cp1emu.c revision 49a89efbbbcc178a39555c43bd59a7593c429664 
1/*
2 * cp1emu.c: a MIPS coprocessor 1 (fpu) instruction emulator
3 *
4 * MIPS floating point support
5 * Copyright (C) 1994-2000 Algorithmics Ltd.
6 * http://www.algor.co.uk
7 *
8 * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
9 * Copyright (C) 2000  MIPS Technologies, Inc.
10 *
11 *  This program is free software; you can distribute it and/or modify it
12 *  under the terms of the GNU General Public License (Version 2) as
13 *  published by the Free Software Foundation.
14 *
15 *  This program is distributed in the hope it will be useful, but WITHOUT
16 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
17 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
18 *  for more details.
19 *
20 *  You should have received a copy of the GNU General Public License along
21 *  with this program; if not, write to the Free Software Foundation, Inc.,
22 *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
23 *
24 * A complete emulator for MIPS coprocessor 1 instructions.  This is
25 * required for #float(switch) or #float(trap), where it catches all
26 * COP1 instructions via the "CoProcessor Unusable" exception.
27 *
28 * More surprisingly it is also required for #float(ieee), to help out
29 * the hardware fpu at the boundaries of the IEEE-754 representation
30 * (denormalised values, infinities, underflow, etc).  It is made
31 * quite nasty because emulation of some non-COP1 instructions is
32 * required, e.g. in branch delay slots.
33 *
34 * Note if you know that you won't have an fpu, then you'll get much
35 * better performance by compiling with -msoft-float!
36 */
37#include <linux/sched.h>
38#include <linux/debugfs.h>
39
40#include <asm/inst.h>
41#include <asm/bootinfo.h>
42#include <asm/processor.h>
43#include <asm/ptrace.h>
44#include <asm/signal.h>
45#include <asm/mipsregs.h>
46#include <asm/fpu_emulator.h>
47#include <asm/uaccess.h>
48#include <asm/branch.h>
49
50#include "ieee754.h"
51#include "dsemul.h"
52
53/* Strap kernel emulator for full MIPS IV emulation */
54
55#ifdef __mips
56#undef __mips
57#endif
58#define __mips 4
59
60/* Function which emulates a floating point instruction. */
61
62static int fpu_emu(struct pt_regs *, struct mips_fpu_struct *,
63	mips_instruction);
64
65#if __mips >= 4 && __mips != 32
66static int fpux_emu(struct pt_regs *,
67	struct mips_fpu_struct *, mips_instruction);
68#endif
69
70/* Further private data for which no space exists in mips_fpu_struct */
71
72struct mips_fpu_emulator_stats fpuemustats;
73
74/* Control registers */
75
76#define FPCREG_RID	0	/* $0  = revision id */
77#define FPCREG_CSR	31	/* $31 = csr */
78
79/* Convert Mips rounding mode (0..3) to IEEE library modes. */
80static const unsigned char ieee_rm[4] = {
81	[FPU_CSR_RN] = IEEE754_RN,
82	[FPU_CSR_RZ] = IEEE754_RZ,
83	[FPU_CSR_RU] = IEEE754_RU,
84	[FPU_CSR_RD] = IEEE754_RD,
85};
86/* Convert IEEE library modes to Mips rounding mode (0..3). */
87static const unsigned char mips_rm[4] = {
88	[IEEE754_RN] = FPU_CSR_RN,
89	[IEEE754_RZ] = FPU_CSR_RZ,
90	[IEEE754_RD] = FPU_CSR_RD,
91	[IEEE754_RU] = FPU_CSR_RU,
92};
93
94#if __mips >= 4
95/* convert condition code register number to csr bit */
96static const unsigned int fpucondbit[8] = {
97	FPU_CSR_COND0,
98	FPU_CSR_COND1,
99	FPU_CSR_COND2,
100	FPU_CSR_COND3,
101	FPU_CSR_COND4,
102	FPU_CSR_COND5,
103	FPU_CSR_COND6,
104	FPU_CSR_COND7
105};
106#endif
107
108
109/*
110 * Redundant with logic already in kernel/branch.c,
111 * embedded in compute_return_epc.  At some point,
112 * a single subroutine should be used across both
113 * modules.
114 */
115static int isBranchInstr(mips_instruction * i)
116{
117	switch (MIPSInst_OPCODE(*i)) {
118	case spec_op:
119		switch (MIPSInst_FUNC(*i)) {
120		case jalr_op:
121		case jr_op:
122			return 1;
123		}
124		break;
125
126	case bcond_op:
127		switch (MIPSInst_RT(*i)) {
128		case bltz_op:
129		case bgez_op:
130		case bltzl_op:
131		case bgezl_op:
132		case bltzal_op:
133		case bgezal_op:
134		case bltzall_op:
135		case bgezall_op:
136			return 1;
137		}
138		break;
139
140	case j_op:
141	case jal_op:
142	case jalx_op:
143	case beq_op:
144	case bne_op:
145	case blez_op:
146	case bgtz_op:
147	case beql_op:
148	case bnel_op:
149	case blezl_op:
150	case bgtzl_op:
151		return 1;
152
153	case cop0_op:
154	case cop1_op:
155	case cop2_op:
156	case cop1x_op:
157		if (MIPSInst_RS(*i) == bc_op)
158			return 1;
159		break;
160	}
161
162	return 0;
163}
164
165/*
166 * In the Linux kernel, we support selection of FPR format on the
167 * basis of the Status.FR bit.  This does imply that, if a full 32
168 * FPRs are desired, there needs to be a flip-flop that can be written
169 * to one at that bit position.  In any case, O32 MIPS ABI uses
170 * only the even FPRs (Status.FR = 0).
