On Tue, Jun 18, 2024 at 07:05:41PM +0200, Andrew Jones wrote: > On Tue, Jun 18, 2024 at 05:59:22PM GMT, Conor Dooley wrote: > > On Tue, Jun 18, 2024 at 06:01:04PM +0200, Andrew Jones wrote: > > > On Tue, Jun 18, 2024 at 03:48:59PM GMT, Clément Léger wrote: > > > > On 26/04/2024 12:08, Andrew Jones wrote: > > > > > > > > BTW, the spec also states that "When the TW (Timeout Wait) bit in > > > > mstatus is set and WRS.NTO is executed in any privilege mode other than > > > > M mode, and it does not complete within an implementation-specific > > > > bounded time limit, the WRS.NTO instruction will cause an illegal > > > > instruction exception." so I guess the process will be killed in this case ? > > > > > > We don't expect mstatus.TW to be set. If it is, then wfi would likely kill > > > the kernel before wrs.nto gets a chance to, but one or the other will > > > certainly ensure usermode never gets a chance to try it :-) > > > > > > We have a handful of these assumptions about how M-mode has configured > > > things prior to Linux starting. It'd be good if we documented them all > > > somewhere. > > > > Boot.rst :) If you're adding a new assumption, I think it should go > > there. > > It's an old assumption (wfi has been counting on it since the beginning of > time). But documenting it, along with anything else similar to it, in > boot.rst is a good idea. I've added that to my TODO. Misunderstanding of "new" I think, I meant new to documentation not just new to the kernel :)
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