xref: /openbmc/linux/arch/mips/kernel/genex.S (revision 1fa6ac37) 
1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License.  See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 1994 - 2000, 2001, 2003 Ralf Baechle
7 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
8 * Copyright (C) 2001 MIPS Technologies, Inc.
9 * Copyright (C) 2002, 2007  Maciej W. Rozycki
10 */
11#include <linux/init.h>
12
13#include <asm/asm.h>
14#include <asm/asmmacro.h>
15#include <asm/cacheops.h>
16#include <asm/irqflags.h>
17#include <asm/regdef.h>
18#include <asm/fpregdef.h>
19#include <asm/mipsregs.h>
20#include <asm/stackframe.h>
21#include <asm/war.h>
22#include <asm/page.h>
23#include <asm/thread_info.h>
24
25#define PANIC_PIC(msg)					\
26		.set push;				\
27		.set	reorder;			\
28		PTR_LA	a0,8f;				\
29		.set	noat;				\
30		PTR_LA	AT, panic;			\
31		jr	AT;				\
329:		b	9b;				\
33		.set	pop;				\
34		TEXT(msg)
35
36	__INIT
37
38NESTED(except_vec0_generic, 0, sp)
39	PANIC_PIC("Exception vector 0 called")
40	END(except_vec0_generic)
41
42NESTED(except_vec1_generic, 0, sp)
43	PANIC_PIC("Exception vector 1 called")
44	END(except_vec1_generic)
45
46/*
47 * General exception vector for all other CPUs.
48 *
49 * Be careful when changing this, it has to be at most 128 bytes
50 * to fit into space reserved for the exception handler.
51 */
52NESTED(except_vec3_generic, 0, sp)
53	.set	push
54	.set	noat
55#if R5432_CP0_INTERRUPT_WAR
56	mfc0	k0, CP0_INDEX
57#endif
58	mfc0	k1, CP0_CAUSE
59	andi	k1, k1, 0x7c
60#ifdef CONFIG_64BIT
61	dsll	k1, k1, 1
62#endif
63	PTR_L	k0, exception_handlers(k1)
64	jr	k0
65	.set	pop
66	END(except_vec3_generic)
67
68/*
69 * General exception handler for CPUs with virtual coherency exception.
70 *
71 * Be careful when changing this, it has to be at most 256 (as a special
72 * exception) bytes to fit into space reserved for the exception handler.
73 */
74NESTED(except_vec3_r4000, 0, sp)
75	.set	push
76	.set	mips3
77	.set	noat
78	mfc0	k1, CP0_CAUSE
79	li	k0, 31<<2
80	andi	k1, k1, 0x7c
81	.set	push
82	.set	noreorder
83	.set	nomacro
84	beq	k1, k0, handle_vced
85	 li	k0, 14<<2
86	beq	k1, k0, handle_vcei
87#ifdef CONFIG_64BIT
88	 dsll	k1, k1, 1
89#endif
90	.set	pop
91	PTR_L	k0, exception_handlers(k1)
92	jr	k0
93
94	/*
95	 * Big shit, we now may have two dirty primary cache lines for the same
96	 * physical address.  We can safely invalidate the line pointed to by
97	 * c0_badvaddr because after return from this exception handler the
98	 * load / store will be re-executed.
99	 */
100handle_vced:
101	MFC0	k0, CP0_BADVADDR
102	li	k1, -4					# Is this ...
103	and	k0, k1					# ... really needed?
104	mtc0	zero, CP0_TAGLO
105	cache	Index_Store_Tag_D, (k0)
106	cache	Hit_Writeback_Inv_SD, (k0)
107#ifdef CONFIG_PROC_FS
108	PTR_LA	k0, vced_count
109	lw	k1, (k0)
110	addiu	k1, 1
111	sw	k1, (k0)
112#endif
113	eret
114
115handle_vcei:
116	MFC0	k0, CP0_BADVADDR
117	cache	Hit_Writeback_Inv_SD, (k0)		# also cleans pi
118#ifdef CONFIG_PROC_FS
119	PTR_LA	k0, vcei_count
120	lw	k1, (k0)
121	addiu	k1, 1
122	sw	k1, (k0)
123#endif
124	eret
125	.set	pop
126	END(except_vec3_r4000)
127
128	__FINIT
129
130	.align	5	/* 32 byte rollback region */
131LEAF(r4k_wait)
132	.set	push
133	.set	noreorder
134	/* start of rollback region */
135	LONG_L	t0, TI_FLAGS($28)
136	nop
137	andi	t0, _TIF_NEED_RESCHED
138	bnez	t0, 1f
139	 nop
140	nop
141	nop
142	.set	mips3
143	wait
144	/* end of rollback region (the region size must be power of two) */
145	.set	pop
1461:
147	jr	ra
148	END(r4k_wait)
149
150	.macro	BUILD_ROLLBACK_PROLOGUE handler
151	FEXPORT(rollback_\handler)
152	.set	push
153	.set	noat
154	MFC0	k0, CP0_EPC
155	PTR_LA	k1, r4k_wait
156	ori	k0, 0x1f	/* 32 byte rollback region */
157	xori	k0, 0x1f
158	bne	k0, k1, 9f
159	MTC0	k0, CP0_EPC
1609:
161	.set pop
162	.endm
163
164	.align  5
165BUILD_ROLLBACK_PROLOGUE handle_int
166NESTED(handle_int, PT_SIZE, sp)
167#ifdef CONFIG_TRACE_IRQFLAGS
168	/*
169	 * Check to see if the interrupted code has just disabled
170	 * interrupts and ignore this interrupt for now if so.
