[POWERPC] 64bit FPSCR support

Forthcoming machines will extend the FPSCR to 64 bits.  We already
had a 64-bit save area for the FPSCR, but we need to use a new form
of the mtfsf instruction.  Fortunately this new form is decoded as
an ordinary mtfsf by existing 64-bit processors.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

diff --git a/arch/powerpc/kernel/fpu.S b/arch/powerpc/kernel/fpu.S
index 340730f..01f7120 100644 (file)
--- a/arch/powerpc/kernel/fpu.S
+++ b/arch/powerpc/kernel/fpu.S
@@ -72,7 +72,7 @@ _GLOBAL(load_up_fpu)
        std     r12,_MSR(r1)
 #endif
        lfd     fr0,THREAD_FPSCR(r5)
-       mtfsf   0xff,fr0
+       MTFSF_L(fr0)
        REST_32FPRS(0, r5)
 #ifndef CONFIG_SMP
        subi    r4,r5,THREAD
@@ -127,7 +127,7 @@ _GLOBAL(giveup_fpu)
 
 _GLOBAL(cvt_fd)
        lfd     0,THREAD_FPSCR(r5)      /* load up fpscr value */
-       mtfsf   0xff,0
+       MTFSF_L(0)
        lfs     0,0(r3)
        stfd    0,0(r4)
        mffs    0
@@ -136,7 +136,7 @@ _GLOBAL(cvt_fd)
 
 _GLOBAL(cvt_df)
        lfd     0,THREAD_FPSCR(r5)      /* load up fpscr value */
-       mtfsf   0xff,0
+       MTFSF_L(0)
        lfd     0,0(r3)
        stfs    0,0(r4)
        mffs    0

diff --git a/arch/powerpc/kernel/vector.S b/arch/powerpc/kernel/vector.S
index 66b3d03..9416b4a 100644 (file)
--- a/arch/powerpc/kernel/vector.S
+++ b/arch/powerpc/kernel/vector.S
@@ -53,12 +53,12 @@ fpenable:
        stfd    fr31,8(r1)
        LDCONST(fr1, fpzero)
        mffs    fr31
-       mtfsf   0xff,fr1
+       MTFSF_L(fr1)
        blr
 
 fpdisable:
        mtlr    r12
-       mtfsf   0xff,fr31
+       MTFSF_L(fr31)
        lfd     fr31,8(r1)
        lfd     fr1,16(r1)
        lfd     fr0,24(r1)

diff --git a/include/asm-powerpc/reg.h b/include/asm-powerpc/reg.h
index 3779b21..bfc7dc1 100644 (file)
--- a/include/asm-powerpc/reg.h
+++ b/include/asm-powerpc/reg.h
@@ -499,6 +499,19 @@
 #define MMCR0_PMC2_LOADMISSTIME        0x5
 #endif
 
+/*
+ * An mtfsf instruction with the L bit set. On CPUs that support this a
+ * full 64bits of FPSCR is restored and on other CPUs it is ignored.
+ *
+ * Until binutils gets the new form of mtfsf, hardwire the instruction.
+ */
+#ifdef CONFIG_PPC64
+#define MTFSF_L(REG) \
+       .long (0xfc00058e | ((0xff) << 17) | ((REG) << 11) | (1 << 25))
+#else
+#define MTFSF_L(REG)   mtfsf   0xff, (REG)
+#endif
+
 /* Processor Version Register (PVR) field extraction */
 
 #define PVR_VER(pvr)   (((pvr) >>  16) & 0xFFFF)       /* Version field */