Commit 921d701e authored Apr 02, 2017 by Tobias Klauser Committed by Ley Foon Tan Apr 02, 2017

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>

parent a71c9a1c

arch/nios2/kernel/prom.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -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;

arch/nios2/kernel/setup.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -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();

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