# Re: \[PATCH v22 8/8\] x86/vdso: Add ENDBR64 to \_\_vdso\_sgx\_enter\_enclave

- From: Jarkko Sakkinen \<jarkko@kernel.org\>
- Date: 2021-03-12 16:57:44 
- List: linux-doc
- Page: https://ratatoskr.run/linux-doc/2021/03/6298646
- Thread: https://ratatoskr.run/linux-doc/2021/03/6295910/t.md

```text
On Thu, Mar 11, 2021 at 09:42:05AM +0100, Peter Zijlstra wrote:
> On Thu, Mar 11, 2021 at 05:36:06AM +0200, Jarkko Sakkinen wrote:
> > Does it do any harm to put it there unconditionally?
> 
> Blows up your text footprint and I$ pressure. These instructions are 4
> bytes each.
> 
> Aside from that, they're a NOP, so only consume front-end resources
> (hopefully) on older CPUs and when IBT is disabled.

OK, understood, thanks for the explanation.

/Jarkko
```