Re: [PATCH v38 21/24] x86/vdso: Implement a vDSO for Intel SGX enclave call

[Jethro Beekman]

On 2020-09-25 03:00, Jarkko Sakkinen wrote:
> End result:
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-sgx.git/tree/arch/x86/include/uapi/asm/sgx.h
> 
> I'm wondering this sentence:
> 
> "The calling convention is custom and does not follow System V x86-64 ABI."
> 
> AFAIK, now the vDSO is fully C-callable but waiting for feedback before
> removing it.

It's C-callable *iff your enclave follows the System V x86-64 ABI*. In addition, all registers not clobbered by the SGX ISA are passed to the enclave, not just those specified as parameter passing registers in the ABI. This is intentional to make the vDSO function usable in applications that use the current flexibility of ENCLU.

--
Jethro Beekman | Fortanix

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