MIPS: Fix race condition with FPU thread task flag during context switch.
[ralf@linux-mips.org: Cosmetic changes; also fixed up r2300_switch.S and
octeon_switch.S which needed similar modifications.]
Signed-off-by: Leonid Yegoshin <yegoshin@mips.com>
Signed-off-by: Steven J. Hill <sjhill@mips.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3784/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/octeon_switch.S b/arch/mips/kernel/octeon_switch.S
index ce89c80..0441f54 100644
--- a/arch/mips/kernel/octeon_switch.S
+++ b/arch/mips/kernel/octeon_switch.S
@@ -31,7 +31,7 @@
/*
* task_struct *resume(task_struct *prev, task_struct *next,
- * struct thread_info *next_ti)
+ * struct thread_info *next_ti, int usedfpu)
*/
.align 7
LEAF(resume)
diff --git a/arch/mips/kernel/r2300_switch.S b/arch/mips/kernel/r2300_switch.S
index 2938983..9c51be5 100644
--- a/arch/mips/kernel/r2300_switch.S
+++ b/arch/mips/kernel/r2300_switch.S
@@ -43,7 +43,7 @@
/*
* task_struct *resume(task_struct *prev, task_struct *next,
- * struct thread_info *next_ti) )
+ * struct thread_info *next_ti, int usedfpu)
*/
LEAF(resume)
mfc0 t1, CP0_STATUS
@@ -51,18 +51,9 @@
cpu_save_nonscratch a0
sw ra, THREAD_REG31(a0)
- /*
- * check if we need to save FPU registers
- */
- lw t3, TASK_THREAD_INFO(a0)
- lw t0, TI_FLAGS(t3)
- li t1, _TIF_USEDFPU
- and t2, t0, t1
- beqz t2, 1f
- nor t1, zero, t1
+ beqz a3, 1f
- and t0, t0, t1
- sw t0, TI_FLAGS(t3)
+ PTR_L t3, TASK_THREAD_INFO(a0)
/*
* clear saved user stack CU1 bit
diff --git a/arch/mips/kernel/r4k_switch.S b/arch/mips/kernel/r4k_switch.S
index 9414f93..42d2a39 100644
--- a/arch/mips/kernel/r4k_switch.S
+++ b/arch/mips/kernel/r4k_switch.S
@@ -41,7 +41,7 @@
/*
* task_struct *resume(task_struct *prev, task_struct *next,
- * struct thread_info *next_ti)
+ * struct thread_info *next_ti, int usedfpu)
*/
.align 5
LEAF(resume)
@@ -53,16 +53,10 @@
/*
* check if we need to save FPU registers
*/
+
+ beqz a3, 1f
+
PTR_L t3, TASK_THREAD_INFO(a0)
- LONG_L t0, TI_FLAGS(t3)
- li t1, _TIF_USEDFPU
- and t2, t0, t1
- beqz t2, 1f
- nor t1, zero, t1
-
- and t0, t0, t1
- LONG_S t0, TI_FLAGS(t3)
-
/*
* clear saved user stack CU1 bit
*/