[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>

2 files changed, 11 insertions, 12 deletions

diff --git a/include/asm-mips/asmmacro-32.h b/include/asm-mips/asmmacro-32.h
index 11daf5ceb7b4..5de3963f511e 100644
--- a/include/asm-mips/asmmacro-32.h
+++ b/include/asm-mips/asmmacro-32.h
@@ -12,7 +12,7 @@
 #include <asm/fpregdef.h>
 #include <asm/mipsregs.h>
 
-        .macro  fpu_save_double thread status tmp1=t0 tmp2
+        .macro  fpu_save_double thread status tmp1=t0
         cfc1    \tmp1,  fcr31
         sdc1    $f0,  THREAD_FPR0(\thread)
         sdc1    $f2,  THREAD_FPR2(\thread)
@@ -70,7 +70,7 @@
         sw      \tmp, THREAD_FCR31(\thread)
         .endm
 
-        .macro  fpu_restore_double thread tmp=t0
+        .macro  fpu_restore_double thread status tmp=t0
         lw      \tmp, THREAD_FCR31(\thread)
         ldc1    $f0,  THREAD_FPR0(\thread)
         ldc1    $f2,  THREAD_FPR2(\thread)
diff --git a/include/asm-mips/asmmacro-64.h b/include/asm-mips/asmmacro-64.h
index 559c355b9b86..225feefcb25d 100644
--- a/include/asm-mips/asmmacro-64.h
+++ b/include/asm-mips/asmmacro-64.h
@@ -53,12 +53,12 @@
         sdc1    $f31, THREAD_FPR31(\thread)
         .endm
 
-        .macro  fpu_save_double thread status tmp1 tmp2
-        sll     \tmp2, \tmp1, 5
-        bgez    \tmp2, 2f
+        .macro  fpu_save_double thread status tmp
+        sll     \tmp, \status, 5
+        bgez    \tmp, 2f
         fpu_save_16odd \thread
 2:
-        fpu_save_16even \thread \tmp1                   # clobbers t1
+        fpu_save_16even \thread \tmp
         .endm
 
         .macro  fpu_restore_16even thread tmp=t0
@@ -101,13 +101,12 @@
         ldc1    $f31, THREAD_FPR31(\thread)
         .endm
 
-        .macro  fpu_restore_double thread tmp
-        mfc0    t0, CP0_STATUS
-        sll     t1, t0, 5
-        bgez    t1, 1f                          # 16 register mode?
+        .macro  fpu_restore_double thread status tmp
+        sll     \tmp, \status, 5
+        bgez    \tmp, 1f                                # 16 register mode?
 
-        fpu_restore_16odd a0
-1:      fpu_restore_16even a0, t0               # clobbers t0
+        fpu_restore_16odd \thread
+1:      fpu_restore_16even \thread \tmp
         .endm
 
         .macro  cpu_save_nonscratch thread