Change in coreboot[master]: riscv: temporarily block multiple-threads

[Anonymous Coward (Code Review)]

Anonymous Coward (1001664) has uploaded this change for review. ( https://review.coreboot.org/27358

Change subject: riscv: temporarily block multiple-threads
......................................................................

riscv: temporarily block multiple-threads

Sometime needs to temporarily block multiple-threads.
So add this code.

Change-Id: Ia0eeed51e0952c66a9a9f25a90105fe471ffa70e
Signed-off-by: Xiang Wang 
---
M src/arch/riscv/include/arch/smp/smp.h
1 file changed, 30 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/58/27358/1

diff --git a/src/arch/riscv/include/arch/smp/smp.h b/src/arch/riscv/include/arch/smp/smp.h
index bdf8ec4..2672595 100644
--- a/src/arch/riscv/include/arch/smp/smp.h
+++ b/src/arch/riscv/include/arch/smp/smp.h
@@ -1,6 +1,8 @@
 /*
  * This file is part of the coreboot project.
  *
+ * Copyright (C) 2018 HardenedLinux.
+ *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; version 2 of the License.
@@ -10,3 +12,31 @@
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  */
+#ifndef _SMP_H
+#define _SMP_H
+
+#include <arch/smp/atomic.h>
+#include <arch/smp/spinlock.h>
+
+ /*
+  * If your code needs to temporarily block multiple-threads, do this:
+  *      if(RUNNING_ON_HART(active)) // `active` is hartid of working thread
+  *      {
+  *          ... single-threaded work ...
+  *      }
+  *      SMP_SYNC();
+  *      //`SMP_SYNC` is not required, if other hart not need to wait for
+  *      //the single-threaded work to complete.
+  *  ... multi-threaded work ...
+  */
+
+
+#define RUNNING_ON_HART(active) ((active) == read_csr(mhartid))
+
+#define SMP_SYNC()  do {\
+static int counter;\
+atomic_add(&counter, 1);\
+do { barrier(); } while (counter < CONFIG_HART_NUM);\
+} while (0)
+
+ #endif //_SMP_H