m68k: mm: Move initrd phys_to_virt handling after paging_init()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: m68k: mm: Move initrd phys_to_virt handling after paging_init() When booting with an initial ramdisk on platforms where physical memory does not start at address zero (e.g. on Amiga): initrd: 0ef0602c - 0f800000 Zone ranges: DMA [mem 0x0000000008000000-0x000000f7ffffffff] Normal empty Movable zone start for each node Early memory node ranges node 0: [mem 0x0000000008000000-0x000000000f7fffff] Initmem setup node 0 [mem 0x0000000008000000-0x000000000f7fffff] Unable to handle kernel access at virtual address (ptrval) Oops: 00000000 Modules linked in: PC: [<00201d3c>] memcmp+0x28/0x56 As phys_to_virt() relies on m68k_memoffset and module_fixup(), it must not be called before paging_init(). Hence postpone the phys_to_virt handling for the initial ramdisk until after calling paging_init(). While at it, reduce #ifdef clutter by using IS_ENABLED() instead.

References

• https://git.kernel.org/stable/c/ceb089e2337f810d3594d310953d9af4783f660a
• https://git.kernel.org/stable/c/58662cfb459150b9c0c22d20cddaea439b3844bd
• https://git.kernel.org/stable/c/d4b97925e87eb133e400fe4a482d750c74ce392f