Commit 7a2ad752 authored by Sohil Mehta's avatar Sohil Mehta Committed by Ingo Molnar
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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: default avatarSohil Mehta <sohil.mehta@intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250219184133.816753-11-sohil.mehta@intel.com
parent 58d1c1fd

arch/x86/kernel/smpboot.c

+3 −3
Original line number Diff line number Diff line
@@ -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;

	}