Home Home > GIT Browse
summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorPavel Tatashin <pasha.tatashin@oracle.com>2017-10-27 20:11:00 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-11-15 10:09:19 +0100
commitb192d70c54b74684a2fd515a13da60ace3270daa (patch)
treeef6567d4023ccf7d6b3c0ee36358b598d7f0fc48
parent466d590ebd51a8af77116fe81cf13a134ea5b119 (diff)
x86/smpboot: Make optimization of delay calibration work correctly
commit 76ce7cfe35ef58f34e6ba85327afb5fbf6c3ff9b upstream. If the TSC has constant frequency then the delay calibration can be skipped when it has been calibrated for a package already. This is checked in calibrate_delay_is_known(), but that function is buggy in two aspects: It returns 'false' if (!tsc_disabled && !cpu_has(&cpu_data(cpu), X86_FEATURE_CONSTANT_TSC) which is obviously the reverse of the intended check and the check for the sibling mask cannot work either because the topology links have not been set up yet. Correct the condition and move the call to set_cpu_sibling_map() before invoking calibrate_delay() so the sibling check works correctly. [ tglx: Rewrote changelong ] Fixes: c25323c07345 ("x86/tsc: Use topology functions") Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: peterz@infradead.org Cc: bob.picco@oracle.com Cc: steven.sistare@oracle.com Cc: daniel.m.jordan@oracle.com Link: https://lkml.kernel.org/r/20171028001100.26603-1-pasha.tatashin@oracle.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/x86/kernel/smpboot.c11
-rw-r--r--arch/x86/kernel/tsc.c8
2 files changed, 9 insertions, 10 deletions
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 54b9e89d4d6b..893fd8c849e2 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -194,6 +194,12 @@ static void smp_callin(void)
smp_store_cpu_info(cpuid);
/*
+ * The topology information must be up to date before
+ * calibrate_delay() and notify_cpu_starting().
+ */
+ set_cpu_sibling_map(raw_smp_processor_id());
+
+ /*
* Get our bogomips.
* Update loops_per_jiffy in cpu_data. Previous call to
* smp_store_cpu_info() stored a value that is close but not as
@@ -203,11 +209,6 @@ static void smp_callin(void)
cpu_data(cpuid).loops_per_jiffy = loops_per_jiffy;
pr_debug("Stack at about %p\n", &cpuid);
- /*
- * This must be done before setting cpu_online_mask
- * or calling notify_cpu_starting.
- */
- set_cpu_sibling_map(raw_smp_processor_id());
wmb();
notify_cpu_starting(cpuid);
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 796d96bb0821..ad2b925a808e 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1346,12 +1346,10 @@ void __init tsc_init(void)
unsigned long calibrate_delay_is_known(void)
{
int sibling, cpu = smp_processor_id();
- struct cpumask *mask = topology_core_cpumask(cpu);
+ int constant_tsc = cpu_has(&cpu_data(cpu), X86_FEATURE_CONSTANT_TSC);
+ const struct cpumask *mask = topology_core_cpumask(cpu);
- if (!tsc_disabled && !cpu_has(&cpu_data(cpu), X86_FEATURE_CONSTANT_TSC))
- return 0;
-
- if (!mask)
+ if (tsc_disabled || !constant_tsc || !mask)
return 0;
sibling = cpumask_any_but(mask, cpu);