171 */
172
173#define CP0_STATUS_FR_SUPPORT
174
175#ifdef CP0_STATUS_FR_SUPPORT
176#define FR_BIT ST0_FR
177#else
178#define FR_BIT 0
179#endif
180
181#define SIFROMREG(si,x)	((si) = \
182			(xcp->cp0_status & FR_BIT) || !(x & 1) ? \
183			(int)ctx->fpr[x] : \
184			(int)(ctx->fpr[x & ~1] >> 32 ))
185#define SITOREG(si,x)	(ctx->fpr[x & ~((xcp->cp0_status & FR_BIT) == 0)] = \
186			(xcp->cp0_status & FR_BIT) || !(x & 1) ? \
187			ctx->fpr[x & ~1] >> 32 << 32 | (u32)(si) : \
188			ctx->fpr[x & ~1] << 32 >> 32 | (u64)(si) << 32)
189
190#define DIFROMREG(di,x)	((di) = \
191			ctx->fpr[x & ~((xcp->cp0_status & FR_BIT) == 0)])
192#define DITOREG(di,x)	(ctx->fpr[x & ~((xcp->cp0_status & FR_BIT) == 0)] \
193			= (di))
194
195#define SPFROMREG(sp,x)	SIFROMREG((sp).bits,x)
196#define SPTOREG(sp,x)	SITOREG((sp).bits,x)
197#define DPFROMREG(dp,x)	DIFROMREG((dp).bits,x)
198#define DPTOREG(dp,x)	DITOREG((dp).bits,x)
199
200/*
201 * Emulate the single floating point instruction pointed at by EPC.
202 * Two instructions if the instruction is in a branch delay slot.
203 */
204
205static int cop1Emulate(struct pt_regs *xcp, struct mips_fpu_struct *ctx)
206{
207	mips_instruction ir;
208	unsigned long emulpc, contpc;
209	unsigned int cond;
210
211	if (get_user(ir, (mips_instruction __user *) xcp->cp0_epc)) {
212		fpuemustats.errors++;
213		return SIGBUS;
214	}
215
216	/* XXX NEC Vr54xx bug workaround */
217	if ((xcp->cp0_cause & CAUSEF_BD) && !isBranchInstr(&ir))
218		xcp->cp0_cause &= ~CAUSEF_BD;
219
220	if (xcp->cp0_cause & CAUSEF_BD) {
221		/*
222		 * The instruction to be emulated is in a branch delay slot
223		 * which means that we have to  emulate the branch instruction
224		 * BEFORE we do the cop1 instruction.
225		 *
226		 * This branch could be a COP1 branch, but in that case we
227		 * would have had a trap for that instruction, and would not
228		 * come through this route.
229		 *
230		 * Linux MIPS branch emulator operates on context, updating the
231		 * cp0_epc.
232		 */
233		emulpc = xcp->cp0_epc + 4;	/* Snapshot emulation target */
234
235		if (__compute_return_epc(xcp)) {
236#ifdef CP1DBG
237			printk("failed to emulate branch at %p\n",
238				(void *) (xcp->cp0_epc));
239#endif
240			return SIGILL;
241		}
242		if (get_user(ir, (mips_instruction __user *) emulpc)) {
243			fpuemustats.errors++;
244			return SIGBUS;
245		}
246		/* __compute_return_epc() will have updated cp0_epc */
247		contpc = xcp->cp0_epc;
248		/* In order not to confuse ptrace() et al, tweak context */
249		xcp->cp0_epc = emulpc - 4;
250	} else {
251		emulpc = xcp->cp0_epc;
252		contpc = xcp->cp0_epc + 4;
253	}
254
255      emul:
256	fpuemustats.emulated++;
257	switch (MIPSInst_OPCODE(ir)) {
258	case ldc1_op:{
259		u64 __user *va = (u64 __user *) (xcp->regs[MIPSInst_RS(ir)] +
260			MIPSInst_SIMM(ir));
261		u64 val;
262
263		fpuemustats.loads++;
264		if (get_user(val, va)) {
265			fpuemustats.errors++;
266			return SIGBUS;
267		}
268		DITOREG(val, MIPSInst_RT(ir));
269		break;
270	}
271
272	case sdc1_op:{
273		u64 __user *va = (u64 __user *) (xcp->regs[MIPSInst_RS(ir)] +
274			MIPSInst_SIMM(ir));
275		u64 val;
276
277		fpuemustats.stores++;
278		DIFROMREG(val, MIPSInst_RT(ir));
279		if (put_user(val, va)) {
280			fpuemustats.errors++;
281			return SIGBUS;
282		}
283		break;
284	}
285
286	case lwc1_op:{
287		u32 __user *va = (u32 __user *) (xcp->regs[MIPSInst_RS(ir)] +
288			MIPSInst_SIMM(ir));
289		u32 val;
290
291		fpuemustats.loads++;
292		if (get_user(val, va)) {
293			fpuemustats.errors++;
294			return SIGBUS;
295		}
296		SITOREG(val, MIPSInst_RT(ir));
297		break;
298	}
299
300	case swc1_op:{
301		u32 __user *va = (u32 __user *) (xcp->regs[MIPSInst_RS(ir)] +
302			MIPSInst_SIMM(ir));
303		u32 val;
304
305		fpuemustats.stores++;
306		SIFROMREG(val, MIPSInst_RT(ir));
307		if (put_user(val, va)) {
308			fpuemustats.errors++;
309			return SIGBUS;
310		}
311		break;
312	}
313
314	case cop1_op:
315		switch (MIPSInst_RS(ir)) {
316
317#if defined(__mips64)
318		case dmfc_op:
319			/* copregister fs -> gpr[rt] */
320			if (MIPSInst_RT(ir) != 0) {
321				DIFROMREG(xcp->regs[MIPSInst_RT(ir)],
