From: Marc Zyngier <maz@kernel.org>
To: Oliver Upton <oupton@google.com>
Cc: Linus Walleij <linus.walleij@linaro.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Shier <pshier@google.com>,
Raghavendra Rao Ananta <rananta@google.com>,
Ricardo Koller <ricarkol@google.com>
Subject: Re: [PATCH v2] clocksource/arm_arch_timer: Fix masking for high freq counters
Date: Sun, 08 Aug 2021 11:40:30 +0100 [thread overview]
Message-ID: <87lf5c1aox.wl-maz@kernel.org> (raw)
In-Reply-To: <CAOQ_QsiECN7iVDyiyos12tk__viGkFhH9b6ZfkZVAYjeKhB=pQ@mail.gmail.com>
On Sun, 08 Aug 2021 02:14:35 +0100,
Oliver Upton <oupton@google.com> wrote:
> The only other sane idea that I could come up with is providing this
> information to the kernel through DT, although that would leave ACPI
> systems behind.
It also has the disadvantage that a large number of DT timer nodes are
a mess of cargo-culted, copy-pasted idioms, and that adding another
property would only make it worse. I'm more confident with something
that can be either:
- checked from EL2 using CNTVOFF, which is complicated, doesn't work
at EL1, and leaves us in a weird state if we have different counter
width views in the system (BL is such a wonderful concept)
- or computed from first principle based on the requirements of the
architecture.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
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next prev parent reply other threads:[~2021-08-08 10:42 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-07 19:14 [PATCH v2] clocksource/arm_arch_timer: Fix masking for high freq counters Oliver Upton
2021-08-07 22:30 ` Linus Walleij
2021-08-08 1:14 ` Oliver Upton
2021-08-08 10:40 ` Marc Zyngier [this message]
2021-08-08 19:01 ` Oliver Upton
2021-08-09 10:45 ` Marc Zyngier
2021-08-09 15:08 ` Oliver Upton
2021-08-08 10:29 ` Marc Zyngier
2021-08-09 11:07 ` Marc Zyngier
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