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Message-ID: <20240425215846.3276082-1-jeffxu@chromium.org>
Date: Thu, 25 Apr 2024 21:58:46 +0000
From: jeffxu@...omium.org
To: aruna.ramakrishna@...cle.com
Cc: andrew.brownsword@...cle.com,
dave.hansen@...ux.intel.com,
linux-kernel@...r.kernel.org,
matthias.neugschwandtner@...cle.com,
tglx@...utronix.de,
jeffxu@...omium.org,
jeffxu@...gle.com,
jannh@...gle.com,
sroettger@...gle.com,
x86@...nel.org
Subject: Re: [RFC PATCH v2 1/1] x86/pkeys: update PKRU to enable pkey 0 before XSAVE
From: Jeff Xu <jeffxu@...omium.org>
>The semantics you've implemented for sigaltstacks are not the only possible
>ones. In principle, a signal handler with its own stack might want to have
>its own key(s) enabled. In a way a Linux signal handler is a mini-thread
>created on the fly, with its own stack and its own attributes. Some thought
>& analysis should go into which way to go here, and the best path should be
>chosen. Fixing the SIGSEGV you observed should be a happy side effect of
>other worthwile improvements.
>
This is exactly right. we wants to use altstack with its own pkey. The pkey
won't be writeable during thread's normal operation, only by signaling
handling itself.
Thanks
-Jeff
>Thanks,
>
> Ingo
>
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