322					MIPSInst_RD(ir));
323			}
324			break;
325
326		case dmtc_op:
327			/* copregister fs <- rt */
328			DITOREG(xcp->regs[MIPSInst_RT(ir)], MIPSInst_RD(ir));
329			break;
330#endif
331
332		case mfc_op:
333			/* copregister rd -> gpr[rt] */
334			if (MIPSInst_RT(ir) != 0) {
335				SIFROMREG(xcp->regs[MIPSInst_RT(ir)],
336					MIPSInst_RD(ir));
337			}
338			break;
339
340		case mtc_op:
341			/* copregister rd <- rt */
342			SITOREG(xcp->regs[MIPSInst_RT(ir)], MIPSInst_RD(ir));
343			break;
344
345		case cfc_op:{
346			/* cop control register rd -> gpr[rt] */
347			u32 value;
348
349			if (ir == CP1UNDEF) {
350				return do_dsemulret(xcp);
351			}
352			if (MIPSInst_RD(ir) == FPCREG_CSR) {
353				value = ctx->fcr31;
354				value = (value & ~0x3) | mips_rm[value & 0x3];
355#ifdef CSRTRACE
356				printk("%p gpr[%d]<-csr=%08x\n",
357					(void *) (xcp->cp0_epc),
358					MIPSInst_RT(ir), value);
359#endif
360			}
361			else if (MIPSInst_RD(ir) == FPCREG_RID)
362				value = 0;
363			else
364				value = 0;
365			if (MIPSInst_RT(ir))
366				xcp->regs[MIPSInst_RT(ir)] = value;
367			break;
368		}
369
370		case ctc_op:{
371			/* copregister rd <- rt */
372			u32 value;
373
374			if (MIPSInst_RT(ir) == 0)
375				value = 0;
376			else
377				value = xcp->regs[MIPSInst_RT(ir)];
378
379			/* we only have one writable control reg
380			 */
381			if (MIPSInst_RD(ir) == FPCREG_CSR) {
382#ifdef CSRTRACE
383				printk("%p gpr[%d]->csr=%08x\n",
384					(void *) (xcp->cp0_epc),
385					MIPSInst_RT(ir), value);
386#endif
387				value &= (FPU_CSR_FLUSH | FPU_CSR_ALL_E | FPU_CSR_ALL_S | 0x03);
388				ctx->fcr31 &= ~(FPU_CSR_FLUSH | FPU_CSR_ALL_E | FPU_CSR_ALL_S | 0x03);
389				/* convert to ieee library modes */
390				ctx->fcr31 |= (value & ~0x3) | ieee_rm[value & 0x3];
391			}
392			if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) {
393				return SIGFPE;
394			}
395			break;
396		}
397
398		case bc_op:{
399			int likely = 0;
400
401			if (xcp->cp0_cause & CAUSEF_BD)
402				return SIGILL;
403
404#if __mips >= 4
405			cond = ctx->fcr31 & fpucondbit[MIPSInst_RT(ir) >> 2];
406#else
407			cond = ctx->fcr31 & FPU_CSR_COND;
408#endif
409			switch (MIPSInst_RT(ir) & 3) {
410			case bcfl_op:
411				likely = 1;
412			case bcf_op:
413				cond = !cond;
414				break;
415			case bctl_op:
416				likely = 1;
417			case bct_op:
418				break;
419			default:
420				/* thats an illegal instruction */
421				return SIGILL;
422			}
423
424			xcp->cp0_cause |= CAUSEF_BD;
425			if (cond) {
426				/* branch taken: emulate dslot
427				 * instruction
428				 */
429				xcp->cp0_epc += 4;
430				contpc = (xcp->cp0_epc +
431					(MIPSInst_SIMM(ir) << 2));
432
433				if (get_user(ir,
434				    (mips_instruction __user *) xcp->cp0_epc)) {
435					fpuemustats.errors++;
436					return SIGBUS;
437				}
438
439				switch (MIPSInst_OPCODE(ir)) {
440				case lwc1_op:
441				case swc1_op:
442#if (__mips >= 2 || defined(__mips64))
443				case ldc1_op:
444				case sdc1_op:
445#endif
446				case cop1_op:
447#if __mips >= 4 && __mips != 32
448				case cop1x_op:
449#endif
450					/* its one of ours */
451					goto emul;
452#if __mips >= 4
453				case spec_op:
454					if (MIPSInst_FUNC(ir) == movc_op)
455						goto emul;
456					break;
457#endif
458				}
459
460				/*
461				 * Single step the non-cp1
462				 * instruction in the dslot
463				 */
464				return mips_dsemul(xcp, ir, contpc);
465			}
466			else {
467				/* branch not taken */
468				if (likely) {
469					/*
470					 * branch likely nullifies
471					 * dslot if not taken
472					 */
473					xcp->cp0_epc += 4;
474					contpc += 4;
475					/*
476					 * else continue & execute
477					 * dslot as normal insn
478					 */
479				}
480			}
481			break;
482		}
483
484		default:
485			if (!(MIPSInst_RS(ir) & 0x10))
486				return SIGILL;
487			{
488				int sig;
489
490				/* a real fpu computation instruction */
491				if ((sig = fpu_emu(xcp, ctx, ir)))
492					return sig;
493			}
494		}
495		break;
496
497#if __mips >= 4 && __mips != 32
498	case cop1x_op:{
499		int sig;
500
501		if ((sig = fpux_emu(xcp, ctx, ir)))
502			return sig;
503		break;
504	}
505#endif
506
