On Mon, Jun 18, 2018 at 01:03:00PM +0100, Mark Rutland wrote:
> +asmlinkage void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr,
> + syscall_fn_t syscall_table[])
> +{
> + unsigned long flags = current_thread_info()->flags;
> +
> + regs->orig_x0 = regs->regs[0];
> + regs->syscallno = scno;
> +
> + local_daif_restore(DAIF_PROCCTX);
> + user_exit();
> +
> + if (has_syscall_work(flags)) {
> + /* set default errno for user-issued syscall(-1) */
> + if (scno == NO_SYSCALL)
> + regs->regs[0] = -ENOSYS;
> + scno = syscall_trace_enter(regs);
> + if (scno == NO_SYSCALL)
> + goto trace_exit;
> + }
> +
> + invoke_syscall(regs, scno, sc_nr, syscall_table);
> +
> + /*
> + * The tracing status may have changed under our feet, so we have to
> + * check again. However, if we were tracing entry, then we always trace
> + * exit regardless, as the old entry assembly did.
> + */
> + if (!has_syscall_work(flags)) {
> + local_daif_mask();
> + flags = current_thread_info()->flags;
> + if (!has_syscall_work(flags))
> + return;
> + local_daif_restore(DAIF_PROCCTX);
> + }
IIUC the above 'if' block replaces ret_fast_syscall in entry.S with the
work_pending handled via ret_to_user (we used to check _TIF_WORK_MASK in
two places).
Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
