Re: [PATCH v4 07/36] arm64/gcs: Provide copy_to_user_gcs()

On Mon, Aug 07, 2023 at 11:00:12PM +0100, Mark Brown wrote:

+static inline int copy_to_user_gcs(unsigned long __user *addr,

• 		   unsigned long *val,
  

• 		   int count)
  

+{

• int ret = -EFAULT;
• int i;
• if (access_ok((char __user *)addr, count * sizeof(u64))) {

• uaccess_ttbr0_enable();
  

• for (i = 0; i < count; i++) {
  

• 	ret = gcssttr(addr++, *val++);
  

• 	if (ret != 0)
  

• 		break;
  

• }
  

• uaccess_ttbr0_disable();
  

• }
• return ret;

+}

I think it makes more sense to have a put_user_gcs() of a single element. I've only seen it used with 2 elements in the signal code but we could as well do two put_user_gcs() calls (as we do for other stuff that we push to the signal frame).