From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Nathaniel McCallum <npmccallum@redhat.com>,
Cedric Xing <cedric.xing@intel.com>,
Jethro Beekman <jethro@fortanix.com>,
Andy Lutomirski <luto@amacapital.net>,
linux-sgx@vger.kernel.org
Subject: Re: [PATCH for_v29 2/8] x86/sgx: vdso: Make the %rsp fixup on return from handler relative
Date: Fri, 20 Mar 2020 04:39:47 +0200 [thread overview]
Message-ID: <20200320023947.GD183331@linux.intel.com> (raw)
In-Reply-To: <20200319011130.8556-3-sean.j.christopherson@intel.com>
On Wed, Mar 18, 2020 at 06:11:24PM -0700, Sean Christopherson wrote:
> Modify the %rsp fixup after returning from the exit handler to be
> relative instead of absolute to avoid clobbering any %rsp adjustments
> made by the exit handler, e.g. if the exit handler modifies the stack
> prior to re-entering the enclave.
>
> Reported-by: Nathaniel McCallum <npmccallum@redhat.com>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> ---
>
> I'm on the fence as to whether or not this is a good idea. It's not super
> painful, but it's not exactly standard/obvious code. Part of me thinks
> its a bug to not let the exit handler manipulate %rsp, the other part of
> me thinks it's straight up crazy :-)
After some hours of processing this, I think this makes sense.
It makes the interface more robust. This is not printf().
/Jarkko
next prev parent reply other threads:[~2020-03-20 2:39 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-19 1:11 [PATCH for_v29 0/8] x86/sgx: Make vDSO callable from C Sean Christopherson
2020-03-19 1:11 ` [PATCH for_v29 1/8] x86/sgx: vdso: Remove an incorrect statement the enter enclave comment Sean Christopherson
2020-03-19 20:49 ` Jarkko Sakkinen
2020-03-19 1:11 ` [PATCH for_v29 2/8] x86/sgx: vdso: Make the %rsp fixup on return from handler relative Sean Christopherson
2020-03-20 2:39 ` Jarkko Sakkinen [this message]
2020-03-20 2:42 ` Jarkko Sakkinen
2020-03-19 1:11 ` [PATCH for_v29 3/8] x86/sgx: vdso: Make __vdso_sgx_enter_enclave() callable from C code Sean Christopherson
2020-03-19 20:03 ` Xing, Cedric
2020-03-19 20:11 ` Sean Christopherson
2020-03-20 3:07 ` Jarkko Sakkinen
2020-03-20 23:26 ` Sean Christopherson
2020-03-21 0:57 ` Jarkko Sakkinen
2020-03-19 1:11 ` [PATCH for_v29 4/8] x86/sgx: vdso: Define a typedef for __vdso_sgx_enter_enclave Sean Christopherson
2020-03-19 1:11 ` [PATCH for_v29 5/8] selftests/x86: sgx: Zero out @result before invoking vDSO sub-test Sean Christopherson
2020-03-19 1:11 ` [PATCH for_v29 6/8] selftests/x86: sgx: Pass EENTER to vDSO wrapper instead of hardcoding Sean Christopherson
2020-03-19 1:11 ` [PATCH for_v29 7/8] selftests/x86: sgx: Stop clobbering non-volatile registers Sean Christopherson
2020-03-19 1:11 ` [PATCH for_v29 8/8] selftests/x86: Add selftest to invoke __vsgx_enter_enclave() from C Sean Christopherson
2020-03-20 0:57 ` [PATCH for_v29 0/8] x86/sgx: Make vDSO callable " Jarkko Sakkinen
2020-03-20 23:25 ` Sean Christopherson
2020-03-21 0:55 ` Jarkko Sakkinen
2020-03-21 20:11 ` Sean Christopherson
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