From: Sohil Mehta sohil.mehta@intel.com
[ Upstream commit 7a2ad752746bfb13e89a83984ecc52a48bae4969 ]
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 sohil.mehta@intel.com Signed-off-by: Ingo Molnar mingo@kernel.org Link: https://lore.kernel.org/r/20250219184133.816753-11-sohil.mehta@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/kernel/smpboot.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index c10850ae6f094..3d5069ee297bf 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -676,9 +676,9 @@ static void __init smp_quirk_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; }