171	 *
172	 * local_irq_disable() disables interrupts and then calls
173	 * trace_hardirqs_off() to track the state. If an interrupt is taken
174	 * after interrupts are disabled but before the state is updated
175	 * it will appear to restore_all that it is incorrectly returning with
176	 * interrupts disabled
177	 */
178	.set	push
179	.set	noat
180	mfc0	k0, CP0_STATUS
181#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
182	and	k0, ST0_IEP
183	bnez	k0, 1f
184
185	mfc0	k0, CP0_EPC
186	.set	noreorder
187	j	k0
188	rfe
189#else
190	and	k0, ST0_IE
191	bnez	k0, 1f
192
193	eret
194#endif
1951:
196	.set pop
197#endif
198	SAVE_ALL
199	CLI
200	TRACE_IRQS_OFF
201
202	LONG_L	s0, TI_REGS($28)
203	LONG_S	sp, TI_REGS($28)
204	PTR_LA	ra, ret_from_irq
205	j	plat_irq_dispatch
206	END(handle_int)
207
208	__INIT
209
210/*
211 * Special interrupt vector for MIPS64 ISA & embedded MIPS processors.
212 * This is a dedicated interrupt exception vector which reduces the
213 * interrupt processing overhead.  The jump instruction will be replaced
214 * at the initialization time.
215 *
216 * Be careful when changing this, it has to be at most 128 bytes
217 * to fit into space reserved for the exception handler.
218 */
219NESTED(except_vec4, 0, sp)
2201:	j	1b			/* Dummy, will be replaced */
221	END(except_vec4)
222
223/*
224 * EJTAG debug exception handler.
225 * The EJTAG debug exception entry point is 0xbfc00480, which
226 * normally is in the boot PROM, so the boot PROM must do a
227 * unconditional jump to this vector.
228 */
229NESTED(except_vec_ejtag_debug, 0, sp)
230	j	ejtag_debug_handler
231	END(except_vec_ejtag_debug)
232
233	__FINIT
234
235/*
236 * Vectored interrupt handler.
237 * This prototype is copied to ebase + n*IntCtl.VS and patched
238 * to invoke the handler
239 */
240BUILD_ROLLBACK_PROLOGUE except_vec_vi
241NESTED(except_vec_vi, 0, sp)
242	SAVE_SOME
243	SAVE_AT
244	.set	push
245	.set	noreorder
246#ifdef CONFIG_MIPS_MT_SMTC
247	/*
248	 * To keep from blindly blocking *all* interrupts
249	 * during service by SMTC kernel, we also want to
250	 * pass the IM value to be cleared.
251	 */
252FEXPORT(except_vec_vi_mori)
253	ori	a0, $0, 0
254#endif /* CONFIG_MIPS_MT_SMTC */
255FEXPORT(except_vec_vi_lui)
256	lui	v0, 0		/* Patched */
257	j	except_vec_vi_handler
258FEXPORT(except_vec_vi_ori)
259	 ori	v0, 0		/* Patched */
260	.set	pop
261	END(except_vec_vi)
262EXPORT(except_vec_vi_end)
263
264/*
265 * Common Vectored Interrupt code
266 * Complete the register saves and invoke the handler which is passed in $v0
267 */
268NESTED(except_vec_vi_handler, 0, sp)
269	SAVE_TEMP
270	SAVE_STATIC
271#ifdef CONFIG_MIPS_MT_SMTC
272	/*
273	 * SMTC has an interesting problem that interrupts are level-triggered,
274	 * and the CLI macro will clear EXL, potentially causing a duplicate
275	 * interrupt service invocation. So we need to clear the associated
276	 * IM bit of Status prior to doing CLI, and restore it after the
277	 * service routine has been invoked - we must assume that the
278	 * service routine will have cleared the state, and any active
279	 * level represents a new or otherwised unserviced event...
