Rob, On Thu, Jul 28, 2016 at 04:55:11PM +0900, AKASHI Takahiro wrote: > Rob, > > On Wed, Jul 27, 2016 at 10:09:33AM -0500, Rob Herring wrote: > > On Tue, Jul 26, 2016 at 05:02:06PM +0900, AKASHI Takahiro wrote: > > > From: James Morse <james.morse@xxxxxxx> > > > > > > Add documentation for > > > linux,crashkernel-base and crashkernel-size, > > > linux,usable-memory-range, and > > > linux,elfcorehdr > > > used by arm64 kexec/kdump to decribe the kdump reserved area, and > > > the elfcorehdr's location within it. > > > > > > Signed-off-by: James Morse <james.morse@xxxxxxx> > > > [takahiro.akashi@xxxxxxxxxx: > > > renamed "usable-memory" to "usable-memory-range", > > > added "linux,crashkernel-base" and "-size" ] > > > Signed-off-by: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx> > > > --- > > > Documentation/devicetree/bindings/chosen.txt | 45 ++++++++++++++++++++++++++++ > > > 1 file changed, 45 insertions(+) > > > > > > diff --git a/Documentation/devicetree/bindings/chosen.txt b/Documentation/devicetree/bindings/chosen.txt > > > index 6ae9d82..d7a3a86 100644 > > > --- a/Documentation/devicetree/bindings/chosen.txt > > > +++ b/Documentation/devicetree/bindings/chosen.txt > > > @@ -52,3 +52,48 @@ This property is set (currently only on PowerPC, and only needed on > > > book3e) by some versions of kexec-tools to tell the new kernel that it > > > is being booted by kexec, as the booting environment may differ (e.g. > > > a different secondary CPU release mechanism) > > > + > > > +linux,crashkernel-base > > > +linux,crashkernel-size > > > +---------------------- > > > +These properties are set (on PowerPC and arm64) during kdump to tell > > > +use-space tools, like kexec-tools, the base address of the crash-dump > > > > s/use/user/ > > > > Ideally, userspace should not care whether this comes from DT, kernel > > command-line or somewhere else and should be exposed in some source > > independent way. However, that's not really the problem for the binding. > > Yeah, I will remove "user-space"-related description as Mark also > commented before. > > > > +kernel's reserved area of memory and the size. e.g. > > > + > > > +/ { > > > + chosen { > > > + linux,crashkernel-base = <0x9 0xf0000000>; > > > + linux,crashkernel-size = <0x0 0x10000000>; > > > + }; > > > +}; > > > + > > > +linux,usable-memory-range > > > +------------------------- > > > + > > > +This property is set (currently only on arm64) during kdump to tell > > > +the crash-dump kernel the base address of its reserved area of memory, > > > +and the size. e.g. > > > + > > > +/ { > > > + chosen { > > > + linux,usable-memory-range = <0x9 0xf0000000 0x0 0x10000000>; > > > > This is the same range as linux,crashkernel-*, but used by the 2nd > > kernel? Why not just update the memory node or use command line mem= > > parameter? > > Please see: > http://lists.infradead.org/pipermail/linux-arm-kernel/2016-July/443225.html > > There was also a discussion that simply appending "mem=", or more generally > any parameter, to a command line might break some assumption of order of > parameters in the future. > So adding a DT property would be a better way. Do you have any other comments about those properties? -Takahiro AKASHI > Thanks, > -Takahiro AKASHI > > > Why has PPC not need this and ARM does? > > > > > + }; > > > +}; > > > + > > > +Please note that, if this property is present, any memory regions under > > > +"memory" nodes will be ignored. > > > + > > > +linux,elfcorehdr > > > +---------------- > > > + > > > +This property is set (currently only on arm64) during kdump to tell > > > +the crash-dump kernel the address and size of the elfcorehdr that describes > > > +the old kernel's memory as an elf file. This memory must reside within > > > +the area described by 'linux,usable-memory-range'. e.g. > > > + > > > +/ { > > > + chosen { > > > + linux,usable-memory = <0x9 0xf0000000 0x0 0x10000000>; > > > + linux,elfcorehdr = <0x9 0xfffff000 0x0 0x800>; > > > + }; > > > +}; > > > -- > > > 2.9.0 > > > -- 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