[IA64-SGI] Fix sn_flush_device_kernel & spinlock initialization

This patch separates the sn_flush_device_list struct into kernel and
common (both kernel and PROM accessible) structures.  As it was, if the
size of a spinlock_t changed (due to additional CONFIG options, etc.) the
sal call which populated the sn_flush_device_list structs would erroneously
write data (and cause memory corruption and/or a panic).

This patch does the following:

1.  Removes sn_flush_device_list and adds sn_flush_device_common and
sn_flush_device_kernel.

2.  Adds a new SAL call to populate a sn_flush_device_common struct per
device, not per widget as previously done.

3.  Correctly initializes each device's sn_flush_device_kernel spinlock_t
struct (before it was only doing each widget's first device).

Signed-off-by: Prarit Bhargava <prarit@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

4 files changed, 93 insertions, 71 deletions

diff --git a/arch/ia64/sn/include/xtalk/hubdev.h b/arch/ia64/sn/include/xtalk/hubdev.h
index 71c2b271b4c6..4d417c301201 100644
--- a/arch/ia64/sn/include/xtalk/hubdev.h
+++ b/arch/ia64/sn/include/xtalk/hubdev.h
@@ -26,11 +26,14 @@
 #define IIO_NUM_ITTES   7
 #define HUB_NUM_BIG_WINDOW      (IIO_NUM_ITTES - 1)
 
-struct sn_flush_device_list {
+/* This struct is shared between the PROM and the kernel.
+ * Changes to this struct will require corresponding changes to the kernel.
+ */
+struct sn_flush_device_common {
         int sfdl_bus;
         int sfdl_slot;
         int sfdl_pin;
-        struct bar_list {
+        struct common_bar_list {
                 unsigned long start;
                 unsigned long end;
         } sfdl_bar_list[6];
@@ -40,14 +43,19 @@ struct sn_flush_device_list {
         uint32_t sfdl_persistent_busnum;
         uint32_t sfdl_persistent_segment;
         struct pcibus_info *sfdl_pcibus_info;
+};
+
+/* This struct is kernel only and is not used by the PROM */
+struct sn_flush_device_kernel {
         spinlock_t sfdl_flush_lock;
+        struct sn_flush_device_common *common;
 };
 
 /*
- * **widget_p - Used as an array[wid_num][device] of sn_flush_device_list.
+ * **widget_p - Used as an array[wid_num][device] of sn_flush_device_kernel.
  */
 struct sn_flush_nasid_entry  {
-        struct sn_flush_device_list **widget_p; /* Used as a array of wid_num */
+        struct sn_flush_device_kernel **widget_p; // Used as an array of wid_num
         uint64_t iio_itte[8];
 };
 
diff --git a/arch/ia64/sn/kernel/io_init.c b/arch/ia64/sn/kernel/io_init.c
index 318087e35b66..258d9d7aff98 100644
--- a/arch/ia64/sn/kernel/io_init.c
+++ b/arch/ia64/sn/kernel/io_init.c
@@ -76,11 +76,12 @@ static struct sn_pcibus_provider sn_pci_default_provider = {
 };
 
 /*
- * Retrieve the DMA Flush List given nasid.  This list is needed 
- * to implement the WAR - Flush DMA data on PIO Reads.
+ * Retrieve the DMA Flush List given nasid, widget, and device.
+ * This list is needed to implement the WAR - Flush DMA data on PIO Reads.
  */
-static inline uint64_t
-sal_get_widget_dmaflush_list(u64 nasid, u64 widget_num, u64 address)
+static inline u64
+sal_get_device_dmaflush_list(u64 nasid, u64 widget_num, u64 device_num,
+                             u64 address)
 {
 
         struct ia64_sal_retval ret_stuff;
@@ -88,17 +89,17 @@ sal_get_widget_dmaflush_list(u64 nasid, u64 widget_num, u64 address)
         ret_stuff.v0 = 0;
 
