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>,
Oleg Nesterov <oleg@redhat.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
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 10:23:29 +0100 [thread overview]
Message-ID: <20200601092329.GX5031@arm.com> (raw)
In-Reply-To: <CABV8kRwhsPhhqUXS46Rwh-xDEDY2q=KSd-xz1W-pu4Gy4KVp8Q@mail.gmail.com>
On Sun, May 31, 2020 at 12:20:51PM -0400, Keno Fischer wrote:
> > Can't PTRACE_SYSEMU be emulated by using PTRACE_SYSCALL, cancelling the
> > syscall at the syscall enter stop, then modifying the regs at the
> > syscall exit stop?
>
> Yes, it can. The idea behind SYSEMU is to be able to save half the
> ptrace traps that would require, in theory making the ptracer
> a decent amount faster. That said, the x7 issue is orthogonal to
> SYSEMU, you'd have the same issues if you used PTRACE_SYSCALL.
Right, I just wondered whether there was some deeper difference between
the two approaches.
Cheers
---Dave
next prev parent reply other threads:[~2020-06-01 9:23 UTC|newest]
Thread overview: 17+ 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 8:15 ` Will Deacon
2020-05-19 8:37 ` Keno Fischer
2020-05-20 17:41 ` Will Deacon
2020-05-23 5:35 ` Keno Fischer
2020-05-24 6:56 ` Keno Fischer
2020-05-27 9:55 ` Will Deacon
2020-05-27 10:19 ` Dave Martin
2020-05-31 9:33 ` Will Deacon
2020-05-31 16:13 ` Keno Fischer
2020-06-01 9:14 ` Dave Martin
2020-06-01 9:23 ` Keno Fischer
2020-06-01 9:52 ` Dave Martin
2020-05-31 16:20 ` Keno Fischer
2020-06-01 9:23 ` Dave Martin [this message]
2020-06-01 9:40 ` Keno Fischer
2020-06-01 9:59 ` Dave Martin
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