Hooray, changing SYS_CAR_ADDR to 0x10000 in arch/x86/cpu/qemu/Kconfig does the trick. Bin, what do you think about it?
Best regards, Anton Gerasimov On 11/10/2017 06:25 PM, Anton Gerasimov wrote: > Yes, apparently 0xdfffc is in ROM area for QEMU (0xc0000 -- 0xe0000, > defined in include/hw/loader.h). The next thing to figure out is why > u-boot uses it as a stack area. > > Best regards, > Anton Gerasimov > > On 11/10/2017 06:04 PM, Anton Gerasimov wrote: >> New guess: >> >> in the most safe configuration of u-boot (CONFIG_SMP=n, lacpi disabled) >> with Igor's patch applied `qemu-system-i386 -bios /path/to/uboot.rom` >> fails on the first 'ret' instruction. GDB shows that memory at $esp >> (0xdfffc at the entrance to board_init_f_mem) and everything around it >> is zero despite 'call' and 'push' instructions executed. If you go one >> commit before the breaking one it works fine, stuff gets put onto stack. >> Could it that be that stack itself is in this 'readonly' area? >> >> Thanks, >> Anton Gerasimov >> >> On 11/09/2017 02:58 AM, Bin Meng wrote: >>> On Wed, Nov 8, 2017 at 9:05 PM, Anton Gerasimov >>> <an...@advancedtelematic.com> wrote: >>>> Adding Igor Mammedov to the loop. >>>> >>> Really add Igor Mammedov. >>> >>> Igor, can you help look at this? >>> >>>> On 11/08/2017 01:59 PM, Anton Gerasimov wrote: >>>>> To whoever might be interested: I've bisected qemu and the breaking >>>>> commit is 208fa0e43645edd0b0d8f838857dfc79daff40a8 (pc: make 'pc.rom' >>>>> readonly when machine has PCI enabled). It's just three lines added, >>>>> I'll paste the whole patch here. Not quite sure what can we do here >>>>> though. >>>>> >>>>> >>>>> diff --git a/hw/i386/pc.c b/hw/i386/pc.c >>>>> index 22e16031b0..59435390ba 100644 >>>>> --- a/hw/i386/pc.c >>>>> +++ b/hw/i386/pc.c >>>>> @@ -1443,6 +1443,9 @@ void pc_memory_init(PCMachineState *pcms, >>>>> option_rom_mr = g_malloc(sizeof(*option_rom_mr)); >>>>> memory_region_init_ram(option_rom_mr, NULL, "pc.rom", PC_ROM_SIZE, >>>>> &error_fatal); >>>>> + if (pcmc->pci_enabled) { >>>>> + memory_region_set_readonly(option_rom_mr, true); >>>>> + } >>>>> memory_region_add_subregion_overlap(rom_memory, >>>>> PC_ROM_MIN_VGA, >>>>> option_rom_mr, >>>>> >>>>> >>> Regards, >>> Bin -- Anton Gerasimov, ATS Advanced Telematic Systems GmbH Kantstrasse 162, 10623 Berlin Managing Directors: Dirk Pöschl, Armin G. Schmidt Register Court: HRB 151501 B, Amtsgericht Charlottenburg