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Date:   Thu, 11 Jul 2019 01:46:28 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To:     "Xing, Cedric" <cedric.xing@intel.com>
Cc:     linux-kernel@vger.kernel.org, linux-sgx@vger.kernel.org,
        akpm@linux-foundation.org, dave.hansen@intel.com,
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        shay.katz-zamir@intel.com, haitao.huang@intel.com,
        kai.svahn@intel.com, kai.huang@intel.com
Subject: Re: [RFC PATCH v2 0/3] An alternative __vdso_sgx_enter_enclave() to
 allow enclave/host parameter passing using untrusted stack
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On Wed, Jul 10, 2019 at 11:08:37AM -0700, Xing, Cedric wrote:
> > With these conclusions I think the current vDSO API is sufficient for
> > Linux.
> 
> The new vDSO API is to support data exchange on stack. It has nothing to do
> with debugging. BTW, the community has closed on this.

And how that is useful?

> The CFI directives are for stack unwinding. They don't affect what the code
> does so you can just treat them as NOPs if you don't understand what they
> do. However, they are useful to not only debuggers but also exception
> handling code. libunwind also has a setjmp()/longjmp() implementation based
> on CFI directives.

Of course I won't merge code of which usefulness I don't understand.

/Jarkko