1 files changed, 205 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/pseries/nvram.c b/arch/powerpc/platforms/pseries/nvram.c
index bc3c7f2abd79..7e828ba29bc3 100644
--- a/arch/powerpc/platforms/pseries/nvram.c
+++ b/arch/powerpc/platforms/pseries/nvram.c
@@ -22,11 +22,25 @@
 #include <asm/prom.h>
 #include <asm/machdep.h>
 
+/* Max bytes to read/write in one go */
+#define NVRW_CNT 0x20
+
 static unsigned int nvram_size;
 static int nvram_fetch, nvram_store;
 static char nvram_buf[NVRW_CNT];        /* assume this is in the first 4GB */
 static DEFINE_SPINLOCK(nvram_lock);
 
+static long nvram_error_log_index = -1;
+static long nvram_error_log_size = 0;
+
+struct err_log_info {
+        int error_type;
+        unsigned int seq_num;
+};
+#define NVRAM_MAX_REQ           2079
+#define NVRAM_MIN_REQ           1055
+
+#define NVRAM_LOG_PART_NAME     "ibm,rtas-log"
 
 static ssize_t pSeries_nvram_read(char *buf, size_t count, loff_t *index)
 {
@@ -119,6 +133,197 @@ static ssize_t pSeries_nvram_get_size(void)
         return nvram_size ? nvram_size : -ENODEV;
 }
 
