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Prefer CPUID leaf 1Fh for Intel CPU topology detection.

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Leaf 1Fh is a prefered extended version of 0Bh.  It is supported by
new Lader Lake CPUs, though does not report anything new so far.

MFC after:	2 weeks
This commit is contained in:
Alexander Motin 2021-11-06 00:48:37 -04:00
parent 74aec9618f
commit 6badb512a9
1 changed files with 17 additions and 8 deletions
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25
sys/x86/x86/mp_x86.c
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@ -380,7 +380,7 @@ topo_probe_intel_0x4(void)
/*
* Determine topology of processing units for Intel CPUs
* using CPUID Leaf 11, if supported.
* using CPUID Leaf 1Fh or 0Bh, if supported.
* See:
* - Intel 64 Architecture Processor Topology Enumeration
* - Intel 64 and IA-32 ArchitecturesSoftware Developer’s Manual,
@ -390,13 +390,23 @@ topo_probe_intel_0x4(void)
static void
topo_probe_intel_0xb(void)
{
u_int p[4];
u_int leaf;
u_int p[4] = { 0 };
int bits;
int type;
int i;
/* Fall back if CPU leaf 11 doesn't really exist. */
cpuid_count(0x0b, 0, p);
/* Prefer leaf 1Fh (V2 Extended Topology Enumeration). */
if (cpu_high >= 0x1f) {
leaf = 0x1f;
cpuid_count(leaf, 0, p);
}
/* Fall back to leaf 0Bh (Extended Topology Enumeration). */
if (p[1] == 0) {
leaf = 0x0b;
cpuid_count(leaf, 0, p);
}
/* Fall back to leaf 04h (Deterministic Cache Parameters). */
if (p[1] == 0) {
topo_probe_intel_0x4();
return;
@ -404,7 +414,7 @@ topo_probe_intel_0xb(void)
/* We only support three levels for now. */
for (i = 0; ; i++) {
cpuid_count(0x0b, i, p);
cpuid_count(leaf, i, p);
bits = p[0] & 0x1f;
type = (p[2] >> 8) & 0xff;
@ -412,13 +422,12 @@ topo_probe_intel_0xb(void)
if (type == 0)
break;
/* TODO: check for duplicate (re-)assignment */
if (type == CPUID_TYPE_SMT)
core_id_shift = bits;
else if (type == CPUID_TYPE_CORE)
pkg_id_shift = bits;
else
printf("unknown CPU level type %d\n", type);
else if (bootverbose)
printf("Topology level type %d shift: %d\n", type, bits);
}
if (pkg_id_shift < core_id_shift) {