sgi-gru: add support for a user to explicitly unload a GRU context

Add support for a user to explicitly unload a GRU context.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 36 insertions, 0 deletions

diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c
index 61aa80a8411b..8ae426edc854 100644
--- a/drivers/misc/sgi-gru/grufault.c
+++ b/drivers/misc/sgi-gru/grufault.c
@@ -32,6 +32,7 @@
 #include <linux/device.h>
 #include <linux/io.h>
 #include <linux/uaccess.h>
+#include <linux/security.h>
 #include <asm/pgtable.h>
 #include "gru.h"
 #include "grutables.h"
@@ -575,6 +576,38 @@ int gru_get_exception_detail(unsigned long arg)
 /*
  * User request to unload a context. Content is saved for possible reload.
  */
+static int gru_unload_all_contexts(void)
+{
+        struct gru_thread_state *gts;
+        struct gru_state *gru;
+        int maxgid, gid, ctxnum;
+        int nodesperblade;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+        if (num_online_nodes() > 1 &&
+                        (uv_node_to_blade_id(1) == uv_node_to_blade_id(0)))
+                nodesperblade = 2;
+        else
+                nodesperblade = 1;
+        maxgid = GRU_CHIPLETS_PER_BLADE * num_online_nodes() / nodesperblade;
+        for (gid = 0; gid < maxgid; gid++) {
+                gru = GID_TO_GRU(gid);
+                spin_lock(&gru->gs_lock);
+                for (ctxnum = 0; ctxnum < GRU_NUM_CCH; ctxnum++) {
+                        gts = gru->gs_gts[ctxnum];
+                        if (gts && mutex_trylock(&gts->ts_ctxlock)) {
+                                spin_unlock(&gru->gs_lock);
+                                gru_unload_context(gts, 1);
+                                gru_unlock_gts(gts);
+                                spin_lock(&gru->gs_lock);
+                        }
+                }
+                spin_unlock(&gru->gs_lock);
+        }
+        return 0;
+}
+
 int gru_user_unload_context(unsigned long arg)
 {
         struct gru_thread_state *gts;
@@ -586,6 +619,9 @@ int gru_user_unload_context(unsigned long arg)
 
         gru_dbg(grudev, "gseg 0x%lx\n", req.gseg);
 
+        if (!req.gseg)
+                return gru_unload_all_contexts();
+
         gts = gru_find_lock_gts(req.gseg);
         if (!gts)
                 return -EINVAL;