From: Will Deacon <will.deacon@arm.com>
To: Suzuki K Poulose <Suzuki.Poulose@arm.com>
Cc: catalin.marinas@arm.com, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, steve.capper@linaro.org,
Mark Rutland <mark.rutland@arm.com>
Subject: Re: [PATCH] arm64: cpuinfo: Expose MIDR_EL1 and REVIDR_EL1 to sysfs
Date: Mon, 13 Jun 2016 13:37:42 +0100 [thread overview]
Message-ID: <20160613123742.GD1605@arm.com> (raw)
In-Reply-To: <575EA0DC.2080801@arm.com>
On Mon, Jun 13, 2016 at 01:02:36PM +0100, Suzuki K Poulose wrote:
> On 10/06/16 18:02, Will Deacon wrote:
> >On Fri, Jun 10, 2016 at 04:19:44PM +0100, Suzuki K Poulose wrote:
> >>From: Steve Capper <steve.capper@linaro.org>
> >>
> >>It can be useful for JIT software to be aware of MIDR_EL1 and
> >>REVIDR_EL1 to ascertain the presence of any core errata that could
> >>affect codegen.
> >>
> >>This patch exposes these registers through sysfs:
> >>
> >>/sys/devices/system/cpu/cpu$ID/identification/midr
> >>/sys/devices/system/cpu/cpu$ID/identification/revidr
>
>
> >>+
> >>+#define CPUINFO_ATTR_RO(_name) \
> >>+ static ssize_t show_##_name (struct device *dev, \
> >>+ struct device_attribute *attr, char *buf) \
> >>+ { \
> >>+ struct cpuinfo_arm64 *info = &per_cpu(cpu_data, dev->id); \
> >>+ if (!cpu_present(dev->id)) \
> >>+ return -ENODEV; \
> >>+ \
> >>+ if (info->reg_midr) \
> >>+ return sprintf(buf, "0x%016x\n", info->reg_##_name); \
> >
> >Should this be 0x%08x, as these are 32-bit registers?
>
> Yes. Will change it. As per Mark's comments, I can change them to 64bit in
> a separate patch
No -- this is a sysfs ABI and I think we should be consistent from the
beginning. I'm fine with having them 64-bit, since Mark's comments make
sense, but a comment justifying that would be a good idea.
Will
next prev parent reply other threads:[~2016-06-13 12:37 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-10 15:19 [PATCH] arm64: cpuinfo: Expose MIDR_EL1 and REVIDR_EL1 to sysfs Suzuki K Poulose
2016-06-10 17:02 ` Will Deacon
2016-06-13 9:07 ` Mark Rutland
2016-06-13 12:02 ` Suzuki K Poulose
2016-06-13 12:37 ` Will Deacon [this message]
2016-06-13 13:25 ` Suzuki K Poulose
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