From: Jules Irenge <jbi.octave@gmail.com>
To: mingo@redhat.com
Cc: tglx@linutronix.de, bp@alien8.de, x86@kernel.org, hpa@zytor.com,
peterz@infradead.org, rdunlap@infradead.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 1/3] x86/tsc: Use div64_ul instead of do_div()
Date: Sun, 28 Apr 2024 18:31:16 +0100 [thread overview]
Message-ID: <Zi6H5P_mc6DPR_v3@octinomon.home> (raw)
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_ul instead
Signed-off-by: Jules Irenge <jbi.octave@gmail.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 5a69a49acc96..2da37f33dd17 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -484,7 +484,7 @@ static unsigned long pit_calibrate_tsc(u32 latch, unsigned long ms, int loopmin)
/* Calculate the PIT value */
delta = t2 - t1;
- do_div(delta, ms);
+ div64_ul(delta, ms);
return delta;
}
--
2.43.2
next reply other threads:[~2024-04-28 17:31 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-28 17:31 Jules Irenge [this message]
2024-04-28 19:13 ` [PATCH 1/3] x86/tsc: Use div64_ul instead of do_div() H. Peter Anvin
2024-05-02 16:30 ` David Laight
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