1 files changed, 59 insertions, 3 deletions

diff --git a/drivers/s390/char/zcore.c b/drivers/s390/char/zcore.c
index e3b9308b0fe3..681749e7f6dd 100644
--- a/drivers/s390/char/zcore.c
+++ b/drivers/s390/char/zcore.c
@@ -62,6 +62,7 @@ static struct dentry *zcore_dir;
 static struct dentry *zcore_file;
 static struct dentry *zcore_memmap_file;
 static struct dentry *zcore_reipl_file;
+static struct dentry *zcore_hsa_file;
 static struct ipl_parameter_block *ipl_block;
 
 /*
@@ -77,6 +78,8 @@ static int memcpy_hsa(void *dest, unsigned long src, size_t count, int mode)
         int offs, blk_num;
         static char buf[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
 
+        if (!hsa_available)
+                return -ENODATA;
         if (count == 0)
                 return 0;
 
@@ -278,6 +281,15 @@ next:
 }
 
 /*
+ * Release the HSA
+ */
+static void release_hsa(void)
+{
+        diag308(DIAG308_REL_HSA, NULL);
+        hsa_available = 0;
+}
+
+/*
  * Read routine for zcore character device
  * First 4K are dump header
  * Next 32MB are HSA Memory
@@ -363,8 +375,8 @@ static int zcore_open(struct inode *inode, struct file *filp)
 
 static int zcore_release(struct inode *inode, struct file *filep)
 {
-        diag308(DIAG308_REL_HSA, NULL);
-        hsa_available = 0;
+        if (hsa_available)
+                release_hsa();
         return 0;
 }
 
@@ -474,6 +486,41 @@ static const struct file_operations zcore_reipl_fops = {
         .llseek         = no_llseek,
 };
 
+static ssize_t zcore_hsa_read(struct file *filp, char __user *buf,
+                              size_t count, loff_t *ppos)
+{
+        static char str[18];
+
+        if (hsa_available)
+                snprintf(str, sizeof(str), "%lx\n", ZFCPDUMP_HSA_SIZE);
+        else
+                snprintf(str, sizeof(str), "0\n");
+        return simple_read_from_buffer(buf, count, ppos, str, strlen(str));
+}
+
+static ssize_t zcore_hsa_write(struct file *filp, const char __user *buf,
+                               size_t count, loff_t *ppos)
+{
+        char value;
+
+        if (*ppos != 0)
+                return -EPIPE;
+        if (copy_from_user(&value, buf, 1))
+                return -EFAULT;
+        if (value != '0')
+                return -EINVAL;
+        release_hsa();
+        return count;
+}
+
+static const struct file_operations zcore_hsa_fops = {
+        .owner          = THIS_MODULE,
+        .write          = zcore_hsa_write,
+        .read           = zcore_hsa_read,
+        .open           = nonseekable_open,
+        .llseek         = no_llseek,
+};
+
 #ifdef CONFIG_32BIT
 
 static void __init set_lc_mask(struct save_area *map)
@@ -658,6 +705,7 @@ static int __init zcore_init(void)
         rc = check_sdias();
         if (rc)
                 goto fail;
+        hsa_available = 1;
 
         rc = memcpy_hsa_kernel(&arch, __LC_AR_MODE_ID, 1);
         if (rc)
@@ -714,9 +762,16 @@ static int __init zcore_init(void)
                 rc = -ENOMEM;
                 goto fail_memmap_file;
         }
-        hsa_available = 1;
+        zcore_hsa_file = debugfs_create_file("hsa", S_IRUSR|S_IWUSR, zcore_dir,
+                                             NULL, &zcore_hsa_fops);
+        if (!zcore_hsa_file) {
+                rc = -ENOMEM;
+                goto fail_reipl_file;
+        }
         return 0;
 
+fail_reipl_file:
+        debugfs_remove(zcore_reipl_file);
 fail_memmap_file:
         debugfs_remove(zcore_memmap_file);
 fail_file:
@@ -733,6 +788,7 @@ static void __exit zcore_exit(void)
         debug_unregister(zcore_dbf);
         sclp_sdias_exit();
         free_page((unsigned long) ipl_block);
+        debugfs_remove(zcore_hsa_file);
         debugfs_remove(zcore_reipl_file);
         debugfs_remove(zcore_memmap_file);
         debugfs_remove(zcore_file);