[PATCH 4.17 007/220] x86/mce: Check for alternate indication of machine check recovery on Skylake

[Greg Kroah-Hartman]

4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tony Luck <tony.luck@xxxxxxxxx>

commit 4c5717da1d021cf368eabb3cb1adcaead56c0d1e upstream.

Currently we just check the "CAPID0" register to see whether the CPU
can recover from machine checks.

But there are also some special SKUs which do not have all advanced
RAS features, but do enable machine check recovery for use with NVDIMMs.

Add a check for any of bits {8:5} in the "CAPID5" register (each
reports some NVDIMM mode available, if any of them are set, then
the system supports memory machine check recovery).

Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Qiuxu Zhuo <qiuxu.zhuo@xxxxxxxxx>
Cc: Ashok Raj <ashok.raj@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # 4.9
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Link: https://lkml.kernel.org/r/03cbed6e99ddafb51c2eadf9a3b7c8d7a0cc204e.1527283897.git.tony.luck@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/x86/kernel/quirks.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

--- a/arch/x86/kernel/quirks.c
+++ b/arch/x86/kernel/quirks.c
@@ -645,12 +645,19 @@ static void quirk_intel_brickland_xeon_r
 /* Skylake */
 static void quirk_intel_purley_xeon_ras_cap(struct pci_dev *pdev)
 {
-	u32 capid0;
+	u32 capid0, capid5;
 
 	pci_read_config_dword(pdev, 0x84, &capid0);
+	pci_read_config_dword(pdev, 0x98, &capid5);
 
-	if ((capid0 & 0xc0) == 0xc0)
+	/*
+	 * CAPID0{7:6} indicate whether this is an advanced RAS SKU
+	 * CAPID5{8:5} indicate that various NVDIMM usage modes are
+	 * enabled, so memory machine check recovery is also enabled.
+	 */
+	if ((capid0 & 0xc0) == 0xc0 || (capid5 & 0x1e0))
 		static_branch_inc(&mcsafe_key);
+
 }
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x0ec3, quirk_intel_brickland_xeon_ras_cap);
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x2fc0, quirk_intel_brickland_xeon_ras_cap);