arm64: __clean_dcache_area_poc 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.

Because the code is shared with __dma_clean_area, it changes the
parameters for that as well. However, __dma_clean_area is local to
cache.S, so no other users are affected.

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/20210524083001.2586635-14-tabba@google.com
Signed-off-by: Will Deacon <will@kernel.org>

Author: Fuad Tabba

arch/arm64/include/asm/cacheflush.h

@@ -60,7 +60,7 @@ extern void __flush_icache_range(unsigned long start, unsigned long end);
 extern void invalidate_icache_range(unsigned long start, unsigned long end);
 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(void *addr, size_t len);
+extern void __clean_dcache_area_poc(unsigned long start, unsigned long end);
 extern void __clean_dcache_area_pop(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);

arch/arm64/kernel/efi-entry.S

@@ -28,6 +28,7 @@ SYM_CODE_START(efi_enter_kernel)
 	 * stale icache entries from before relocation.
 	 */
 	ldr	w1, =kernel_size
+	add	x1, x0, x1
 	bl	__clean_dcache_area_poc
 	ic	ialluis
 
@@ -36,7 +37,7 @@ SYM_CODE_START(efi_enter_kernel)
 	 * so that we can safely disable the MMU and caches.
 	 */
 	adr	x0, 0f
-	ldr	w1, 3f
+	adr	x1, 3f
 	bl	__clean_dcache_area_poc
 0:
 	/* Turn off Dcache and MMU */
@@ -64,5 +65,5 @@ SYM_CODE_START(efi_enter_kernel)
 	mov	x2, xzr
 	mov	x3, xzr
 	br	x19
+3:
 SYM_CODE_END(efi_enter_kernel)
-3:	.long	. - 0b

arch/arm64/mm/cache.S

@@ -171,24 +171,23 @@ SYM_FUNC_END_PI(__inval_dcache_area)
 SYM_FUNC_END(__dma_inv_area)
 
 /*
- *	__clean_dcache_area_poc(kaddr, size)
+ *	__clean_dcache_area_poc(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 PoC.
  *
- *	- kaddr   - kernel address
- *	- size    - size in question
+ *	- start   - virtual start address of region
+ *	- end     - virtual end address of region
  */
 SYM_FUNC_START_LOCAL(__dma_clean_area)
 SYM_FUNC_START_PI(__clean_dcache_area_poc)
 	/* FALLTHROUGH */
 
 /*
- *	__dma_clean_area(start, size)
+ *	__dma_clean_area(start, end)
  *	- start   - virtual start address of region
- *	- size    - size in question
+ *	- end     - virtual end address of region
  */
-	add	x1, x0, x1
 	dcache_by_line_op cvac, sy, x0, x1, x2, x3
 	ret
 SYM_FUNC_END_PI(__clean_dcache_area_poc)
@@ -204,10 +203,10 @@ SYM_FUNC_END(__dma_clean_area)
  *	- size    - size in question
  */
 SYM_FUNC_START_PI(__clean_dcache_area_pop)
+	add	x1, x0, x1
 	alternative_if_not ARM64_HAS_DCPOP
 	b	__clean_dcache_area_poc
 	alternative_else_nop_endif
-	add	x1, x0, x1
 	dcache_by_line_op cvap, sy, x0, x1, x2, x3
 	ret
 SYM_FUNC_END_PI(__clean_dcache_area_pop)
@@ -236,7 +235,6 @@ SYM_FUNC_START_PI(__dma_map_area)
 	add	x1, x0, x1
 	cmp	w2, #DMA_FROM_DEVICE
 	b.eq	__dma_inv_area
-	sub	x1, x1, x0
 	b	__dma_clean_area
 SYM_FUNC_END_PI(__dma_map_area)