linux-kernel - [PATCH 3/3] x86/tsc: Use div64_64 instead of do

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Date: Sun, 28 Apr 2024 18:32:57 +0100
From: Jules Irenge <jbi.octave@...il.com>
To: mingo@...gat.com
Cc: tglx@...utronix.de, bp@...en8.de, x86@...nel.org, hpa@...or.com,
	peterz@...radead.org, rdunlap@...radead.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 3/3] x86/tsc: Use div64_64 instead of do_div()

do_div() truncates a u64 divisor to 32 bit.
This can lead to non-zero being truncated to zero for division.

Fix coccinelle warning
WARNING: do_div() does a 64-by-32 division, please consider using div64_64 instead

Signed-off-by: Jules Irenge <jbi.octave@...il.com>
---
 arch/x86/kernel/tsc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 2ed154a2642c..9106069f18b2 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -401,7 +401,7 @@ static unsigned long calc_pmtimer_ref(u64 deltatsc, u64 pm1, u64 pm2)
 	pm2 -= pm1;
 	tmp = pm2 * 1000000000LL;
 	do_div(tmp, PMTMR_TICKS_PER_SEC);
-	do_div(deltatsc, tmp);
+	div64_u64(deltatsc, tmp);
 
 	return (unsigned long) deltatsc;
 }
-- 
2.43.2