From: Rongwei Wang <rongwei.wang@linux.alibaba.com>
To: Borislav Petkov <bp@alien8.de>
Cc: catalin.marinas@arm.com, Will Deacon <will@kernel.org>,
bjorn.andersson@linaro.org, shawnguo@kernel.org,
vkoul@kernel.org, geert+renesas@glider.be, Anson.Huang@nxp.com,
michael@walle.cc, krzk@kernel.org, olof@lixom.net,
vincenzo.frascino@arm.com, ardb@kernel.org, masahiroy@kernel.org,
gshan@redhat.com, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/3] arm64:msr: Add MSR driver
Date: Thu, 3 Dec 2020 10:09:36 +0800 [thread overview]
Message-ID: <F3E3ED35-F1E9-46ED-A7EC-FBF30D8DC45F@linux.alibaba.com> (raw)
In-Reply-To: <20201201152552.GD22927@zn.tnic>
> 2020年12月1日 下午11:25，Borislav Petkov <bp@alien8.de> 写道：
>
> On Tue, Dec 01, 2020 at 11:17:39PM +0800, Rongwei Wang wrote:
>> In ARM, the system registers can only be accessed through msr and mrs,
>> so the problem created by MSR driver (depend on rdmsr and wrmsr) in
>> x86 is not necessarily present in ARM, which is very different from
>> x86.
>
> No, the point I'm making is that it doesn't matter what the architecture
> does or does not, register *writes* from userspace are a bad bad idea
> for the reasons I described.
Sorry, I was away for two days and didn't reply in time.
In fact, we find MSR in the x86 architecture to be a particularly useful interface. It helped us a lot when we were doing some kernel debugging. So we consider implementing a similar feature in ARM.
So as a debugging tool, could it exist, e.g. if I change CONFIG_ARM64_MSR to CONFIG_ARM64_MSR_DEBUG or others. Do you think this adjustment is possible?
>
> --
> Regards/Gruss,
> Boris.
>
> https://people.kernel.org/tglx/notes-about-netiquette
Regards,
Rongwei Wang.
next prev parent reply other threads:[~2020-12-03 2:10 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-30 17:48 Rongwei Wang
2020-11-30 17:48 ` [PATCH 1/3] arm64:insn: Export symbols for MSR ARM driver Rongwei Wang
2020-11-30 17:48 ` [PATCH 2/3] arm64:msr: Introduce " Rongwei Wang
2020-11-30 17:48 ` [PATCH 3/3] arm64:msr: Enable " Rongwei Wang
2020-11-30 17:57 ` [PATCH 0/3] arm64:msr: Add MSR driver Will Deacon
2020-12-01 2:55 ` wangrongwei
2020-12-01 5:44 ` wangrongwei
2020-11-30 18:05 ` Marc Zyngier
2020-11-30 18:20 ` Randy Dunlap
2020-12-01 3:09 ` wangrongwei
2020-12-01 8:12 ` Marc Zyngier
2020-12-01 14:25 ` wangrongwei
2020-12-01 15:37 ` Marc Zyngier
2020-12-03 5:45 ` Rongwei Wang
2020-12-03 8:35 ` Marc Zyngier
2020-12-03 11:25 ` Rongwei Wang
2020-12-03 11:45 ` Marc Zyngier
2020-12-03 12:22 ` Rongwei Wang
2020-12-03 11:50 ` Mark Rutland
2020-11-30 19:03 ` Borislav Petkov
2020-12-01 3:44 ` wangrongwei
2020-12-01 11:26 ` Borislav Petkov
2020-12-01 14:33 ` wangrongwei
2020-12-01 14:54 ` Borislav Petkov
2020-12-01 15:17 ` Rongwei Wang
2020-12-01 15:25 ` Borislav Petkov
2020-12-03 2:09 ` Rongwei Wang [this message]
2020-12-01 15:26 ` Ard Biesheuvel
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