powerpc/powernv: Invoke opal call to handle hmi.

When we hit the HMI in Linux, invoke opal call to handle/recover from HMI
errors in real mode and then in virtual mode during check_irq_replay()
invoke opal_poll_events()/opal_do_notifier() to retrieve HMI event from
OPAL and act accordingly.

Now that we are ready to handle HMI interrupt directly in linux, remove
the HMI interrupt registration with firmware.

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

6 files changed, 267 insertions, 7 deletions

diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index efc16c37b959..b2f8ce1fd0d7 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -148,6 +148,7 @@ struct opal_sg_list {
 #define OPAL_DUMP_RESEND                        91
 #define OPAL_DUMP_INFO2                         94
 #define OPAL_PCI_EEH_FREEZE_SET                 97
+#define OPAL_HANDLE_HMI                         98
 
 #ifndef __ASSEMBLY__
 
@@ -245,6 +246,7 @@ enum OpalMessageType {
         OPAL_MSG_MEM_ERR,
         OPAL_MSG_EPOW,
         OPAL_MSG_SHUTDOWN,
+        OPAL_MSG_HMI_EVT,
         OPAL_MSG_TYPE_MAX,
 };
 
@@ -513,6 +515,50 @@ struct OpalMemoryErrorData {
         } u;
 };
 
+/* HMI interrupt event */
+enum OpalHMI_Version {
+        OpalHMIEvt_V1 = 1,
+};
+
+enum OpalHMI_Severity {
+        OpalHMI_SEV_NO_ERROR = 0,
+        OpalHMI_SEV_WARNING = 1,
+        OpalHMI_SEV_ERROR_SYNC = 2,
+        OpalHMI_SEV_FATAL = 3,
+};
+
+enum OpalHMI_Disposition {
+        OpalHMI_DISPOSITION_RECOVERED = 0,
+        OpalHMI_DISPOSITION_NOT_RECOVERED = 1,
+};
+
+enum OpalHMI_ErrType {
+        OpalHMI_ERROR_MALFUNC_ALERT     = 0,
+        OpalHMI_ERROR_PROC_RECOV_DONE,
+        OpalHMI_ERROR_PROC_RECOV_DONE_AGAIN,
+        OpalHMI_ERROR_PROC_RECOV_MASKED,
+        OpalHMI_ERROR_TFAC,
+        OpalHMI_ERROR_TFMR_PARITY,
+        OpalHMI_ERROR_HA_OVERFLOW_WARN,
+        OpalHMI_ERROR_XSCOM_FAIL,
+        OpalHMI_ERROR_XSCOM_DONE,
+        OpalHMI_ERROR_SCOM_FIR,
+        OpalHMI_ERROR_DEBUG_TRIG_FIR,
+        OpalHMI_ERROR_HYP_RESOURCE,
+};
+
+struct OpalHMIEvent {
+        uint8_t         version;        /* 0x00 */
+        uint8_t         severity;       /* 0x01 */
+        uint8_t         type;           /* 0x02 */
+        uint8_t         disposition;    /* 0x03 */
+        uint8_t         reserved_1[4];  /* 0x04 */
+
+        __be64          hmer;
+        /* TFMR register. Valid only for TFAC and TFMR_PARITY error type. */
+        __be64          tfmr;
+};
+
 enum {
         OPAL_P7IOC_DIAG_TYPE_NONE       = 0,
         OPAL_P7IOC_DIAG_TYPE_RGC        = 1,
@@ -873,6 +919,7 @@ int64_t opal_get_param(uint64_t token, uint32_t param_id, uint64_t buffer,
 int64_t opal_set_param(uint64_t token, uint32_t param_id, uint64_t buffer,
                 uint64_t length);
 int64_t opal_sensor_read(uint32_t sensor_hndl, int token, __be32 *sensor_data);
+int64_t opal_handle_hmi(void);
 
 /* Internal functions */
 extern int early_init_dt_scan_opal(unsigned long node, const char *uname,
diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h
index 5abde4e223bb..a5139ea6910b 100644
--- a/arch/powerpc/include/asm/paca.h
+++ b/arch/powerpc/include/asm/paca.h
@@ -167,6 +167,7 @@ struct paca_struct {
          * and already using emergency stack.
          */
         u16 in_mce;
+        u8 hmi_event_available;          /* HMI event is available */
 #endif
 