         SAL_CALL_NOLOCK(ret_stuff,
-                        (u64) SN_SAL_IOIF_GET_WIDGET_DMAFLUSH_LIST,
-                        (u64) nasid, (u64) widget_num, (u64) address, 0, 0, 0,
-                        0);
-        return ret_stuff.v0;
+                        (u64) SN_SAL_IOIF_GET_DEVICE_DMAFLUSH_LIST,
+                        (u64) nasid, (u64) widget_num,
+                        (u64) device_num, (u64) address, 0, 0, 0);
+        return ret_stuff.status;
 
 }
 
 /*
  * Retrieve the hub device info structure for the given nasid.
  */
-static inline uint64_t sal_get_hubdev_info(u64 handle, u64 address)
+static inline u64 sal_get_hubdev_info(u64 handle, u64 address)
 {
 
         struct ia64_sal_retval ret_stuff;
@@ -114,7 +115,7 @@ static inline uint64_t sal_get_hubdev_info(u64 handle, u64 address)
 /*
  * Retrieve the pci bus information given the bus number.
  */
-static inline uint64_t sal_get_pcibus_info(u64 segment, u64 busnum, u64 address)
+static inline u64 sal_get_pcibus_info(u64 segment, u64 busnum, u64 address)
 {
 
         struct ia64_sal_retval ret_stuff;
@@ -130,7 +131,7 @@ static inline uint64_t sal_get_pcibus_info(u64 segment, u64 busnum, u64 address)
 /*
  * Retrieve the pci device information given the bus and device|function number.
  */
-static inline uint64_t
+static inline u64
 sal_get_pcidev_info(u64 segment, u64 bus_number, u64 devfn, u64 pci_dev, 
                         u64 sn_irq_info)
 {
@@ -170,12 +171,12 @@ sn_pcidev_info_get(struct pci_dev *dev)
  */
 static void sn_fixup_ionodes(void)
 {
-
-        struct sn_flush_device_list *sn_flush_device_list;
+        struct sn_flush_device_kernel *sn_flush_device_kernel;
+        struct sn_flush_device_kernel *dev_entry;
         struct hubdev_info *hubdev;
-        uint64_t status;
-        uint64_t nasid;
-        int i, widget;
+        u64 status;
+        u64 nasid;
+        int i, widget, device;
 
         /*
          * Get SGI Specific HUB chipset information.
@@ -186,7 +187,7 @@ static void sn_fixup_ionodes(void)
                 nasid = cnodeid_to_nasid(i);
                 hubdev->max_segment_number = 0xffffffff;
                 hubdev->max_pcibus_number = 0xff;
-                status = sal_get_hubdev_info(nasid, (uint64_t) __pa(hubdev));
+                status = sal_get_hubdev_info(nasid, (u64) __pa(hubdev));
                 if (status)
                         continue;
 
@@ -213,38 +214,49 @@ static void sn_fixup_ionodes(void)
 
                 hubdev->hdi_flush_nasid_list.widget_p =
                     kmalloc((HUB_WIDGET_ID_MAX + 1) *
-                            sizeof(struct sn_flush_device_list *), GFP_KERNEL);
-
+                            sizeof(struct sn_flush_device_kernel *),
+                            GFP_KERNEL);
                 memset(hubdev->hdi_flush_nasid_list.widget_p, 0x0,
                        (HUB_WIDGET_ID_MAX + 1) *
-                       sizeof(struct sn_flush_device_list *));
+                       sizeof(struct sn_flush_device_kernel *));
 
