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Date:   Tue, 30 Jun 2020 10:41:28 +0200
From:   Borislav Petkov <bp@alien8.de>
To:     Sean Christopherson <sean.j.christopherson@intel.com>
Cc:     Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>, x86@kernel.org,
        linux-sgx@vger.kernel.org, linux-kernel@vger.kernel.org,
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        josh@joshtriplett.org, kai.huang@intel.com, kai.svahn@intel.com,
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        nhorman@redhat.com, npmccallum@redhat.com, puiterwijk@redhat.com,
        rientjes@google.com, tglx@linutronix.de, yaozhangx@google.com
Subject: Re: [PATCH v33 15/21] x86/vdso: Add support for exception fixup in
 vDSO functions
Message-ID: <20200630084128.GA1093@zn.tnic>
References: <20200617220844.57423-1-jarkko.sakkinen@linux.intel.com>
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 <20200629171022.GC32176@zn.tnic>
 <20200630060055.GS12312@linux.intel.com>
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On Mon, Jun 29, 2020 at 11:00:55PM -0700, Sean Christopherson wrote:
> E.g. the vDSO function should get the fixup even if userspace screws
> up mmap() and invokes __vdso_sgx_enter_enclave() without being tagged
> an SGX task.

I sincerely hope you don't mean this seriously.

Please add a member to task_struct which denotes that a task is an
sgx task, test that member where needed and forget real quickly about
running *any* *fixup* for unrelated tasks.

> No hard dependency, it's normal kernel code.  My reasoning for dropping it
> in .../vdso was largely to co-locate it with vdso/extable.h due to the
> dependency on the format of 'struct vdso_exception_table_entry'.

A struct which you defined instead of simply using struct
exception_table_entry even if it has a handler member which would remain
unused?

Let's not put code in vdso/ if it doesn't really belong there pls.

> Ya, shouldn't be a problem to stub it out for SGX=n.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette