xref: /linux/arch/mips/mm/page.c (revision 40d269c000bda9fcd276a0412a9cebd3f6e344c5)
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) 2003, 04, 05 Ralf Baechle (ralf@linux-mips.org)
7  * Copyright (C) 2007  Maciej W. Rozycki
8  * Copyright (C) 2008  Thiemo Seufer
9  * Copyright (C) 2012  MIPS Technologies, Inc.
10  */
11 #include <linux/kernel.h>
12 #include <linux/sched.h>
13 #include <linux/smp.h>
14 #include <linux/mm.h>
15 #include <linux/proc_fs.h>
16 
17 #include <asm/bugs.h>
18 #include <asm/cacheops.h>
19 #include <asm/cpu-type.h>
20 #include <asm/inst.h>
21 #include <asm/io.h>
22 #include <asm/page.h>
23 #include <asm/prefetch.h>
24 #include <asm/bootinfo.h>
25 #include <asm/mipsregs.h>
26 #include <asm/mmu_context.h>
27 #include <asm/regdef.h>
28 #include <asm/cpu.h>
29 
30 #ifdef CONFIG_SIBYTE_DMA_PAGEOPS
31 #include <asm/sibyte/sb1250.h>
32 #include <asm/sibyte/sb1250_regs.h>
33 #include <asm/sibyte/sb1250_dma.h>
34 #endif
35 
36 #include <asm/uasm.h>
37 
38 /* Handle labels (which must be positive integers). */
39 enum label_id {
40 	label_clear_nopref = 1,
41 	label_clear_pref,
42 	label_copy_nopref,
43 	label_copy_pref_both,
44 	label_copy_pref_store,
45 };
46 
47 UASM_L_LA(_clear_nopref)
48 UASM_L_LA(_clear_pref)
49 UASM_L_LA(_copy_nopref)
50 UASM_L_LA(_copy_pref_both)
51 UASM_L_LA(_copy_pref_store)
52 
53 /* We need one branch and therefore one relocation per target label. */
54 static struct uasm_label labels[5];
55 static struct uasm_reloc relocs[5];
56 
57 #define cpu_is_r4600_v1_x()	((read_c0_prid() & 0xfffffff0) == 0x00002010)
58 #define cpu_is_r4600_v2_x()	((read_c0_prid() & 0xfffffff0) == 0x00002020)
59 
60 /*
61  * R6 has a limited offset of the pref instruction.
62  * Skip it if the offset is more than 9 bits.
63  */
64 #define _uasm_i_pref(a, b, c, d)		\
65 do {						\
66 	if (cpu_has_mips_r6) {			\
67 		if (c <= 0xff && c >= -0x100)	\
68 			uasm_i_pref(a, b, c, d);\
69 	} else {				\
70 		uasm_i_pref(a, b, c, d);	\
71 	}					\
72 } while(0)
73 
74 static int pref_bias_clear_store;
75 static int pref_bias_copy_load;
76 static int pref_bias_copy_store;
77 
78 static u32 pref_src_mode;
79 static u32 pref_dst_mode;
80 
81 static int clear_word_size;
82 static int copy_word_size;
83 
84 static int half_clear_loop_size;
85 static int half_copy_loop_size;
86 
87 static int cache_line_size;
88 #define cache_line_mask() (cache_line_size - 1)
89 
90 static inline void
91 pg_addiu(u32 **buf, unsigned int reg1, unsigned int reg2, unsigned int off)
92 {
93 	if (cpu_has_64bit_gp_regs &&
94 	    IS_ENABLED(CONFIG_CPU_DADDI_WORKAROUNDS) &&
95 	    r4k_daddiu_bug()) {
96 		if (off > 0x7fff) {
97 			uasm_i_lui(buf, GPR_T9, uasm_rel_hi(off));
98 			uasm_i_addiu(buf, GPR_T9, GPR_T9, uasm_rel_lo(off));
99 		} else
100 			uasm_i_addiu(buf, GPR_T9, GPR_ZERO, off);
101 		uasm_i_daddu(buf, reg1, reg2, GPR_T9);
102 	} else {
103 		if (off > 0x7fff) {
104 			uasm_i_lui(buf, GPR_T9, uasm_rel_hi(off));
105 			uasm_i_addiu(buf, GPR_T9, GPR_T9, uasm_rel_lo(off));
106 			UASM_i_ADDU(buf, reg1, reg2, GPR_T9);
107 		} else
108 			UASM_i_ADDIU(buf, reg1, reg2, off);
109 	}
110 }
111 
112 static void set_prefetch_parameters(void)
113 {
114 	if (cpu_has_64bit_gp_regs || cpu_has_64bit_zero_reg)
115 		clear_word_size = 8;
116 	else
117 		clear_word_size = 4;
118 
119 	if (cpu_has_64bit_gp_regs)
120 		copy_word_size = 8;
121 	else
122 		copy_word_size = 4;
123 
124 	/*
125 	 * The pref's used here are using "streaming" hints, which cause the
126 	 * copied data to be kicked out of the cache sooner.  A page copy often
127 	 * ends up copying a lot more data than is commonly used, so this seems
128 	 * to make sense in terms of reducing cache pollution, but I've no real
129 	 * performance data to back this up.
130 	 */
131 	if (cpu_has_prefetch) {
132 		/*
133 		 * XXX: Most prefetch bias values in here are based on
134 		 * guesswork.
135 		 */
136 		cache_line_size = cpu_dcache_line_size();
137 		switch (current_cpu_type()) {
138 		case CPU_R5500:
139 		case CPU_TX49XX:
140 			/* These processors only support the Pref_Load. */
141 			pref_bias_copy_load = 256;
142 			break;
143 
144 		case CPU_R10000:
145 		case CPU_R12000:
146 		case CPU_R14000:
147 		case CPU_R16000:
148 			/*
149 			 * Those values have been experimentally tuned for an
150 			 * Origin 200.
151 			 */
152 			pref_bias_clear_store = 512;
153 			pref_bias_copy_load = 256;
154 			pref_bias_copy_store = 256;
155 			pref_src_mode = Pref_LoadStreamed;
156 			pref_dst_mode = Pref_StoreStreamed;
157 			break;
158 
159 		case CPU_SB1:
160 		case CPU_SB1A:
161 			pref_bias_clear_store = 128;
162 			pref_bias_copy_load = 128;
163 			pref_bias_copy_store = 128;
164 			/*
165 			 * SB1 pass1 Pref_LoadStreamed/Pref_StoreStreamed
166 			 * hints are broken.
167 			 */
168 			if (current_cpu_type() == CPU_SB1 &&
169 			    (current_cpu_data.processor_id & 0xff) < 0x02) {
170 				pref_src_mode = Pref_Load;
171 				pref_dst_mode = Pref_Store;
172 			} else {
173 				pref_src_mode = Pref_LoadStreamed;
174 				pref_dst_mode = Pref_StoreStreamed;
175 			}
176 			break;
177 
178 		case CPU_LOONGSON64:
179 			/* Loongson-3 only support the Pref_Load/Pref_Store. */
180 			pref_bias_clear_store = 128;
181 			pref_bias_copy_load = 128;
182 			pref_bias_copy_store = 128;
183 			pref_src_mode = Pref_Load;
184 			pref_dst_mode = Pref_Store;
185 			break;
186 
187 		default:
188 			pref_bias_clear_store = 128;
189 			pref_bias_copy_load = 256;
190 			pref_bias_copy_store = 128;
191 			pref_src_mode = Pref_LoadStreamed;
192 			if (cpu_has_mips_r6)
193 				/*
194 				 * Bit 30 (Pref_PrepareForStore) has been
195 				 * removed from MIPS R6. Use bit 5
196 				 * (Pref_StoreStreamed).
197 				 */
198 				pref_dst_mode = Pref_StoreStreamed;
199 			else
200 				pref_dst_mode = Pref_PrepareForStore;
201 			break;
202 		}
203 	} else {
204 		if (cpu_has_cache_cdex_s)
205 			cache_line_size = cpu_scache_line_size();
206 		else if (cpu_has_cache_cdex_p)
207 			cache_line_size = cpu_dcache_line_size();
208 	}
209 	/*
210 	 * Too much unrolling will overflow the available space in
211 	 * clear_space_array / copy_page_array.
