commit 102cedc32a6e3cd537374a3678d407591d5a6fab
author Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Mon Mar 25 12:09:02 2013 -0500
committer Ralf Baechle <ralf@linux-mips.org> Thu May 09 17:55:18 2013 +0200
tree 7a91493a82e65c0da845afb12020e1534d83ee5d
parent cf6d905828c2c75ebe8c818901e71e09ffe6f629

MIPS: microMIPS: Floating point support.

Add logic needed to do floating point emulation in microMIPS mode.

Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Steven J. Hill <Steven. Hill@imgtec.com>

arch/mips/kernel/unaligned.c

diff --git a/arch/mips/kernel/unaligned.c b/arch/mips/kernel/unaligned.c
index 6087a54..f4c94ff 100644
--- a/arch/mips/kernel/unaligned.c
+++ b/arch/mips/kernel/unaligned.c
@@ -83,6 +83,8 @@
 #include <asm/branch.h>
 #include <asm/byteorder.h>
 #include <asm/cop2.h>
+#include <asm/fpu.h>
+#include <asm/fpu_emulator.h>
 #include <asm/inst.h>
 #include <asm/uaccess.h>
 
@@ -108,6 +110,7 @@
 	union mips_instruction insn;
 	unsigned long value;
 	unsigned int res;
+	void __user *fault_addr = NULL;
 
 	perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, 0);
 
@@ -447,10 +450,21 @@
 	case ldc1_op:
 	case swc1_op:
 	case sdc1_op:
-		/*
-		 * I herewith declare: this does not happen.  So send SIGBUS.
-		 */
-		goto sigbus;
+		die_if_kernel("Unaligned FP access in kernel code", regs);
+		BUG_ON(!used_math());
+		BUG_ON(!is_fpu_owner());
+
+		lose_fpu(1);	/* Save FPU state for the emulator. */
+		res = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 1,
+					       &fault_addr);
+		own_fpu(1);	/* Restore FPU state. */
+
+		/* Signal if something went wrong. */
+		process_fpemu_return(res, fault_addr);
+
+		if (res == 0)
+			break;
+		return;
 
 	/*
 	 * COP2 is available to implementor for application specific use.