From 2647c43c7f3ba4b752bfce261d53b16e2f5bc9e3 Mon Sep 17 00:00:00 2001 From: Mike Travis Date: Tue, 2 Oct 2018 13:01:46 -0500 Subject: [PATCH] x86/tsc: Fix UV TSC initialization The recent rework of the TSC calibration code introduced a regression on UV systems as it added a call to tsc_early_init() which initializes the TSC ADJUST values before acpi_boot_table_init(). In the case of UV systems, that is a necessary step that calls uv_system_init(). This informs tsc_sanitize_first_cpu() that the kernel runs on a platform with async TSC resets as documented in commit 341102c3ef29 ("x86/tsc: Add option that TSC on Socket 0 being non-zero is valid") Fix it by skipping the early tsc initialization on UV systems and let TSC init tests take place later in tsc_init(). Fixes: cf7a63ef4e02 ("x86/tsc: Calibrate tsc only once") Suggested-by: Hedi Berriche Signed-off-by: Mike Travis Signed-off-by: Thomas Gleixner Reviewed-by: Russ Anderson Reviewed-by: Dimitri Sivanich Cc: "H. Peter Anvin" Cc: Russ Anderson Cc: Dimitri Sivanich Cc: Borislav Petkov Cc: Kate Stewart Cc: Greg Kroah-Hartman Cc: Philippe Ombredanne Cc: Pavel Tatashin Cc: Peter Zijlstra Cc: Len Brown Cc: Dou Liyang Cc: Xiaoming Gao Cc: Rajvi Jingar Link: https://lkml.kernel.org/r/20181002180144.923579706@stormcage.americas.sgi.com --- arch/x86/kernel/tsc.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 6490f618e096..b52bd2b6cdb4 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -26,6 +26,7 @@ #include #include #include +#include unsigned int __read_mostly cpu_khz; /* TSC clocks / usec, not used here */ EXPORT_SYMBOL(cpu_khz); @@ -1433,6 +1434,9 @@ void __init tsc_early_init(void) { if (!boot_cpu_has(X86_FEATURE_TSC)) return; + /* Don't change UV TSC multi-chassis synchronization */ + if (is_early_uv_system()) + return; if (!determine_cpu_tsc_frequencies(true)) return; loops_per_jiffy = get_loops_per_jiffy();