507#if __mips >= 4
508	case spec_op:
509		if (MIPSInst_FUNC(ir) != movc_op)
510			return SIGILL;
511		cond = fpucondbit[MIPSInst_RT(ir) >> 2];
512		if (((ctx->fcr31 & cond) != 0) == ((MIPSInst_RT(ir) & 1) != 0))
513			xcp->regs[MIPSInst_RD(ir)] =
514				xcp->regs[MIPSInst_RS(ir)];
515		break;
516#endif
517
518	default:
519		return SIGILL;
520	}
521
522	/* we did it !! */
523	xcp->cp0_epc = contpc;
524	xcp->cp0_cause &= ~CAUSEF_BD;
525
526	return 0;
527}
528
529/*
530 * Conversion table from MIPS compare ops 48-63
531 * cond = ieee754dp_cmp(x,y,IEEE754_UN,sig);
532 */
533static const unsigned char cmptab[8] = {
534	0,			/* cmp_0 (sig) cmp_sf */
535	IEEE754_CUN,		/* cmp_un (sig) cmp_ngle */
536	IEEE754_CEQ,		/* cmp_eq (sig) cmp_seq */
537	IEEE754_CEQ | IEEE754_CUN,	/* cmp_ueq (sig) cmp_ngl  */
538	IEEE754_CLT,		/* cmp_olt (sig) cmp_lt */
539	IEEE754_CLT | IEEE754_CUN,	/* cmp_ult (sig) cmp_nge */
540	IEEE754_CLT | IEEE754_CEQ,	/* cmp_ole (sig) cmp_le */
541	IEEE754_CLT | IEEE754_CEQ | IEEE754_CUN,	/* cmp_ule (sig) cmp_ngt */
542};
543
544
545#if __mips >= 4 && __mips != 32
546
547/*
548 * Additional MIPS4 instructions
549 */
550
551#define DEF3OP(name, p, f1, f2, f3) \
552static ieee754##p fpemu_##p##_##name(ieee754##p r, ieee754##p s, \
553    ieee754##p t) \
554{ \
555	struct _ieee754_csr ieee754_csr_save; \
556	s = f1(s, t); \
557	ieee754_csr_save = ieee754_csr; \
558	s = f2(s, r); \
559	ieee754_csr_save.cx |= ieee754_csr.cx; \
560	ieee754_csr_save.sx |= ieee754_csr.sx; \
561	s = f3(s); \
562	ieee754_csr.cx |= ieee754_csr_save.cx; \
563	ieee754_csr.sx |= ieee754_csr_save.sx; \
564	return s; \
565}
566
567static ieee754dp fpemu_dp_recip(ieee754dp d)
568{
569	return ieee754dp_div(ieee754dp_one(0), d);
570}
571
572static ieee754dp fpemu_dp_rsqrt(ieee754dp d)
573{
574	return ieee754dp_div(ieee754dp_one(0), ieee754dp_sqrt(d));
575}
576
577static ieee754sp fpemu_sp_recip(ieee754sp s)
578{
579	return ieee754sp_div(ieee754sp_one(0), s);
580}
581
582static ieee754sp fpemu_sp_rsqrt(ieee754sp s)
583{
584	return ieee754sp_div(ieee754sp_one(0), ieee754sp_sqrt(s));
585}
586
587DEF3OP(madd, sp, ieee754sp_mul, ieee754sp_add,);
588DEF3OP(msub, sp, ieee754sp_mul, ieee754sp_sub,);
589DEF3OP(nmadd, sp, ieee754sp_mul, ieee754sp_add, ieee754sp_neg);
590DEF3OP(nmsub, sp, ieee754sp_mul, ieee754sp_sub, ieee754sp_neg);
591DEF3OP(madd, dp, ieee754dp_mul, ieee754dp_add,);
592DEF3OP(msub, dp, ieee754dp_mul, ieee754dp_sub,);
593DEF3OP(nmadd, dp, ieee754dp_mul, ieee754dp_add, ieee754dp_neg);
594DEF3OP(nmsub, dp, ieee754dp_mul, ieee754dp_sub, ieee754dp_neg);
595
596static int fpux_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
597	mips_instruction ir)
598{
599	unsigned rcsr = 0;	/* resulting csr */
600
601	fpuemustats.cp1xops++;
602
603	switch (MIPSInst_FMA_FFMT(ir)) {
604	case s_fmt:{		/* 0 */
605
606		ieee754sp(*handler) (ieee754sp, ieee754sp, ieee754sp);
607		ieee754sp fd, fr, fs, ft;
608		u32 __user *va;
609		u32 val;
610
611		switch (MIPSInst_FUNC(ir)) {
612		case lwxc1_op:
613			va = (void __user *) (xcp->regs[MIPSInst_FR(ir)] +
614				xcp->regs[MIPSInst_FT(ir)]);
615
616			fpuemustats.loads++;
617			if (get_user(val, va)) {
618				fpuemustats.errors++;
619				return SIGBUS;
620			}
621			SITOREG(val, MIPSInst_FD(ir));
622			break;
623
624		case swxc1_op:
625			va = (void __user *) (xcp->regs[MIPSInst_FR(ir)] +
626				xcp->regs[MIPSInst_FT(ir)]);
627
628			fpuemustats.stores++;
629
630			SIFROMREG(val, MIPSInst_FS(ir));
631			if (put_user(val, va)) {
632				fpuemustats.errors++;
633				return SIGBUS;
634			}
635			break;
636
637		case madd_s_op:
638			handler = fpemu_sp_madd;
639			goto scoptop;
640		case msub_s_op:
641			handler = fpemu_sp_msub;
642			goto scoptop;
643		case nmadd_s_op:
644			handler = fpemu_sp_nmadd;
645			goto scoptop;
646		case nmsub_s_op:
647			handler = fpemu_sp_nmsub;
648			goto scoptop;
649
650		      scoptop:
651			SPFROMREG(fr, MIPSInst_FR(ir));
652			SPFROMREG(fs, MIPSInst_FS(ir));
653			SPFROMREG(ft, MIPSInst_FT(ir));
654			fd = (*handler) (fr, fs, ft);
655			SPTOREG(fd, MIPSInst_FD(ir));
656
657		      copcsr:
658			if (ieee754_cxtest(IEEE754_INEXACT))
