[PATCH v18 01/13] cxl/ras: Fix cxl_rch_get_aer_severity() wrong severity register

[Terry Bowman]

cxl_rch_get_aer_severity() classifies RCH Downstream Port uncorrectable
errors as fatal or non-fatal by ANDing uncorrectable status with
PCI_ERR_ROOT_FATAL_RCV. This is wrong because PCI_ERR_ROOT_FATAL_RCV is a
Root Error Status register bit (bit 6), not a severity bit. ANDing it
against uncorrectable status tests a reserved bit and produces incorrect
severity classification.

Fix by ANDing the unmasked uncor_status against uncor_severity. Per
PCIe Base Spec r6.0 Section 7.8.4.4, each bit in the Uncorrectable
Error Severity register indicates whether the corresponding error is
fatal (1) or non-fatal (0).

Fixes: 6ac07883dbb5 ("cxl/pci: Add RCH downstream port error logging")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Terry Bowman <terry.bowman@xxxxxxx>

---

Changes in v17 -> v18:
- New patch.
---
 drivers/cxl/core/ras_rch.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/cxl/core/ras_rch.c b/drivers/cxl/core/ras_rch.c
index 0a8b3b9b63884..44b335d560708 100644
--- a/drivers/cxl/core/ras_rch.c
+++ b/drivers/cxl/core/ras_rch.c
@@ -80,7 +80,8 @@ static bool cxl_rch_get_aer_severity(struct aer_capability_regs *aer_regs,
 				     int *severity)
 {
 	if (aer_regs->uncor_status & ~aer_regs->uncor_mask) {
-		if (aer_regs->uncor_status & PCI_ERR_ROOT_FATAL_RCV)
+		if ((aer_regs->uncor_status & ~aer_regs->uncor_mask) &
+		    aer_regs->uncor_severity)
 			*severity = AER_FATAL;
 		else
 			*severity = AER_NONFATAL;
-- 
2.34.1