[MIPS] Fix fpu_save_double on 64-bit.
> Without this fix, _save_fp() in 64-bit kernel is seriously broken.
>
> ffffffff8010bec0 <_save_fp>:
> ffffffff8010bec0: 400d6000 mfc0 t1,c0_status
> ffffffff8010bec4: 000c7140 sll t2,t0,0x5
> ffffffff8010bec8: 05c10011 bgez t2,ffffffff8010bf10 <_save_fp+0x50>
> ffffffff8010becc: 00000000 nop
> ffffffff8010bed0: f4810328 sdc1 $f1,808(a0)
> ...
Fix register usage in fpu_save_double() and make fpu_restore_double()
more symmetric with fpu_save_double().
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/r4k_switch.S b/arch/mips/kernel/r4k_switch.S
index 0b1b54a..db94e55 100644
--- a/arch/mips/kernel/r4k_switch.S
+++ b/arch/mips/kernel/r4k_switch.S
@@ -75,8 +75,8 @@
and t0, t0, t1
LONG_S t0, ST_OFF(t3)
- fpu_save_double a0 t1 t0 t2 # c0_status passed in t1
- # clobbers t0 and t2
+ fpu_save_double a0 t0 t1 # c0_status passed in t0
+ # clobbers t1
1:
/*
@@ -129,9 +129,9 @@
*/
LEAF(_save_fp)
#ifdef CONFIG_64BIT
- mfc0 t1, CP0_STATUS
+ mfc0 t0, CP0_STATUS
#endif
- fpu_save_double a0 t1 t0 t2 # clobbers t1
+ fpu_save_double a0 t0 t1 # clobbers t1
jr ra
END(_save_fp)
@@ -139,7 +139,10 @@
* Restore a thread's fp context.
*/
LEAF(_restore_fp)
- fpu_restore_double a0, t1 # clobbers t1
+#ifdef CONFIG_64BIT
+ mfc0 t0, CP0_STATUS
+#endif
+ fpu_restore_double a0 t0 t1 # clobbers t1
jr ra
END(_restore_fp)