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. > 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. [...] -- Best regards, Marek Vasut _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
