From: Russell King - ARM Linux <linux@armlinux.org.uk>
To: Will Deacon <will.deacon@arm.com>
Cc: Jeremy Linton <jeremy.linton@arm.com>,
linux-arm-kernel@lists.infradead.org, mark.rutland@arm.com,
steve.capper@arm.com, mlangsdorf@redhat.com,
punit.agrawal@arm.com, linux-acpi@vger.kernel.org,
msalter@redhat.com
Subject: Re: [PATCH V10 2/6] arm: arm64: Add routine to determine cpuid of other cpus
Date: Tue, 29 Nov 2016 10:46:18 +0000 [thread overview]
Message-ID: <20161129104617.GV14217@n2100.armlinux.org.uk> (raw)
In-Reply-To: <20161129103112.GC30283@arm.com>
On Tue, Nov 29, 2016 at 10:31:12AM +0000, Will Deacon wrote:
> [adding Russell]
>
> On Wed, Nov 09, 2016 at 05:39:49PM -0600, Jeremy Linton wrote:
> > It is helpful if we can read the cpuid/midr of other CPUs
> > in the system independent of arm/arm64.
> >
> > Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
> > ---
> > arch/arm/include/asm/cputype.h | 2 ++
> > arch/arm64/include/asm/cputype.h | 3 +++
> > 2 files changed, 5 insertions(+)
> >
> > diff --git a/arch/arm/include/asm/cputype.h b/arch/arm/include/asm/cputype.h
> > index 522b5fe..31fb273 100644
> > --- a/arch/arm/include/asm/cputype.h
> > +++ b/arch/arm/include/asm/cputype.h
> > @@ -235,6 +235,8 @@ static inline unsigned int __attribute_const__ read_cpuid_mpidr(void)
> > #define cpu_is_sa1100() (read_cpuid_part() == ARM_CPU_PART_SA1100)
> > #define cpu_is_sa1110() (read_cpuid_part() == ARM_CPU_PART_SA1110)
> >
> > +#define read_specific_cpuid(cpu_num) per_cpu_ptr(&cpu_data, cpu_num)->cpuid
> > +
> > /*
> > * Intel's XScale3 core supports some v6 features (supersections, L2)
> > * but advertises itself as v5 as it does not support the v6 ISA. For
>
> Russell -- are you ok with adding this macro to arch/arm/? It will get used
> by the CPU PMU driver, which needs a portable (i.e. between arm and arm64)
> way to convert a logical CPU ID into the MIDR register for that CPU.
No, because we don't set the cpuid member in uniprocessor configurations,
so it's going to be a fragile macro - it'll return zero for kernels
configured without SMP support.
I'd ideally like cpuid for the boot CPU to be set early, so that we can
get rid of many ifdefs in this area, but haven't convinced myself that
it's safe to do so in all configurations with the percpu stuff not being
up and running in setup_arch().
--
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
next prev parent reply other threads:[~2016-11-29 10:46 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-09 23:39 [PATCH V10 0/6] Enable PMUs in ACPI Systems Jeremy Linton
2016-11-09 23:39 ` [PATCH V10 1/6] arm64: Rename the common MADT parse routine Jeremy Linton
2016-11-09 23:39 ` [PATCH V10 2/6] arm: arm64: Add routine to determine cpuid of other cpus Jeremy Linton
2016-11-29 10:31 ` Will Deacon
2016-11-29 10:46 ` Russell King - ARM Linux [this message]
2016-11-29 18:25 ` Jeremy Linton
2016-11-09 23:39 ` [PATCH V10 3/6] arm64: pmu: Cache PMU interrupt numbers from MADT parse Jeremy Linton
2016-11-09 23:39 ` [PATCH V10 4/6] arm: arm64: pmu: Assign platform PMU CPU affinity Jeremy Linton
2016-11-29 10:52 ` Will Deacon
2016-11-29 21:44 ` Jeremy Linton
2016-11-09 23:39 ` [PATCH V10 5/6] arm64: pmu: Detect and enable multiple PMUs in an ACPI system Jeremy Linton
2016-11-29 10:29 ` Will Deacon
2016-11-09 23:39 ` [PATCH V10 6/6] arm: pmu: Add PMU definitions for cores not initially online Jeremy Linton
2016-11-21 16:34 ` [PATCH V10 0/6] Enable PMUs in ACPI Systems Punit Agrawal
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20161129104617.GV14217@n2100.armlinux.org.uk \
--to=linux@armlinux.org.uk \
--cc=jeremy.linton@arm.com \
--cc=linux-acpi@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=mark.rutland@arm.com \
--cc=mlangsdorf@redhat.com \
--cc=msalter@redhat.com \
--cc=punit.agrawal@arm.com \
--cc=steve.capper@arm.com \
--cc=will.deacon@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).