Subject: [patch 08/38] x86/tsc: Use rdtsc() instead of get_cycles()

From: Thomas Gleixner <[email-masked]>
Date: Fri, 10 Apr 2026 14:19:08 +0200

This code knows that TSC is available so there is no point to use the TSC
feature guarded get_cycles().

No functional change.

Signed-off-by: Thomas Gleixner <[email-masked]>
---
 arch/x86/kernel/tsc.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -371,12 +371,12 @@ static u64 tsc_read_refs(u64 *p, int hpe
 	int i;
 
 	for (i = 0; i < MAX_RETRIES; i++) {
-		t1 = get_cycles();
+		t1 = rdtsc();
 		if (hpet)
 			*p = hpet_readl(HPET_COUNTER) & 0xFFFFFFFF;
 		else
 			*p = acpi_pm_read_early();
-		t2 = get_cycles();
+		t2 = rdtsc();
 		if ((t2 - t1) < thresh)
 			return t2;
 	}
@@ -468,13 +468,13 @@ static unsigned long pit_calibrate_tsc(u
 	outb(latch & 0xff, 0x42);
 	outb(latch >> 8, 0x42);
 
-	tsc = t1 = t2 = get_cycles();
+	tsc = t1 = t2 = rdtsc();
 
 	pitcnt = 0;
 	tscmax = 0;
 	tscmin = ULONG_MAX;
 	while ((inb(0x61) & 0x20) == 0) {
-		t2 = get_cycles();
+		t2 = rdtsc();
 		delta = t2 - tsc;
 		tsc = t2;
 		if ((unsigned long) delta < tscmin)
@@ -553,9 +553,9 @@ static inline int pit_expect_msb(unsigne
 		if (!pit_verify_msb(val))
 			break;
 		prev_tsc = tsc;
-		tsc = get_cycles();
+		tsc = rdtsc();
 	}
-	*deltap = get_cycles() - prev_tsc;
+	*deltap = rdtsc() - prev_tsc;
 	*tscp = tsc;
 
 	/*