arm64: lib: clear_page with non-temporal store

Bug 1512428

Change-Id: Ic9541339b8d6113fe929bc2f7619bce9adce6c97
Signed-off-by: Alex Van Brunt <avanbrunt@nvidia.com>
Reviewed-on: http://git-master/r/411674
Reviewed-by: Mandar Padmawar <mpadmawar@nvidia.com>
Tested-by: Mandar Padmawar <mpadmawar@nvidia.com>

2 files changed, 12 insertions, 39 deletions

diff --git a/arch/arm64/lib/clear_page.S b/arch/arm64/lib/clear_page.S
deleted file mode 100644
index ef08e905e35b..000000000000
--- a/arch/arm64/lib/clear_page.S
+++ /dev/null
@@ -1,39 +0,0 @@
-/*
- * Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include <linux/linkage.h>
-#include <linux/const.h>
-#include <asm/assembler.h>
-#include <asm/page.h>
-
-/*
- * Clear page @dest
- *
- * Parameters:
- *	x0 - dest
- */
-ENTRY(clear_page)
-	mrs	x1, dczid_el0
-	and	w1, w1, #0xf
-	mov	x2, #4
-	lsl	x1, x2, x1
-
-1:	dc	zva, x0
-	add	x0, x0, x1
-	tst	x0, #(PAGE_SIZE - 1)
-	b.ne	1b
-	ret
-ENDPROC(clear_page)
diff --git a/arch/arm64/lib/clear_page.c b/arch/arm64/lib/clear_page.c
new file mode 100644
index 000000000000..45ecbda81c48
--- /dev/null
+++ b/arch/arm64/lib/clear_page.c
@@ -0,0 +1,12 @@
+#include <asm/page.h>
+#include <linux/types.h>
+
+
+void clear_page(void *to) {
+	u64 *buffer = (u64 *) to;
+	u64 zero = 0ULL;
+	u32 i;
+
+	for (i = 0; i < PAGE_SIZE / sizeof(u64); i += 2)
+		asm volatile("stnp  %0, %0, %1" : : "r" (zero), "Q" (buffer[i]) : );
+}