Re: [PATCH v3 05/25] arm64: context switch POR_EL0 register

On Fri, Nov 24, 2023 at 04:34:50PM +0000, Joey Gouly wrote:

@@ -498,6 +508,17 @@ static void erratum_1418040_new_exec(void) preempt_enable(); } +static void permission_overlay_switch(struct task_struct *next) +{

• if (system_supports_poe()) {

• current->thread.por_el0 = read_sysreg_s(SYS_POR_EL0);
  

• if (current->thread.por_el0 != next->thread.por_el0) {
  

• 	write_sysreg_s(next->thread.por_el0, SYS_POR_EL0);
  

• 	isb();
  

• }
  

• }

Nitpick: use "if (!system_supports_poe()) return;" to avoid too much indentation.

W.r.t. the isb(), I think we accumulated quite a lot on this path. It might be worth going through them and having one at the end, where possible.