Hi, On Mon, 10 Jul 2023 at 14:13, Tom Rini <[email protected]> wrote: > > On Mon, Jul 10, 2023 at 01:45:46PM -0600, Simon Glass wrote: > > Hi David, > > > > On Sun, 9 Jul 2023 at 19:11, David Virag <[email protected]> wrote: > > > > > > Hi, > > > > > > I'm trying to port U-Boot to a new board (Samsung JACKPOTLTE, ARMv8, > > > Exynos7885) but when CONFIG_ARCH_FIXUP_FDT_MEMORY is enabled, the bootm > > > command leads to an unaligned memory access, which results in a > > > synchronous abort. > > > > > > After a long debugging session, I concluded that fdt_pack_reg in > > > common/fdt_support.c writes to unaligned addresses in its for loop. > > > In the case of address_cells being 2, and size_cells being 1, the > > > buffer pointer gets incremented by 12 in each loop, making the second > > > iteration (i=1) write a 64bit value to a non 64bit aligned address. > > > > > > Turning the alignment check enable bit (A) off in SCTLR makes the > > > function work as intended. I couldn't find code that touches this bit, > > > but I may have missed something. I don't think writing in two parts > > > should be the fix, but something should be done about this. As far as I > > > understand, any arm64 board that has this bit turned on, either from > > > previous code or just the initial status of the bit after power on, > > > could crash here. > > > > > > This is on top of the latest commit as of now > > > (0beb649053b86b2cfd5cf55a0fc68bc2fe91a430) > > > > > > What should be done here? > > > > +Tom Rini > > ... I was hoping you had an idea Simon. Is this part of the code we > share with libfdt itself, or one of the helpers we made?
Hmmm, is the DT itself 64-bit aligned? It needs to be. Looking at fdt_find_separate() it needs _end Looking at arch/arm/cpu/armv8/u-boot.lds I don't see an ALIGN before _end. So perhaps that is the problem? Regards, Simon
