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>
next prev parent reply other threads:[~2016-01-06 12:15 UTC|newest]
Thread overview: 57+ 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 ` [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 ` [PATCH v9 04/13] task_isolation: add initial support Chris Metcalf
2016-01-19 15:42 ` Frederic Weisbecker
2016-01-19 20:45 ` Chris Metcalf
2016-01-28 0:28 ` Frederic Weisbecker
2016-01-29 18:18 ` Chris Metcalf
2016-01-30 21:11 ` Frederic Weisbecker
2016-02-11 19:24 ` Chris Metcalf
2016-03-04 12:56 ` Frederic Weisbecker
2016-03-09 19:39 ` Chris Metcalf
2016-04-08 13:56 ` Frederic Weisbecker
2016-04-08 16:34 ` Chris Metcalf
2016-04-12 18:41 ` Chris Metcalf
2016-04-22 13:16 ` Frederic Weisbecker
2016-04-25 20:36 ` Chris Metcalf
2016-05-26 1:07 ` Frederic Weisbecker
2016-06-03 19:32 ` Chris Metcalf
2016-06-29 15:18 ` Frederic Weisbecker
2016-07-01 20:59 ` Chris Metcalf
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 ` [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 20:33 ` Mark Rutland
2016-01-04 21:01 ` Chris Metcalf
2016-01-05 17:21 ` Mark Rutland
2016-01-05 17:33 ` [PATCH 1/2] arm64: entry: remove pointless SPSR mode check Mark Rutland
2016-01-06 12:15 ` Catalin Marinas [this message]
2016-01-05 17:33 ` [PATCH 2/2] arm64: factor work_pending state machine to C Mark Rutland
2016-01-05 18:53 ` Chris Metcalf
2016-01-06 12:30 ` Catalin Marinas
2016-01-06 12:47 ` Mark Rutland
2016-01-06 13:43 ` Mark Rutland
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
2016-01-05 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 ` [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
2016-01-12 10:07 ` Will Deacon
2016-01-12 17:49 ` Chris Metcalf
2016-01-13 10:44 ` Ingo Molnar
2016-01-13 21:19 ` Chris Metcalf
2016-01-20 13:27 ` Mark Rutland
2016-01-12 10:53 ` Ingo Molnar
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