On Tue, Jun 19, 2018 at 03:32:45PM +0100, Catalin Marinas wrote:
> 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).
Yes. This replaces the _TIF_SYSCALL_WORK check from ret_fast_syscall,
leaving the _TIF_WORK_MASK check to the usual ret_to_user path.
> Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Thanks!
Mark.
