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. > .. and nothing actually proves that control_address follows anything > in the driver, so this seems like a terrifying blind assumption, but > everything about the iomap in this ACPI binding seems totally bonkers > so that is in good company I guess. There are basically two kinds of CRB devices in the wild: 1. ACPI start devices that use DMA 2. CRB MMIO devices For 1 you always iomap control area. For 2 the ACPI object given buffer covers the control area. 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. > .. and the comment says this only holds for 'crb start only' devices, > but the code doesn't actually act differently based on what sort of > device we have.. > > Your commit message also seems to imply the new registers are only on > newer hardware, but nothing seems to check for that before acessing > them? Confusing. That's why there's this thing called RFC :) > Jason /Jarkko ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ tpmdd-devel mailing list tpmdd-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/tpmdd-devel
