experimentation

src/patch/0000-export-dcache-clean-poc-dbg.patch

@@ -0,0 +1,58 @@
+diff --git a/arch/arm64/include/asm/cacheflush_extra.h b/arch/arm64/include/asm/cacheflush_extra.h
+new file mode 100644
+index 000000000000..98eadccbcde4
+--- /dev/null
++++ b/arch/arm64/include/asm/cacheflush_extra.h
+@@ -0,0 +1,13 @@
++/*
++ * 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);
++extern void __dcache_clean_poc_dbg(
++	unsigned long start, unsigned long end, unsigned long long *runtime);
++
++#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..f8920b1187ef 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 +64,24 @@ 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);
++
++void __dcache_clean_poc_dbg(ulong start, ulong end, u64 *runtime)
++{
++	u64 calltime, rettime;
++
++	calltime = ktime_get_ns();
++	dcache_clean_poc(start, end);
++	rettime = ktime_get_ns();
++
++	*runtime = rettime - calltime;
++}
++EXPORT_SYMBOL(__dcache_clean_poc_dbg);
++
+ /*
+  * 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,