On Mon, Oct 30, 2017 at 04:09:43PM +0100, Arnd Bergmann wrote: > On Fri, Oct 27, 2017 at 5:27 PM, Russell King - ARM Linux > <li...@armlinux.org.uk> wrote: > > > > > There's three things wrong, all of which I have patches to address: > > > > 1. The decompressor code reading the image data sometimes issues unaligned > > reads. Some compilers get this wrong and cause an abort. Arnds patch > > addresses this. > > > > 2. Additional sections can appear in the zImage binary which adds extra > > bytes on the end of the image. Concatenating the zImage with the > > extra bytes onto a DTB is the same thing as doing this: > > > > cat zImage extrabytes foo.dtb > image > > > > and the decompressor tolerates no additional bytes between the > > _official_ end of the zImage and the DTB. I've added a patch which > > detects this situation and fails the kernel build when it happens. > > > > 3. Ard's patch "efi/libstub: arm: omit sorting of the UEFI memory map" > > gets rid of the additional sections that (a) change the alignment > > of the compressed data, and (b) add additional unexpected bytes on > > the end of zImage. > > It's possible that we still need yet another patch to address the gcc bug that > Alex Graf found, i.e. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82445 > > Without the latest gcc, we might still get into a situation in which we get > an unaligned strd when compiling for armv5te or armv6 with gcc-7.[012]. > As someone mentioned in the bug report, that problem doesn't seem > to happen with gcc-6 or -mtune=xscale, or with gcc-7 -march=armv7-a.
There is another solution which we've used in the past - we could detect these compiler versions and refuse to build with the broken compilers. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up According to speedtest.net: 8.21Mbps down 510kbps up
