From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: Nicholas Piggin <npiggin@gmail.com>, linuxppc-dev@lists.ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail.com>
Subject: Re: [PATCH] powerpc/64s/exception: Fix machine check early corrupting AMR
Date: Sat, 29 Jun 2019 21:37:54 +1000 (AEST) [thread overview]
Message-ID: <45bWpV1jWCz9s5c@ozlabs.org> (raw)
In-Reply-To: <20190621225554.1913-1-npiggin@gmail.com>
On Fri, 2019-06-21 at 22:55:54 UTC, Nicholas Piggin wrote:
> The early machine check runs in real mode, so locking is unnecessary.
> Worse, the windup does not restore AMR, so this can result in a false
> KUAP fault after a recoverable machine check hits inside a user copy
> operation.
>
> Fix this similarly to HMI by just avoiding the kuap lock in the
> early machine check handler (it will be set by the late handler that
> runs in virtual mode if that runs). If the virtual mode handler is
> reached, it will lock and restore the AMR.
>
> Fixes: 890274c2dc4c0 ("powerpc/64s: Implement KUAP for Radix MMU")
> Cc: Russell Currey <ruscur@russell.cc>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Applied to powerpc fixes, thanks.
https://git.kernel.org/powerpc/c/e13e7cd4c0c1cc9984d9b6a8663e10d76b53f2aa
cheers
next prev parent reply other threads:[~2019-06-29 11:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-21 22:55 [PATCH] powerpc/64s/exception: Fix machine check early corrupting AMR Nicholas Piggin
2019-06-29 11:37 ` Michael Ellerman [this message]
2019-06-29 12:25 ` Michael Ellerman
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