From ae76eb1198fb9f90217d6f36072b780a250dda98 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(). [dwmw2: Backport to 4.9] Signed-off-by: Thomas Gleixner Acked-by: Ingo Molnar Signed-off-by: David Woodhouse Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/amd.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index e9b613a..fa2bdf5 100644 --- 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 cpuinfo_x86 *c) */ 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) -- 2.7.4