Frank Rowand <frowand.l...@gmail.com> writes: > Hi Michael, > > On 11/12/17 03:49, Michael Ellerman wrote: ... >> >> On our bare metal machines the device tree comes from skiboot >> (firmware), with some of the content provided by hostboot (other >> firmware), both of which are open source, so in theory most of the >> information is available in *some* source tree. But there's still >> information about runtime allocations etc. that is not available in the >> source anywhere. > > Thanks for the additional information. > > Can you explain a little bit what "runtime allocations" are? Are you > referring to the memory reservation block, the memory node(s) and the > chosen node? Or other information?
Yeah I was thinking of memory reservations. They're under the reserved-memory node as well as the reservation block, eg: $ ls -1 /proc/device-tree/reserved-memory/ ibm,firmware-allocs-memory@1000000000 ibm,firmware-allocs-memory@1800000000 ibm,firmware-allocs-memory@39c00000 ibm,firmware-allocs-memory@800000000 ibm,firmware-code@30000000 ibm,firmware-data@31000000 ibm,firmware-heap@30300000 ibm,firmware-stacks@31c00000 ibm,hbrt-code-image@1ffd510000 ibm,hbrt-target-image@1ffd6a0000 ibm,hbrt-vpd-image@1ffd700000 ibm,slw-image@1ffda00000 ibm,slw-image@1ffde00000 ibm,slw-image@1ffe200000 ibm,slw-image@1ffe600000 There's also some new systems where a catalog of PMU events is stored in flash as a DTB and then stitched into the device tree by skiboot before booting Linux. Anyway my point was mainly just that the device tree is not simply a copy of something in the kernel source. cheers
