Re: [PATCH v22 8/8] x86/vdso: Add ENDBR64 to __vdso_sgx_enter_enclave

From: Peter Zijlstra
Date: Thu Mar 11 2021 - 03:44:01 EST


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.