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x86/cpu/common: Provide detect_ht_early() 

To support force disabling of SMT it's required to know the number of
thread siblings early. detect_ht() cannot be called before the APIC driver
is selected, so split out the part which initializes smp_num_siblings.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Thomas Gleixner 2018-06-06 00:53:57 +02:00
parent 44ca36de56
commit 545401f444
2 changed files with 16 additions and 11 deletions
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26
arch/x86/kernel/cpu/common.c
View File

@ -658,32 +658,36 @@ static void cpu_detect_tlb(struct cpuinfo_x86 *c)
tlb_lld_4m[ENTRIES], tlb_lld_1g[ENTRIES]);
}
void detect_ht(struct cpuinfo_x86 *c)
int detect_ht_early(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_SMP
u32 eax, ebx, ecx, edx;
int index_msb, core_bits;
if (!cpu_has(c, X86_FEATURE_HT))
return;
return -1;
if (cpu_has(c, X86_FEATURE_CMP_LEGACY))
return;
return -1;
if (cpu_has(c, X86_FEATURE_XTOPOLOGY))
return;
return -1;
cpuid(1, &eax, &ebx, &ecx, &edx);
smp_num_siblings = (ebx & 0xff0000) >> 16;
if (!smp_num_siblings)
smp_num_siblings = 1;
if (smp_num_siblings == 1) {
if (smp_num_siblings == 1)
pr_info_once("CPU0: Hyper-Threading is disabled\n");
#endif
return 0;
}
void detect_ht(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_SMP
int index_msb, core_bits;
if (detect_ht_early(c) < 0)
return;
}
index_msb = get_count_order(smp_num_siblings);
c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, index_msb);

1
arch/x86/kernel/cpu/cpu.h
View File

@ -56,6 +56,7 @@ extern void init_amd_cacheinfo(struct cpuinfo_x86 *c);
extern void detect_num_cpu_cores(struct cpuinfo_x86 *c);
extern int detect_extended_topology(struct cpuinfo_x86 *c);
extern int detect_ht_early(struct cpuinfo_x86 *c);
extern void detect_ht(struct cpuinfo_x86 *c);
unsigned int aperfmperf_get_khz(int cpu);