From: Stefano Stabellini <sstabellini@kernel.org>
To: Julien Grall <julien.grall@arm.com>
Cc: andre.przywara@arm.com,
Stefano Stabellini <sstabellini@kernel.org>,
steve.capper@arm.com, wei.chen@arm.com, xen-devel@lists.xen.org
Subject: Re: [PATCH v3 10/16] xen/arm: cpufeature: Provide an helper to check if a capability is supported
Date: Wed, 22 Jun 2016 11:14:55 +0100 (BST) [thread overview]
Message-ID: <alpine.DEB.2.10.1606221114190.2575@sstabellini-ThinkPad-X260> (raw)
In-Reply-To: <576A63D6.6070306@arm.com>
On Wed, 22 Jun 2016, Julien Grall wrote:
> Hi Stefano,
>
> On 22/06/16 10:59, Stefano Stabellini wrote:
> > On Tue, 7 Jun 2016, Julien Grall wrote:
> > > The CPU capabilities will be set depending on the value found in the CPU
> > > registers. This patch provides a generic to go through a set of
> > > capabilities
> > > and find which one should be enabled.
> > >
> > > The parameter "info" is used to display the kind of capability updated
> > > (e.g
> > > workaround, feature...).
> > >
> > > Signed-off-by: Julien Grall <julien.grall@arm.com>
> > >
> > > ---
> > > Changes in v3:
> > > - Patch added. The code was previously part of "Detect
> > > silicon...".
> > > ---
> > > xen/arch/arm/cpufeature.c | 16 ++++++++++++++++
> > > xen/include/asm-arm/cpufeature.h | 9 +++++++++
> > > 2 files changed, 25 insertions(+)
> > >
> > > diff --git a/xen/arch/arm/cpufeature.c b/xen/arch/arm/cpufeature.c
> > > index 7a1b56b..088625b 100644
> > > --- a/xen/arch/arm/cpufeature.c
> > > +++ b/xen/arch/arm/cpufeature.c
> > > @@ -24,6 +24,22 @@
> > >
> > > DECLARE_BITMAP(cpu_hwcaps, ARM_NCAPS);
> > >
> > > +void update_cpu_capabilities(const struct arm_cpu_capabilities *caps,
> > > + const char *info)
> > > +{
> > > + int i;
> > > +
> > > + for ( i = 0; caps[i].matches; i++ )
> > > + {
> > > + if ( !caps[i].matches(&caps[i]) )
> > > + continue;
> > > +
> > > + if ( !cpus_have_cap(caps[i].capability) && caps[i].desc )
> > > + printk(XENLOG_INFO "%s: %s\n", info, caps[i].desc);
> >
> > The patch is OK. I still have the same comment as before: if an info
> > parameter is passed to this function with a string, then I think the
> > string should contain some useful information. Not a generic message.
>
> It is useful. As mentioned in the commit message the parameter "info" is used
> to display the kind of capability updated (e.g workaround, feature, ...).
>
> > I would just do:
> >
> > printk(XENLOG_INFO "enable workaround for: %s\n", caps[i].desc);
> >
> > If one day we need to change the message depending on the caller, then
> > that day we'll add a parameter to update_cpu_capabilities.
>
> We both know that this function will be used for other purpose very soon. So I
> would rather avoid to modify again in the future. That is why I described the
> purpose in the commit message.
I am unconvinced, but I'll leave it be.
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
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next prev parent reply other threads:[~2016-06-22 10:14 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-07 16:06 [PATCH v3 00/16] xen/arm: Introduce alternative runtime patching for ARM64 Julien Grall
2016-06-07 16:06 ` [PATCH v3 01/16] xen/arm: Makefile: Sort the entries alphabetically Julien Grall
2016-06-07 16:06 ` [PATCH v3 02/16] xen/arm: Include the header asm-arm/system.h in asm-arm/page.h Julien Grall
2016-06-07 16:06 ` [PATCH v3 03/16] xen/arm: Add macros to handle the MIDR Julien Grall
2016-06-07 16:06 ` [PATCH v3 04/16] xen/arm: Add cpu_hwcap bitmap Julien Grall
2016-06-07 16:06 ` [PATCH v3 05/16] xen/arm64: Add an helper to invalidate all instruction caches Julien Grall
2016-06-07 16:06 ` [PATCH v3 06/16] xen/arm: arm64: Move the define BRK_BUG_FRAME into a separate header Julien Grall
2016-06-07 16:06 ` [PATCH v3 07/16] xen/arm: arm64: Reserve a brk immediate to fault on purpose Julien Grall
2016-06-07 16:06 ` [PATCH v3 08/16] xen/arm: arm64: Add helpers to decode and encode branch instructions Julien Grall
2016-06-07 16:06 ` [PATCH v3 09/16] xen/arm: Introduce alternative runtime patching Julien Grall
2016-06-07 17:24 ` Konrad Rzeszutek Wilk
2016-06-08 9:39 ` Julien Grall
2016-06-08 18:17 ` Konrad Rzeszutek Wilk
2016-06-08 18:22 ` Julien Grall
2016-06-08 18:35 ` Konrad Rzeszutek Wilk
2016-06-09 13:33 ` Julien Grall
2016-06-07 16:06 ` [PATCH v3 10/16] xen/arm: cpufeature: Provide an helper to check if a capability is supported Julien Grall
2016-06-22 9:59 ` Stefano Stabellini
2016-06-22 10:09 ` Julien Grall
2016-06-22 10:14 ` Stefano Stabellini [this message]
2016-06-07 16:06 ` [PATCH v3 11/16] xen/arm: Detect silicon revision and set cap bits accordingly Julien Grall
2016-06-22 10:00 ` Stefano Stabellini
2016-06-07 16:06 ` [PATCH v3 12/16] xen/arm: Document the errata implemented in Xen Julien Grall
2016-06-22 10:03 ` Stefano Stabellini
2016-06-07 16:06 ` [PATCH v3 13/16] xen/arm: arm64: Add Cortex-A53 cache errata workaround Julien Grall
2016-06-22 10:04 ` Stefano Stabellini
2016-06-07 16:06 ` [PATCH v3 14/16] xen/arm: arm64: Add cortex-A57 erratum 832075 workaround Julien Grall
2016-06-22 10:10 ` Stefano Stabellini
2016-06-07 16:06 ` [PATCH v3 15/16] xen/arm: traps: Don't inject a fault if the translation VA -> IPA fails Julien Grall
2016-06-07 16:06 ` [PATCH v3 16/16] xen/arm: arm64: Document Cortex-A57 erratum 834220 Julien Grall
2016-06-14 12:15 ` Julien Grall
2016-06-22 10:08 ` Stefano Stabellini
2016-06-22 10:18 ` Julien Grall
2016-06-22 10:37 ` Stefano Stabellini
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