From: Catalin Marinas <catalin.marinas@arm.com>
To: Mark Rutland <mark.rutland@arm.com>
Cc: cmetcalf@ezchip.com, will.deacon@arm.com,
linux-kernel@vger.kernel.org, luto@amacapital.net,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/2] arm64: entry: remove pointless SPSR mode check
Date: Wed, 6 Jan 2016 12:15:25 +0000 [thread overview]
Message-ID: <20160106121524.GL6301@e104818-lin.cambridge.arm.com> (raw)
In-Reply-To: <1452015215-29506-1-git-send-email-mark.rutland@arm.com>
On Tue, Jan 05, 2016 at 05:33:34PM +0000, Mark Rutland wrote:
> In work_pending we may skip work if the stacked SPSR value represents
> anything other than an EL0 context. We then immediately invoke the
> kernel_exit 0 macro as part of ret_to_user, assuming a return to EL0.
> This is somewhat confusing.
>
> We use work_pending as part of the ret_to_user/ret_fast_syscall state
> machine. We only use ret_fast_syscall in the return from an SVC issued
> from EL0. We use ret_to_user for return from EL0 exception handlers and
> also for return from ret_from_fork in the case the task was not a kernel
> thread (i.e. it is a user task).
>
> Thus in all cases the stacked SPSR value must represent an EL0 context,
> and the check is redundant. This patch removes it, along with the now
> unused no_work_pending label.
>
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Chris Metcalf <cmetcalf@ezchip.com>
> Cc: Will Deacon <will.deacon@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
WARNING: multiple messages have this Message-ID (diff)
From: catalin.marinas@arm.com (Catalin Marinas)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/2] arm64: entry: remove pointless SPSR mode check
Date: Wed, 6 Jan 2016 12:15:25 +0000 [thread overview]
Message-ID: <20160106121524.GL6301@e104818-lin.cambridge.arm.com> (raw)
In-Reply-To: <1452015215-29506-1-git-send-email-mark.rutland@arm.com>
On Tue, Jan 05, 2016 at 05:33:34PM +0000, Mark Rutland wrote:
> In work_pending we may skip work if the stacked SPSR value represents
> anything other than an EL0 context. We then immediately invoke the
> kernel_exit 0 macro as part of ret_to_user, assuming a return to EL0.
> This is somewhat confusing.
>
> We use work_pending as part of the ret_to_user/ret_fast_syscall state
> machine. We only use ret_fast_syscall in the return from an SVC issued
> from EL0. We use ret_to_user for return from EL0 exception handlers and
> also for return from ret_from_fork in the case the task was not a kernel
> thread (i.e. it is a user task).
>
> Thus in all cases the stacked SPSR value must represent an EL0 context,
> and the check is redundant. This patch removes it, along with the now
> unused no_work_pending label.
>
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Chris Metcalf <cmetcalf@ezchip.com>
> Cc: Will Deacon <will.deacon@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
next prev parent reply other threads:[~2016-01-06 12:15 UTC|newest]
Thread overview: 92+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-04 19:34 [PATCH v9 00/13] support "task_isolation" mode for nohz_full Chris Metcalf
2016-01-04 19:34 ` Chris Metcalf
2016-01-04 19:34 ` [PATCH v9 01/13] vmstat: provide a function to quiet down the diff processing Chris Metcalf
2016-01-04 19:34 ` [PATCH v9 02/13] vmstat: add vmstat_idle function Chris Metcalf
2016-01-04 19:34 ` [PATCH v9 03/13] lru_add_drain_all: factor out lru_add_drain_needed Chris Metcalf
2016-01-04 19:34 ` Chris Metcalf
2016-01-04 19:34 ` [PATCH v9 04/13] task_isolation: add initial support Chris Metcalf
2016-01-04 19:34 ` Chris Metcalf
2016-01-19 15:42 ` Frederic Weisbecker
2016-01-19 20:45 ` Chris Metcalf
2016-01-19 20:45 ` Chris Metcalf
2016-01-28 0:28 ` Frederic Weisbecker
2016-01-29 18:18 ` Chris Metcalf
2016-01-29 18:18 ` Chris Metcalf
2016-01-30 21:11 ` Frederic Weisbecker
