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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /arch/arm64/lib/clear_page.S
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/arm64/lib/clear_page.S')
-rw-r--r--arch/arm64/lib/clear_page.S40
1 files changed, 40 insertions, 0 deletions
diff --git a/arch/arm64/lib/clear_page.S b/arch/arm64/lib/clear_page.S
new file mode 100644
index 0000000000..ebde40e7fa
--- /dev/null
+++ b/arch/arm64/lib/clear_page.S
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ */
+
+#include <linux/linkage.h>
+#include <linux/const.h>
+#include <asm/assembler.h>
+#include <asm/page.h>
+
+/*
+ * Clear page @dest
+ *
+ * Parameters:
+ * x0 - dest
+ */
+SYM_FUNC_START(__pi_clear_page)
+ mrs x1, dczid_el0
+ tbnz x1, #4, 2f /* Branch if DC ZVA is prohibited */
+ 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
+
+2: stnp xzr, xzr, [x0]
+ stnp xzr, xzr, [x0, #16]
+ stnp xzr, xzr, [x0, #32]
+ stnp xzr, xzr, [x0, #48]
+ add x0, x0, #64
+ tst x0, #(PAGE_SIZE - 1)
+ b.ne 2b
+ ret
+SYM_FUNC_END(__pi_clear_page)
+SYM_FUNC_ALIAS(clear_page, __pi_clear_page)
+EXPORT_SYMBOL(clear_page)