From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [PATCH v23 9/9] Documentation: dt: chosen properties for arm64 kdump Date: Wed, 27 Jul 2016 10:09:33 -0500 Message-ID: <20160727150933.GA25732@rob-hp-laptop> References: <20160726075659.2290-1-takahiro.akashi@linaro.org> <20160726080206.2441-1-takahiro.akashi@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20160726080206.2441-1-takahiro.akashi-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: AKASHI Takahiro Cc: catalin.marinas-5wv7dgnIgG8@public.gmane.org, will.deacon-5wv7dgnIgG8@public.gmane.org, frowand.list-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, james.morse-5wv7dgnIgG8@public.gmane.org, geoff-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, bauerman-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org, dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: devicetree@vger.kernel.org On Tue, Jul 26, 2016 at 05:02:06PM +0900, AKASHI Takahiro wrote: > From: James Morse > > 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 > [takahiro.akashi-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org: > renamed "usable-memory" to "usable-memory-range", > added "linux,crashkernel-base" and "-size" ] > Signed-off-by: AKASHI Takahiro > --- > 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. > +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? 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-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html