x86/smpboot: Fix INIT delay assignment for extended Intel Families

Some old crusty CPUs need an extra delay that slows down booting. See
the comment above 'init_udelay' for details. Newer CPUs don't need the
delay.

Right now, for Intel, Family 6 and only Family 6 skips the delay. That
leaves out both the Family 15 (Pentium 4s) and brand new Family 18/19
models.

The omission of Family 15 (Pentium 4s) seems like an oversight and 18/19
do not need the delay.

Skip the delay on all Intel processors Family 6 and beyond.

Signed-off-by: Sohil Mehta <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: sohilmeh

arch/x86/kernel/smpboot.c

@@ -656,9 +656,9 @@ static void __init smp_set_init_udelay(void)
 		return;
 
 	/* if modern processor, use no delay */
-	if (((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) && (boot_cpu_data.x86 == 6)) ||
-	    ((boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) && (boot_cpu_data.x86 >= 0x18)) ||
-	    ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD) && (boot_cpu_data.x86 >= 0xF))) {
+	if ((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL && boot_cpu_data.x86_vfm >= INTEL_PENTIUM_PRO) ||
+	    (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON && boot_cpu_data.x86 >= 0x18) ||
+	    (boot_cpu_data.x86_vendor == X86_VENDOR_AMD   && boot_cpu_data.x86 >= 0xF)) {
 		init_udelay = 0;
 		return;
 	}