From: Dave Martin <Dave.Martin@arm.com>
To: Keno Fischer <keno@juliacomputing.com>
Cc: Kyle Huey <khuey@pernos.co>,
Catalin Marinas <catalin.marinas@arm.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Oleg Nesterov <oleg@redhat.com>, Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: Re: arm64: Register modification during syscall entry/exit stop
Date: Mon, 1 Jun 2020 10:14:41 +0100 [thread overview]
Message-ID: <20200601091441.GW5031@arm.com> (raw)
In-Reply-To: <CABV8kRyHo+EAWaMUzGA220z=HJRBCpH6UWiYGb84uSL3h8HQHw@mail.gmail.com>
On Sun, May 31, 2020 at 12:13:18PM -0400, Keno Fischer wrote:
> > Keno -- are you planning to send out a patch? You previously spoke about
> > implementing this using PTRACE_SETOPTIONS.
>
> Yes, I'll have a patch for you. Though I've come to the conclusion
> that introducing a new regset is probably a better way to solve it.
> We can then also expose orig_x0 at the same time and give it sane semantics
> (there's some problems with the way it works currently - I'll write it up
> together with the patch).
I'd worry that having a new ptrace option would be useless bug-
compatibility that is just going to bitrot.
Can you explain why userspace would write a changed value for x7
but at the same time need that new to be thrown away?
That sounds like a nonsensical thing for userspace to be doing.
Cheers
---Dave
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WARNING: multiple messages have this Message-ID (diff)
From: Dave Martin <Dave.Martin@arm.com>
To: Keno Fischer <keno@juliacomputing.com>
Cc: Will Deacon <will@kernel.org>, Kyle Huey <khuey@pernos.co>,
Catalin Marinas <catalin.marinas@arm.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Oleg Nesterov <oleg@redhat.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: arm64: Register modification during syscall entry/exit stop
Date: Mon, 1 Jun 2020 10:14:41 +0100 [thread overview]
Message-ID: <20200601091441.GW5031@arm.com> (raw)
In-Reply-To: <CABV8kRyHo+EAWaMUzGA220z=HJRBCpH6UWiYGb84uSL3h8HQHw@mail.gmail.com>
On Sun, May 31, 2020 at 12:13:18PM -0400, Keno Fischer wrote:
> > Keno -- are you planning to send out a patch? You previously spoke about
> > implementing this using PTRACE_SETOPTIONS.
>
> Yes, I'll have a patch for you. Though I've come to the conclusion
> that introducing a new regset is probably a better way to solve it.
> We can then also expose orig_x0 at the same time and give it sane semantics
> (there's some problems with the way it works currently - I'll write it up
> together with the patch).
I'd worry that having a new ptrace option would be useless bug-
compatibility that is just going to bitrot.
Can you explain why userspace would write a changed value for x7
but at the same time need that new to be thrown away?
That sounds like a nonsensical thing for userspace to be doing.
Cheers
---Dave
next prev parent reply other threads:[~2020-06-01 9:14 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-19 1:05 arm64: Register modification during syscall entry/exit stop Keno Fischer
2020-05-19 1:05 ` Keno Fischer
2020-05-19 8:15 ` Will Deacon
2020-05-19 8:15 ` Will Deacon
2020-05-19 8:37 ` Keno Fischer
2020-05-19 8:37 ` Keno Fischer
2020-05-20 17:41 ` Will Deacon
2020-05-20 17:41 ` Will Deacon
2020-05-23 5:35 ` Keno Fischer
2020-05-23 5:35 ` Keno Fischer
2020-05-24 6:56 ` Keno Fischer
2020-05-24 6:56 ` Keno Fischer
2020-05-27 9:55 ` Will Deacon
2020-05-27 9:55 ` Will Deacon
2020-05-27 10:19 ` Dave Martin
2020-05-27 10:19 ` Dave Martin
2020-05-31 9:33 ` Will Deacon
2020-05-31 9:33 ` Will Deacon
2020-05-31 16:13 ` Keno Fischer
2020-05-31 16:13 ` Keno Fischer
2020-06-01 9:14 ` Dave Martin [this message]
2020-06-01 9:14 ` Dave Martin
2020-06-01 9:23 ` Keno Fischer
2020-06-01 9:23 ` Keno Fischer
2020-06-01 9:52 ` Dave Martin
2020-06-01 9:52 ` Dave Martin
2020-05-31 16:20 ` Keno Fischer
2020-05-31 16:20 ` Keno Fischer
2020-06-01 9:23 ` Dave Martin
2020-06-01 9:23 ` Dave Martin
2020-06-01 9:40 ` Keno Fischer
2020-06-01 9:40 ` Keno Fischer
2020-06-01 9:59 ` Dave Martin
2020-06-01 9:59 ` Dave Martin
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