nios2: reserve boot memory for device tree
authorTobias Klauser <tklauser@distanz.ch>
Mon, 3 Apr 2017 03:08:04 +0000 (20:08 -0700)
committerLey Foon Tan <ley.foon.tan@intel.com>
Mon, 3 Apr 2017 03:13:57 +0000 (20:13 -0700)
commit921d701e6f31e1ffaca3560416af1aa04edb4c4f
tree44cec5977023a0e15e7f5da612405fb174617b97
parenta71c9a1c779f2499fb2afc0553e543f18aff6edf
nios2: reserve boot memory for device tree

Make sure to reserve the boot memory for the flattened device tree.
Otherwise it might get overwritten, e.g. when initial_boot_params is
copied, leading to a corrupted FDT and a boot hang/crash:

  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!

Guenter Roeck says:

> 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().

Cc: stable@vger.kernel.org
Reported-by: Guenter Roeck <linux@roeck-us.net>
Reference: http://lkml.kernel.org/r/20170226210338.GA19476@roeck-us.net
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Ley Foon Tan <ley.foon.tan@intel.com>
arch/nios2/kernel/prom.c
arch/nios2/kernel/setup.c