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SubjectRe: [PATCH v2 1/2] selftests/sgx: Use rip relative addressing for encl_stack
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On 3/30/2022 12:03 PM, Jarkko Sakkinen wrote:
> On Wed, 2022-03-30 at 10:40 -0700, Reinette Chatre wrote:
>> Could you please elaborate how the compiler will fix it up?
>
> Sure.
>
> Here's the disassembly of the RBX version:
>
> [0x000021a9]> pi 1
> lea rax, [rbx + loc.encl_stack]
>
> Here's the same with s/RBX/RIP/:
>
> [0x000021a9]> pi 5
> lea rax, loc.encl_stack
>
> Compiler will substitute correct offset relative to the RIP,
> well, because it can and it makes sense.

It does not make sense to me because, as proven with my test,
the two threads end up sharing the same stack memory.

Reinette

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