         /* Stuff for accurate time accounting */
diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile
index 70b758aaaffa..f241accc053d 100644
--- a/arch/powerpc/platforms/powernv/Makefile
+++ b/arch/powerpc/platforms/powernv/Makefile
@@ -1,7 +1,7 @@
 obj-y                   += setup.o opal-wrappers.o opal.o opal-async.o
 obj-y                   += opal-rtc.o opal-nvram.o opal-lpc.o opal-flash.o
 obj-y                   += rng.o opal-elog.o opal-dump.o opal-sysparam.o opal-sensor.o
-obj-y                   += opal-msglog.o
+obj-y                   += opal-msglog.o opal-hmi.o
 
 obj-$(CONFIG_SMP)       += smp.o subcore.o subcore-asm.o
 obj-$(CONFIG_PCI)       += pci.o pci-p5ioc2.o pci-ioda.o
diff --git a/arch/powerpc/platforms/powernv/opal-hmi.c b/arch/powerpc/platforms/powernv/opal-hmi.c
new file mode 100644
index 000000000000..97ac8dc33667
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/opal-hmi.c
@@ -0,0 +1,188 @@
+/*
+ * OPAL hypervisor Maintenance interrupt handling support in PowreNV.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright 2014 IBM Corporation
+ * Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
+ */
+
+#undef DEBUG
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/of.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+
+#include <asm/opal.h>
+#include <asm/cputable.h>
+
+static int opal_hmi_handler_nb_init;
+struct OpalHmiEvtNode {
+        struct list_head list;
+        struct OpalHMIEvent hmi_evt;
+};
+static LIST_HEAD(opal_hmi_evt_list);
+static DEFINE_SPINLOCK(opal_hmi_evt_lock);
+
+static void print_hmi_event_info(struct OpalHMIEvent *hmi_evt)
+{
+        const char *level, *sevstr, *error_info;
+        static const char *hmi_error_types[] = {
+                "Malfunction Alert",
+                "Processor Recovery done",
+                "Processor recovery occurred again",
+                "Processor recovery occurred for masked error",
+                "Timer facility experienced an error",
+                "TFMR SPR is corrupted",
+                "UPS (Uniterrupted Power System) Overflow indication",
+                "An XSCOM operation failure",
+                "An XSCOM operation completed",
+                "SCOM has set a reserved FIR bit to cause recovery",
+                "Debug trigger has set a reserved FIR bit to cause recovery",
+                "A hypervisor resource error occurred"
+        };
+
+        /* Print things out */
+        if (hmi_evt->version != OpalHMIEvt_V1) {
+                pr_err("HMI Interrupt, Unknown event version %d !\n",
+                        hmi_evt->version);
+                return;
+        }
+        switch (hmi_evt->severity) {
+        case OpalHMI_SEV_NO_ERROR:
+                level = KERN_INFO;
+                sevstr = "Harmless";
+                break;
+        case OpalHMI_SEV_WARNING:
+                level = KERN_WARNING;
+                sevstr = "";
+                break;
+        case OpalHMI_SEV_ERROR_SYNC:
+                level = KERN_ERR;
+                sevstr = "Severe";
+                break;
+        case OpalHMI_SEV_FATAL:
+        default:
+                level = KERN_ERR;
+                sevstr = "Fatal";
+                break;
+        }
+
+        printk("%s%s Hypervisor Maintenance interrupt [%s]\n",
+                level, sevstr,
+                hmi_evt->disposition == OpalHMI_DISPOSITION_RECOVERED ?
+                "Recovered" : "Not recovered");
+        error_info = hmi_evt->type < ARRAY_SIZE(hmi_error_types) ?
+                        hmi_error_types[hmi_evt->type]
+                        : "Unknown";
+        printk("%s Error detail: %s\n", level, error_info);
+        printk("%s      HMER: %016llx\n", level, be64_to_cpu(hmi_evt->hmer));
+        if ((hmi_evt->type == OpalHMI_ERROR_TFAC) ||
+                (hmi_evt->type == OpalHMI_ERROR_TFMR_PARITY))
+                printk("%s      TFMR: %016llx\n", level,
+                                                be64_to_cpu(hmi_evt->tfmr));
+}
+
+static void hmi_event_handler(struct work_struct *work)
+{
+        unsigned long flags;
+        struct OpalHMIEvent *hmi_evt;
+        struct OpalHmiEvtNode *msg_node;
+        uint8_t disposition;
+
+        spin_lock_irqsave(&opal_hmi_evt_lock, flags);
+        while (!list_empty(&opal_hmi_evt_list)) {
+                msg_node = list_entry(opal_hmi_evt_list.next,
+                                           struct OpalHmiEvtNode, list);
+                list_del(&msg_node->list);
+                spin_unlock_irqrestore(&opal_hmi_evt_lock, flags);
+
+                hmi_evt = (struct OpalHMIEvent *) &msg_node->hmi_evt;
+                print_hmi_event_info(hmi_evt);
+                disposition = hmi_evt->disposition;
+                kfree(msg_node);
+
+                /*
+                 * Check if HMI event has been recovered or not. If not
+                 * then we can't continue, invoke panic.
+                 */
+                if (disposition != OpalHMI_DISPOSITION_RECOVERED)
+                        panic("Unrecoverable HMI exception");
+
+                spin_lock_irqsave(&opal_hmi_evt_lock, flags);
+        }
+        spin_unlock_irqrestore(&opal_hmi_evt_lock, flags);
+}
+
+static DECLARE_WORK(hmi_event_work, hmi_event_handler);
+/*
+ * opal_handle_hmi_event - notifier handler that queues up HMI events
+ * to be preocessed later.
+ */
+static int opal_handle_hmi_event(struct notifier_block *nb,
+                          unsigned long msg_type, void *msg)
+{
+        unsigned long flags;
+        struct OpalHMIEvent *hmi_evt;
+        struct opal_msg *hmi_msg = msg;
+        struct OpalHmiEvtNode *msg_node;
+
+        /* Sanity Checks */
+        if (msg_type != OPAL_MSG_HMI_EVT)
+                return 0;
+
+        /* HMI event info starts from param[0] */
+        hmi_evt = (struct OpalHMIEvent *)&hmi_msg->params[0];
+
+        /* Delay the logging of HMI events to workqueue. */
+        msg_node = kzalloc(sizeof(*msg_node), GFP_ATOMIC);
+        if (!msg_node) {
+                pr_err("HMI: out of memory, Opal message event not handled\n");
+                return -ENOMEM;
+        }
+        memcpy(&msg_node->hmi_evt, hmi_evt, sizeof(struct OpalHMIEvent));
+
+        spin_lock_irqsave(&opal_hmi_evt_lock, flags);
+        list_add(&msg_node->list, &opal_hmi_evt_list);
+        spin_unlock_irqrestore(&opal_hmi_evt_lock, flags);
+
+        schedule_work(&hmi_event_work);
+        return 0;
+}
+
+static struct notifier_block opal_hmi_handler_nb = {
+        .notifier_call  = opal_handle_hmi_event,
+        .next           = NULL,
+        .priority       = 0,
+};
+
+static int __init opal_hmi_handler_init(void)
+{
+        int ret;
+
+        if (!opal_hmi_handler_nb_init) {
+                ret = opal_message_notifier_register(
+                                OPAL_MSG_HMI_EVT, &opal_hmi_handler_nb);
+                if (ret) {
+                        pr_err("%s: Can't register OPAL event notifier (%d)\n",
+                               __func__, ret);
+                        return ret;
+                }
+                opal_hmi_handler_nb_init = 1;
+        }
+        return 0;
+}
+subsys_initcall(opal_hmi_handler_init);
diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S b/arch/powerpc/platforms/powernv/opal-wrappers.S
index 3dda49957158..a328be44880f 100644
--- a/arch/powerpc/platforms/powernv/opal-wrappers.S
+++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
@@ -244,3 +244,4 @@ OPAL_CALL(opal_sync_host_reboot,		OPAL_SYNC_HOST_REBOOT);
 OPAL_CALL(opal_sensor_read,                     OPAL_SENSOR_READ);
 OPAL_CALL(opal_get_param,                       OPAL_GET_PARAM);
 OPAL_CALL(opal_set_param,                       OPAL_SET_PARAM);
+OPAL_CALL(opal_handle_hmi,                      OPAL_HANDLE_HMI);
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index d20d69921376..f0a01a46a57d 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -194,9 +194,6 @@ static int __init opal_register_exception_handlers(void)
          * fwnmi area at 0x7000 to provide the glue space to OPAL
          */
         glue = 0x7000;
-        opal_register_exception_handler(OPAL_HYPERVISOR_MAINTENANCE_HANDLER,
-                                        0, glue);
-        glue += 128;
         opal_register_exception_handler(OPAL_SOFTPATCH_HANDLER, 0, glue);
 #endif
 
