arm64: __inval_dcache_area 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_inv_area, it changes the
parameters for that as well. However, __dma_inv_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/20210524083001.2586635-11-tabba@google.com
Signed-off-by: Will Deacon <will@kernel.org>

arch/arm64/include/asm/cacheflush.h

@@ -59,7 +59,7 @@
 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(void *addr, size_t len);
-extern void __inval_dcache_area(void *addr, size_t len);
+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_pop(void *addr, size_t len);
 extern void __clean_dcache_area_pou(void *addr, size_t len);

arch/arm64/kernel/head.S

@@ -117,7 +117,7 @@ SYM_CODE_START_LOCAL(preserve_boot_args)
 	dmb	sy				// needed before dc ivac with
 						// MMU off
 
-	mov	x1, #0x20			// 4 x 8 bytes
+	add	x1, x0, #0x20			// 4 x 8 bytes
 	b	__inval_dcache_area		// tail call
 SYM_CODE_END(preserve_boot_args)
 
@@ -268,7 +268,6 @@ SYM_FUNC_START_LOCAL(__create_page_tables)
 	 */
 	adrp	x0, init_pg_dir
 	adrp	x1, init_pg_end
-	sub	x1, x1, x0
 	bl	__inval_dcache_area
 
 	/*
@@ -382,12 +381,10 @@ SYM_FUNC_START_LOCAL(__create_page_tables)
 
 	adrp	x0, idmap_pg_dir
 	adrp	x1, idmap_pg_end
-	sub	x1, x1, x0
 	bl	__inval_dcache_area
 
 	adrp	x0, init_pg_dir
 	adrp	x1, init_pg_end
-	sub	x1, x1, x0
 	bl	__inval_dcache_area
 
 	ret	x28

arch/arm64/mm/cache.S

@@ -131,25 +131,24 @@ alternative_else_nop_endif
 SYM_FUNC_END(__clean_dcache_area_pou)
 
 /*
- *	__inval_dcache_area(kaddr, size)
+ *	__inval_dcache_area(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 invalidated. Any partial lines at the ends of the interval are
  *	also cleaned to PoC to prevent data loss.
  *
- *	- kaddr   - kernel address
- *	- size    - size in question
+ *	- start   - kernel start address of region
+ *	- end     - kernel end address of region
  */
 SYM_FUNC_START_LOCAL(__dma_inv_area)
 SYM_FUNC_START_PI(__inval_dcache_area)
 	/* FALLTHROUGH */
 
 /*
- *	__dma_inv_area(start, size)
+ *	__dma_inv_area(start, end)
  *	- start   - virtual start address of region
- *	- size    - size in question
+ *	- end     - virtual end address of region
  */
-	add	x1, x1, x0
 	dcache_line_size x2, x3
 	sub	x3, x2, #1
 	tst	x1, x3				// end cache line aligned?
@@ -230,8 +229,10 @@ SYM_FUNC_END_PI(__dma_flush_area)
  *	- dir	- DMA direction
  */
 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)
 
@@ -242,6 +243,7 @@ SYM_FUNC_END_PI(__dma_map_area)
  *	- dir	- DMA direction
  */
 SYM_FUNC_START_PI(__dma_unmap_area)
+	add	x1, x0, x1
 	cmp	w2, #DMA_TO_DEVICE
 	b.ne	__dma_inv_area
 	ret

arch/arm64/mm/flush.c

@@ -90,7 +90,7 @@ EXPORT_SYMBOL_GPL(arch_wb_cache_pmem);
 
 void arch_invalidate_pmem(void *addr, size_t size)
 {
-	__inval_dcache_area(addr, size);
+	__inval_dcache_area((unsigned long)addr, (unsigned long)addr + size);
 }
 EXPORT_SYMBOL_GPL(arch_invalidate_pmem);
 #endif