212 	 */
213 	half_clear_loop_size = min(16 * clear_word_size,
214 				   max(cache_line_size >> 1,
215 				       4 * clear_word_size));
216 	half_copy_loop_size = min(16 * copy_word_size,
217 				  max(cache_line_size >> 1,
218 				      4 * copy_word_size));
219 }
220 
221 static void build_clear_store(u32 **buf, int off)
222 {
223 	if (cpu_has_64bit_gp_regs || cpu_has_64bit_zero_reg) {
224 		uasm_i_sd(buf, GPR_ZERO, off, GPR_A0);
225 	} else {
226 		uasm_i_sw(buf, GPR_ZERO, off, GPR_A0);
227 	}
228 }
229 
230 static inline void build_clear_pref(u32 **buf, int off)
231 {
232 	if (off & cache_line_mask())
233 		return;
234 
235 	if (pref_bias_clear_store) {
236 		_uasm_i_pref(buf, pref_dst_mode, pref_bias_clear_store + off,
237 			    GPR_A0);
238 	} else if (cache_line_size == (half_clear_loop_size << 1)) {
239 		if (cpu_has_cache_cdex_s) {
240 			uasm_i_cache(buf, Create_Dirty_Excl_SD, off, GPR_A0);
241 		} else if (cpu_has_cache_cdex_p) {
242 			if (IS_ENABLED(CONFIG_WAR_R4600_V1_HIT_CACHEOP) &&
243 			    cpu_is_r4600_v1_x()) {
244 				uasm_i_nop(buf);
245 				uasm_i_nop(buf);
246 				uasm_i_nop(buf);
247 				uasm_i_nop(buf);
248 			}
249 
250 			if (IS_ENABLED(CONFIG_WAR_R4600_V2_HIT_CACHEOP) &&
251 			    cpu_is_r4600_v2_x())
252 				uasm_i_lw(buf, GPR_ZERO, GPR_ZERO, GPR_AT);
253 
254 			uasm_i_cache(buf, Create_Dirty_Excl_D, off, GPR_A0);
255 		}
256 	}
257 }
258 
259 extern u32 __clear_page_start;
260 extern u32 __clear_page_end;
261 extern u32 __copy_page_start;
262 extern u32 __copy_page_end;
263 
264 void build_clear_page(void)
265 {
266 	int off;
267 	u32 *buf = &__clear_page_start;
268 	struct uasm_label *l = labels;
269 	struct uasm_reloc *r = relocs;
270 	int i;
271 	static atomic_t run_once = ATOMIC_INIT(0);
272 
273 	if (atomic_xchg(&run_once, 1)) {
274 		return;
275 	}
276 
277 	memset(labels, 0, sizeof(labels));
278 	memset(relocs, 0, sizeof(relocs));
279 
280 	set_prefetch_parameters();
281 
282 	/*
283 	 * This algorithm makes the following assumptions:
284 	 *   - The prefetch bias is a multiple of 2 words.
285 	 *   - The prefetch bias is less than one page.
286 	 */
287 	BUG_ON(pref_bias_clear_store % (2 * clear_word_size));
288 	BUG_ON(PAGE_SIZE < pref_bias_clear_store);
289 
290 	off = PAGE_SIZE - pref_bias_clear_store;
291 	if (off > 0xffff || !pref_bias_clear_store)
292 		pg_addiu(&buf, GPR_A2, GPR_A0, off);
293 	else
294 		uasm_i_ori(&buf, GPR_A2, GPR_A0, off);
295 
296 	if (IS_ENABLED(CONFIG_WAR_R4600_V2_HIT_CACHEOP) && cpu_is_r4600_v2_x())
297 		uasm_i_lui(&buf, GPR_AT, uasm_rel_hi(0xa0000000));
298 
299 	off = cache_line_size ? min(8, pref_bias_clear_store / cache_line_size)
300 				* cache_line_size : 0;
301 	while (off) {
302 		build_clear_pref(&buf, -off);
303 		off -= cache_line_size;
304 	}
305 	uasm_l_clear_pref(&l, buf);
306 	do {
307 		build_clear_pref(&buf, off);
308 		build_clear_store(&buf, off);
309 		off += clear_word_size;
310 	} while (off < half_clear_loop_size);
