From: Michael Ellerman <mpe@ellerman.id.au>
To: Christophe Leroy <christophe.leroy@c-s.fr>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH v2 5/6] powerpc/32s: prepare prevent_user_access() for user_access_end()
Date: Thu, 23 Jan 2020 21:59:07 +1100 [thread overview]
Message-ID: <87pnfaiglg.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <824b69f5452d1d41d12c4dbd306d4b8f32d493fc.1579715466.git.christophe.leroy@c-s.fr>
Christophe Leroy <christophe.leroy@c-s.fr> writes:
> In preparation of implementing user_access_begin and friends
> on powerpc, the book3s/32 version of prevent_user_access() need
> to be prepared for user_access_end().
>
> user_access_end() doesn't provide the address and size which
> were passed to user_access_begin(), required by prevent_user_access()
> to know which segment to modify.
>
> The list of segments which where unprotected by allow_user_access()
> are available in current->kuap. But we don't want prevent_user_access()
> to read this all the time, especially everytime it is 0 (for instance
> because the access was not a write access).
>
> Implement a special direction case named KUAP_SELF. In this case only,
> the addr and end are retrieved from current->kuap.
Can we call it KUAP_CURRENT?
ie. "use the KUAP state in current"
cheers
next prev parent reply other threads:[~2020-01-23 10:59 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-22 17:52 [PATCH v2 1/6] fs/readdir: Fix filldir() and filldir64() use of user_access_begin() Christophe Leroy
2020-01-22 17:52 ` [PATCH v2 2/6] powerpc/32s: Fix bad_kuap_fault() Christophe Leroy
2020-01-22 17:52 ` [PATCH v2 3/6] powerpc/kuap: Fix set direction in allow/prevent_user_access() Christophe Leroy
2020-01-22 17:52 ` [PATCH v2 4/6] powerpc/32s: Drop NULL addr verification Christophe Leroy
2020-01-22 17:52 ` [PATCH v2 5/6] powerpc/32s: prepare prevent_user_access() for user_access_end() Christophe Leroy
2020-01-23 10:59 ` Michael Ellerman [this message]
2020-01-22 17:52 ` [PATCH v2 6/6] powerpc: Implement user_access_begin and friends Christophe Leroy
2020-01-23 12:05 ` Michael Ellerman
2020-01-23 12:31 ` Michael Ellerman
2020-01-24 11:40 ` Christophe Leroy
[not found] ` <CAHk-=wgNQ-rWoLg0OCJYYYbKBnRAUK4NPU-OD+vv-6fWnd=8kA@mail.gmail.com>
2020-01-22 20:00 ` [PATCH v2 1/6] fs/readdir: Fix filldir() and filldir64() use of user_access_begin() Linus Torvalds
2020-01-22 20:15 ` Linus Torvalds
2020-01-22 20:37 ` Linus Torvalds
2020-01-23 6:27 ` Christophe Leroy
2020-01-23 11:56 ` Michael Ellerman
2020-01-23 12:00 ` Michael Ellerman
2020-01-23 12:43 ` Christophe Leroy
2020-01-23 18:38 ` Linus Torvalds
2020-01-24 10:42 ` Michael Ellerman
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