arm64: __clean_dcache_area_pou to take end parameter instead of size

To be consistent with other functions with similar names and
functionality in cacheflush.h, cache.S, and cachetlb.rst, change
to specify the range in terms of start and end, as opposed to
start and size.

No functional change intended.

Reported-by: Will Deacon <will@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20210524083001.2586635-16-tabba@google.com
Signed-off-by: Will Deacon <will@kernel.org>

Author: Fuad Tabba

arch/arm64/include/asm/cacheflush.h

@@ -62,7 +62,7 @@ extern void __flush_dcache_area(unsigned long start, unsigned long end);
 extern void __inval_dcache_area(unsigned long start, unsigned long end);
 extern void __clean_dcache_area_poc(unsigned long start, unsigned long end);
 extern void __clean_dcache_area_pop(unsigned long start, unsigned long end);
-extern void __clean_dcache_area_pou(void *addr, size_t len);
+extern void __clean_dcache_area_pou(unsigned long start, unsigned long end);
 extern long __flush_cache_user_range(unsigned long start, unsigned long end);
 extern void sync_icache_aliases(void *kaddr, unsigned long len);
 

arch/arm64/mm/cache.S

@@ -113,20 +113,19 @@ SYM_FUNC_START_PI(__flush_dcache_area)
 SYM_FUNC_END_PI(__flush_dcache_area)
 
 /*
- *	__clean_dcache_area_pou(kaddr, size)
+ *	__clean_dcache_area_pou(start, end)
  *
- * 	Ensure that any D-cache lines for the interval [kaddr, kaddr+size)
+ * 	Ensure that any D-cache lines for the interval [start, end)
  * 	are cleaned to the PoU.
  *
- *	- kaddr   - kernel address
- *	- size    - size in question
+ *	- start   - virtual start address of region
+ *	- end     - virtual end address of region
  */
 SYM_FUNC_START(__clean_dcache_area_pou)
 alternative_if ARM64_HAS_CACHE_IDC
 	dsb	ishst
 	ret
 alternative_else_nop_endif
-	add	x1, x0, x1
 	dcache_by_line_op cvau, ish, x0, x1, x2, x3
 	ret
 SYM_FUNC_END(__clean_dcache_area_pou)

arch/arm64/mm/flush.c

@@ -19,7 +19,7 @@ void sync_icache_aliases(void *kaddr, unsigned long len)
 	unsigned long addr = (unsigned long)kaddr;
 
 	if (icache_is_aliasing()) {
-		__clean_dcache_area_pou(kaddr, len);
+		__clean_dcache_area_pou(kaddr, kaddr + len);
 		__flush_icache_all();
 	} else {
 		/*