From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sean Christopherson To: Andy Lutomirski CC: Andy Lutomirski , Jann Horn , "Hansen, Dave" , Linus Torvalds , Rich Felker , Dave Hansen , Jethro Beekman , Jarkko Sakkinen , Florian Weimer , Linux API , X86 ML , linux-arch , LKML , Peter Zijlstra , "nhorman@redhat.com" , "npmccallum@redhat.com" , "Ayoun, Serge" , "Katz-zamir, Shay" , "linux-sgx@vger.kernel.org" , Andy Shevchenko , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Carlos O'Donell , "adhemerval.zanella@linaro.org" Subject: Re: RFC: userspace exception fixups Sender: "linux-kernel-owner@vger.kernel.org" Date: Tue, 6 Nov 2018 09:19:10 -0800 Message-ID: <1541524750.7839.51.camel@intel.com> References: <20181102163034.GB7393@linux.intel.com> <7050972d-a874-dc08-3214-93e81181da60@intel.com> <20181102170627.GD7393@linux.intel.com> <20181102173350.GF7393@linux.intel.com> <20181102182712.GG7393@linux.intel.com> <20181102220437.GI7393@linux.intel.com> <1541518670.7839.31.camel@intel.com> In-Reply-To: Content-Type: text/plain; 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d="scan'208";a="106372057" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.154]) by orsmga002.jf.intel.com with ESMTP; 06 Nov 2018 09:19:10 -0800 Message-ID: <1541524750.7839.51.camel@intel.com> Subject: Re: RFC: userspace exception fixups From: Sean Christopherson To: Andy Lutomirski Cc: Andy Lutomirski , Jann Horn , Dave Hansen , Linus Torvalds , Rich Felker , Dave Hansen , Jethro Beekman , Jarkko Sakkinen , Florian Weimer , Linux API , X86 ML , linux-arch , LKML , Peter Zijlstra , nhorman@redhat.com, npmccallum@redhat.com, "Ayoun, Serge" , shay.katz-zamir@intel.com, linux-sgx@vger.kernel.org, Andy Shevchenko , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Carlos O'Donell , adhemerval.zanella@linaro.org Date: Tue, 06 Nov 2018 09:19:10 -0800 In-Reply-To: References: <20181102163034.GB7393@linux.intel.com> <7050972d-a874-dc08-3214-93e81181da60@intel.com> <20181102170627.GD7393@linux.intel.com> <20181102173350.GF7393@linux.intel.com> <20181102182712.GG7393@linux.intel.com> <20181102220437.GI7393@linux.intel.com> <1541518670.7839.31.camel@intel.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.18.5.2-0ubuntu3.2 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-sgx-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org Message-ID: <20181106171910.0X0v9oupqbXwIHS0NH3xYaIZSL47g3XLG8hu9CfRjJM@z> On Tue, 2018-11-06 at 08:57 -0800, Andy Lutomirski wrote: > > So I guess the non-enclave code basically can’t trust its stack pointer > because of these shenanigans. And the AEP code has to live with the fact > that its RSP is basically arbitrary and probably can’t even be unwound > by a debugger? The SDK provides a Python GDB plugin to hook into the out-call flow and do more stack shenanigans.  From what I can tell it's fudging the stack to make it look like a normal stack frame so the debugger can do it's thing. > And the EENTER code has to deal with the fact that its red zone can be > blatantly violated by the enclave? That's my understanding of things.  So yeah, if it wasn't obvious before, the trusted and untrusted parts of the SDK are very tightly coupled.