From: Peter Zijlstra <peterz@infradead.org>
Date: Fri, 4 Mar 2022 15:19:54 +0000 (+0100)
Subject: x86/tsc: Be consistent about use_tsc_delay()
X-Git-Tag: v6.1-rc5~1706^2~19
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=69f8aeab437c6bae1394673154917e0a218edb44;p=platform%2Fkernel%2Flinux-starfive.git

x86/tsc: Be consistent about use_tsc_delay()

Currently loops_per_jiffy is set in tsc_early_init(), but then don't
switch to delay_tsc, with the result that delay_loop is used with
loops_per_jiffy set for delay_tsc.

Then in (late) tsc_init() lpj_fine is set (which is mostly unused) and
after which use_tsc_delay() is finally called.

Move both loops_per_jiffy and use_tsc_delay() into
tsc_enable_sched_clock() which is called the moment tsc_khz is
determined, be it early or late. Keeping the lot consistent.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220304152135.914397165@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index a698196..cafacb2 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1487,6 +1487,9 @@ static unsigned long __init get_loops_per_jiffy(void)
 
 static void __init tsc_enable_sched_clock(void)
 {
+	loops_per_jiffy = get_loops_per_jiffy();
+	use_tsc_delay();
+
 	/* Sanitize TSC ADJUST before cyc2ns gets initialized */
 	tsc_store_and_check_tsc_adjust(true);
 	cyc2ns_init_boot_cpu();
@@ -1502,8 +1505,6 @@ void __init tsc_early_init(void)
 		return;
 	if (!determine_cpu_tsc_frequencies(true))
 		return;
-	loops_per_jiffy = get_loops_per_jiffy();
-
 	tsc_enable_sched_clock();
 }
 
@@ -1537,7 +1538,6 @@ void __init tsc_init(void)
 		enable_sched_clock_irqtime();
 
 	lpj_fine = get_loops_per_jiffy();
-	use_tsc_delay();
 
 	check_system_tsc_reliable();