of/fdt: run soc memory setup when early_init_dt_scan_memory fails

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: of/fdt: run soc memory setup when early_init_dt_scan_memory fails If memory has been found early_init_dt_scan_memory now returns 1. If it hasn't found any memory it will return 0, allowing other memory setup mechanisms to carry on. Previously early_init_dt_scan_memory always returned 0 without distinguishing between any kind of memory setup being done or not. Any code path after the early_init_dt_scan memory call in the ramips plat_mem_setup code wouldn't be executed anymore. Making early_init_dt_scan_memory the only way to initialize the memory. Some boards, including my mt7621 based Cudy X6 board, depend on memory initialization being done via the soc_info.mem_detect function pointer. Those wouldn't be able to obtain memory and panic the kernel during early bootup with the message "early_init_dt_alloc_memory_arch: Failed to allocate 12416 bytes align=0x40".

References

• https://git.kernel.org/stable/c/04836fc5b720dfa32ff781383d84f63019abf9b9
• https://git.kernel.org/stable/c/c4849f18185fd4e93b04cd45552f8d68c0240e21
• https://git.kernel.org/stable/c/2a12187d5853d9fd5102278cecef7dac7c8ce7ea