280	 */
281	mfc0	t1, CP0_STATUS
282	and	t0, a0, t1
283#ifdef CONFIG_MIPS_MT_SMTC_IM_BACKSTOP
284	mfc0	t2, CP0_TCCONTEXT
285	or	t2, t0, t2
286	mtc0	t2, CP0_TCCONTEXT
287#endif /* CONFIG_MIPS_MT_SMTC_IM_BACKSTOP */
288	xor	t1, t1, t0
289	mtc0	t1, CP0_STATUS
290	_ehb
291#endif /* CONFIG_MIPS_MT_SMTC */
292	CLI
293#ifdef CONFIG_TRACE_IRQFLAGS
294	move	s0, v0
295#ifdef CONFIG_MIPS_MT_SMTC
296	move	s1, a0
297#endif
298	TRACE_IRQS_OFF
299#ifdef CONFIG_MIPS_MT_SMTC
300	move	a0, s1
301#endif
302	move	v0, s0
303#endif
304
305	LONG_L	s0, TI_REGS($28)
306	LONG_S	sp, TI_REGS($28)
307	PTR_LA	ra, ret_from_irq
308	jr	v0
309	END(except_vec_vi_handler)
310
311/*
312 * EJTAG debug exception handler.
313 */
314NESTED(ejtag_debug_handler, PT_SIZE, sp)
315	.set	push
316	.set	noat
317	MTC0	k0, CP0_DESAVE
318	mfc0	k0, CP0_DEBUG
319
320	sll	k0, k0, 30	# Check for SDBBP.
321	bgez	k0, ejtag_return
322
323	PTR_LA	k0, ejtag_debug_buffer
324	LONG_S	k1, 0(k0)
325	SAVE_ALL
326	move	a0, sp
327	jal	ejtag_exception_handler
328	RESTORE_ALL
329	PTR_LA	k0, ejtag_debug_buffer
330	LONG_L	k1, 0(k0)
331
332ejtag_return:
333	MFC0	k0, CP0_DESAVE
334	.set	mips32
335	deret
336	.set pop
337	END(ejtag_debug_handler)
338
339/*
340 * This buffer is reserved for the use of the EJTAG debug
341 * handler.
342 */
343	.data
344EXPORT(ejtag_debug_buffer)
345	.fill	LONGSIZE
346	.previous
347
348	__INIT
349
350/*
351 * NMI debug exception handler for MIPS reference boards.
352 * The NMI debug exception entry point is 0xbfc00000, which
353 * normally is in the boot PROM, so the boot PROM must do a
354 * unconditional jump to this vector.
355 */
356NESTED(except_vec_nmi, 0, sp)
357	j	nmi_handler
358	END(except_vec_nmi)
359
360	__FINIT
361
362NESTED(nmi_handler, PT_SIZE, sp)
363	.set	push
364	.set	noat
365	SAVE_ALL
366 	move	a0, sp
367	jal	nmi_exception_handler
368	RESTORE_ALL
369	.set	mips3
370	eret
371	.set	pop
372	END(nmi_handler)
373
374	.macro	__build_clear_none
375	.endm
376
377	.macro	__build_clear_sti
378	TRACE_IRQS_ON
379	STI
380	.endm
381
382	.macro	__build_clear_cli
383	CLI
384	TRACE_IRQS_OFF
385	.endm
386
387	.macro	__build_clear_fpe
388	.set	push
389	/* gas fails to assemble cfc1 for some archs (octeon).*/ \
390	.set	mips1
391	cfc1	a1, fcr31
392	li	a2, ~(0x3f << 12)
393	and	a2, a1
394	ctc1	a2, fcr31
395	.set	pop
396	TRACE_IRQS_ON
397	STI
398	.endm
399
400	.macro	__build_clear_ade
401	MFC0	t0, CP0_BADVADDR
402	PTR_S	t0, PT_BVADDR(sp)
403	KMODE
404	.endm
405
406	.macro	__BUILD_silent exception
407	.endm
408
409	/* Gas tries to parse the PRINT argument as a string containing
410	   string escapes and emits bogus warnings if it believes to
411	   recognize an unknown escape code.  So make the arguments
412	   start with an n and gas will believe \n is ok ...  */
413	.macro	__BUILD_verbose	nexception
414	LONG_L	a1, PT_EPC(sp)
415#ifdef CONFIG_32BIT
416	PRINT("Got \nexception at %08lx\012")
417#endif
418#ifdef CONFIG_64BIT
419	PRINT("Got \nexception at %016lx\012")
420#endif
421	.endm
422
423	.macro	__BUILD_count exception
424	LONG_L	t0,exception_count_\exception
425	LONG_ADDIU t0, 1
426	LONG_S	t0,exception_count_\exception
427	.comm	exception_count\exception, 8, 8
428	.endm
429
430	.macro	__BUILD_HANDLER exception handler clear verbose ext
