Messages in this thread | | | Subject | Re: [PATCH v40 19/24] x86/vdso: Implement a vDSO for Intel SGX enclave call | From | Dave Hansen <> | Date | Sun, 8 Nov 2020 12:30:27 -0800 |
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On 11/8/20 12:20 PM, Jethro Beekman wrote: >> The vDSO function calling convention uses the standard RDI RSI, RDX, RCX, >> R8 and R9 registers. This makes it possible to declare the vDSO as a C >> prototype, but other than that there is no specific support for SystemV >> ABI. Things like storing XSAVE are the responsibility of the enclave and >> the runtime. > I suppose this may be covered under "no specific support for SystemV > ABI" but with sgx_enclave_run.user_handler=NULL, R12~R15 *will* get > clobbered when __vdso_sgx_enter_enclave returns from an SGX AEX. IMO > this makes the whole "try to be like System V ABI" rather useless, > but I suppose it doesn't matter too much.
What?
It *says*: "there is no specific support for SystemV ABI." That's the point. It's a tiny *PART* of the ABI, used to "make it possible to declare the vDSO as a C prototype".
That's far from useless.
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