1 files changed, 33 insertions, 10 deletions

diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c
index 376fcbc3f8da..71c101601e3e 100644
--- a/arch/ia64/kernel/perfmon.c
+++ b/arch/ia64/kernel/perfmon.c
@@ -1265,6 +1265,8 @@ out:
 }
 EXPORT_SYMBOL(pfm_unregister_buffer_fmt);
 
+extern void update_pal_halt_status(int);
+
 static int
 pfm_reserve_session(struct task_struct *task, int is_syswide, unsigned int cpu)
 {
@@ -1311,6 +1313,11 @@ pfm_reserve_session(struct task_struct *task, int is_syswide, unsigned int cpu)
                 is_syswide,
                 cpu));
 
+        /*
+         * disable default_idle() to go to PAL_HALT
+         */
+        update_pal_halt_status(0);
+
         UNLOCK_PFS(flags);
 
         return 0;
@@ -1366,6 +1373,12 @@ pfm_unreserve_session(pfm_context_t *ctx, int is_syswide, unsigned int cpu)
                 is_syswide,
                 cpu));
 
+        /*
+         * if possible, enable default_idle() to go into PAL_HALT
+         */
+        if (pfm_sessions.pfs_task_sessions == 0 && pfm_sessions.pfs_sys_sessions == 0)
+                update_pal_halt_status(1);
+
         UNLOCK_PFS(flags);
 
         return 0;
@@ -4202,7 +4215,7 @@ pfm_context_load(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
                 DPRINT(("cannot load to [%d], invalid ctx_state=%d\n",
                         req->load_pid,
                         ctx->ctx_state));
-                return -EINVAL;
+                return -EBUSY;
         }
 
         DPRINT(("load_pid [%d] using_dbreg=%d\n", req->load_pid, ctx->ctx_fl_using_dbreg));
@@ -4704,16 +4717,26 @@ recheck:
         if (task == current || ctx->ctx_fl_system) return 0;
 
         /*
-         * if context is UNLOADED we are safe to go
-         */
-        if (state == PFM_CTX_UNLOADED) return 0;
-
-        /*
-         * no command can operate on a zombie context
+         * we are monitoring another thread
          */
-        if (state == PFM_CTX_ZOMBIE) {
-                DPRINT(("cmd %d state zombie cannot operate on context\n", cmd));
-                return -EINVAL;
+        switch(state) {
+                case PFM_CTX_UNLOADED:
+                        /*
+                         * if context is UNLOADED we are safe to go
+                         */
+                        return 0;
+                case PFM_CTX_ZOMBIE:
+                        /*
+                         * no command can operate on a zombie context
+                         */
+                        DPRINT(("cmd %d state zombie cannot operate on context\n", cmd));
+                        return -EINVAL;
+                case PFM_CTX_MASKED:
+                        /*
+                         * PMU state has been saved to software even though
+                         * the thread may still be running.
+                         */
+                        if (cmd != PFM_UNLOAD_CONTEXT) return 0;
         }
 
         /*