dd458c42c2
commit 17f6bac2249356c795339e03a0742cd79be3cab8 upstream.
Loops per jiffy is calculated by multiplying tsc_khz with 1e3 and then
dividing it by HZ.
Both tsc_khz and the temporary variable holding the multiplication result
are of type unsigned long, so on 32bit the result is truncated to the lower
32bit.
Use u64 as type for the temporary variable and cast tsc_khz to it before
multiplying.
[ tglx: Massaged changelog and removed pointless braces ]
[ tglx: Backport to stable. Due to massive code changes is the upstream
commit not applicable anymore. The issue has gone unnoticed in
kernels pre 4.19 because the bogus LPJ value gets fixed up in a
later stage of early boot, but it still might cause subtle and hard
to debug issues between these two points. ]
Fixes: cf7a63ef4e02 ("x86/tsc: Calibrate tsc only once")
Signed-off-by: Chuanhua Lei <chuanhua.lei@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: yixin.zhu@linux.intel.com
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Tatashin <pasha.tatashin@microsoft.com>
Cc: Rajvi Jingar <rajvi.jingar@intel.com>
Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
Link: https://lkml.kernel.org/r/1536228203-18701-1-git-send-email-chuanhua.lei@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.