On Thu, Mar 09, 2017 at 03:43:40PM +0100, Tobias Klauser wrote: > On 2017-03-09 at 14:20:51 +0100, Guenter Roeck <li...@roeck-us.net> wrote: > > On 03/07/2017 04:46 AM, Tobias Klauser wrote: > > [ ... ] > > > > > > > >Linux version 4.11.0-rc1-dirty (tobiask@ziws08) (gcc version 7.0.1 > > >20170226 (experimental) (GCC) ) #46 Tue Mar 7 13:40:53 CET 2017 > > >bootconsole [early0] enabled > > >Early console on uart16650 initialized at 0xf8001600 > > >OF: fdt: Error -11 processing FDT > > >Kernel panic - not syncing: setup_cpuinfo: No CPU found in devicetree! > > > > > >---[ end Kernel panic - not syncing: setup_cpuinfo: No CPU found in > > >devicetree! > > > > > >Looks like the in-memory device tree somehow gets corrupted. Not sure > > >yet why and how this is linked to the Kconfig options selected but at > > >least we now have a possibility to use debug messages earlier on. > > > > > > > I think I found the problem. In unflatten_and_copy_device_tree(), with added > > debug information: > > > > OF: fdt: initial_boot_params=c861e400, dt=c861f000 size=28874 (0x70ca) > > > > ... and then initial_boot_params is copied to dt, which results in corrupted > > fdt since the memory overlaps. Looks like the initial_boot_params memory > > is not reserved and (re-)allocated by early_init_dt_alloc_memory_arch(). > > Thanks for the analysis. That certainly explains the issue. The > following patch solves the issue for me. Though I'm not entirely sure if > it is correct and that is all that is needed. Do we need to retain the > memory for initial_boot_params after bootmem is freed? >
I don't know if it is correct either, but it matches what I came up with, and it does work for me as well. Feel free to add Tested-by: Guenter Roeck <li...@roeck-us.net> when you submit the patch for real. Thanks, Guenter > diff --git a/arch/nios2/kernel/prom.c b/arch/nios2/kernel/prom.c > index 099f5ce1f3cb..6869fe03f3ff 100644 > --- a/arch/nios2/kernel/prom.c > +++ b/arch/nios2/kernel/prom.c > @@ -48,6 +48,13 @@ void * __init early_init_dt_alloc_memory_arch(u64 size, > u64 align) > return alloc_bootmem_align(size, align); > } > > +int __init early_init_dt_reserve_memory_arch(phys_addr_t base, > + phys_addr_t size, bool nomap) > +{ > + reserve_bootmem(base, size, BOOTMEM_DEFAULT); > + return 0; > +} > + > void __init early_init_devtree(void *params) > { > __be32 *dtb = (u32 *)__dtb_start; > diff --git a/arch/nios2/kernel/setup.c b/arch/nios2/kernel/setup.c > index 6e57ffa5db27..6044d9be28b4 100644 > --- a/arch/nios2/kernel/setup.c > +++ b/arch/nios2/kernel/setup.c > @@ -201,6 +201,9 @@ void __init setup_arch(char **cmdline_p) > } > #endif /* CONFIG_BLK_DEV_INITRD */ > > + early_init_fdt_reserve_self(); > + early_init_fdt_scan_reserved_mem(); > + > unflatten_and_copy_device_tree(); > > setup_cpuinfo();