Hi Pierre, On Fri, Mar 15, 2024 at 12:13 PM Pierre-Clément Tosi <pt...@google.com> wrote:
> I had a quick look through your logs and notice that U-Boot master attempts to > map addresses in the high VA range e.g. > > Checking if pte fits for virt=ffffffffe4000000 [...] > > while the logs that boot successfully only use the low VA range e.g. > > Checking if pte fits for virt=80193000 [...] > > Unless that has recently changed (since I last worked with U-Boot), U-Boot on > AArch64 only supports identity mappings and therefore was only taught how to > program TTBR0_ELx (i.e. is only able to map low virtual addresses). This means > that the code - with or without 41e2787f5ec4 - would be unable to map > addresses > such as 0xffffffffe4000000. Yes, I found it strange too. I may have done something wrong the last time I instrumented the code. I tried it again and no longer see these unexpected high virtual addresses. Please find the new logs here: https://pastebin.com/raw/qF3GbJry > Now, given that 41e2787f5ec4 only affects implementation details of add_map(), > I am surprised that reverting that commit changes the arguments received by > the > function such as virt. As a reminder, add_map() is exclusively used on > mem_map: > > for (i = 0; mem_map[i].size || mem_map[i].attrs; i++) > add_map(&mem_map[i]); > > > > > That's the only issue preventing colibri-imx8x from booting mainline U-Boot. > > If I read the U-Boot configs right i.e. > > - configs/colibri-imx8x_defconfig: CONFIG_ARCH_IMX8=y > - arch/arm/mach-imx/imx8/Makefile: obj-y += cpu.o > - arch/arm/mach-imx/imx8/cpu.c: struct mm_region *mem_map = imx8_mem_map; Correct, these are the relevant files for the i.MXQ8XP. > There is a possibility that your mem_map is getting modified by MACH-specific > code. In particular, enable_caches() seems to dynamically get the MMU mappings > from some RPC mechanism (see get_owned_memreg() and sc_rm_get_memreg_info()). > > Could it be that whatever services those requests might be returning > unexpected > values? Instrumenting arch/arm/mach-imx/imx8/cpu.c and dumping mem_map (and > the RPC messages) with/without the patch would help clear this up. I tried dumping the page table entries, but could not notice anything that looked suspicious. Please let me know if you have any suggestions. Thanks