@@ -517,15 +514,41 @@ int opal_machine_check(struct pt_regs *regs)
 /* Early hmi handler called in real mode. */
 int opal_hmi_exception_early(struct pt_regs *regs)
 {
-        /* TODO: Call opal hmi handler. */
+        s64 rc;
+
+        /*
+         * call opal hmi handler. Pass paca address as token.
+         * The return value OPAL_SUCCESS is an indication that there is
+         * an HMI event generated waiting to pull by Linux.
+         */
+        rc = opal_handle_hmi();
+        if (rc == OPAL_SUCCESS) {
+                local_paca->hmi_event_available = 1;
+                return 1;
+        }
         return 0;
 }
 
 /* HMI exception handler called in virtual mode during check_irq_replay. */
 int opal_handle_hmi_exception(struct pt_regs *regs)
 {
-        /* TODO: Retrive and print HMI event from OPAL. */
-        return 0;
+        s64 rc;
+        __be64 evt = 0;
+
+        /*
+         * Check if HMI event is available.
+         * if Yes, then call opal_poll_events to pull opal messages and
+         * process them.
+         */
+        if (!local_paca->hmi_event_available)
+                return 0;
+
+        local_paca->hmi_event_available = 0;
+        rc = opal_poll_events(&evt);
+        if (rc == OPAL_SUCCESS && evt)
+                opal_do_notifier(be64_to_cpu(evt));
+
+        return 1;
 }
 
 static uint64_t find_recovery_address(uint64_t nip)