+
+/* nvram_write_error_log
+ *
+ * We need to buffer the error logs into nvram to ensure that we have
+ * the failure information to decode.  If we have a severe error there
+ * is no way to guarantee that the OS or the machine is in a state to
+ * get back to user land and write the error to disk.  For example if
+ * the SCSI device driver causes a Machine Check by writing to a bad
+ * IO address, there is no way of guaranteeing that the device driver
+ * is in any state that is would also be able to write the error data
+ * captured to disk, thus we buffer it in NVRAM for analysis on the
+ * next boot.
+ *
+ * In NVRAM the partition containing the error log buffer will looks like:
+ * Header (in bytes):
+ * +-----------+----------+--------+------------+------------------+
+ * | signature | checksum | length | name       | data             |
+ * |0          |1         |2      3|4         15|16        length-1|
+ * +-----------+----------+--------+------------+------------------+
+ *
+ * The 'data' section would look like (in bytes):
+ * +--------------+------------+-----------------------------------+
+ * | event_logged | sequence # | error log                         |
+ * |0            3|4          7|8            nvram_error_log_size-1|
+ * +--------------+------------+-----------------------------------+
+ *
+ * event_logged: 0 if event has not been logged to syslog, 1 if it has
+ * sequence #: The unique sequence # for each event. (until it wraps)
+ * error log: The error log from event_scan
+ */
+int nvram_write_error_log(char * buff, int length,
+                          unsigned int err_type, unsigned int error_log_cnt)
+{
+        int rc;
+        loff_t tmp_index;
+        struct err_log_info info;
+        
+        if (nvram_error_log_index == -1) {
+                return -ESPIPE;
+        }
+
+        if (length > nvram_error_log_size) {
+                length = nvram_error_log_size;
+        }
+
+        info.error_type = err_type;
+        info.seq_num = error_log_cnt;
+
+        tmp_index = nvram_error_log_index;
+
+        rc = ppc_md.nvram_write((char *)&info, sizeof(struct err_log_info), &tmp_index);
+        if (rc <= 0) {
+                printk(KERN_ERR "nvram_write_error_log: Failed nvram_write (%d)\n", rc);
+                return rc;
+        }
+
+        rc = ppc_md.nvram_write(buff, length, &tmp_index);
+        if (rc <= 0) {
+                printk(KERN_ERR "nvram_write_error_log: Failed nvram_write (%d)\n", rc);
+                return rc;
+        }
+        
+        return 0;
+}
+
+/* nvram_read_error_log
+ *
+ * Reads nvram for error log for at most 'length'
+ */
+int nvram_read_error_log(char * buff, int length,
+                         unsigned int * err_type, unsigned int * error_log_cnt)
+{
+        int rc;
+        loff_t tmp_index;
+        struct err_log_info info;
+        
+        if (nvram_error_log_index == -1)
+                return -1;
+
+        if (length > nvram_error_log_size)
+                length = nvram_error_log_size;
+
+        tmp_index = nvram_error_log_index;
+
+        rc = ppc_md.nvram_read((char *)&info, sizeof(struct err_log_info), &tmp_index);
+        if (rc <= 0) {
+                printk(KERN_ERR "nvram_read_error_log: Failed nvram_read (%d)\n", rc);
+                return rc;
+        }
+
+        rc = ppc_md.nvram_read(buff, length, &tmp_index);
+        if (rc <= 0) {
+                printk(KERN_ERR "nvram_read_error_log: Failed nvram_read (%d)\n", rc);
+                return rc;
+        }
+
+        *error_log_cnt = info.seq_num;
+        *err_type = info.error_type;
+
+        return 0;
+}
+
+/* This doesn't actually zero anything, but it sets the event_logged
+ * word to tell that this event is safely in syslog.
+ */
+int nvram_clear_error_log(void)
+{
+        loff_t tmp_index;
+        int clear_word = ERR_FLAG_ALREADY_LOGGED;
+        int rc;
+
+        if (nvram_error_log_index == -1)
+                return -1;
+
+        tmp_index = nvram_error_log_index;
+        
+        rc = ppc_md.nvram_write((char *)&clear_word, sizeof(int), &tmp_index);
+        if (rc <= 0) {
+                printk(KERN_ERR "nvram_clear_error_log: Failed nvram_write (%d)\n", rc);
+                return rc;
+        }
+
+        return 0;
+}
+
+/* pseries_nvram_init_log_partition
+ *
+ * This will setup the partition we need for buffering the
+ * error logs and cleanup partitions if needed.
+ *
+ * The general strategy is the following:
+ * 1.) If there is log partition large enough then use it.
+ * 2.) If there is none large enough, search
+ * for a free partition that is large enough.
+ * 3.) If there is not a free partition large enough remove 
+ * _all_ OS partitions and consolidate the space.
+ * 4.) Will first try getting a chunk that will satisfy the maximum
+ * error log size (NVRAM_MAX_REQ).
+ * 5.) If the max chunk cannot be allocated then try finding a chunk
+ * that will satisfy the minum needed (NVRAM_MIN_REQ).
+ */
+static int __init pseries_nvram_init_log_partition(void)
+{
+        loff_t p;
+        int size;
+
+        /* Scan nvram for partitions */
+        nvram_scan_partitions();
+
+        /* Lookg for ours */
+        p = nvram_find_partition(NVRAM_LOG_PART_NAME, NVRAM_SIG_OS, &size);
+
+        /* Found one but too small, remove it */
+        if (p && size < NVRAM_MIN_REQ) {
+                pr_info("nvram: Found too small "NVRAM_LOG_PART_NAME" partition"
+                        ",removing it...");
+                nvram_remove_partition(NVRAM_LOG_PART_NAME, NVRAM_SIG_OS);
+                p = 0;
+        }
+
+        /* Create one if we didn't find */
+        if (!p) {
+                p = nvram_create_partition(NVRAM_LOG_PART_NAME, NVRAM_SIG_OS,
+                                           NVRAM_MAX_REQ, NVRAM_MIN_REQ);
+                /* No room for it, try to get rid of any OS partition
+                 * and try again
+                 */
+                if (p == -ENOSPC) {
+                        pr_info("nvram: No room to create "NVRAM_LOG_PART_NAME
+                                " partition, deleting all OS partitions...");
+                        nvram_remove_partition(NULL, NVRAM_SIG_OS);
+                        p = nvram_create_partition(NVRAM_LOG_PART_NAME,
+                                                   NVRAM_SIG_OS, NVRAM_MAX_REQ,
+                                                   NVRAM_MIN_REQ);
+                }
+        }
+
+        if (p <= 0) {
+                pr_err("nvram: Failed to find or create "NVRAM_LOG_PART_NAME
+                       " partition, err %d\n", (int)p);
+                return 0;
+        }
+
+        nvram_error_log_index = p;
+        nvram_error_log_size = nvram_get_partition_size(p) -
+                sizeof(struct err_log_info);
+        
+        return 0;
+}
+machine_arch_initcall(pseries, pseries_nvram_init_log_partition);
+
 int __init pSeries_nvram_init(void)
 {
         struct device_node *nvram;