powerpc/eeh: Don't collect PCI-CFG data on PHB

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>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
index e5796524631c56bb06d4e28f1c8857ed3a52fefb..416fb432d7e284721641318ff6becc659555fd29 100644 (file)
--- 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);
 }