commit 0f672f6c0b52b7b0700b0915c72b540721af4465
author David Brazdil <dbrazdil@google.com> Tue Dec 10 10:32:29 2019 +0000
committer David Brazdil <dbrazdil@google.com> Tue Dec 10 19:03:18 2019 +0000
tree 85c8cba019caa205e4f8920d72d93f6d6deaf29c
parent 3a0ad55d848b50499b68d7141d4eca997fce28ef

Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd

arch/riscv/kernel/process.c

diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
index d7c6ca7..85e3c39 100644
--- a/arch/riscv/kernel/process.c
+++ b/arch/riscv/kernel/process.c
@@ -1,25 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
  *  Chen Liqin <liqin.chen@sunplusct.com>
  *  Lennox Wu <lennox.wu@sunplusct.com>
  * Copyright (C) 2012 Regents of the University of California
  * Copyright (C) 2017 SiFive
- *
- * 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; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, see the file COPYING, or write
- * to the Free Software Foundation, Inc.,
  */
 
+#include <linux/cpu.h>
 #include <linux/kernel.h>
 #include <linux/sched.h>
 #include <linux/sched/task_stack.h>
@@ -32,6 +20,7 @@
 #include <asm/csr.h>
 #include <asm/string.h>
 #include <asm/switch_to.h>
+#include <asm/thread_info.h>
 
 extern asmlinkage void ret_from_fork(void);
 extern asmlinkage void ret_from_kernel_thread(void);
@@ -76,7 +65,15 @@
 void start_thread(struct pt_regs *regs, unsigned long pc,
 	unsigned long sp)
 {
-	regs->sstatus = SR_SPIE /* User mode, irqs on */ | SR_FS_INITIAL;
+	regs->sstatus = SR_SPIE;
+	if (has_fpu) {
+		regs->sstatus |= SR_FS_INITIAL;
+		/*
+		 * Restore the initial value to the FP register
+		 * before starting the user program.
+		 */
+		fstate_restore(current, regs);
+	}
 	regs->sepc = pc;
 	regs->sp = sp;
 	set_fs(USER_DS);
@@ -84,12 +81,15 @@
 
 void flush_thread(void)
 {
+#ifdef CONFIG_FPU
 	/*
-	 * Reset FPU context
+	 * Reset FPU state and context
 	 *	frm: round to nearest, ties to even (IEEE default)
 	 *	fflags: accrued exceptions cleared
 	 */
+	fstate_off(current, task_pt_regs(current));
 	memset(&current->thread.fstate, 0, sizeof(current->thread.fstate));
+#endif
 }
 
 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)