[ARM] FP emulation IRQ handling cleanup.

Rather than handling the IRQ state each time we emulate each
instruction, we enable the IRQ before we enter the FP emulator.
We don't require any IRQ protection in the emulator anyway, so
it's safe to implement this trivial performance enhancement.

arch/arm/kernel/entry-armv.S

@@ -912,11 +912,12 @@ __und_usr:	sub	sp, sp, #S_FRAME_SIZE		@ Allocate frame size in one go
 		alignment_trap r4, r7, __temp_und
 		zero_fp
 		tst	r6, #PSR_T_BIT			@ Thumb mode?
-		bne	fpundefinstr
+		bne	fpundefinstr			@ ignore FP
 		adrsvc	al, r9, ret_from_exception	@ r9  = normal FP return
 		adrsvc	al, lr, fpundefinstr		@ lr  = undefined instr return
 
-call_fpe:	get_thread_info r10			@ get current thread
+call_fpe:	set_cpsr_c r0, #MODE_SVC		@ Enable interrupts
+		get_thread_info r10			@ get current thread
 		ldr	r4, [r10, #TI_TASK]		@ get current task
 		mov	r8, #1
 		strb	r8, [r4, #TSK_USED_MATH]	@ set current->used_math
@@ -924,8 +925,7 @@ call_fpe:	get_thread_info r10			@ get current thread
 		add	r10, r10, #TI_FPSTATE		@ r10 = workspace
 		ldr	pc, [r4]			@ Call FP module USR entry point
 
-fpundefinstr:	set_cpsr_c r0, #MODE_SVC		@ Enable interrupts
-		mov	r0, sp
+fpundefinstr:	mov	r0, sp
 		adrsvc	al, lr, ret_from_exception
 		b	do_undefinstr
 

arch/arm/nwfpe/fpa11.c

@@ -142,9 +142,6 @@ void FPA11_CheckInit(void)
 unsigned int EmulateAll(unsigned int opcode)
 {
   unsigned int nRc = 1, code;
-  unsigned long flags;
-
-  save_flags(flags); sti();
 
   code = opcode & 0x00000f00;
   if (code == 0x00000100 || code == 0x00000200)
@@ -180,8 +177,6 @@ unsigned int EmulateAll(unsigned int opcode)
     }
   }
 
-  restore_flags(flags);
-
   return(nRc);
 }