzzey
2014-08-07  8:54           ` Shawn Guo

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