This is due to 'dcbz' instruction being used on non-cached memory.
'dcbz' instruction is used by memset() to zeroize a complete
cacheline at once, and memset() is not expected to be used on non
cached memory.
When performing a 'sparse' check on fbdev driver, it also appears
that the use of memset() is unexpected:
drivers/video/fbdev/chipsfb.c:334:17: warning: incorrect type in argument 1 (different address spaces)
drivers/video/fbdev/chipsfb.c:334:17: expected void *
drivers/video/fbdev/chipsfb.c:334:17: got char [noderef] __iomem *screen_base
drivers/video/fbdev/chipsfb.c:334:15: warning: memset with byte count of 1048576
Use fb_memset() instead of memset(). fb_memset() is defined as
memset_io() for powerpc.