From 1e1d7e25fd759eddf96d8ab39d0a90a1979b2d8c 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 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 --- 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 d120e5cefca9..b20dee982a53 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 @@ -681,6 +692,8 @@ static void early_init_amd(struct cpuinfo_x86 *c) set_cpu_bug(c, X86_BUG_AMD_E400); early_detect_mem_encrypt(c); + + amd_get_topology_early(c); } static void init_amd_k8(struct cpuinfo_x86 *c) -- 2.45.2