From: Pavel Machek <pavel@ucw.cz>
To: mingo@kernel.org, bpetkov@suse.de, peterz@infradead.org,
bp@alien8.de, tglx@linutronix.de, hpa@zytor.com, luto@kernel.org,
torvalds@linux-foundation.org, pmenzel@molgen.mpg.de,
linux-kernel@vger.kernel.org
Cc: linux-tip-commits@vger.kernel.org
Subject: Re: [tip:x86/urgent] x86/mm/32: Load a sane CR3 before cpu_init() on secondary CPUs
Date: Wed, 20 Sep 2017 14:52:58 +0200 [thread overview]
Message-ID: <20170920125258.GA3716@amd> (raw)
In-Reply-To: <tip-4ba55e65f471d011d3ba2ac2022180ea0877d68e@git.kernel.org>
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On Sun 2017-09-17 11:19:53, tip-bot for Andy Lutomirski wrote:
> Commit-ID: 4ba55e65f471d011d3ba2ac2022180ea0877d68e
> Gitweb: http://git.kernel.org/tip/4ba55e65f471d011d3ba2ac2022180ea0877d68e
> Author: Andy Lutomirski <luto@kernel.org>
> AuthorDate: Sun, 17 Sep 2017 09:03:51 -0700
> Committer: Ingo Molnar <mingo@kernel.org>
> CommitDate: Sun, 17 Sep 2017 18:59:09 +0200
>
> x86/mm/32: Load a sane CR3 before cpu_init() on secondary CPUs
>
> For unknown historical reasons (i.e. Borislav doesn't recall),
> 32-bit kernels invoke cpu_init() on secondary CPUs with
> initial_page_table loaded into CR3. Then they set
> current->active_mm to &init_mm and call enter_lazy_tlb() before
> fixing CR3. This means that the x86 TLB code gets invoked while CR3
> is inconsistent, and, with the improved PCID sanity checks I added,
> we warn.
>
> Fix it by loading swapper_pg_dir (i.e. init_mm.pgd) earlier.
>
> Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
> Reported-by: Pavel Machek <pavel@ucw.cz>
4.14.0-rc1-next-20170919 does not produce the warning during bootup.
Pavel
Tested-by: Pavel Machek <pavel@ucw.cz>
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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prev parent reply other threads:[~2017-09-20 12:53 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-17 16:03 [PATCH 0/4] More PCID fixes Andy Lutomirski
2017-09-17 16:03 ` [PATCH 1/4] x86/mm: Factor out CR3-building code Andy Lutomirski
2017-09-17 18:18 ` [tip:x86/urgent] " tip-bot for Andy Lutomirski
2017-09-17 16:03 ` [PATCH 2/4] x86/mm/64: Stop using CR3.PCID == 0 in ASID-aware code Andy Lutomirski
2017-09-17 18:19 ` [tip:x86/urgent] " tip-bot for Andy Lutomirski
2017-09-17 16:03 ` [PATCH 3/4] x86/mm/32: Move setup_clear_cpu_cap(X86_FEATURE_PCID) earlier Andy Lutomirski
2017-09-17 18:19 ` [tip:x86/urgent] " tip-bot for Andy Lutomirski
2017-09-17 16:03 ` [PATCH 4/4] x86/mm/32: Load a sane CR3 before cpu_init() on secondary CPUs Andy Lutomirski
2017-09-17 18:19 ` [tip:x86/urgent] " tip-bot for Andy Lutomirski
2017-09-18 8:17 ` Paul Menzel
2017-09-20 12:52 ` Pavel Machek [this message]
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