+/*
+ * Reload the blade's kernel context into a GRU chiplet. Called holding
+ * the bs_kgts_sema for READ. Will steal user contexts if necessary.
+ */
+static void gru_load_kernel_context(struct gru_blade_state *bs, int blade_id)
+{
+ struct gru_state *gru;
+ struct gru_thread_state *kgts;
+ void *vaddr;
+ int ctxnum, ncpus;
+
+ up_read(&bs->bs_kgts_sema);
+ down_write(&bs->bs_kgts_sema);
+
+ if (!bs->bs_kgts)
+ bs->bs_kgts = gru_alloc_gts(NULL, 0, 0, 0, 0);
+ kgts = bs->bs_kgts;
+
+ if (!kgts->ts_gru) {
+ STAT(load_kernel_context);
+ ncpus = uv_blade_nr_possible_cpus(blade_id);
+ kgts->ts_cbr_au_count = GRU_CB_COUNT_TO_AU(
+ GRU_NUM_KERNEL_CBR * ncpus + bs->bs_async_cbrs);
+ kgts->ts_dsr_au_count = GRU_DS_BYTES_TO_AU(
+ GRU_NUM_KERNEL_DSR_BYTES * ncpus +
+ bs->bs_async_dsr_bytes);
+ while (!gru_assign_gru_context(kgts, blade_id)) {
+ msleep(1);
+ gru_steal_context(kgts, blade_id);
+ }
+ gru_load_context(kgts);
+ gru = bs->bs_kgts->ts_gru;
+ vaddr = gru->gs_gru_base_vaddr;
+ ctxnum = kgts->ts_ctxnum;
+ bs->kernel_cb = get_gseg_base_address_cb(vaddr, ctxnum, 0);
+ bs->kernel_dsr = get_gseg_base_address_ds(vaddr, ctxnum, 0);
+ }
+ downgrade_write(&bs->bs_kgts_sema);
+}
+
+/*
+ * Free all kernel contexts that are not currently in use.
+ * Returns 0 if all freed, else number of inuse context.
+ */
+static int gru_free_kernel_contexts(void)
+{
+ struct gru_blade_state *bs;
+ struct gru_thread_state *kgts;
+ int bid, ret = 0;
+
+ for (bid = 0; bid < GRU_MAX_BLADES; bid++) {
+ bs = gru_base[bid];
+ if (!bs)
+ continue;
+ if (down_write_trylock(&bs->bs_kgts_sema)) {
+ kgts = bs->bs_kgts;
+ if (kgts && kgts->ts_gru)
+ gru_unload_context(kgts, 0);
+ kfree(kgts);
+ bs->bs_kgts = NULL;
+ up_write(&bs->bs_kgts_sema);
+ } else {
+ ret++;
+ }
+ }
+ return ret;
+}
+
+/*
+ * Lock & load the kernel context for the specified blade.
+ */
+static struct gru_blade_state *gru_lock_kernel_context(int blade_id)
+{
+ struct gru_blade_state *bs;
+
+ STAT(lock_kernel_context);
+ bs = gru_base[blade_id];
+
+ down_read(&bs->bs_kgts_sema);
+ if (!bs->bs_kgts || !bs->bs_kgts->ts_gru)
+ gru_load_kernel_context(bs, blade_id);
+ return bs;
+
+}
+
+/*
+ * Unlock the kernel context for the specified blade. Context is not
+ * unloaded but may be stolen before next use.
+ */
+static void gru_unlock_kernel_context(int blade_id)
+{
+ struct gru_blade_state *bs;
+
+ bs = gru_base[blade_id];
+ up_read(&bs->bs_kgts_sema);
+ STAT(unlock_kernel_context);
+}
+
+/*
+ * Reserve & get pointers to the DSR/CBRs reserved for the current cpu.
+ * - returns with preemption disabled
+ */