Re: [PATCH v5 06/30] arm64: context switch POR_EL0 register

On Wed, Sep 04, 2024 at 11:22:54AM +0100, Will Deacon wrote:

On Tue, Sep 03, 2024 at 03:54:13PM +0100, Joey Gouly wrote:

...

commit 3141fb86bee8d48ae47cab1594dad54f974a8899 Author: Joey Gouly joey.gouly@arm.com Date: Tue Sep 3 15:47:26 2024 +0100

fixup! arm64: context switch POR_EL0 register

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index a3a61ecdb165..c224b0955f1a 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -515,11 +515,8 @@ static void permission_overlay_switch(struct task_struct *next) return;

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

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

•   if (current->thread.por_el0 != next->thread.por_el0)
            write_sysreg_s(next->thread.por_el0, SYS_POR_EL0);
  

•           /* ISB required for kernel uaccess routines when chaning POR_EL0 */
  

•           isb();
  

•   }
  

}

What about the one in flush_poe()? I'm inclined to drop that as well.

Yes, that's a similar thing.