[PATCH v3 1/3] arm64: mm: add __clean_dcache_area()

[Kwangwoo Lee]

Ensure D-cache lines are cleaned to the PoC(Point of Coherency).

This function is called by arch_wb_cache_pmem() to clean the cache lines
and remain the data in cache for the next access.

Signed-off-by: Kwangwoo Lee <kwangwoo.lee@xxxxxx>
---
 arch/arm64/include/asm/cacheflush.h |  1 +
 arch/arm64/mm/cache.S               | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h
index c64268d..903a94f 100644
--- a/arch/arm64/include/asm/cacheflush.h
+++ b/arch/arm64/include/asm/cacheflush.h
@@ -68,6 +68,7 @@
 extern void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end);
 extern void flush_icache_range(unsigned long start, unsigned long end);
 extern void __flush_dcache_area(void *addr, size_t len);
+extern void __clean_dcache_area(void *addr, size_t len);
 extern void __clean_dcache_area_pou(void *addr, size_t len);
 extern long __flush_cache_user_range(unsigned long start, unsigned long end);
 
diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S
index 6df0706..5a350e4 100644
--- a/arch/arm64/mm/cache.S
+++ b/arch/arm64/mm/cache.S
@@ -93,6 +93,24 @@ ENTRY(__flush_dcache_area)
 ENDPIPROC(__flush_dcache_area)
 
 /*
+ *	__clean_dcache_area(kaddr, size)
+ *
+ * 	Ensure that any D-cache lines for the interval [kaddr, kaddr+size)
+ * 	are cleaned to the PoC.
+ *
+ *	- kaddr   - kernel address
+ *	- size    - size in question
+ */
+ENTRY(__clean_dcache_area)
+alternative_if_not ARM64_WORKAROUND_CLEAN_CACHE
+	dcache_by_line_op cvac, sy, x0, x1, x2, x3
+alternative_else
+	dcache_by_line_op civac, sy, x0, x1, x2, x3
+alternative_endif
+	ret
+ENDPROC(__clean_dcache_area)
+
+/*
  *	__clean_dcache_area_pou(kaddr, size)
  *
  * 	Ensure that any D-cache lines for the interval [kaddr, kaddr+size)
-- 
2.5.0