[S390] Show loaded DCSS segments under /proc/iomem.

Currently loaded DCSS segments are now listed in /proc/iomem with
their name followed by a trailing "(DCSS)".

Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

2 files changed, 56 insertions, 12 deletions

diff --git a/arch/s390/mm/extmem.c b/arch/s390/mm/extmem.c
index 775bf19e742b..8bffadb5e537 100644
--- a/arch/s390/mm/extmem.c
+++ b/arch/s390/mm/extmem.c
@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/bootmem.h>
 #include <linux/ctype.h>
+#include <linux/ioport.h>
 #include <asm/page.h>
 #include <asm/pgtable.h>
 #include <asm/ebcdic.h>
@@ -70,6 +71,7 @@ struct qin64 {
 struct dcss_segment {
         struct list_head list;
         char dcss_name[8];
+        char res_name[15];
         unsigned long start_addr;
         unsigned long end;
         atomic_t ref_count;
@@ -77,6 +79,7 @@ struct dcss_segment {
         unsigned int vm_segtype;
         struct qrange range[6];
         int segcnt;
+        struct resource *res;
 };
 
 static DEFINE_MUTEX(dcss_lock);
@@ -303,6 +306,29 @@ __segment_load (char *name, int do_nonshared, unsigned long *addr, unsigned long
                 goto out_free;
         }
 
