Messages in this thread | | | Subject | Re: [PATCH v28 21/22] x86/vdso: Implement a vDSO for Intel SGX enclave call | From | "Xing, Cedric" <> | Date | Tue, 17 Mar 2020 14:40:34 -0700 |
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Hi Nathaniel,
I reread your email today and thought I might have misunderstood your email earlier. What changes are you asking for exactly? Is that just passing @leaf in %ecx rather than in %eax? If so, I wouldn't have any problem. I agree with you that the resulted API would then be callable from C, even though it wouldn't be able to return back to C due to tampered %rbx. But I think the vDSO API can preserve %rbx too, given it is used by both EENTER and EEXIT (so is unavailable for parameter passing anyway). Alternatively, the C caller can setjmp() to be longjmp()'d back from within the exit handler.
-Cedric
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