linux-kernel - [PATCH v2] x86/apic: Update TSC_DEADLINE quirk with additional SKX stepping

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Message-Id: <60f2bbf7cf617e212b522e663f84225bfebc50e5.1507756305.git.len.brown@intel.com>
Date:   Wed, 11 Oct 2017 17:16:04 -0400
From:   Len Brown <lenb@...nel.org>
To:     peterz@...radead.org
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org,
        Len Brown <len.brown@...el.com>
Subject: [PATCH v2] x86/apic: Update TSC_DEADLINE quirk with additional SKX stepping

From: Len Brown <len.brown@...el.com>

SKX stepping-3 fixed the TSC_DEADLINE issue in a different ucode
version number than stepping-4.  Linux needs to know this stepping-3
specific version number to also enable the TSC_DEADLINE on stepping-3.

The steppings and ucode versions are documented in the SKX BIOS update:
https://downloadmirror.intel.com/26978/eng/ReleaseNotes_R00.01.0004.txt

Signed-off-by: Len Brown <len.brown@...el.com>
---
wups, clicked send too quick on previous version, which
had HSX in the commit message, rather than SKX.

Peterz,
as this is a patch to your patch, appreciate your ack.

thanks,
-Len

---
 arch/x86/kernel/apic/apic.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index d705c769f77d..da13b6abef2c 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -573,11 +573,21 @@ static u32 bdx_deadline_rev(void)
 	return ~0U;
 }
 
+static u32 skx_deadline_rev(void)
+{
+	switch (boot_cpu_data.x86_mask) {
+	case 0x03: return 0x01000136;
+	case 0x04: return 0x02000014;
+	}
+
+	return ~0U;
+}
+
 static const struct x86_cpu_id deadline_match[] = {
 	DEADLINE_MODEL_MATCH_FUNC( INTEL_FAM6_HASWELL_X,	hsx_deadline_rev),
 	DEADLINE_MODEL_MATCH_REV ( INTEL_FAM6_BROADWELL_X,	0x0b000020),
 	DEADLINE_MODEL_MATCH_FUNC( INTEL_FAM6_BROADWELL_XEON_D,	bdx_deadline_rev),
-	DEADLINE_MODEL_MATCH_REV ( INTEL_FAM6_SKYLAKE_X,	0x02000014),
+	DEADLINE_MODEL_MATCH_FUNC( INTEL_FAM6_SKYLAKE_X,	skx_deadline_rev),
 
 	DEADLINE_MODEL_MATCH_REV ( INTEL_FAM6_HASWELL_CORE,	0x22),
 	DEADLINE_MODEL_MATCH_REV ( INTEL_FAM6_HASWELL_ULT,	0x20),
-- 
2.14.0-rc0