linux-kernel - [PATCH] x86/apic: Use div64_ul() instead of do

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Date: Tue, 27 Feb 2024 12:43:34 +0100
From: Thorsten Blum <thorsten.blum@...lux.com>
To: Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	x86@...nel.org
Cc: "H. Peter Anvin" <hpa@...or.com>,
	"Peter Zijlstra (Intel)" <peterz@...radead.org>,
	Wei Liu <wei.liu@...nel.org>,
	linux-kernel@...r.kernel.org,
	Thorsten Blum <thorsten.blum@...lux.com>
Subject: [PATCH] x86/apic: Use div64_ul() instead of do_div()

Fixes Coccinelle/coccicheck warnings reported by do_div.cocci.

Change deltapm to unsigned long and replace do_div() with div64_ul()
which doesn't implicitly cast the divisor and doesn't unnecessarily
calculate the remainder.

Signed-off-by: Thorsten Blum <thorsten.blum@...lux.com>
---
 arch/x86/kernel/apic/apic.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 4667bc4b00ab..facfb03ef5c8 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -699,7 +699,7 @@ static void __init lapic_cal_handler(struct clock_event_device *dev)
 }
 
 static int __init
-calibrate_by_pmtimer(long deltapm, long *delta, long *deltatsc)
+calibrate_by_pmtimer(unsigned long deltapm, long *delta, long *deltatsc)
 {
 	const long pm_100ms = PMTMR_TICKS_PER_SEC / 10;
 	const long pm_thresh = pm_100ms / 100;
@@ -710,7 +710,7 @@ calibrate_by_pmtimer(long deltapm, long *delta, long *deltatsc)
 	return -1;
 #endif
 
-	apic_printk(APIC_VERBOSE, "... PM-Timer delta = %ld\n", deltapm);
+	apic_printk(APIC_VERBOSE, "... PM-Timer delta = %lu\n", deltapm);
 
 	/* Check, if the PM timer is available */
 	if (!deltapm)
@@ -724,14 +724,14 @@ calibrate_by_pmtimer(long deltapm, long *delta, long *deltatsc)
 		return 0;
 	}
 
-	res = (((u64)deltapm) *  mult) >> 22;
+	res = (((u64)deltapm) * mult) >> 22;
 	do_div(res, 1000000);
 	pr_warn("APIC calibration not consistent "
 		"with PM-Timer: %ldms instead of 100ms\n", (long)res);
 
 	/* Correct the lapic counter value */
 	res = (((u64)(*delta)) * pm_100ms);
-	do_div(res, deltapm);
+	res = div64_ul(res, deltapm);
 	pr_info("APIC delta adjusted to PM-Timer: "
 		"%lu (%ld)\n", (unsigned long)res, *delta);
 	*delta = (long)res;
@@ -739,7 +739,7 @@ calibrate_by_pmtimer(long deltapm, long *delta, long *deltatsc)
 	/* Correct the tsc counter value */
 	if (boot_cpu_has(X86_FEATURE_TSC)) {
 		res = (((u64)(*deltatsc)) * pm_100ms);
-		do_div(res, deltapm);
+		res = div64_ul(res, deltapm);
 		apic_printk(APIC_VERBOSE, "TSC delta adjusted to "
 					  "PM-Timer: %lu (%ld)\n",
 					(unsigned long)res, *deltatsc);
-- 
2.43.2