On Tue, Nov 27, 2018 at 4:47 PM Marek Vasut <marek.va...@gmail.com> wrote: > > On 11/27/2018 04:26 PM, Simon Goldschmidt wrote: > > On 27.11.2018 14:09, Marek Vasut wrote: > >> On 11/27/2018 01:33 PM, Simon Goldschmidt wrote: > >>> On Tue, Nov 27, 2018 at 1:25 PM Marek Vasut <marek.va...@gmail.com> > >>> wrote: > >>>> On 11/27/2018 08:03 AM, Simon Goldschmidt wrote: > >>>>> On Tue, Nov 27, 2018 at 1:11 AM Marek Vasut <marek.va...@gmail.com> > >>>>> wrote: > >>>>>> Convert all Renesas R-Car boards to bootm_size of 256 MiB and drop > >>>>>> both > >>>>>> fdt_high and initrd_high. This change implies that the FDT and initrd > >>>>>> will always be copied into the first 256 MiB of RAM instead of being > >>>>>> used in place, which can cause various kinds of inobvious problems. > >>>>>> > >>>>>> The simpler problems include FDT or initrd being overwritten or being > >>>>>> used from unaligned addresses, especially on ARM64. The overhead of > >>>>>> copying the FDT to aligned location is negligible and these problems > >>>>>> go away, so the benefit is significant. > >>>>>> > >>>>>> Regarding alignment problems with fitImage. The alignment of DT > >>>>>> properties > >>>>>> is always 32 bits, which implies that the alignment of the "data" > >>>>>> property > >>>>>> in fitImage is also 32 bits. The /incbin/ syntax plays no role > >>>>>> here. The > >>>>>> kernel expects all elements, including DT and initrd, to be > >>>>>> aligned to > >>>>>> 64 bits on ARM64, thus using them in place may not be possible. > >>>>>> Using the > >>>>>> bootm_size assures correct alignment, again with negligible overhead. > >>>>> In my opinion, all of these raw addresses defined in scripts or config > >>>>> should be removed: They are probably vulnerable to overwriting > >>>>> themselves as they only provide an address, not a range. > >>>> This is not an address, it's size. And this one at least assures that > >>>> the first 256 MiB are reserved for the kernel/FDT/initrd during > >>>> bootm time. > >>> Sorry I did not express myself clear enough. I meant that "fdt_high" > >>> and "initrd_high" are bad because they contain an address only, not a > >>> range. The 'bootm_size' thing is much better! > >> Well the fdt_high and intrd_high can also contain a special ~0 value, > >> which says "use the fdt/initrd in place", which is dangerous. > >> > >>>>> Just out of curiosity: is it required to put fdt and initrd into the > >>>>> first 256 MiB or is this just some 'random' limit to ensure we use lmb > >>>>> but don't overwrite U-Boot (text, heap, stack, etc)? Because if so, my > >>>>> series to fix the recent CVE issues improves lmb to not overwrite > >>>>> U-Boot and other reserved addresses and you might be able to remove > >>>>> 'bootm_size', too. The improved lmb code would just allocate an > >>>>> aligned address somewhere in the available RAM. > >>>> It's just the first 256 MiB from the beginning, so there's enough space > >>>> between that and U-Boot on all these boards. > >>> Of course. I wanted to know if it would be good enough if U-Boot would > >>> just put it somewhere without overwriting things or do you really need > >>> them in the first 256 MiB? Because the revised lmb code would make > >>> sure there's nothing overwritten, so there would be no need to trim at > >>> 256 MiB. > >> You can put them anywhere, you just need to meet the alignment > >> requirements. Can the new LMB code help somehow with that ? And if so, > >> how ? > > > > My additions to the LMB code should only ensure nothing gets overwritten > > so you don't have to limit boom_size to 256MiB (but use the complete RAM > > when bootm_size is not set). > > Alignment does not change but should already be OK with LMB as you use it? > > If I can use the entire RAM (except U-Boot and fitImage), that'd be > nice. What change do I need to do ?
I don't know yet, sorry. I basically asked this question to find out about the usage of 'bootm_size'. It's not really documented and I couldn't find out it's full meaning yet. Because e.g. it is set to 16 MiB for socfpga gen5, which sounds a little low... From reading the code, doesn't it already work when leaving out 'bootm_size'? (And leaving out 'bootm_mapsize' as well and not defining CONFIG_SYS_BOOTMAPSZ?) But I don't really know, finding that out and making it work is one of my goals for that series I'm working on. The series started with allowing all subitems in a FIT to be uncompressed but I found some issues there and it grows... Regards, Simon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
