[PATCH] s390: debug feature changes

debug feature changes/bug fixes:

- Use get_clock() function instead of private inline assembly.

- Use 'struct timeval' instead of 'struct timespec' for call to
  tod_to_timeval().  Now the microsecond part of the timestamp is correct
  again.

- Fix a locking problem: when creating a snapshot of the current content
  of the debug areas, lock the entire debug_info object.

Signed-off-by: Michael Holzheu <holzheu@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 32 insertions, 20 deletions

diff --git a/arch/s390/kernel/debug.c b/arch/s390/kernel/debug.c
index 960ba6029c3a..bc59282da762 100644
--- a/arch/s390/kernel/debug.c
+++ b/arch/s390/kernel/debug.c
@@ -62,7 +62,7 @@ typedef struct
 } debug_sprintf_entry_t;
 
 
-extern void tod_to_timeval(uint64_t todval, struct timeval *xtime);
+extern void tod_to_timeval(uint64_t todval, struct timespec *xtime);
 
 /* internal function prototyes */
 
@@ -374,9 +374,24 @@ debug_info_copy(debug_info_t* in, int mode)
 {
         int i,j;
         debug_info_t* rc;
+        unsigned long flags;
+
+        /* get a consistent copy of the debug areas */
+        do {
+                rc = debug_info_alloc(in->name, in->pages_per_area,
+                        in->nr_areas, in->buf_size, in->level, mode);
+                spin_lock_irqsave(&in->lock, flags);
+                if(!rc)
+                        goto out;
+                /* has something changed in the meantime ? */
+                if((rc->pages_per_area == in->pages_per_area) &&
+                   (rc->nr_areas == in->nr_areas)) {
+                        break;
+                }
+                spin_unlock_irqrestore(&in->lock, flags);
+                debug_info_free(rc);
+        } while (1);
 
-        rc = debug_info_alloc(in->name, in->pages_per_area, in->nr_areas,
-                                in->buf_size, in->level, mode);
         if(!rc || (mode == NO_AREAS))
                 goto out;
 
@@ -386,6 +401,7 @@ debug_info_copy(debug_info_t* in, int mode)
                 }
         }
 out:
+        spin_unlock_irqrestore(&in->lock, flags);
         return rc;
 }
 
@@ -593,19 +609,15 @@ debug_open(struct inode *inode, struct file *file)
         debug_info_t *debug_info, *debug_info_snapshot;
 
         down(&debug_lock);
-
-        /* find debug log and view */
-        debug_info = debug_area_first;
-        while(debug_info != NULL){
-                for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
-                        if (!debug_info->views[i])
-                                continue;
-                        else if (debug_info->debugfs_entries[i] ==
-                                 file->f_dentry) {
-                                goto found;     /* found view ! */
-                        }
+        debug_info = (struct debug_info*)file->f_dentry->d_inode->u.generic_ip;
+        /* find debug view */
+        for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
+                if (!debug_info->views[i])
+                        continue;
+                else if (debug_info->debugfs_entries[i] ==
+                         file->f_dentry) {
+                        goto found;     /* found view ! */
                 }
-                debug_info = debug_info->next;
         }
         /* no entry found */
         rc = -EINVAL;
@@ -833,7 +845,7 @@ extern inline void
 debug_finish_entry(debug_info_t * id, debug_entry_t* active, int level,
                         int exception)
 {
-        STCK(active->id.stck);
+        active->id.stck = get_clock();
         active->id.fields.cpuid = smp_processor_id();
         active->caller = __builtin_return_address(0);
         active->id.fields.exception = exception;
@@ -1078,7 +1090,7 @@ debug_register_view(debug_info_t * id, struct debug_view *view)
         if (view->input_proc)
                 mode |= S_IWUSR;
         pde = debugfs_create_file(view->name, mode, id->debugfs_root_entry,
-                                NULL, &debug_file_ops);
+                                id , &debug_file_ops);
         if (!pde){
                 printk(KERN_WARNING "debug: debugfs_create_file() failed!"\
                         " Cannot register view %s/%s\n", id->name,view->name);
@@ -1432,7 +1444,7 @@ int
 debug_dflt_header_fn(debug_info_t * id, struct debug_view *view,
                          int area, debug_entry_t * entry, char *out_buf)
 {
-        struct timeval time_val;
+        struct timespec time_spec;
         unsigned long long time;
         char *except_str;
         unsigned long caller;
@@ -1443,7 +1455,7 @@ debug_dflt_header_fn(debug_info_t * id, struct debug_view *view,
         time = entry->id.stck;
         /* adjust todclock to 1970 */
         time -= 0x8126d60e46000000LL - (0x3c26700LL * 1000000 * 4096);
-        tod_to_timeval(time, &time_val);
+        tod_to_timeval(time, &time_spec);
 
         if (entry->id.fields.exception)
                 except_str = "*";
@@ -1451,7 +1463,7 @@ debug_dflt_header_fn(debug_info_t * id, struct debug_view *view,
                 except_str = "-";
         caller = ((unsigned long) entry->caller) & PSW_ADDR_INSN;
         rc += sprintf(out_buf, "%02i %011lu:%06lu %1u %1s %02i %p  ",
-                      area, time_val.tv_sec, time_val.tv_usec, level,
+                      area, time_spec.tv_sec, time_spec.tv_nsec / 1000, level,
                       except_str, entry->id.fields.cpuid, (void *) caller);
         return rc;
 }