powerpc/mem: Blacklist flush_dcache_icache_phys() for kprobe

kprobe does not handle events happening in real mode, all
functions running with MMU disabled have to be blacklisted.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/eaab3bff961c3bfe149f1d0bd3593291ef939dcc.1585670437.git.christophe.leroy@c-s.fr

arch/powerpc/mm/mem.c

@@ -32,6 +32,7 @@
 #include <linux/vmalloc.h>
 #include <linux/memremap.h>
 #include <linux/dma-direct.h>
+#include <linux/kprobes.h>
 
 #include <asm/pgalloc.h>
 #include <asm/prom.h>
@@ -468,6 +469,7 @@ static void flush_dcache_icache_phys(unsigned long physaddr)
 		: "r" (nb), "r" (msr), "i" (bytes), "r" (msr0)
 		: "ctr", "memory");
 }
+NOKPROBE_SYMBOL(flush_dcache_icache_phys)
 #endif // !defined(CONFIG_PPC_8xx) && !defined(CONFIG_PPC64)
 
 /*