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From: Andy Lutomirski <luto@kernel.org>
To: "Bae, Chang Seok" <chang.seok.bae@intel.com>
Cc: Andrew Lutomirski <luto@kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@kernel.org>, Andi Kleen <ak@linux.intel.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	"Metzger, Markus T" <markus.t.metzger@intel.com>,
	"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 7/7] x86/vdso: Move out the CPU number store
Date: Mon, 18 Jun 2018 15:08:33 -0700	[thread overview]
Message-ID: <CALCETrXJ31ArFKt3QYi=p9ufyhBW8ZFBdSaDU3ueDmFEFKvY6g@mail.gmail.com> (raw)
In-Reply-To: <1528391168-22224-8-git-send-email-chang.seok.bae@intel.com>

On Thu, Jun 7, 2018 at 10:06 AM Chang S. Bae <chang.seok.bae@intel.com> wrote:
>
> The CPU (and node) number will be written, as early enough,
> to the segment limit of per CPU data and TSC_AUX MSR entry.
> The information has been retrieved by vgetcpu in user space
> and will be also loaded from the paranoid entry, when
> FSGSBASE enabled.
>
> Now storing CPU number to the CPU_NUMBER segment limit is
> done during the bootstrap, while MSR TSC_AUX is written
> during each CPU initialization that is still before IST
> setup.
>
> The redundant setting of the segment in entry/vdso/vma.c
> was removed; a substantial code removal. It removes a
> hotplug notifier, makes a facility useful to both the kernel
> and userspace unconditionally available much sooner.
> (Thanks to HPA for suggesting the cleanup)

Couldn't setup_cpu_number_segment()'s contents go in setup_cpu_number()?

--Andy

  reply	other threads:[~2018-06-18 22:08 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-07 17:06 [PATCH v3 0/7] x86: infrastructure to enable FSGSBASE Chang S. Bae
2018-06-07 17:06 ` [PATCH v3 1/7] x86/fsgsbase/64: Introduce FS/GS base helper functions Chang S. Bae
2018-06-07 17:06 ` [PATCH v3 2/7] x86/fsgsbase/64: Make ptrace read FS/GS base accurately Chang S. Bae
2018-06-07 17:06 ` [PATCH v3 3/7] x86/fsgsbase/64: Use FS/GS base helpers in core dump Chang S. Bae
2018-06-07 17:06 ` [PATCH v3 4/7] x86/fsgsbase/64: Factor out load FS/GS segments from __switch_to Chang S. Bae
2018-06-18 22:06   ` Andy Lutomirski
2018-06-07 17:06 ` [PATCH v3 5/7] x86/segments/64: Rename PER_CPU segment to CPU_NUMBER Chang S. Bae
2018-06-07 17:06 ` [PATCH v3 6/7] x86/vdso: Introduce CPU number helper functions Chang S. Bae
2018-06-18 22:07   ` Andy Lutomirski
2018-06-07 17:06 ` [PATCH v3 7/7] x86/vdso: Move out the CPU number store Chang S. Bae
2018-06-18 22:08   ` Andy Lutomirski [this message]
2018-06-18 23:12     ` Bae, Chang Seok

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