3 files changed, 100 insertions, 5 deletions

diff --git a/arch/arm64/lib/Makefile b/arch/arm64/lib/Makefile
index 9a8cb96555d6..4e696f96451f 100644
--- a/arch/arm64/lib/Makefile
+++ b/arch/arm64/lib/Makefile
@@ -3,7 +3,7 @@ lib-y		:= bitops.o clear_user.o delay.o copy_from_user.o	\
 		   copy_to_user.o copy_in_user.o copy_page.o		\
 		   clear_page.o memchr.o memcpy.o memmove.o memset.o	\
 		   memcmp.o strcmp.o strncmp.o strlen.o strnlen.o	\
-		   strchr.o strrchr.o
+		   strchr.o strrchr.o tishift.o
 
 # Tell the compiler to treat all general purpose registers (with the
 # exception of the IP registers, which are already handled by the caller
diff --git a/arch/arm64/lib/delay.c b/arch/arm64/lib/delay.c
index dad4ec9bbfd1..e48ac402e7be 100644
--- a/arch/arm64/lib/delay.c
+++ b/arch/arm64/lib/delay.c
@@ -24,10 +24,28 @@
 #include <linux/module.h>
 #include <linux/timex.h>
 
+#include <clocksource/arm_arch_timer.h>
+
+#define USECS_TO_CYCLES(time_usecs)			\
+	xloops_to_cycles((time_usecs) * 0x10C7UL)
+
+static inline unsigned long xloops_to_cycles(unsigned long xloops)
+{
+	return (xloops * loops_per_jiffy * HZ) >> 32;
+}
+
 void __delay(unsigned long cycles)
 {
 	cycles_t start = get_cycles();
 
+	if (arch_timer_evtstrm_available()) {
+		const cycles_t timer_evt_period =
+			USECS_TO_CYCLES(ARCH_TIMER_EVT_STREAM_PERIOD_US);
+
+		while ((get_cycles() - start + timer_evt_period) < cycles)
+			wfe();
+	}
+
 	while ((get_cycles() - start) < cycles)
 		cpu_relax();
 }
@@ -35,10 +53,7 @@ EXPORT_SYMBOL(__delay);
 
 inline void __const_udelay(unsigned long xloops)
 {
-	unsigned long loops;
-
-	loops = xloops * loops_per_jiffy * HZ;
-	__delay(loops >> 32);
+	__delay(xloops_to_cycles(xloops));
 }
 EXPORT_SYMBOL(__const_udelay);
 
diff --git a/arch/arm64/lib/tishift.S b/arch/arm64/lib/tishift.S
new file mode 100644
index 000000000000..0179a43cc045
--- /dev/null
+++ b/arch/arm64/lib/tishift.S
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2017 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ * 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>
+
+ENTRY(__ashlti3)
+	cbz	x2, 1f
+	mov	x3, #64
+	sub	x3, x3, x2
+	cmp	x3, #0
+	b.le	2f
+	lsl	x1, x1, x2
+	lsr	x3, x0, x3
+	lsl	x2, x0, x2
+	orr	x1, x1, x3
+	mov	x0, x2
+1:
+	ret
+2:
+	neg	w1, w3
+	mov	x2, #0
+	lsl	x1, x0, x1
+	mov	x0, x2
+	ret
+ENDPROC(__ashlti3)
+
+ENTRY(__ashrti3)
+	cbz	x2, 3f
+	mov	x3, #64
+	sub	x3, x3, x2
+	cmp	x3, #0
+	b.le	4f
+	lsr	x0, x0, x2
+	lsl	x3, x1, x3
+	asr	x2, x1, x2
+	orr	x0, x0, x3
+	mov	x1, x2
+3:
+	ret
+4:
+	neg	w0, w3
+	asr	x2, x1, #63
+	asr	x0, x1, x0
+	mov	x1, x2
+	ret
+ENDPROC(__ashrti3)
+
+ENTRY(__lshrti3)
+	cbz	x2, 1f
+	mov	x3, #64
+	sub	x3, x3, x2
+	cmp	x3, #0
+	b.le	2f
+	lsr	x0, x0, x2
+	lsl	x3, x1, x3
+	lsr	x2, x1, x2
+	orr	x0, x0, x3
+	mov	x1, x2
+1:
+	ret
+2:
+	neg	w0, w3
+	mov	x2, #0
+	lsr	x0, x1, x0
+	mov	x1, x2
+	ret
+ENDPROC(__lshrti3)