[src/trunk]: src/sys/arch/x86/x86 Don't use TSC freq value from CPUID if cali...

[msaitoh <msaitoh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/c4bf437c46c9
branches:  trunk
changeset: 971991:c4bf437c46c9
user:      msaitoh <msaitoh%NetBSD.org@localhost>
date:      Tue May 12 06:32:05 2020 +0000

description:
Don't use TSC freq value from CPUID if calibration works.

 - When it's the first call of cpu_get_tsc_freq() the HPET is not initialized,
   so try to use CPUID to get TSC freq.
 - If it's the 2nd call, don't use CPUID. Instead, print the difference
   between the calibrated value and CPUID's value if the verbose mode is set.

diffstat:

 sys/arch/x86/x86/cpu.c           |  23 +++++++++++++++++++----
 sys/arch/x86/x86/identcpu_subr.c |   6 +++---
 2 files changed, 22 insertions(+), 7 deletions(-)

diffs (77 lines):

diff -r f5822475f248 -r c4bf437c46c9 sys/arch/x86/x86/cpu.c
--- a/sys/arch/x86/x86/cpu.c    Tue May 12 06:23:07 2020 +0000
+++ b/sys/arch/x86/x86/cpu.c    Tue May 12 06:32:05 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: cpu.c,v 1.190 2020/05/08 22:01:55 ad Exp $     */
+/*     $NetBSD: cpu.c,v 1.191 2020/05/12 06:32:05 msaitoh Exp $        */
 
 /*
  * Copyright (c) 2000-2020 NetBSD Foundation, Inc.
@@ -62,7 +62,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.190 2020/05/08 22:01:55 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.191 2020/05/12 06:32:05 msaitoh Exp $");
 
 #include "opt_ddb.h"
 #include "opt_mpbios.h"                /* for MPDEBUG */
@@ -1320,11 +1320,19 @@
 void
 cpu_get_tsc_freq(struct cpu_info *ci)
 {
-       uint64_t freq = 0, t0, t1;
+       uint64_t freq = 0, freq_from_cpuid, t0, t1;
        int64_t overhead;
 
        if ((ci->ci_flags & CPUF_PRIMARY) != 0 && cpu_hascounter()) {
-               freq = cpu_tsc_freq_cpuid(ci);
+               /*
+                * If it's the first call of this function, try to get TSC
+                * freq from CPUID by calling cpu_tsc_freq_cpuid().
+                * The function also set lapic_per_second variable if it's
+                * known. This is required for Intel's Comet Lake and newer
+                * processors to set LAPIC timer correctly.
+                */
+               if (ci->ci_data.cpu_cc_freq == 0)
+                       freq = freq_from_cpuid = cpu_tsc_freq_cpuid(ci);
 #if NHPET > 0
                if (freq == 0)
                        freq = hpet_tsc_freq();
@@ -1352,6 +1360,13 @@
                        t1 = cpu_counter();
                        freq = (t1 - t0 - overhead) * 10;
                }
+               if (ci->ci_data.cpu_cc_freq != 0) {
+                       freq_from_cpuid = cpu_tsc_freq_cpuid(ci);
+                       if ((freq_from_cpuid != 0)
+                           && (freq != freq_from_cpuid))
+                               aprint_verbose_dev(ci->ci_dev, "TSC freq "
+                                   "calibrated %" PRIu64 " Hz\n", freq);
+               }
        } else {
                freq = cpu_info_primary.ci_data.cpu_cc_freq;
        }
diff -r f5822475f248 -r c4bf437c46c9 sys/arch/x86/x86/identcpu_subr.c
--- a/sys/arch/x86/x86/identcpu_subr.c  Tue May 12 06:23:07 2020 +0000
+++ b/sys/arch/x86/x86/identcpu_subr.c  Tue May 12 06:32:05 2020 +0000
@@ -33,7 +33,7 @@
  * See src/usr.sbin/cpuctl/{Makefile, arch/i386.c}).
  */
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: identcpu_subr.c,v 1.3 2020/04/25 15:26:18 bouyer Exp $");
+__KERNEL_RCSID(0, "$NetBSD: identcpu_subr.c,v 1.4 2020/05/12 06:32:05 msaitoh Exp $");
 
 #ifdef _KERNEL_OPT
 #include "lapic.h"
@@ -139,8 +139,8 @@
 #endif
        }
        if (freq != 0)
-               aprint_verbose_dev(ci->ci_dev, "TSC freq %" PRIu64 " Hz\n",
-                   freq);
+               aprint_verbose_dev(ci->ci_dev, "TSC freq CPUID %" PRIu64
+                   " Hz\n", freq);
 
        return freq;
 }