4.9-stable review patch. If anyone has any objections, please let me know.
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From: Thomas Gleixner tglx@linutronix.de
commit 1e1d7e25fd759eddf96d8ab39d0a90a1979b2d8c upstream
To support force disabling of SMT it's required to know the number of thread siblings early. amd_get_topology() cannot be called before the APIC driver is selected, so split out the part which initializes smp_num_siblings and invoke it from amd_early_init().
[dwmw2: Backport to 4.9]
Signed-off-by: Thomas Gleixner tglx@linutronix.de Acked-by: Ingo Molnar mingo@kernel.org Signed-off-by: David Woodhouse dwmw@amazon.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kernel/cpu/amd.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)
--- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -296,13 +296,24 @@ static int nearby_node(int apicid) } #endif
+#ifdef CONFIG_SMP + +static void amd_get_topology_early(struct cpuinfo_x86 *c) +{ + if (boot_cpu_has(X86_FEATURE_TOPOEXT)) { + u32 eax, ebx, ecx, edx; + + cpuid(0x8000001e, &eax, &ebx, &ecx, &edx); + smp_num_siblings = ((ebx >> 8) & 0xff) + 1; + } +} + /* * Fixup core topology information for * (1) AMD multi-node processors * Assumption: Number of cores in each internal node is the same. * (2) AMD processors supporting compute units */ -#ifdef CONFIG_SMP static void amd_get_topology(struct cpuinfo_x86 *c) { u8 node_id; @@ -633,6 +644,8 @@ static void early_init_amd(struct cpuinf */ if (cpu_has_amd_erratum(c, amd_erratum_400)) set_cpu_bug(c, X86_BUG_AMD_E400); + + amd_get_topology_early(c); }
static void init_amd_k8(struct cpuinfo_x86 *c)