659				rcsr |= FPU_CSR_INE_X | FPU_CSR_INE_S;
660			if (ieee754_cxtest(IEEE754_UNDERFLOW))
661				rcsr |= FPU_CSR_UDF_X | FPU_CSR_UDF_S;
662			if (ieee754_cxtest(IEEE754_OVERFLOW))
663				rcsr |= FPU_CSR_OVF_X | FPU_CSR_OVF_S;
664			if (ieee754_cxtest(IEEE754_INVALID_OPERATION))
665				rcsr |= FPU_CSR_INV_X | FPU_CSR_INV_S;
666
667			ctx->fcr31 = (ctx->fcr31 & ~FPU_CSR_ALL_X) | rcsr;
668			if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) {
669				/*printk ("SIGFPE: fpu csr = %08x\n",
670				   ctx->fcr31); */
671				return SIGFPE;
672			}
673
674			break;
675
676		default:
677			return SIGILL;
678		}
679		break;
680	}
681
682	case d_fmt:{		/* 1 */
683		ieee754dp(*handler) (ieee754dp, ieee754dp, ieee754dp);
684		ieee754dp fd, fr, fs, ft;
685		u64 __user *va;
686		u64 val;
687
688		switch (MIPSInst_FUNC(ir)) {
689		case ldxc1_op:
690			va = (void __user *) (xcp->regs[MIPSInst_FR(ir)] +
691				xcp->regs[MIPSInst_FT(ir)]);
692
693			fpuemustats.loads++;
694			if (get_user(val, va)) {
695				fpuemustats.errors++;
696				return SIGBUS;
697			}
698			DITOREG(val, MIPSInst_FD(ir));
699			break;
700
701		case sdxc1_op:
702			va = (void __user *) (xcp->regs[MIPSInst_FR(ir)] +
703				xcp->regs[MIPSInst_FT(ir)]);
704
705			fpuemustats.stores++;
706			DIFROMREG(val, MIPSInst_FS(ir));
707			if (put_user(val, va)) {
708				fpuemustats.errors++;
709				return SIGBUS;
710			}
711			break;
712
713		case madd_d_op:
714			handler = fpemu_dp_madd;
715			goto dcoptop;
716		case msub_d_op:
717			handler = fpemu_dp_msub;
718			goto dcoptop;
719		case nmadd_d_op:
720			handler = fpemu_dp_nmadd;
721			goto dcoptop;
722		case nmsub_d_op:
723			handler = fpemu_dp_nmsub;
724			goto dcoptop;
725
726		      dcoptop:
727			DPFROMREG(fr, MIPSInst_FR(ir));
728			DPFROMREG(fs, MIPSInst_FS(ir));
729			DPFROMREG(ft, MIPSInst_FT(ir));
730			fd = (*handler) (fr, fs, ft);
731			DPTOREG(fd, MIPSInst_FD(ir));
732			goto copcsr;
733
734		default:
735			return SIGILL;
736		}
737		break;
738	}
739
740	case 0x7:		/* 7 */
741		if (MIPSInst_FUNC(ir) != pfetch_op) {
742			return SIGILL;
743		}
744		/* ignore prefx operation */
745		break;
746
747	default:
748		return SIGILL;
749	}
750
751	return 0;
752}
753#endif
754
755
756
757/*
758 * Emulate a single COP1 arithmetic instruction.
759 */
760static int fpu_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
761	mips_instruction ir)
762{
763	int rfmt;		/* resulting format */
764	unsigned rcsr = 0;	/* resulting csr */
765	unsigned cond;
766	union {
767		ieee754dp d;
768		ieee754sp s;
769		int w;
770#ifdef __mips64
771		s64 l;
772#endif
773	} rv;			/* resulting value */
774
775	fpuemustats.cp1ops++;
776	switch (rfmt = (MIPSInst_FFMT(ir) & 0xf)) {
777	case s_fmt:{		/* 0 */
778		union {
779			ieee754sp(*b) (ieee754sp, ieee754sp);
780			ieee754sp(*u) (ieee754sp);
781		} handler;
782
783		switch (MIPSInst_FUNC(ir)) {
784			/* binary ops */
785		case fadd_op:
786			handler.b = ieee754sp_add;
787			goto scopbop;
788		case fsub_op:
789			handler.b = ieee754sp_sub;
790			goto scopbop;
791		case fmul_op:
792			handler.b = ieee754sp_mul;
793			goto scopbop;
794		case fdiv_op:
795			handler.b = ieee754sp_div;
796			goto scopbop;
797
798			/* unary  ops */
799#if __mips >= 2 || defined(__mips64)
800		case fsqrt_op:
801			handler.u = ieee754sp_sqrt;
802			goto scopuop;
803#endif
804#if __mips >= 4 && __mips != 32
805		case frsqrt_op:
806			handler.u = fpemu_sp_rsqrt;
807			goto scopuop;
808		case frecip_op:
809			handler.u = fpemu_sp_recip;
810			goto scopuop;
811#endif
812#if __mips >= 4
813		case fmovc_op:
814			cond = fpucondbit[MIPSInst_FT(ir) >> 2];
815			if (((ctx->fcr31 & cond) != 0) !=
816				((MIPSInst_FT(ir) & 1) != 0))
817				return 0;
818			SPFROMREG(rv.s, MIPSInst_FS(ir));
819			break;
820		case fmovz_op:
821			if (xcp->regs[MIPSInst_FT(ir)] != 0)
822				return 0;
823			SPFROMREG(rv.s, MIPSInst_FS(ir));
824			break;
825		case fmovn_op:
826			if (xcp->regs[MIPSInst_FT(ir)] == 0)
827				return 0;
828			SPFROMREG(rv.s, MIPSInst_FS(ir));
829			break;
830#endif
831		case fabs_op:
832			handler.u = ieee754sp_abs;
833			goto scopuop;
834		case fneg_op:
835			handler.u = ieee754sp_neg;
