Messages in this thread |  | | Date | Sun, 9 Oct 2016 10:49:05 -0600 | From | Jason Gunthorpe <> | Subject | Re: [PATCH RFC 1/3] tpm_crb: expand struct crb_control_area to struct crb_regs |
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On Sun, Oct 09, 2016 at 12:38:18PM +0300, Jarkko Sakkinen wrote: > On Sat, Oct 08, 2016 at 07:42:56PM -0600, Jason Gunthorpe wrote: > > On Sun, Oct 09, 2016 at 03:15:09AM +0300, Jarkko Sakkinen wrote: > > > + ctrl = crb_map_res(dev, priv, &io_res, buf->control_address, > > > + sizeof(struct crb_regs) - > > > + offsetof(struct crb_regs, ctrl_req)); > > > + if (IS_ERR(ctrl)) > > > + return PTR_ERR(ctrl); > > > + > > > + /* The control area always overrlaps IO memory mapped from the ACPI > > > + * object with CRB start only devices. Thus, this is perfectly safe. > > > + */ > > > + priv->regs = (void *)((unsigned long)ctrl - > > > + offsetof(struct crb_regs, ctrl_req)); > > > > Hum. No, this makes bad assumptions about the structure of iomapping. > > > > The map itself needs to be done with the adjustment: > > > > ctrl = crb_map_res(dev, priv, &io_res, buf->control_address - > > offsetof(struct crb_regs, ctrl_req), > > sizeof(struct crb_regs)); > > That would be wrong address for the control area as it does not start > from the beginning of CRB registers.
Of course, I just pointed out what the map call should look like
Something like this
priv->regs = crb_map_res(dev, priv, &io_res, buf->control_address - offsetof(struct crb_regs, ctrl_req), sizeof(struct crb_regs)); ctrl = &priv->regs.ctrl_req;
> I think the crb_map_io and crb_map_res are too generic. Better way to do > things would be to validate that assumptions for these two cases hold.
If the driver is going to be using a negative offset like this, then it very much should validate the assumptions before doing it.
and not even map these regsiters if they are not supported by hardware.
Jason
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