431	.align	5
432	NESTED(handle_\exception, PT_SIZE, sp)
433	.set	noat
434	SAVE_ALL
435	FEXPORT(handle_\exception\ext)
436	__BUILD_clear_\clear
437	.set	at
438	__BUILD_\verbose \exception
439	move	a0, sp
440	PTR_LA	ra, ret_from_exception
441	j	do_\handler
442	END(handle_\exception)
443	.endm
444
445	.macro	BUILD_HANDLER exception handler clear verbose
446	__BUILD_HANDLER	\exception \handler \clear \verbose _int
447	.endm
448
449	BUILD_HANDLER adel ade ade silent		/* #4  */
450	BUILD_HANDLER ades ade ade silent		/* #5  */
451	BUILD_HANDLER ibe be cli silent			/* #6  */
452	BUILD_HANDLER dbe be cli silent			/* #7  */
453	BUILD_HANDLER bp bp sti silent			/* #9  */
454	BUILD_HANDLER ri ri sti silent			/* #10 */
455	BUILD_HANDLER cpu cpu sti silent		/* #11 */
456	BUILD_HANDLER ov ov sti silent			/* #12 */
457	BUILD_HANDLER tr tr sti silent			/* #13 */
458	BUILD_HANDLER fpe fpe fpe silent		/* #15 */
459	BUILD_HANDLER mdmx mdmx sti silent		/* #22 */
460#ifdef 	CONFIG_HARDWARE_WATCHPOINTS
461	/*
462	 * For watch, interrupts will be enabled after the watch
463	 * registers are read.
464	 */
465	BUILD_HANDLER watch watch cli silent		/* #23 */
466#else
467	BUILD_HANDLER watch watch sti verbose		/* #23 */
468#endif
469	BUILD_HANDLER mcheck mcheck cli verbose		/* #24 */
470	BUILD_HANDLER mt mt sti silent			/* #25 */
471	BUILD_HANDLER dsp dsp sti silent		/* #26 */
472	BUILD_HANDLER reserved reserved sti verbose	/* others */
473
474	.align	5
475	LEAF(handle_ri_rdhwr_vivt)
476#ifdef CONFIG_MIPS_MT_SMTC
477	PANIC_PIC("handle_ri_rdhwr_vivt called")
478#else
479	.set	push
480	.set	noat
481	.set	noreorder
482	/* check if TLB contains a entry for EPC */
483	MFC0	k1, CP0_ENTRYHI
484	andi	k1, 0xff	/* ASID_MASK */
485	MFC0	k0, CP0_EPC
486	PTR_SRL	k0, PAGE_SHIFT + 1
487	PTR_SLL	k0, PAGE_SHIFT + 1
488	or	k1, k0
489	MTC0	k1, CP0_ENTRYHI
490	mtc0_tlbw_hazard
491	tlbp
492	tlb_probe_hazard
493	mfc0	k1, CP0_INDEX
494	.set	pop
495	bltz	k1, handle_ri	/* slow path */
496	/* fall thru */
497#endif
498	END(handle_ri_rdhwr_vivt)
499
500	LEAF(handle_ri_rdhwr)
501	.set	push
502	.set	noat
503	.set	noreorder
504	/* 0x7c03e83b: rdhwr v1,$29 */
505	MFC0	k1, CP0_EPC
506	lui	k0, 0x7c03
507	lw	k1, (k1)
508	ori	k0, 0xe83b
509	.set	reorder
510	bne	k0, k1, handle_ri	/* if not ours */
511	/* The insn is rdhwr.  No need to check CAUSE.BD here. */
512	get_saved_sp	/* k1 := current_thread_info */
513	.set	noreorder
514	MFC0	k0, CP0_EPC
515#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
516	ori	k1, _THREAD_MASK
517	xori	k1, _THREAD_MASK
518	LONG_L	v1, TI_TP_VALUE(k1)
519	LONG_ADDIU	k0, 4
520	jr	k0
521	 rfe
522#else
523#ifndef CONFIG_CPU_DADDI_WORKAROUNDS
524	LONG_ADDIU	k0, 4		/* stall on $k0 */
525#else
526	.set	at=v1
527	LONG_ADDIU	k0, 4
528	.set	noat
529#endif
530	MTC0	k0, CP0_EPC
531	/* I hope three instructions between MTC0 and ERET are enough... */
532	ori	k1, _THREAD_MASK
533	xori	k1, _THREAD_MASK
534	LONG_L	v1, TI_TP_VALUE(k1)
535	.set	mips3
536	eret
537	.set	mips0
538#endif
539	.set	pop
540	END(handle_ri_rdhwr)
541
542#ifdef CONFIG_64BIT
543/* A temporary overflow handler used by check_daddi(). */
544
545	__INIT
546
547	BUILD_HANDLER  daddi_ov daddi_ov none silent	/* #12 */
548#endif
549