From: Alexander Sverdlin alexander.sverdlin@nokia.com
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.
Cc: stable@vger.kernel.org Fixes: a94e4f24ec83 ("MIPS: init: Drop boot_mem_map") Signed-off-by: Alexander Sverdlin alexander.sverdlin@nokia.com --- arch/mips/kernel/setup.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c index 0d42532..f6cf2f6 100644 --- a/arch/mips/kernel/setup.c +++ b/arch/mips/kernel/setup.c @@ -504,6 +504,12 @@ static void __init check_kernel_sections_mem(void) if (!memblock_is_region_memory(start, size)) { pr_info("Kernel sections are not in the memory maps\n"); memblock_add(start, size); + /* + * Octeon bootloader places shared data structure right after + * the kernel => make sure it will not be corrupted. + */ + memblock_reserve(__pa_symbol(&_end), + start + size - __pa_symbol(&_end)); } }