[PATCH 4.17 41/97] x86/cpu/intel: Evaluate smp_num_siblings early

From: Greg Kroah-Hartman
Date: Tue Aug 14 2018 - 13:30:18 EST


4.17-stable review patch. If anyone has any objections, please let me know.

------------------

From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

commit 1910ad5624968f93be48e8e265513c54d66b897c upstream

Make use of the new early detection function to initialize smp_num_siblings
on the boot cpu before the MP-Table or ACPI/MADT scan happens. That's
required for force disabling SMT.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Acked-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/intel.c | 7 +++++++
1 file changed, 7 insertions(+)

--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -301,6 +301,13 @@ static void early_init_intel(struct cpui
}

check_mpx_erratum(c);
+
+ /*
+ * Get the number of SMT siblings early from the extended topology
+ * leaf, if available. Otherwise try the legacy SMT detection.
+ */
+ if (detect_extended_topology_early(c) < 0)
+ detect_ht_early(c);
}

#ifdef CONFIG_X86_32