powernv/eeh: Add buffer for P7IOC hub error data

Prevent ioda_eeh_hub_diag() from clobbering itself when called by supplying
a per-PHB buffer for P7IOC hub diagnostic data.  Take care to inform OPAL of
the correct size for the buffer.

[Small style change to the use of sizeof -- BenH]
Signed-off-by: Brian W Hart <hartb@linux.vnet.ibm.com>
Acked-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/powernv/eeh-ioda.c

@@ -36,7 +36,6 @@
 #include "powernv.h"
 #include "pci.h"
 
-static char *hub_diag = NULL;
 static int ioda_eeh_nb_init = 0;
 
 static int ioda_eeh_event(struct notifier_block *nb,
@@ -140,15 +139,6 @@ static int ioda_eeh_post_init(struct pci_controller *hose)
 		ioda_eeh_nb_init = 1;
 	}
 
-	/* We needn't HUB diag-data on PHB3 */
-	if (phb->type == PNV_PHB_IODA1 && !hub_diag) {
-		hub_diag = (char *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
-		if (!hub_diag) {
-			pr_err("%s: Out of memory !\n", __func__);
-			return -ENOMEM;
-		}
-	}
-
 #ifdef CONFIG_DEBUG_FS
 	if (phb->dbgfs) {
 		debugfs_create_file("err_injct_outbound", 0600,
@@ -633,11 +623,10 @@ static void ioda_eeh_hub_diag_common(struct OpalIoP7IOCErrorData *data)
 static void ioda_eeh_hub_diag(struct pci_controller *hose)
 {
 	struct pnv_phb *phb = hose->private_data;
-	struct OpalIoP7IOCErrorData *data;
+	struct OpalIoP7IOCErrorData *data = &phb->diag.hub_diag;
 	long rc;
 
-	data = (struct OpalIoP7IOCErrorData *)ioda_eeh_hub_diag;
-	rc = opal_pci_get_hub_diag_data(phb->hub_id, data, PAGE_SIZE);
+	rc = opal_pci_get_hub_diag_data(phb->hub_id, data, sizeof(*data));
 	if (rc != OPAL_SUCCESS) {
 		pr_warning("%s: Failed to get HUB#%llx diag-data (%ld)\n",
 			   __func__, phb->hub_id, rc);

arch/powerpc/platforms/powernv/pci.h

@@ -172,11 +172,13 @@ struct pnv_phb {
 		} ioda;
 	};
 
-	/* PHB status structure */
+	/* PHB and hub status structure */
 	union {
 		unsigned char			blob[PNV_PCI_DIAG_BUF_SIZE];
 		struct OpalIoP7IOCPhbErrorData	p7ioc;
+		struct OpalIoP7IOCErrorData 	hub_diag;
 	} diag;
+
 };
 
 extern struct pci_ops pnv_pci_ops;