From: Pedro Alves <palves@redhat.com>
To: Yao Qi <qiyaoltc@gmail.com>, Dave Martin <Dave.Martin@arm.com>
Cc: linux-arch@vger.kernel.org, Florian Weimer <fweimer@redhat.com>,
libc-alpha@sourceware.org,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Marc Zyngier <Marc.Zyngier@arm.com>,
gdb@sourceware.org, Joseph Myers <joseph@codesourcery.com>,
Szabolcs Nagy <szabolcs.nagy@arm.com>,
linux-arm-kernel@lists.infradead.org,
Alan Hayward <alan.hayward@arm.com>,
Torvald Riegel <triegel@redhat.com>,
Christoffer Dall <christoffer.dall@linaro.org>
Subject: Re: [RFC PATCH 08/10] arm64/sve: ptrace: Wire up vector length control and reporting
Date: Mon, 16 Jan 2017 15:47:55 +0000 [thread overview]
Message-ID: <a7261d6b-0074-7345-d380-ef0dd335dd56@redhat.com> (raw)
In-Reply-To: <20170116151156.GI28060@E107787-LIN>
On 01/16/2017 03:11 PM, Yao Qi wrote:
>
>> >
>> > gdb must already re-detect the vector length on stop, since the target
>> > could have called the prctl() in the meantime.
> Yes, gdb assumes the vector length may be changed, so it re-detects on
> every stop, but I don't see the need for gdb to change the vector length.
>
Do we need to consider inferior function calls here?
Say the program is stopped in code that assumes "vector length N", and
the user does "print some_function_that_assumes_some_other_vector_length ()".
Is that a use case we need to cover?
If so, to make it work correctly, the debugger needs to be able to change the
vector length to the length assumed by that called function, and then
restore it back after the call completes (or is aborted).
I have no idea whether the debugger will be able to figure
out a function's assumed vector length from debug info or some such.
Thanks,
Pedro Alves
next prev parent reply other threads:[~2017-01-16 15:48 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
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 [this message]
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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