On Mon, Nov 09, 2020 at 11:34:33AM +0100, Alexander Sverdlin wrote:
Hello Thomas,
On 07/11/2020 10:40, Thomas Bogendoerfer wrote:
Linux doesn't own the memory immediately after the kernel image. On Octeon bootloader places a shared structure right close after the kernel _end, refer to "struct cvmx_bootinfo *octeon_bootinfo" in cavium-octeon/setup.c.
If check_kernel_sections_mem() rounds the PFNs up, first memblock_alloc() inside early_init_dt_alloc_memory_arch() <= device_tree_init() returns memory block overlapping with the above octeon_bootinfo structure, which is being overwritten afterwards.
as this special for Octeon how about added the memblock_reserve in octen specific code ?
while the shared structure which is being corrupted is indeed Octeon-specific, the wrong assumption that the memory right after the kernel can be allocated by memblock allocator and re-used somewhere in Linux is in MIPS-generic check_kernel_sections_mem().
ok, I see your point. IMHO this whole check_kernel_sections_mem() should be removed. IMHO memory adding should only be done my memory detection code.
Could you send a patch, which removes check_kernel_section_mem completly ?
Thomas.