836			goto scopuop;
837		case fmov_op:
838			/* an easy one */
839			SPFROMREG(rv.s, MIPSInst_FS(ir));
840			goto copcsr;
841
842			/* binary op on handler */
843		      scopbop:
844			{
845				ieee754sp fs, ft;
846
847				SPFROMREG(fs, MIPSInst_FS(ir));
848				SPFROMREG(ft, MIPSInst_FT(ir));
849
850				rv.s = (*handler.b) (fs, ft);
851				goto copcsr;
852			}
853		      scopuop:
854			{
855				ieee754sp fs;
856
857				SPFROMREG(fs, MIPSInst_FS(ir));
858				rv.s = (*handler.u) (fs);
859				goto copcsr;
860			}
861		      copcsr:
862			if (ieee754_cxtest(IEEE754_INEXACT))
863				rcsr |= FPU_CSR_INE_X | FPU_CSR_INE_S;
864			if (ieee754_cxtest(IEEE754_UNDERFLOW))
865				rcsr |= FPU_CSR_UDF_X | FPU_CSR_UDF_S;
866			if (ieee754_cxtest(IEEE754_OVERFLOW))
867				rcsr |= FPU_CSR_OVF_X | FPU_CSR_OVF_S;
868			if (ieee754_cxtest(IEEE754_ZERO_DIVIDE))
869				rcsr |= FPU_CSR_DIV_X | FPU_CSR_DIV_S;
870			if (ieee754_cxtest(IEEE754_INVALID_OPERATION))
871				rcsr |= FPU_CSR_INV_X | FPU_CSR_INV_S;
872			break;
873
874			/* unary conv ops */
875		case fcvts_op:
876			return SIGILL;	/* not defined */
877		case fcvtd_op:{
878			ieee754sp fs;
879
880			SPFROMREG(fs, MIPSInst_FS(ir));
881			rv.d = ieee754dp_fsp(fs);
882			rfmt = d_fmt;
883			goto copcsr;
884		}
885		case fcvtw_op:{
886			ieee754sp fs;
887
888			SPFROMREG(fs, MIPSInst_FS(ir));
889			rv.w = ieee754sp_tint(fs);
890			rfmt = w_fmt;
891			goto copcsr;
892		}
893
894#if __mips >= 2 || defined(__mips64)
895		case fround_op:
896		case ftrunc_op:
897		case fceil_op:
898		case ffloor_op:{
899			unsigned int oldrm = ieee754_csr.rm;
900			ieee754sp fs;
901
902			SPFROMREG(fs, MIPSInst_FS(ir));
903			ieee754_csr.rm = ieee_rm[MIPSInst_FUNC(ir) & 0x3];
904			rv.w = ieee754sp_tint(fs);
905			ieee754_csr.rm = oldrm;
906			rfmt = w_fmt;
907			goto copcsr;
908		}
909#endif /* __mips >= 2 */
910
911#if defined(__mips64)
912		case fcvtl_op:{
913			ieee754sp fs;
914
915			SPFROMREG(fs, MIPSInst_FS(ir));
916			rv.l = ieee754sp_tlong(fs);
917			rfmt = l_fmt;
918			goto copcsr;
919		}
920
921		case froundl_op:
922		case ftruncl_op:
923		case fceill_op:
924		case ffloorl_op:{
925			unsigned int oldrm = ieee754_csr.rm;
926			ieee754sp fs;
927
928			SPFROMREG(fs, MIPSInst_FS(ir));
929			ieee754_csr.rm = ieee_rm[MIPSInst_FUNC(ir) & 0x3];
930			rv.l = ieee754sp_tlong(fs);
931			ieee754_csr.rm = oldrm;
932			rfmt = l_fmt;
933			goto copcsr;
934		}
935#endif /* defined(__mips64) */
936
937		default:
938			if (MIPSInst_FUNC(ir) >= fcmp_op) {
939				unsigned cmpop = MIPSInst_FUNC(ir) - fcmp_op;
940				ieee754sp fs, ft;
941
942				SPFROMREG(fs, MIPSInst_FS(ir));
943				SPFROMREG(ft, MIPSInst_FT(ir));
944				rv.w = ieee754sp_cmp(fs, ft,
945					cmptab[cmpop & 0x7], cmpop & 0x8);
946				rfmt = -1;
947				if ((cmpop & 0x8) && ieee754_cxtest
948					(IEEE754_INVALID_OPERATION))
949					rcsr = FPU_CSR_INV_X | FPU_CSR_INV_S;
950				else
951					goto copcsr;
952
953			}
954			else {
955				return SIGILL;
956			}
957			break;
958		}
959		break;
960	}
961
962	case d_fmt:{
963		union {
964			ieee754dp(*b) (ieee754dp, ieee754dp);
965			ieee754dp(*u) (ieee754dp);
966		} handler;
967
968		switch (MIPSInst_FUNC(ir)) {
969			/* binary ops */
970		case fadd_op:
971			handler.b = ieee754dp_add;
972			goto dcopbop;
973		case fsub_op:
974			handler.b = ieee754dp_sub;
975			goto dcopbop;
976		case fmul_op:
977			handler.b = ieee754dp_mul;
978			goto dcopbop;
979		case fdiv_op:
980			handler.b = ieee754dp_div;
981			goto dcopbop;
982
983			/* unary  ops */
984#if __mips >= 2 || defined(__mips64)
985		case fsqrt_op:
986			handler.u = ieee754dp_sqrt;
987			goto dcopuop;
988#endif
989#if __mips >= 4 && __mips != 32
990		case frsqrt_op:
991			handler.u = fpemu_dp_rsqrt;
992			goto dcopuop;
993		case frecip_op:
994			handler.u = fpemu_dp_recip;
995			goto dcopuop;
996#endif
997#if __mips >= 4
998		case fmovc_op:
999			cond = fpucondbit[MIPSInst_FT(ir) >> 2];
1000			if (((ctx->fcr31 & cond) != 0) !=
1001				((MIPSInst_FT(ir) & 1) != 0))
1002				return 0;
1003			DPFROMREG(rv.d, MIPSInst_FS(ir));
1004			break;
1005		case fmovz_op:
1006			if (xcp->regs[MIPSInst_FT(ir)] != 0)
