linux-kernel - [PATCH 3/3] x86/tsc: Print tsc_khz, when it differs from cpu

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 22 Dec 2017 00:27:56 -0500
From:   Len Brown <lenb@...nel.org>
To:     x86@...nel.org
Cc:     peterz@...radead.org, linux-kernel@...r.kernel.org,
        Len Brown <len.brown@...el.com>
Subject: [PATCH 3/3] x86/tsc: Print tsc_khz, when it differs from cpu_khz

From: Len Brown <len.brown@...el.com>

When Linux detects the CPU and TSC rate are the same

tsc: Detected 2900.000 MHz processor

tells us both.  But if Linux detects a TSC rate that differs
from the CPU rate, print that also:

tsc: Detected 2904.000 MHz TSC

Signed-off-by: Len Brown <len.brown@...el.com>
---
 arch/x86/kernel/tsc.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 3bf4df7f52d7..6077ef5354d5 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1316,6 +1316,11 @@ void __init tsc_init(void)
 		(unsigned long)cpu_khz / 1000,
 		(unsigned long)cpu_khz % 1000);
 
+	if (cpu_khz != tsc_khz)
+		pr_info("Detected %lu.%03lu MHz TSC",
+			(unsigned long)tsc_khz / 1000,
+			(unsigned long)tsc_khz % 1000);
+
 	/* Sanitize TSC ADJUST before cyc2ns gets initialized */
 	tsc_store_and_check_tsc_adjust(true);
 
-- 
2.14.0-rc0