                 for (widget = 0; widget <= HUB_WIDGET_ID_MAX; widget++) {
-                        sn_flush_device_list = kmalloc(DEV_PER_WIDGET *
-                                                       sizeof(struct
-                                                              sn_flush_device_list),
-                                                       GFP_KERNEL);
-                        memset(sn_flush_device_list, 0x0,
+                        sn_flush_device_kernel = kmalloc(DEV_PER_WIDGET *
+                                                         sizeof(struct
+                                                        sn_flush_device_kernel),
+                                                        GFP_KERNEL);
+                        if (!sn_flush_device_kernel)
+                                BUG();
+                        memset(sn_flush_device_kernel, 0x0,
                                DEV_PER_WIDGET *
-                               sizeof(struct sn_flush_device_list));
-
-                        status =
-                            sal_get_widget_dmaflush_list(nasid, widget,
-                                                         (uint64_t)
-                                                         __pa
-                                                         (sn_flush_device_list));
-                        if (status) {
-                                kfree(sn_flush_device_list);
-                                continue;
+                               sizeof(struct sn_flush_device_kernel));
+
+                        dev_entry = sn_flush_device_kernel;
+                        for (device = 0; device < DEV_PER_WIDGET;
+                             device++,dev_entry++) {
+                                dev_entry->common = kmalloc(sizeof(struct
+                                                        sn_flush_device_common),
+                                                            GFP_KERNEL);
+                                if (!dev_entry->common)
+                                        BUG();
+                                memset(dev_entry->common, 0x0, sizeof(struct
+                                                       sn_flush_device_common));
+
+                                status = sal_get_device_dmaflush_list(nasid,
+                                                                        widget,
+                                                                        device,
+                                                      (u64)(dev_entry->common));
+                                if (status)
+                                        BUG();
+
+                                spin_lock_init(&dev_entry->sfdl_flush_lock);
                         }
 
-                        spin_lock_init(&sn_flush_device_list->sfdl_flush_lock);
-                        hubdev->hdi_flush_nasid_list.widget_p[widget] =
-                            sn_flush_device_list;
-                }
-
+                        if (sn_flush_device_kernel)
+                                hubdev->hdi_flush_nasid_list.widget_p[widget] =
+                                                       sn_flush_device_kernel;
+                }
         }
-
 }
 
 /*
diff --git a/arch/ia64/sn/pci/pcibr/pcibr_dma.c b/arch/ia64/sn/pci/pcibr/pcibr_dma.c
index 34093476e965..e68332d93171 100644
--- a/arch/ia64/sn/pci/pcibr/pcibr_dma.c
+++ b/arch/ia64/sn/pci/pcibr/pcibr_dma.c
@@ -218,7 +218,9 @@ void sn_dma_flush(uint64_t addr)
         uint64_t flags;
         uint64_t itte;
         struct hubdev_info *hubinfo;
-        volatile struct sn_flush_device_list *p;
+        volatile struct sn_flush_device_kernel *p;
+        volatile struct sn_flush_device_common *common;
+
         struct sn_flush_nasid_entry *flush_nasid_list;
 
         if (!sn_ioif_inited)
@@ -268,17 +270,17 @@ void sn_dma_flush(uint64_t addr)
         p = &flush_nasid_list->widget_p[wid_num][0];
 
         /* find a matching BAR */
-        for (i = 0; i < DEV_PER_WIDGET; i++) {
+        for (i = 0; i < DEV_PER_WIDGET; i++,p++) {
+                common = p->common;
                 for (j = 0; j < PCI_ROM_RESOURCE; j++) {
-                        if (p->sfdl_bar_list[j].start == 0)
+                        if (common->sfdl_bar_list[j].start == 0)
                                 break;
-                        if (addr >= p->sfdl_bar_list[j].start
-                            && addr <= p->sfdl_bar_list[j].end)
+                        if (addr >= common->sfdl_bar_list[j].start
+                            && addr <= common->sfdl_bar_list[j].end)
                                 break;
                 }
-                if (j < PCI_ROM_RESOURCE && p->sfdl_bar_list[j].start != 0)
+                if (j < PCI_ROM_RESOURCE && common->sfdl_bar_list[j].start != 0)
                         break;
-                p++;
         }
 
