3 files changed, 28 insertions, 37 deletions

diff --git a/arch/mips/math-emu/cp1emu.c b/arch/mips/math-emu/cp1emu.c
index 890f77927d62..454b53924490 100644
--- a/arch/mips/math-emu/cp1emu.c
+++ b/arch/mips/math-emu/cp1emu.c
@@ -163,33 +163,34 @@ static int isBranchInstr(mips_instruction * i)
 
 /*
  * In the Linux kernel, we support selection of FPR format on the
- * basis of the Status.FR bit.  This does imply that, if a full 32
- * FPRs are desired, there needs to be a flip-flop that can be written
- * to one at that bit position.  In any case, O32 MIPS ABI uses
- * only the even FPRs (Status.FR = 0).
+ * basis of the Status.FR bit.  If an FPU is not present, the FR bit
+ * is hardwired to zero, which would imply a 32-bit FPU even for
+ * 64-bit CPUs.  For 64-bit kernels with no FPU we use TIF_32BIT_REGS
+ * as a proxy for the FR bit so that a 64-bit FPU is emulated.  In any
+ * case, for a 32-bit kernel which uses the O32 MIPS ABI, only the
+ * even FPRs are used (Status.FR = 0).
  */
-
-#define CP0_STATUS_FR_SUPPORT
-
-#ifdef CP0_STATUS_FR_SUPPORT
-#define FR_BIT ST0_FR
+static inline int cop1_64bit(struct pt_regs *xcp)
+{
+	if (cpu_has_fpu)
+		return xcp->cp0_status & ST0_FR;
+#ifdef CONFIG_64BIT
+	return !test_thread_flag(TIF_32BIT_REGS);
 #else
-#define FR_BIT 0
+	return 0;
 #endif
+}
+
+#define SIFROMREG(si, x) ((si) = cop1_64bit(xcp) || !(x & 1) ? \
+			(int)ctx->fpr[x] : (int)(ctx->fpr[x & ~1] >> 32))
 
-#define SIFROMREG(si, x) ((si) = \
-			(xcp->cp0_status & FR_BIT) || !(x & 1) ? \
-			(int)ctx->fpr[x] : \
-			(int)(ctx->fpr[x & ~1] >> 32 ))
-#define SITOREG(si, x)	(ctx->fpr[x & ~((xcp->cp0_status & FR_BIT) == 0)] = \
-			(xcp->cp0_status & FR_BIT) || !(x & 1) ? \
+#define SITOREG(si, x)	(ctx->fpr[x & ~(cop1_64bit(xcp) == 0)] = \
+			cop1_64bit(xcp) || !(x & 1) ? \
 			ctx->fpr[x & ~1] >> 32 << 32 | (u32)(si) : \
 			ctx->fpr[x & ~1] << 32 >> 32 | (u64)(si) << 32)
 
-#define DIFROMREG(di, x) ((di) = \
-			ctx->fpr[x & ~((xcp->cp0_status & FR_BIT) == 0)])
-#define DITOREG(di, x)	(ctx->fpr[x & ~((xcp->cp0_status & FR_BIT) == 0)] \
-			= (di))
+#define DIFROMREG(di, x) ((di) = ctx->fpr[x & ~(cop1_64bit(xcp) == 0)])
+#define DITOREG(di, x)	(ctx->fpr[x & ~(cop1_64bit(xcp) == 0)] = (di))
 
 #define SPFROMREG(sp, x) SIFROMREG((sp).bits, x)
 #define SPTOREG(sp, x)	SITOREG((sp).bits, x)
diff --git a/arch/mips/math-emu/dp_simple.c b/arch/mips/math-emu/dp_simple.c
index 1c555e6c6a9f..d9ae1dbabda7 100644
--- a/arch/mips/math-emu/dp_simple.c
+++ b/arch/mips/math-emu/dp_simple.c
@@ -62,8 +62,6 @@ ieee754dp ieee754dp_neg(ieee754dp x)
 		return ieee754dp_nanxcpt(y, "neg");
 	}
 
-	if (ieee754dp_isnan(x))	/* but not infinity */
-		return ieee754dp_nanxcpt(x, "neg", x);
 	return x;
 }
 
@@ -76,15 +74,12 @@ ieee754dp ieee754dp_abs(ieee754dp x)
 	CLEARCX;
 	FLUSHXDP;
 
+	/* Clear sign ALWAYS, irrespective of NaN */
+	DPSIGN(x) = 0;
+
 	if (xc == IEEE754_CLASS_SNAN) {
-		SETCX(IEEE754_INVALID_OPERATION);
-		return ieee754dp_nanxcpt(ieee754dp_indef(), "neg");
+		return ieee754dp_nanxcpt(ieee754dp_indef(), "abs");
 	}
 
-	if (ieee754dp_isnan(x))	/* but not infinity */
-		return ieee754dp_nanxcpt(x, "abs", x);
-
-	/* quick fix up */
-	DPSIGN(x) = 0;
 	return x;
 }
diff --git a/arch/mips/math-emu/sp_simple.c b/arch/mips/math-emu/sp_simple.c
index 770f0f4677cd..3175477d36f6 100644
--- a/arch/mips/math-emu/sp_simple.c
+++ b/arch/mips/math-emu/sp_simple.c
@@ -62,8 +62,6 @@ ieee754sp ieee754sp_neg(ieee754sp x)
 		return ieee754sp_nanxcpt(y, "neg");
 	}
 
-	if (ieee754sp_isnan(x))	/* but not infinity */
-		return ieee754sp_nanxcpt(x, "neg", x);
 	return x;
 }
 
@@ -76,15 +74,12 @@ ieee754sp ieee754sp_abs(ieee754sp x)
 	CLEARCX;
 	FLUSHXSP;
 
+	/* Clear sign ALWAYS, irrespective of NaN */
+	SPSIGN(x) = 0;
+
 	if (xc == IEEE754_CLASS_SNAN) {
-		SETCX(IEEE754_INVALID_OPERATION);
 		return ieee754sp_nanxcpt(ieee754sp_indef(), "abs");
 	}
 
-	if (ieee754sp_isnan(x))	/* but not infinity */
-		return ieee754sp_nanxcpt(x, "abs", x);
-
-	/* quick fix up */
-	SPSIGN(x) = 0;
 	return x;
 }