1007				return 0;
1008			DPFROMREG(rv.d, MIPSInst_FS(ir));
1009			break;
1010		case fmovn_op:
1011			if (xcp->regs[MIPSInst_FT(ir)] == 0)
1012				return 0;
1013			DPFROMREG(rv.d, MIPSInst_FS(ir));
1014			break;
1015#endif
1016		case fabs_op:
1017			handler.u = ieee754dp_abs;
1018			goto dcopuop;
1019
1020		case fneg_op:
1021			handler.u = ieee754dp_neg;
1022			goto dcopuop;
1023
1024		case fmov_op:
1025			/* an easy one */
1026			DPFROMREG(rv.d, MIPSInst_FS(ir));
1027			goto copcsr;
1028
1029			/* binary op on handler */
1030		      dcopbop:{
1031				ieee754dp fs, ft;
1032
1033				DPFROMREG(fs, MIPSInst_FS(ir));
1034				DPFROMREG(ft, MIPSInst_FT(ir));
1035
1036				rv.d = (*handler.b) (fs, ft);
1037				goto copcsr;
1038			}
1039		      dcopuop:{
1040				ieee754dp fs;
1041
1042				DPFROMREG(fs, MIPSInst_FS(ir));
1043				rv.d = (*handler.u) (fs);
1044				goto copcsr;
1045			}
1046
1047			/* unary conv ops */
1048		case fcvts_op:{
1049			ieee754dp fs;
1050
1051			DPFROMREG(fs, MIPSInst_FS(ir));
1052			rv.s = ieee754sp_fdp(fs);
1053			rfmt = s_fmt;
1054			goto copcsr;
1055		}
1056		case fcvtd_op:
1057			return SIGILL;	/* not defined */
1058
1059		case fcvtw_op:{
1060			ieee754dp fs;
1061
1062			DPFROMREG(fs, MIPSInst_FS(ir));
1063			rv.w = ieee754dp_tint(fs);	/* wrong */
1064			rfmt = w_fmt;
1065			goto copcsr;
1066		}
1067
1068#if __mips >= 2 || defined(__mips64)
1069		case fround_op:
1070		case ftrunc_op:
1071		case fceil_op:
1072		case ffloor_op:{
1073			unsigned int oldrm = ieee754_csr.rm;
1074			ieee754dp fs;
1075
1076			DPFROMREG(fs, MIPSInst_FS(ir));
1077			ieee754_csr.rm = ieee_rm[MIPSInst_FUNC(ir) & 0x3];
1078			rv.w = ieee754dp_tint(fs);
1079			ieee754_csr.rm = oldrm;
1080			rfmt = w_fmt;
1081			goto copcsr;
1082		}
1083#endif
1084
1085#if defined(__mips64)
1086		case fcvtl_op:{
1087			ieee754dp fs;
1088
1089			DPFROMREG(fs, MIPSInst_FS(ir));
1090			rv.l = ieee754dp_tlong(fs);
1091			rfmt = l_fmt;
1092			goto copcsr;
1093		}
1094
1095		case froundl_op:
1096		case ftruncl_op:
1097		case fceill_op:
1098		case ffloorl_op:{
1099			unsigned int oldrm = ieee754_csr.rm;
1100			ieee754dp fs;
1101
1102			DPFROMREG(fs, MIPSInst_FS(ir));
1103			ieee754_csr.rm = ieee_rm[MIPSInst_FUNC(ir) & 0x3];
1104			rv.l = ieee754dp_tlong(fs);
1105			ieee754_csr.rm = oldrm;
1106			rfmt = l_fmt;
1107			goto copcsr;
1108		}
1109#endif /* __mips >= 3 */
1110
1111		default:
1112			if (MIPSInst_FUNC(ir) >= fcmp_op) {
1113				unsigned cmpop = MIPSInst_FUNC(ir) - fcmp_op;
1114				ieee754dp fs, ft;
1115
1116				DPFROMREG(fs, MIPSInst_FS(ir));
1117				DPFROMREG(ft, MIPSInst_FT(ir));
1118				rv.w = ieee754dp_cmp(fs, ft,
1119					cmptab[cmpop & 0x7], cmpop & 0x8);
1120				rfmt = -1;
1121				if ((cmpop & 0x8)
1122					&&
1123					ieee754_cxtest
1124					(IEEE754_INVALID_OPERATION))
1125					rcsr = FPU_CSR_INV_X | FPU_CSR_INV_S;
1126				else
1127					goto copcsr;
1128
1129			}
1130			else {
1131				return SIGILL;
1132			}
1133			break;
1134		}
1135		break;
1136	}
1137
1138	case w_fmt:{
1139		ieee754sp fs;
1140
1141		switch (MIPSInst_FUNC(ir)) {
1142		case fcvts_op:
1143			/* convert word to single precision real */
1144			SPFROMREG(fs, MIPSInst_FS(ir));
1145			rv.s = ieee754sp_fint(fs.bits);
1146			rfmt = s_fmt;
1147			goto copcsr;
1148		case fcvtd_op:
1149			/* convert word to double precision real */
1150			SPFROMREG(fs, MIPSInst_FS(ir));
1151			rv.d = ieee754dp_fint(fs.bits);
1152			rfmt = d_fmt;
1153			goto copcsr;
1154		default:
1155			return SIGILL;
1156		}
1157		break;
1158	}
1159
1160#if defined(__mips64)
1161	case l_fmt:{
1162		switch (MIPSInst_FUNC(ir)) {
1163		case fcvts_op:
1164			/* convert long to single precision real */
1165			rv.s = ieee754sp_flong(ctx->fpr[MIPSInst_FS(ir)]);
1166			rfmt = s_fmt;
1167			goto copcsr;
1168		case fcvtd_op:
1169			/* convert long to double precision real */
1170			rv.d = ieee754dp_flong(ctx->fpr[MIPSInst_FS(ir)]);
1171			rfmt = d_fmt;
1172			goto copcsr;
1173		default:
1174			return SIGILL;
1175		}
1176		break;
1177	}
1178#endif
1179
1180	default:
1181		return SIGILL;
1182	}
1183
1184	/*
1185	 * Update the fpu CSR register for this operation.