         /* if no matching BAR, return without doing anything. */
@@ -304,24 +306,24 @@ void sn_dma_flush(uint64_t addr)
                 if ((1 << XWIDGET_PART_REV_NUM_REV(revnum)) & PV907516) {
                         return;
                 } else {
-                        pcireg_wrb_flush_get(p->sfdl_pcibus_info,
-                                             (p->sfdl_slot - 1));
+                        pcireg_wrb_flush_get(common->sfdl_pcibus_info,
+                                             (common->sfdl_slot - 1));
                 }
         } else {
-                spin_lock_irqsave(&((struct sn_flush_device_list *)p)->
-                                  sfdl_flush_lock, flags);
-
-                *p->sfdl_flush_addr = 0;
+                spin_lock_irqsave((spinlock_t *)&p->sfdl_flush_lock,
+                                  flags);
+                *common->sfdl_flush_addr = 0;
 
                 /* force an interrupt. */
-                *(volatile uint32_t *)(p->sfdl_force_int_addr) = 1;
+                *(volatile uint32_t *)(common->sfdl_force_int_addr) = 1;
 
                 /* wait for the interrupt to come back. */
-                while (*(p->sfdl_flush_addr) != 0x10f)
+                while (*(common->sfdl_flush_addr) != 0x10f)
                         cpu_relax();
 
                 /* okay, everything is synched up. */
-                spin_unlock_irqrestore((spinlock_t *)&p->sfdl_flush_lock, flags);
+                spin_unlock_irqrestore((spinlock_t *)&p->sfdl_flush_lock,
+                                       flags);
         }
         return;
 }
diff --git a/arch/ia64/sn/pci/pcibr/pcibr_provider.c b/arch/ia64/sn/pci/pcibr/pcibr_provider.c
index 1f500c81002c..e328e948175d 100644
--- a/arch/ia64/sn/pci/pcibr/pcibr_provider.c
+++ b/arch/ia64/sn/pci/pcibr/pcibr_provider.c
@@ -92,7 +92,8 @@ pcibr_bus_fixup(struct pcibus_bussoft *prom_bussoft, struct pci_controller *cont
         cnodeid_t near_cnode;
         struct hubdev_info *hubdev_info;
         struct pcibus_info *soft;
-        struct sn_flush_device_list *sn_flush_device_list;
+        struct sn_flush_device_kernel *sn_flush_device_kernel;
+        struct sn_flush_device_common *common;
 
         if (! IS_PCI_BRIDGE_ASIC(prom_bussoft->bs_asic_type)) {
                 return NULL;
@@ -137,20 +138,19 @@ pcibr_bus_fixup(struct pcibus_bussoft *prom_bussoft, struct pci_controller *cont
         hubdev_info = (struct hubdev_info *)(NODEPDA(cnode)->pdinfo);
 
         if (hubdev_info->hdi_flush_nasid_list.widget_p) {
-                sn_flush_device_list = hubdev_info->hdi_flush_nasid_list.
+                sn_flush_device_kernel = hubdev_info->hdi_flush_nasid_list.
                     widget_p[(int)soft->pbi_buscommon.bs_xid];
-                if (sn_flush_device_list) {
+                if (sn_flush_device_kernel) {
                         for (j = 0; j < DEV_PER_WIDGET;
-                             j++, sn_flush_device_list++) {
-                                if (sn_flush_device_list->sfdl_slot == -1)
+                             j++, sn_flush_device_kernel++) {
+                                common = sn_flush_device_kernel->common;
+                                if (common->sfdl_slot == -1)
                                         continue;
-                                if ((sn_flush_device_list->
-                                     sfdl_persistent_segment ==
+                                if ((common->sfdl_persistent_segment ==
                                      soft->pbi_buscommon.bs_persist_segment) &&
-                                     (sn_flush_device_list->
-                                     sfdl_persistent_busnum ==
+                                     (common->sfdl_persistent_busnum ==
                                      soft->pbi_buscommon.bs_persist_busnum))
-                                        sn_flush_device_list->sfdl_pcibus_info =
+                                        common->sfdl_pcibus_info =
                                             soft;
                         }
                 }