Re: [PATCH v11 21/39] arm64/gcs: Ensure that new threads have a GCS

On Thu, Aug 22, 2024 at 02:15:24AM +0100, Mark Brown wrote:

@@ -512,10 +538,16 @@ static void gcs_thread_switch(struct task_struct *next) gcs_set_el0_mode(next); /*

• * Ensure that GCS changes are observable by/from other PEs in
  

• * case of migration.
  

• * Ensure that GCS memory effects of the 'prev' thread are
  

• * ordered before other memory accesses with release semantics
  

• * (or preceded by a DMB) on the current PE. In addition, any
  

• * memory accesses with acquire semantics (or succeeded by a
  

• * DMB) are ordered before GCS memory effects of the 'next'
  

• * thread. This will ensure that the GCS memory effects are
  

• * visible to other PEs in case of migration.
  

  */

• gcsb_dsync();

• if (task_gcs_el0_enabled(current) || task_gcs_el0_enabled(next))

• gcsb_dsync();
  

}

Ah, the comment turned up in this patch. It looks fine.

Reviewed-by: Catalin Marinas catalin.marinas@arm.com