From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: Nicholas Piggin <npiggin@gmail.com>, linuxppc-dev@lists.ozlabs.org
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>,
Nicholas Piggin <npiggin@gmail.com>
Subject: Re: powerpc/vas: do not set uses_vas for kernel windows
Date: Wed, 14 Feb 2018 16:43:46 +1100 (AEDT) [thread overview]
Message-ID: <3zh7cf17qqz9t3F@ozlabs.org> (raw)
In-Reply-To: <20180208091838.27992-1-npiggin@gmail.com>
On Thu, 2018-02-08 at 09:18:38 UTC, Nicholas Piggin wrote:
> cp_abort is only required or user windows, because kernel context
> must not be preempted between a copy/paste pair.
>
> Without this patch, the init task gets used_vas set when it runs
> the nx842_powernv_init initcall, which opens windows for kernel
> usage.
>
> used_vas is then never cleared anywhere, so it gets propagated
> into all other tasks. It's a property of the address space, so it
> should really be cleared when a new mm is created (or in dup_mmap
> if the mmaps are marked as VM_DONTCOPY). For now we seem to have
> no such driver, so leave that for another patch.
>
> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> Reviewed-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Applied to powerpc fixes, thanks.
https://git.kernel.org/powerpc/c/b00b62898631b756c3e123542bbb04
cheers
prev parent reply other threads:[~2018-02-14 5:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-08 9:18 [PATCH] powerpc/vas: do not set uses_vas for kernel windows Nicholas Piggin
2018-02-10 4:57 ` Sukadev Bhattiprolu
2018-02-14 5:43 ` Michael Ellerman [this message]
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