[PATCH][next] arm64: fix the mm build error in mm/kfence/core.c

[Hui Su]

When I build kernel with ARCH=arm64, the building errors came out like
this:
  CC      mm/kfence/core.o
In file included from ../mm/kfence/core.c:21:
../arch/arm64/include/asm/kfence.h: In function ‘kfence_protect_page’:
../arch/arm64/include/asm/kfence.h:12:2: error: implicit declaration of
function ‘set_memory_valid’ [-Werror=implicit-function-declaration]
   12 |  set_memory_valid(addr, 1, !protect);
      |  ^~~~~~~~~~~~~~~~
cc1: some warnings being treated as errors

which introduced by commit d54febeba2ff ("kfence: use pt_regs to
generate stack trace on faults").

Signed-off-by: Hui Su <sh_def@xxxxxxx>
---
 arch/arm64/include/asm/kfence.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/include/asm/kfence.h b/arch/arm64/include/asm/kfence.h
index 6c0afeeab635..4d73e34da59d 100644
--- a/arch/arm64/include/asm/kfence.h
+++ b/arch/arm64/include/asm/kfence.h
@@ -4,6 +4,7 @@
 #define __ASM_KFENCE_H
 
 #include <asm/cacheflush.h>
+#include <linux/set_memory.h>
 
 static inline bool arch_kfence_init_pool(void) { return true; }
 
-- 
2.25.1