From: Yao Qi <qiyaoltc@gmail.com>
To: Dave Martin <Dave.Martin@arm.com>
Cc: linux-arm-kernel@lists.infradead.org,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Marc Zyngier <Marc.Zyngier@arm.com>,
Alan Hayward <alan.hayward@arm.com>,
Christoffer Dall <christoffer.dall@linaro.org>,
linux-arch@vger.kernel.org, libc-alpha@sourceware.org,
Florian Weimer <fweimer@redhat.com>,
Joseph Myers <joseph@codesourcery.com>,
Szabolcs Nagy <szabolcs.nagy@arm.com>,
Torvald Riegel <triegel@redhat.com>,
gdb@sourceware.org
Subject: Re: [RFC PATCH 08/10] arm64/sve: ptrace: Wire up vector length control and reporting
Date: Mon, 16 Jan 2017 12:20:38 +0000 [thread overview]
Message-ID: <20170116122038.GG28060@E107787-LIN> (raw)
In-Reply-To: <1484220369-23970-9-git-send-email-Dave.Martin@arm.com>
On 17-01-12 11:26:07, Dave Martin wrote:
> This patch adds support for manipulating a task's vector length at
> runtime via ptrace.
>
I hope kernel doesn't provide such interface to ptracer to change vector
length. The vector length is sort of a read-only property of thread/process/
program to debugger, unless we really have a clear requirement to modify
vector length in debugging. I may miss something because I haven't debug
SVE code yet.
> As a simplification, we turn the task back into an FPSIMD-only task
> when changing the vector length. If the register data is written
> too, we then turn the task back into an SVE task, with changed
> task_struct layout for the SVE data, before the actual data writing
> is done.
>
> Because the vector length is now variable, sve_get() now needs to
> return the real maximum for user_sve_header.max_vl, since .vl may
> be less than this (that's the whole point).
>
--
Yao (齐尧)
next prev parent reply other threads:[~2017-01-16 12:20 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-12 11:25 [RFC PATCH 00/10] arm64/sve: Add userspace vector length control API Dave Martin
2017-01-12 11:25 ` Dave Martin
2017-01-12 11:26 ` [RFC PATCH 01/10] prctl: Add skeleton for PR_SVE_{SET,GET}_VL controls Dave Martin
2017-01-12 11:26 ` Dave Martin
2017-01-12 11:26 ` [RFC PATCH 02/10] arm64/sve: Track vector length for each task Dave Martin
2017-01-12 11:26 ` Dave Martin
2017-01-12 11:26 ` [RFC PATCH 03/10] arm64/sve: Set CPU vector length to match current task Dave Martin
2017-01-12 11:26 ` Dave Martin
2017-01-12 11:26 ` [RFC PATCH 04/10] arm64/sve: Factor out clearing of tasks' SVE regs Dave Martin
2017-01-12 11:26 ` Dave Martin
2017-01-12 11:26 ` [RFC PATCH 05/10] arm64/sve: Wire up vector length control prctl() calls Dave Martin
2017-01-12 11:26 ` [RFC PATCH 06/10] arm64/sve: Disallow VL setting for individual threads by default Dave Martin
2017-01-16 11:34 ` Yao Qi
2017-01-16 11:34 ` Yao Qi
2017-01-16 12:23 ` Dave Martin
2017-01-12 11:26 ` [RFC PATCH 07/10] arm64/sve: Add vector length inheritance control Dave Martin
2017-01-16 12:27 ` Yao Qi
2017-01-16 13:34 ` Dave Martin
2017-01-12 11:26 ` [RFC PATCH 08/10] arm64/sve: ptrace: Wire up vector length control and reporting Dave Martin
2017-01-16 12:20 ` Yao Qi [this message]
2017-01-16 12:20 ` Yao Qi
2017-01-16 13:32 ` Dave Martin
2017-01-16 15:11 ` Yao Qi
2017-01-16 15:11 ` Yao Qi
2017-01-16 15:47 ` Pedro Alves
2017-01-16 16:31 ` Dave Martin
2017-01-16 16:31 ` Dave Martin
2017-01-17 10:03 ` Dave Martin
2017-01-17 10:03 ` Dave Martin
2017-01-17 13:31 ` Alan Hayward
2017-01-19 17:11 ` Dave Martin
2017-01-19 17:11 ` Dave Martin
2017-01-12 11:26 ` [RFC PATCH 09/10] arm64/sve: Enable default vector length control via procfs Dave Martin
2017-01-12 11:26 ` [RFC PATCH 10/10] Revert "arm64/sve: Limit vector length to 512 bits by default" Dave Martin
2017-01-12 11:26 ` Dave Martin
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