diff --git a/src/aarch64-linux-flush-dcache/my_shmem.c b/src/aarch64-linux-flush-dcache/my_shmem.c
index 7aa5285..325ef6d 100644
--- a/src/aarch64-linux-flush-dcache/my_shmem.c
+++ b/src/aarch64-linux-flush-dcache/my_shmem.c
@@ -1,6 +1,5 @@
 // [TODO] Clean up headers...
 // #include <asm/cacheflush.h>
-#include <asm/cacheflush.h>
 #include "linux/atomic/atomic-long.h"
 #include <linux/device.h>
 #include "linux/gfp.h"
@@ -20,6 +19,8 @@
 #include <linux/kernel.h>
 #include <linux/version.h>
 
+#include <asm/cacheflush_extra.h>
+
 MODULE_AUTHOR("Zk.");
 MODULE_DESCRIPTION("4.2.W1: mmap for point of coherency");
 MODULE_LICENSE("GPL");
@@ -59,7 +60,7 @@ static void my_shmem_vmops_close(struct vm_area_struct *vma)
 			__func__, page_address(pg), *(ulong *)(page_address(pg)),
 			sizeof(ulong));
 		// [!!] `dcache_clean_poc` seems not exported.
-		dcache_clean_poc(vaddr_start, vaddr_start + PAGE_SIZE);
+		__dcache_clean_poc(vaddr_start, vaddr_start + PAGE_SIZE);
 		pr_info("[%s] After flush: 0x%px has 0x%lx [+%ld].\n",
 			__func__, page_address(pg), *(ulong *)(page_address(pg)),
 			sizeof(ulong));
@@ -282,4 +283,4 @@ static void __exit my_shmem_exit(void)
 }
 
 module_init(my_shmem_init);
-module_exit(my_shmem_exit);
\ No newline at end of file
+module_exit(my_shmem_exit);
diff --git a/src/patch/0000-export-dcache-clean-poc.patch b/src/patch/0000-export-dcache-clean-poc.patch
new file mode 100644
index 0000000..0d65f3b
--- /dev/null
+++ b/src/patch/0000-export-dcache-clean-poc.patch
@@ -0,0 +1,44 @@
+diff --git a/arch/arm64/include/asm/cacheflush_extra.h b/arch/arm64/include/asm/cacheflush_extra.h
+new file mode 100644
+index 000000000000..d989e93ff01a
+--- /dev/null
++++ b/arch/arm64/include/asm/cacheflush_extra.h
+@@ -0,0 +1,11 @@
++/*
++ * Get dcache_clean|inval_poc out to driverland!
++ */
++
++#ifndef __ASM_CACHEFLUSH_EX_H
++#define __ASM_CACHEFLUSH_EX_H
++
++/* Ref. cacheflush.h */
++extern void __dcache_clean_poc(unsigned long start, unsigned long end);
++
++#endif /* __ASM_CACHEFLUSH_EX_H */
+\ No newline at end of file
+diff --git a/arch/arm64/mm/flush.c b/arch/arm64/mm/flush.c
+index 013eead9b695..d9bb343d4b5e 100644
+--- a/arch/arm64/mm/flush.c
++++ b/arch/arm64/mm/flush.c
+@@ -15,6 +15,8 @@
+ #include <asm/cache.h>
+ #include <asm/tlbflush.h>
+ 
++#include <asm/cacheflush_extra.h>
++
+ void sync_icache_aliases(unsigned long start, unsigned long end)
+ {
+ 	if (icache_is_aliasing()) {
+@@ -62,6 +64,12 @@ void __sync_icache_dcache(pte_t pte)
+ }
+ EXPORT_SYMBOL_GPL(__sync_icache_dcache);
+ 
++void __dcache_clean_poc(ulong start, ulong end)
++{
++	dcache_clean_poc(start, end);
++}
++EXPORT_SYMBOL(__dcache_clean_poc);
++
+ /*
+  * This function is called when a page has been modified by the kernel. Mark
+  * it as dirty for later flushing when mapped in user space (if executable,