On Tue, Nov 18, 2014 at 4:11 PM, Grant Likely <grant.likely@xxxxxxxxxx> wrote: > On Tue, 18 Nov 2014 17:25:45 +0000 > , Mark Rutland <mark.rutland@xxxxxxx> > wrote: >> On Tue, Nov 18, 2014 at 04:51:45PM +0000, Grant Likely wrote: >> > On Fri, 14 Nov 2014 18:05:35 +0100 >> > , Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> >> > wrote: >> > > Create a new /sys entry '/sys/firmware/fdt' to export the FDT blob >> > > that was passed to the kernel by the bootloader. This allows userland >> > > applications such as kexec to access the raw binary. [...] >> > * It also helps with exposing the reserved map to userspace, but kexec >> > has done without that feature for years, and it is in the process of >> > being deprecated in favour of /reserved-memory anyway. >> >> This is the first I'd heard of the reserve map being deprecated, and >> we're going to have DTs with reserved map entries for a long time going >> forwards. > > Deprecated, not removed or disabled. It will still work pretty much > forever, but users should be encouraged to move to the reserve-memory > tree. I thought you had said reserve map was still the right way for memory the kernel should never touch. >> Can't we expose the header fields under something like >> /sys/firmware/devicetree/dtb-header/, parallel to the usual >> /sys/firmware/devicetree/base for nodes? > > We could do that too. > > Honestly though, I'm just unsure of what the best thing to do is. If you > and a few others tell me that, "no, exporting the raw dtb is the right > thing to do", then I'll be okay, merge the patch and sleep properly. I always sleep better when others can take the blame. What happens when we rev the dtb format? Is the ABI the blob or the format of the blob? I lean towards we should add this. This is providing what is "in the firmware" while /proc/devicetree provides the live tree state including overlays. Rob -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
