From 1d74f6bc85cbdc4601e5aea1e67ccbd259f0c7f4 Mon Sep 17 00:00:00 2001
From: Ralf Baechle <ralf@linux-mips.org>
Date: Mon, 9 May 2005 13:16:07 +0000
Subject: __compute_return_epc() uses CFC1 instruction which might result in a
 coprocessor unusable exception since the process can lose its fpu context by
 preemption.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---
 arch/mips/kernel/branch.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

(limited to 'arch/mips')

diff --git a/arch/mips/kernel/branch.c b/arch/mips/kernel/branch.c
index 01117e977a7..56aea5f526a 100644
--- a/arch/mips/kernel/branch.c
+++ b/arch/mips/kernel/branch.c
@@ -12,6 +12,7 @@
 #include <asm/branch.h>
 #include <asm/cpu.h>
 #include <asm/cpu-features.h>
+#include <asm/fpu.h>
 #include <asm/inst.h>
 #include <asm/ptrace.h>
 #include <asm/uaccess.h>
@@ -161,10 +162,13 @@ int __compute_return_epc(struct pt_regs *regs)
 	 * And now the FPA/cp1 branch instructions.
 	 */
 	case cop1_op:
-		if (!cpu_has_fpu)
-			fcr31 = current->thread.fpu.soft.fcr31;
-		else
+		preempt_disable();
+		if (is_fpu_owner())
 			asm volatile("cfc1\t%0,$31" : "=r" (fcr31));
+		else
+			fcr31 = current->thread.fpu.hard.fcr31;
+		preempt_enable();
+
 		bit = (insn.i_format.rt >> 2);
 		bit += (bit != 0);
 		bit += 23;
-- 
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