Memory range end be inclusive or exclusive? Re: [PATCH v1 1/4] kexec: (bugfix) calc correct end address of memory ranges in device tree

[Simon Horman]

Hi Akashi-san,

sorry for the long delay(s).

The patch below seems reasonable to me and I'm happy to apply it.

On Mon, Oct 31, 2016 at 05:50:09PM +0900, AKASHI Takahiro wrote:
> Simon,
> 
> On Tue, Sep 06, 2016 at 09:29:59AM +0900, AKASHI Takahiro wrote:
> > Simon,
> > 
> > What is your opinion on this issue?
> 
> Pinged you several times so far.
> 
> Can you please give me your comment?
> (attached below is the original patch.)
> 
> -Takahiro AKASHI
> 
> > 
> > On Mon, Aug 01, 2016 at 01:52:40PM +0900, AKASHI Takahiro wrote:
> > > On Fri, Jul 29, 2016 at 06:23:56PM +0100, Russell King - ARM Linux wrote:
> > > > On Fri, Jul 29, 2016 at 10:12:26AM -0700, Geoff Levand wrote:
> > > > > On Fri, 2016-07-29 at 09:27 +0100, Russell King - ARM Linux wrote:
> > > > > 
> > > > > > So, these functions are a mess and need fixing.
> > > > > 
> > > > > Since this change isn't really related to arm64 support, I'll
> > > > > drop this patch from my series.
> > > > 
> > > > Do you have a case which triggers bugs in this code?
> > > 
> > > Actually, this patch was necessary when my kdump used "usable-memory"
> > > properties in "memory" nodes, as on ppc64, to limit the usable memory
> > > regions that can be used by crash dump kernel.
> > > Since then, I've moved to the approach of using "mem=" kernel parameter,
> > > then introducing a new property, "linux,usable-memory-range," under /chosen
> > > and now we don't need this patch any more.
> > > 
> > > So, we can drop it but I still believe that it is buggy.
> > 
> > Due to the discussions[1], I may want to re-enable "usable-memory"
> > property on arm64. In addition, I would like to add a function,
> > dtb_add_usable_memory_properties(), a variant of
> > add_usable_memory_properties(), to kexec/dt-ops.c.
> > So this issue is quite crucial now.
> > 
> > [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-August/452685.html
> > 
> > -Takahiro AKASHI
> > 
> > > Thanks,
> > > -Takahiro AKASHI
> > > 
> > > > -- 
> > > > RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
> > > > FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
> > > > according to speedtest.net.
> ===8<===
> From: AKASHI Takahiro <takahiro.akashi at linaro.org>
> 
> The end address of "reg" attribute in device tree's memory should be
> inclusive.
> ---
>  kexec/fs2dt.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/kexec/fs2dt.c b/kexec/fs2dt.c
> index 79aa0f3..953f78a 100644
> --- a/kexec/fs2dt.c
> +++ b/kexec/fs2dt.c
> @@ -236,7 +236,8 @@ static void add_dyn_reconf_usable_mem_property__(int fd)
>  						    ranges_size*8);
>  				}
>  				ranges[rlen++] = cpu_to_be64(loc_base);
> -				ranges[rlen++] = cpu_to_be64(loc_end - loc_base);
> +				ranges[rlen++] = cpu_to_be64(loc_end
> +								- loc_base + 1);
>  				rngs_cnt++;
>  			}
>  		}
> @@ -350,7 +351,7 @@ static void add_usable_mem_property(int fd, size_t len)
>  					    ranges_size*sizeof(*ranges));
>  			}
>  			ranges[rlen++] = cpu_to_be64(loc_base);
> -			ranges[rlen++] = cpu_to_be64(loc_end - loc_base);
> +			ranges[rlen++] = cpu_to_be64(loc_end - loc_base + 1);
>  		}
>  	}
>  
> -- 
> 2.10.0
>