+        seg->res = kzalloc(sizeof(struct resource), GFP_KERNEL);
+        if (seg->res == NULL) {
+                rc = -ENOMEM;
+                goto out_shared;
+        }
+        seg->res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
+        seg->res->start = seg->start_addr;
+        seg->res->end = seg->end;
+        memcpy(&seg->res_name, seg->dcss_name, 8);
+        EBCASC(seg->res_name, 8);
+        seg->res_name[8] = '\0';
+        strncat(seg->res_name, " (DCSS)", 7);
+        seg->res->name = seg->res_name;
+        rc = seg->vm_segtype;
+        if (rc == SEG_TYPE_SC ||
+            ((rc == SEG_TYPE_SR || rc == SEG_TYPE_ER) && !do_nonshared))
+                seg->res->flags |= IORESOURCE_READONLY;
+        if (request_resource(&iomem_resource, seg->res)) {
+                rc = -EBUSY;
+                kfree(seg->res);
+                goto out_shared;
+        }
+
         if (do_nonshared)
                 dcss_command = DCSS_LOADNSR;
         else
@@ -316,12 +342,11 @@ __segment_load (char *name, int do_nonshared, unsigned long *addr, unsigned long
                 rc = dcss_diag_translate_rc (seg->end);
                 dcss_diag(DCSS_PURGESEG, seg->dcss_name,
                                 &seg->start_addr, &seg->end);
-                goto out_shared;
+                goto out_resource;
         }
         seg->do_nonshared = do_nonshared;
         atomic_set(&seg->ref_count, 1);
         list_add(&seg->list, &dcss_list);
-        rc = seg->vm_segtype;
         *addr = seg->start_addr;
         *end  = seg->end;
         if (do_nonshared)
@@ -329,12 +354,16 @@ __segment_load (char *name, int do_nonshared, unsigned long *addr, unsigned long
                                 "type %s in non-shared mode\n", name,
                                 (void*)seg->start_addr, (void*)seg->end,
                                 segtype_string[seg->vm_segtype]);
-        else
+        else {
                 PRINT_INFO ("segment_load: loaded segment %s range %p .. %p "
                                 "type %s in shared mode\n", name,
                                 (void*)seg->start_addr, (void*)seg->end,
                                 segtype_string[seg->vm_segtype]);
+        }
         goto out;
+ out_resource:
+        release_resource(seg->res);
+        kfree(seg->res);
  out_shared:
         remove_shared_memory(seg->start_addr, seg->end - seg->start_addr + 1);
  out_free:
@@ -401,6 +430,7 @@ segment_load (char *name, int do_nonshared, unsigned long *addr,
  * -ENOENT  : no such segment (segment gone!)
  * -EAGAIN  : segment is in use by other exploiters, try later
  * -EINVAL  : no segment with the given name is currently loaded - name invalid
+ * -EBUSY   : segment can temporarily not be used (overlaps with dcss)
  * 0        : operation succeeded
  */
 int
@@ -428,12 +458,24 @@ segment_modify_shared (char *name, int do_nonshared)
                 rc = -EAGAIN;
                 goto out_unlock;
         }
-        dcss_diag(DCSS_PURGESEG, seg->dcss_name,
-                  &dummy, &dummy);
-        if (do_nonshared)
+        release_resource(seg->res);
+        if (do_nonshared) {
                 dcss_command = DCSS_LOADNSR;
-        else
-        dcss_command = DCSS_LOADNOLY;
+                seg->res->flags &= ~IORESOURCE_READONLY;
+        } else {
+                dcss_command = DCSS_LOADNOLY;
+                if (seg->vm_segtype == SEG_TYPE_SR ||
+                    seg->vm_segtype == SEG_TYPE_ER)
+                        seg->res->flags |= IORESOURCE_READONLY;
+        }
+        if (request_resource(&iomem_resource, seg->res)) {
+                PRINT_WARN("segment_modify_shared: could not reload segment %s"
+                           " - overlapping resources\n", name);
+                rc = -EBUSY;
+                kfree(seg->res);
+                goto out_del;
+        }
+        dcss_diag(DCSS_PURGESEG, seg->dcss_name, &dummy, &dummy);
         diag_cc = dcss_diag(dcss_command, seg->dcss_name,
                         &seg->start_addr, &seg->end);
         if (diag_cc > 1) {
@@ -446,9 +488,9 @@ segment_modify_shared (char *name, int do_nonshared)
         rc = 0;
         goto out_unlock;
  out_del:
+        remove_shared_memory(seg->start_addr, seg->end - seg->start_addr + 1);
         list_del(&seg->list);
-        dcss_diag(DCSS_PURGESEG, seg->dcss_name,
-                  &dummy, &dummy);
+        dcss_diag(DCSS_PURGESEG, seg->dcss_name, &dummy, &dummy);
         kfree(seg);
  out_unlock:
         mutex_unlock(&dcss_lock);
@@ -478,6 +520,8 @@ segment_unload(char *name)
         }
         if (atomic_dec_return(&seg->ref_count) != 0)
                 goto out_unlock;
+        release_resource(seg->res);
+        kfree(seg->res);
         remove_shared_memory(seg->start_addr, seg->end - seg->start_addr + 1);
         list_del(&seg->list);
         dcss_diag(DCSS_PURGESEG, seg->dcss_name, &dummy, &dummy);
diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
index be9b05347b4f..bd1b66a54c21 100644
--- a/drivers/s390/block/dcssblk.c
+++ b/drivers/s390/block/dcssblk.c
@@ -230,7 +230,7 @@ dcssblk_shared_store(struct device *dev, struct device_attribute *attr, const ch
                                            SEGMENT_SHARED);
                 if (rc < 0) {
                         BUG_ON(rc == -EINVAL);
-                        if (rc == -EIO || rc == -ENOENT)
+                        if (rc != -EAGAIN)
                                 goto removeseg;
                 } else {
                         dev_info->is_shared = 1;
@@ -253,7 +253,7 @@ dcssblk_shared_store(struct device *dev, struct device_attribute *attr, const ch
                                            SEGMENT_EXCLUSIVE);
                 if (rc < 0) {
                         BUG_ON(rc == -EINVAL);
-                        if (rc == -EIO || rc == -ENOENT)
+                        if (rc != -EAGAIN)
                                 goto removeseg;
                 } else {
                         dev_info->is_shared = 0;