From 63f2c9b0d42f7afcdd698025885dd48bc73a8a5b Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 6 Jun 2018 00:57:38 +0200 Subject: [PATCH] x86/cpu/AMD: Evaluate smp_num_siblings early 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(). Signed-off-by: Thomas Gleixner Acked-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/amd.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index f9b3011..bac32d1 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -315,6 +315,17 @@ static void legacy_fixup_core_id(struct cpuinfo_x86 *c) c->cpu_core_id %= cus_per_node; } + +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 @@ -668,6 +679,8 @@ static void early_init_amd(struct cpuinfo_x86 *c) clear_cpu_cap(c, X86_FEATURE_SME); } } + + amd_get_topology_early(c); } static void init_amd_k8(struct cpuinfo_x86 *c) -- 2.7.4