[PATCH 1/8] powerpc/eeh: Don't collect PCI-CFG data on PHB

[Gavin Shan <shangw@linux.vnet.ibm.com>]

When the PHB is fenced or dead, it's pointless to collect the data
from PCI config space of subordinate PCI devices since it should
return 0xFF's. The patch also fixes overwritten buffer while getting
PCI config data.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/eeh.c |   34 ++++++++++++++++++++++++----------
 1 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
index 951a632..2dd0bd1 100644
--- a/arch/powerpc/kernel/eeh.c
+++ b/arch/powerpc/kernel/eeh.c
@@ -232,16 +232,30 @@ void eeh_slot_error_detail(struct eeh_pe *pe, int severity)
 {
 	size_t loglen = 0;
 	struct eeh_dev *edev;
+	bool valid_cfg_log = true;
 
-	eeh_pci_enable(pe, EEH_OPT_THAW_MMIO);
-	eeh_ops->configure_bridge(pe);
-	eeh_pe_restore_bars(pe);
-
-	pci_regs_buf[0] = 0;
-	eeh_pe_for_each_dev(pe, edev) {
-		loglen += eeh_gather_pci_data(edev, pci_regs_buf,
-				EEH_PCI_REGS_LOG_LEN);
-        }
+	/*
+	 * When the PHB is fenced or dead, it's pointless to collect
+	 * the data from PCI config space because it should return
+	 * 0xFF's. For ER, we still retrieve the data from the PCI
+	 * config space.
+	 */
+	if (eeh_probe_mode_dev() &&
+	    (pe->type & EEH_PE_PHB) &&
+	    (pe->state & (EEH_PE_ISOLATED | EEH_PE_PHB_DEAD)))
+		valid_cfg_log = false;
+
+	if (valid_cfg_log) {
+		eeh_pci_enable(pe, EEH_OPT_THAW_MMIO);
+		eeh_ops->configure_bridge(pe);
+		eeh_pe_restore_bars(pe);
+
+		pci_regs_buf[0] = 0;
+		eeh_pe_for_each_dev(pe, edev) {
+			loglen += eeh_gather_pci_data(edev, pci_regs_buf + loglen,
+						      EEH_PCI_REGS_LOG_LEN - loglen);
+		}
+	}
 
 	eeh_ops->get_log(pe, severity, pci_regs_buf, loglen);
 }
-- 
1.7.5.4