1186	 * If an exception is required, generate a tidy SIGFPE exception,
1187	 * without updating the result register.
1188	 * Note: cause exception bits do not accumulate, they are rewritten
1189	 * for each op; only the flag/sticky bits accumulate.
1190	 */
1191	ctx->fcr31 = (ctx->fcr31 & ~FPU_CSR_ALL_X) | rcsr;
1192	if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) {
1193		/*printk ("SIGFPE: fpu csr = %08x\n",ctx->fcr31); */
1194		return SIGFPE;
1195	}
1196
1197	/*
1198	 * Now we can safely write the result back to the register file.
1199	 */
1200	switch (rfmt) {
1201	case -1:{
1202#if __mips >= 4
1203		cond = fpucondbit[MIPSInst_FD(ir) >> 2];
1204#else
1205		cond = FPU_CSR_COND;
1206#endif
1207		if (rv.w)
1208			ctx->fcr31 |= cond;
1209		else
1210			ctx->fcr31 &= ~cond;
1211		break;
1212	}
1213	case d_fmt:
1214		DPTOREG(rv.d, MIPSInst_FD(ir));
1215		break;
1216	case s_fmt:
1217		SPTOREG(rv.s, MIPSInst_FD(ir));
1218		break;
1219	case w_fmt:
1220		SITOREG(rv.w, MIPSInst_FD(ir));
1221		break;
1222#if defined(__mips64)
1223	case l_fmt:
1224		DITOREG(rv.l, MIPSInst_FD(ir));
1225		break;
1226#endif
1227	default:
1228		return SIGILL;
1229	}
1230
1231	return 0;
1232}
1233
1234int fpu_emulator_cop1Handler(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
1235	int has_fpu)
1236{
1237	unsigned long oldepc, prevepc;
1238	mips_instruction insn;
1239	int sig = 0;
1240
1241	oldepc = xcp->cp0_epc;
1242	do {
1243		prevepc = xcp->cp0_epc;
1244
1245		if (get_user(insn, (mips_instruction __user *) xcp->cp0_epc)) {
1246			fpuemustats.errors++;
1247			return SIGBUS;
1248		}
1249		if (insn == 0)
1250			xcp->cp0_epc += 4;	/* skip nops */
1251		else {
1252			/*
1253			 * The 'ieee754_csr' is an alias of
1254			 * ctx->fcr31.  No need to copy ctx->fcr31 to
1255			 * ieee754_csr.  But ieee754_csr.rm is ieee
1256			 * library modes. (not mips rounding mode)
1257			 */
1258			/* convert to ieee library modes */
1259			ieee754_csr.rm = ieee_rm[ieee754_csr.rm];
1260			sig = cop1Emulate(xcp, ctx);
1261			/* revert to mips rounding mode */
1262			ieee754_csr.rm = mips_rm[ieee754_csr.rm];
1263		}
1264
1265		if (has_fpu)
1266			break;
1267		if (sig)
1268			break;
1269
1270		cond_resched();
1271	} while (xcp->cp0_epc > prevepc);
1272
1273	/* SIGILL indicates a non-fpu instruction */
1274	if (sig == SIGILL && xcp->cp0_epc != oldepc)
1275		/* but if epc has advanced, then ignore it */
1276		sig = 0;
1277
1278	return sig;
1279}
1280
1281#ifdef CONFIG_DEBUG_FS
1282extern struct dentry *mips_debugfs_dir;
1283static int __init debugfs_fpuemu(void)
1284{
1285	struct dentry *d, *dir;
1286	int i;
1287	static struct {
1288		const char *name;
1289		unsigned int *v;
1290	} vars[] __initdata = {
1291		{ "emulated", &fpuemustats.emulated },
1292		{ "loads",    &fpuemustats.loads },
1293		{ "stores",   &fpuemustats.stores },
1294		{ "cp1ops",   &fpuemustats.cp1ops },
1295		{ "cp1xops",  &fpuemustats.cp1xops },
1296		{ "errors",   &fpuemustats.errors },
1297	};
1298
1299	if (!mips_debugfs_dir)
1300		return -ENODEV;
1301	dir = debugfs_create_dir("fpuemustats", mips_debugfs_dir);
1302	if (IS_ERR(dir))
1303		return PTR_ERR(dir);
1304	for (i = 0; i < ARRAY_SIZE(vars); i++) {
1305		d = debugfs_create_u32(vars[i].name, S_IRUGO, dir, vars[i].v);
1306		if (IS_ERR(d))
1307			return PTR_ERR(d);
1308	}
1309	return 0;
1310}
1311__initcall(debugfs_fpuemu);
1312#endif
1313