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[PATCH] x86-64/i386: Intel HT, Multi core detection fixes

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Fields obtained through cpuid vector 0x1(ebx[16:23]) and
vector 0x4(eax[14:25], eax[26:31]) indicate the maximum values and might not
always be the same as what is available and what OS sees.  So make sure
"siblings" and "cpu cores" values in /proc/cpuinfo reflect the values as seen
by OS instead of what cpuid instruction says. This will also fix the buggy BIOS
cases (for example where cpuid on a single core cpu says there are "2" siblings,
even when HT is disabled in the BIOS.
http://bugzilla.kernel.org/show_bug.cgi?id=4359)

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Siddha, Suresh B
2005-11-05 17:25:54 +01:00
committed by Linus Torvalds
parent e90f22edf4
commit 94605eff57
11 changed files with 178 additions and 110 deletions
Download Patch File Download Diff File Expand all files Collapse all files

36
arch/i386/kernel/cpu/common.c
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@@ -335,7 +335,7 @@ void __devinit identify_cpu(struct cpuinfo_x86 *c)
c->x86_model = c->x86_mask = 0; /* So far unknown... */
c->x86_vendor_id[0] = '\0'; /* Unset */
c->x86_model_id[0] = '\0'; /* Unset */
c->x86_num_cores = 1;
c->x86_max_cores = 1;
memset(&c->x86_capability, 0, sizeof c->x86_capability);
if (!have_cpuid_p()) {
@@ -446,52 +446,44 @@ void __devinit identify_cpu(struct cpuinfo_x86 *c)
void __devinit detect_ht(struct cpuinfo_x86 *c)
{
u32 eax, ebx, ecx, edx;
int index_msb, tmp;
int index_msb, core_bits;
int cpu = smp_processor_id();
cpuid(1, &eax, &ebx, &ecx, &edx);
c->apicid = phys_pkg_id((ebx >> 24) & 0xFF, 0);
if (!cpu_has(c, X86_FEATURE_HT) || cpu_has(c, X86_FEATURE_CMP_LEGACY))
return;
cpuid(1, &eax, &ebx, &ecx, &edx);
smp_num_siblings = (ebx & 0xff0000) >> 16;
if (smp_num_siblings == 1) {
printk(KERN_INFO "CPU: Hyper-Threading is disabled\n");
} else if (smp_num_siblings > 1 ) {
index_msb = 31;
if (smp_num_siblings > NR_CPUS) {
printk(KERN_WARNING "CPU: Unsupported number of the siblings %d", smp_num_siblings);
smp_num_siblings = 1;
return;
}
tmp = smp_num_siblings;
while ((tmp & 0x80000000 ) == 0) {
tmp <<=1 ;
index_msb--;
}
if (smp_num_siblings & (smp_num_siblings - 1))
index_msb++;
index_msb = get_count_order(smp_num_siblings);
phys_proc_id[cpu] = phys_pkg_id((ebx >> 24) & 0xFF, index_msb);
printk(KERN_INFO "CPU: Physical Processor ID: %d\n",
phys_proc_id[cpu]);
smp_num_siblings = smp_num_siblings / c->x86_num_cores;
smp_num_siblings = smp_num_siblings / c->x86_max_cores;
tmp = smp_num_siblings;
index_msb = 31;
while ((tmp & 0x80000000) == 0) {
tmp <<=1 ;
index_msb--;
}
index_msb = get_count_order(smp_num_siblings) ;
if (smp_num_siblings & (smp_num_siblings - 1))
index_msb++;
core_bits = get_count_order(c->x86_max_cores);
cpu_core_id[cpu] = phys_pkg_id((ebx >> 24) & 0xFF, index_msb);
cpu_core_id[cpu] = phys_pkg_id((ebx >> 24) & 0xFF, index_msb) &
((1 << core_bits) - 1);
if (c->x86_num_cores > 1)
if (c->x86_max_cores > 1)
printk(KERN_INFO "CPU: Processor Core ID: %d\n",
cpu_core_id[cpu]);
}