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Subject[PATCH 1/4] x86/kernel: Remove requirement that TSC ADJUST must be 0 on socket 0
Remove the requirement that the TSC ADJUST value for socket 0 must
be zero. This is the case when there are multiple chassis are being
reset asynchronously with each other and socket 0 may not necessarily
be starting first.

Signed-off-by: Mike Travis <mike.travis@hpe.com>
Reviewed-by: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Reviewed-by: Russ Anderson <russ.anderson@hpe.com>
---
arch/x86/kernel/tsc_sync.c | 29 +++--------------------------
1 file changed, 3 insertions(+), 26 deletions(-)

--- linux.orig/arch/x86/kernel/tsc_sync.c
+++ linux/arch/x86/kernel/tsc_sync.c
@@ -58,29 +58,6 @@ void tsc_verify_tsc_adjust(bool resume)
}
}

-static void tsc_sanitize_first_cpu(struct tsc_adjust *cur, s64 bootval,
- unsigned int cpu, bool bootcpu)
-{
- /*
- * First online CPU in a package stores the boot value in the
- * adjustment value. This value might change later via the sync
- * mechanism. If that fails we still can yell about boot values not
- * being consistent.
- *
- * On the boot cpu we just force set the ADJUST value to 0 if it's
- * non zero. We don't do that on non boot cpus because physical
- * hotplug should have set the ADJUST register to a value > 0 so
- * the TSC is in sync with the already running cpus.
- */
- if (bootcpu && bootval != 0) {
- pr_warn(FW_BUG "TSC ADJUST: CPU%u: %lld force to 0\n", cpu,
- bootval);
- wrmsrl(MSR_IA32_TSC_ADJUST, 0);
- bootval = 0;
- }
- cur->adjusted = bootval;
-}
-
#ifndef CONFIG_SMP
bool __init tsc_store_and_check_tsc_adjust(bool bootcpu)
{
@@ -92,8 +69,8 @@ bool __init tsc_store_and_check_tsc_adju

rdmsrl(MSR_IA32_TSC_ADJUST, bootval);
cur->bootval = bootval;
+ cur->adjusted = bootval;
cur->nextcheck = jiffies + HZ;
- tsc_sanitize_first_cpu(cur, bootval, smp_processor_id(), bootcpu);
return false;
}

@@ -114,6 +91,7 @@ bool tsc_store_and_check_tsc_adjust(bool

rdmsrl(MSR_IA32_TSC_ADJUST, bootval);
cur->bootval = bootval;
+ cur->adjusted = bootval;
cur->nextcheck = jiffies + HZ;
cur->warned = false;

@@ -128,8 +106,7 @@ bool tsc_store_and_check_tsc_adjust(bool
refcpu = mask ? cpumask_any_but(mask, cpu) : nr_cpu_ids;

if (refcpu >= nr_cpu_ids) {
- tsc_sanitize_first_cpu(cur, bootval, smp_processor_id(),
- bootcpu);
+ cur->adjusted = bootval;
return false;
}

--

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