2016-01-30 21:11 ` Frederic Weisbecker
2016-02-11 19:24 ` Chris Metcalf
2016-02-11 19:24 ` Chris Metcalf
2016-03-04 12:56 ` Frederic Weisbecker
2016-03-09 19:39 ` Chris Metcalf
2016-03-09 19:39 ` Chris Metcalf
2016-04-08 13:56 ` Frederic Weisbecker
2016-04-08 16:34 ` Chris Metcalf
2016-04-08 16:34 ` Chris Metcalf
2016-04-12 18:41 ` Chris Metcalf
2016-04-12 18:41 ` Chris Metcalf
2016-04-22 13:16 ` Frederic Weisbecker
2016-04-25 20:36 ` Chris Metcalf
2016-04-25 20:36 ` Chris Metcalf
2016-05-26 1:07 ` Frederic Weisbecker
2016-06-03 19:32 ` Chris Metcalf
2016-06-03 19:32 ` Chris Metcalf
2016-06-29 15:18 ` Frederic Weisbecker
2016-07-01 20:59 ` Chris Metcalf
2016-07-01 20:59 ` Chris Metcalf
2016-07-05 14:41 ` Frederic Weisbecker
2016-07-05 14:41 ` Frederic Weisbecker
2016-07-05 17:47 ` Christoph Lameter
2016-01-04 19:34 ` [PATCH v9 05/13] task_isolation: support PR_TASK_ISOLATION_STRICT mode Chris Metcalf
2016-01-04 19:34 ` Chris Metcalf
2016-01-04 19:34 ` [PATCH v9 06/13] task_isolation: add debug boot flag Chris Metcalf
2016-01-04 22:52 ` Steven Rostedt
2016-01-04 23:42 ` Chris Metcalf
2016-01-05 13:42 ` Steven Rostedt
2016-01-04 19:34 ` [PATCH v9 07/13] arch/x86: enable task isolation functionality Chris Metcalf
2016-01-04 21:02 ` [PATCH v9bis " Chris Metcalf
2016-01-04 19:34 ` [PATCH v9 08/13] arch/arm64: adopt prepare_exit_to_usermode() model from x86 Chris Metcalf
2016-01-04 19:34 ` Chris Metcalf
2016-01-04 20:33 ` Mark Rutland
2016-01-04 20:33 ` Mark Rutland
2016-01-04 21:01 ` Chris Metcalf
2016-01-04 21:01 ` Chris Metcalf
2016-01-05 17:21 ` Mark Rutland
2016-01-05 17:21 ` Mark Rutland
2016-01-05 17:33 ` [PATCH 1/2] arm64: entry: remove pointless SPSR mode check Mark Rutland
2016-01-05 17:33 ` Mark Rutland
2016-01-06 12:15 ` Catalin Marinas [this message]
2016-01-06 12:15 ` Catalin Marinas
2016-01-05 17:33 ` [PATCH 2/2] arm64: factor work_pending state machine to C Mark Rutland
2016-01-05 17:33 ` Mark Rutland
2016-01-05 18:53 ` Chris Metcalf
2016-01-05 18:53 ` Chris Metcalf
2016-01-06 12:30 ` Catalin Marinas
2016-01-06 12:30 ` Catalin Marinas
2016-01-06 12:47 ` Mark Rutland
2016-01-06 12:47 ` Mark Rutland
2016-01-06 13:43 ` Mark Rutland
2016-01-06 13:43 ` Mark Rutland
2016-01-06 14:17 ` Catalin Marinas
2016-01-06 14:17 ` Catalin Marinas
2016-01-04 22:31 ` [PATCH v9 08/13] arch/arm64: adopt prepare_exit_to_usermode() model from x86 Andy Lutomirski
2016-01-04 22:31 ` Andy Lutomirski
2016-01-05 18:01 ` Mark Rutland
2016-01-05 18:01 ` Mark Rutland
2016-01-04 19:34 ` [PATCH v9 09/13] arch/arm64: enable task isolation functionality Chris Metcalf
2016-01-04 19:34 ` Chris Metcalf
2016-01-04 19:34 ` [PATCH v9 10/13] arch/tile: adopt prepare_exit_to_usermode() model from x86 Chris Metcalf
2016-01-04 19:34 ` [PATCH v9 11/13] arch/tile: move user_exit() to early kernel entry sequence Chris Metcalf
2016-01-04 19:34 ` [PATCH v9 12/13] arch/tile: enable task isolation functionality Chris Metcalf
2016-01-04 19:34 ` [PATCH v9 13/13] arm, tile: turn off timer tick for oneshot_stopped state Chris Metcalf
2016-01-11 21:15 ` [PATCH v9 00/13] support "task_isolation" mode for nohz_full Chris Metcalf
2016-01-11 21:15 ` Chris Metcalf
2016-01-12 10:07 ` Will Deacon
2016-01-12 17:49 ` Chris Metcalf
2016-01-12 17:49 ` Chris Metcalf
2016-01-13 10:44 ` Ingo Molnar
2016-01-13 10:44 ` Ingo Molnar
2016-01-13 21:19 ` Chris Metcalf
2016-01-13 21:19 ` Chris Metcalf
2016-01-20 13:27 ` Mark Rutland
2016-01-12 10:53 ` Ingo Molnar
2016-01-12 10:53 ` Ingo Molnar
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20160106121524.GL6301@e104818-lin.cambridge.arm.com \
--to=catalin.marinas@arm.com \
--cc=cmetcalf@ezchip.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@amacapital.net \
--cc=mark.rutland@arm.com \
--cc=will.deacon@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.