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-rwxr-xr-xcpu/ppc4xx/traps.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/cpu/ppc4xx/traps.c b/cpu/ppc4xx/traps.c
index 2fcce3de8b..6b15a9ea28 100755
--- a/cpu/ppc4xx/traps.c
+++ b/cpu/ppc4xx/traps.c
@@ -151,12 +151,17 @@ MachineCheckException(struct pt_regs *regs)
int uncorr_ecc = 0;
#endif
- /* Probing PCI using config cycles cause this exception
- * when a device is not present. Catch it and return to
- * the PCI exception handler.
+ /* Probing PCI(E) using config cycles may cause this exception
+ * when a device is not present. To gracefully recover in such
+ * scenarios config read/write routines need to be instrumented in
+ * order to return via fixup handler. For examples refer to
+ * pcie_in_8(), pcie_in_le16() and pcie_in_le32()
*/
if ((fixup = search_exception_table(regs->nip)) != 0) {
regs->nip = fixup;
+ val = mfspr(MCSR);
+ /* Clear MCSR */
+ mtspr(SPRN_MCSR, val);
return;
}