From: "H. Peter Anvin" <hpa@zytor.com>
To: Julien Thierry <julien.thierry@arm.com>,
Russell King - ARM Linux <linux@armlinux.org.uk>
Cc: Ingo Molnar <mingo@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
James Morse <james.morse@arm.com>
Subject: Re: Sleeping in user_access section
Date: Tue, 27 Nov 2018 11:05:40 -0800 [thread overview]
Message-ID: <691acc7f-6ce1-69da-d56d-4d3c0fdad9ab@zytor.com> (raw)
In-Reply-To: <44297716-74aa-1f14-67be-3594b5244b74@arm.com>
On 11/23/18 3:57 AM, Julien Thierry wrote:
>
> On x86, the EFLAGS.AC bit is also saved upon exception and I think it is
> cleared upon exception entry so there is implicit exit from the
> user_access mode when taking exception/interrupt.
>
No, it is restored, not cleared.
In summary: on exceptions, user_access regions are suspended, and on
return the user_access status is resumed.
However, explicitly calling sleeping functions is not supported.
-hpa
prev parent reply other threads:[~2018-11-27 19:06 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-23 9:27 Sleeping in user_access section Julien Thierry
2018-11-23 9:57 ` hpa
2018-11-23 10:16 ` Julien Thierry
2018-11-23 10:50 ` Russell King - ARM Linux
2018-11-23 11:57 ` Julien Thierry
2018-11-23 13:04 ` Russell King - ARM Linux
2018-11-27 19:05 ` H. Peter Anvin [this message]
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