From: "Lendacky, Thomas" <Thomas.Lendacky@amd.com>
To: Thomas Gleixner <tglx@linutronix.de>,
"Li, Aubrey" <aubrey.li@linux.intel.com>
Cc: Aubrey Li <aubrey.intel@gmail.com>,
Daniel Drake <drake@endlessm.com>,
"x86@kernel.org" <x86@kernel.org>, Ingo Molnar <mingo@redhat.com>,
"H . Peter Anvin" <hpa@zytor.com>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Endless Linux Upstreaming Team <linux@endlessm.com>
Subject: Re: setup_boot_APIC_clock() NULL dereference during early boot on reduced hardware platforms
Date: Thu, 1 Aug 2019 15:44:19 +0000 [thread overview]
Message-ID: <3d14b0cc-3cca-1874-3521-4ee2ec52141d@amd.com> (raw)
In-Reply-To: <alpine.DEB.2.21.1908011054210.1965@nanos.tec.linutronix.de>
On 8/1/19 5:13 AM, Thomas Gleixner wrote:
> On Thu, 1 Aug 2019, Li, Aubrey wrote:
>> On 2019/8/1 16:13, Thomas Gleixner wrote:
>>> The point is that it does not matter which vendor a CPU comes from. The
>>> kernel does support legacyless boot when the frequencies are known. Whether
>>> that's currently possible on that particular CPU is a different question.
>>>
>> Yeah, I should specify, Daniel, your platform needs a global clock event, ;-)
>
> Care to look at the manuals before making assumptions?
>
> 2.1.9 Timers
>
> Each core includes the following timers. These timers do not vary in
> frequency regardless of the current P-state or C-state.
>
> * Core::X86::Msr::TSC; the TSC increments at the rate specified by the
> P0 Pstate. See Core::X86::Msr::PStateDef.
>
> * The APIC timer (Core::X86::Apic::TimerInitialCount and
> Core::X86::Apic::TimerCurrentCount), which increments at the rate of
> 2xCLKIN; the APIC timer may increment in units of between 1 and 8.
>
> The Ryzens use a 100MHz input clock for the APIC normally, but I'm not sure
> whether this is subject to overclocking. If so then it should be possible
> to figure that out somehow. Tom?
Let me check with the hardware folks and I'll get back to you.
Thanks,
Tom
>
> Thanks,
>
> tglx
>
next prev parent reply other threads:[~2019-08-01 15:45 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-01 6:24 setup_boot_APIC_clock() NULL dereference during early boot on reduced hardware platforms Daniel Drake
2019-08-01 7:16 ` Aubrey Li
2019-08-01 7:35 ` Thomas Gleixner
2019-08-01 7:56 ` Aubrey Li
2019-08-01 8:13 ` Thomas Gleixner
2019-08-01 8:21 ` Li, Aubrey
2019-08-01 10:13 ` Thomas Gleixner
2019-08-01 15:44 ` Lendacky, Thomas [this message]
2019-08-08 20:36 ` Thomas Gleixner
2019-08-08 21:01 ` Lendacky, Thomas
2019-08-08 21:08 ` Thomas Gleixner
2019-08-08 21:36 ` Lendacky, Thomas
2019-08-09 12:54 ` [PATCH] x86/apic: Handle missing global clockevent gracefully Thomas Gleixner
2019-08-09 12:59 ` Jiri Slaby
2019-08-09 13:58 ` Lendacky, Thomas
2019-08-09 19:40 ` Thomas Gleixner
2019-08-12 6:16 ` Daniel Drake
2019-08-12 7:03 ` Jiri Slaby
2019-08-15 5:02 ` Daniel Drake
2019-08-12 7:46 ` Li, Aubrey
2019-08-12 12:24 ` Thomas Gleixner
2019-08-12 12:59 ` Aubrey Li
2019-08-12 17:11 ` Thomas Gleixner
2019-08-19 10:37 ` [tip:x86/urgent] " tip-bot for Thomas Gleixner
2019-08-01 9:00 ` setup_boot_APIC_clock() NULL dereference during early boot on reduced hardware platforms Daniel Drake
2019-08-01 10:17 ` Thomas Gleixner
2019-08-01 7:27 ` Thomas Gleixner
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