From f57a3a31c8d074b309f797a4336101e4c1e5ed39 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Fri, 11 Feb 2022 06:58:12 -0700
Subject: [PATCH] Add aarch64 cpu clock support

We can use cntvct_el0 to read the CPU clock.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 arch/arch-aarch64.h | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/arch/arch-aarch64.h b/arch/arch-aarch64.h
index 2a86cc5a..94571709 100644
--- a/arch/arch-aarch64.h
+++ b/arch/arch-aarch64.h
@@ -27,4 +27,21 @@ static inline int arch_ffz(unsigned long bitmask)
 
 #define ARCH_HAVE_FFZ
 
+static inline unsigned long long get_cpu_clock(void)
+{
+	unsigned long val;
+
+	asm volatile("mrs %0, cntvct_el0" : "=r" (val));
+	return val;
+}
+#define ARCH_HAVE_CPU_CLOCK
+
+#define ARCH_HAVE_INIT
+extern bool tsc_reliable;
+static inline int arch_init(char *envp[])
+{
+	tsc_reliable = true;
+	return 0;
+}
+
 #endif
-- 
2.25.1