311 	pg_addiu(&buf, GPR_A0, GPR_A0, 2 * off);
312 	off = -off;
313 	do {
314 		build_clear_pref(&buf, off);
315 		if (off == -clear_word_size)
316 			uasm_il_bne(&buf, &r, GPR_A0, GPR_A2, label_clear_pref);
317 		build_clear_store(&buf, off);
318 		off += clear_word_size;
319 	} while (off < 0);
320 
321 	if (pref_bias_clear_store) {
322 		pg_addiu(&buf, GPR_A2, GPR_A0, pref_bias_clear_store);
323 		uasm_l_clear_nopref(&l, buf);
324 		off = 0;
325 		do {
326 			build_clear_store(&buf, off);
327 			off += clear_word_size;
328 		} while (off < half_clear_loop_size);
329 		pg_addiu(&buf, GPR_A0, GPR_A0, 2 * off);
330 		off = -off;
331 		do {
332 			if (off == -clear_word_size)
333 				uasm_il_bne(&buf, &r, GPR_A0, GPR_A2,
334 					    label_clear_nopref);
335 			build_clear_store(&buf, off);
336 			off += clear_word_size;
337 		} while (off < 0);
338 	}
339 
340 	uasm_i_jr(&buf, GPR_RA);
341 	uasm_i_nop(&buf);
342 
343 	BUG_ON(buf > &__clear_page_end);
344 
345 	uasm_resolve_relocs(relocs, labels);
346 
347 	pr_debug("Synthesized clear page handler (%u instructions).\n",
348 		 (u32)(buf - &__clear_page_start));
349 
350 	pr_debug("\t.set push\n");
351 	pr_debug("\t.set noreorder\n");
352 	for (i = 0; i < (buf - &__clear_page_start); i++)
353 		pr_debug("\t.word 0x%08x\n", (&__clear_page_start)[i]);
354 	pr_debug("\t.set pop\n");
355 }
356 
357 static void build_copy_load(u32 **buf, int reg, int off)
358 {
359 	if (cpu_has_64bit_gp_regs) {
360 		uasm_i_ld(buf, reg, off, GPR_A1);
361 	} else {
362 		uasm_i_lw(buf, reg, off, GPR_A1);
363 	}
364 }
365 
366 static void build_copy_store(u32 **buf, int reg, int off)
367 {
368 	if (cpu_has_64bit_gp_regs) {
369 		uasm_i_sd(buf, reg, off, GPR_A0);
370 	} else {
371 		uasm_i_sw(buf, reg, off, GPR_A0);
372 	}
373 }
374 
375 static inline void build_copy_load_pref(u32 **buf, int off)
376 {
377 	if (off & cache_line_mask())
378 		return;
379 
380 	if (pref_bias_copy_load)
381 		_uasm_i_pref(buf, pref_src_mode, pref_bias_copy_load + off, GPR_A1);
382 }
383 
384 static inline void build_copy_store_pref(u32 **buf, int off)
385 {
386 	if (off & cache_line_mask())
387 		return;
388 
389 	if (pref_bias_copy_store) {
390 		_uasm_i_pref(buf, pref_dst_mode, pref_bias_copy_store + off,
391 			    GPR_A0);
392 	} else if (cache_line_size == (half_copy_loop_size << 1)) {
393 		if (cpu_has_cache_cdex_s) {
394 			uasm_i_cache(buf, Create_Dirty_Excl_SD, off, GPR_A0);
395 		} else if (cpu_has_cache_cdex_p) {
396 			if (IS_ENABLED(CONFIG_WAR_R4600_V1_HIT_CACHEOP) &&
397 			    cpu_is_r4600_v1_x()) {
398 				uasm_i_nop(buf);
399 				uasm_i_nop(buf);
400 				uasm_i_nop(buf);
401 				uasm_i_nop(buf);
402 			}
403 
404 			if (IS_ENABLED(CONFIG_WAR_R4600_V2_HIT_CACHEOP) &&
405 			    cpu_is_r4600_v2_x())
406 				uasm_i_lw(buf, GPR_ZERO, GPR_ZERO, GPR_AT);
407 
408 			uasm_i_cache(buf, Create_Dirty_Excl_D, off, GPR_A0);
409 		}
410 	}
411 }
412 
413 void build_copy_page(void)
414 {
415 	int off;
416 	u32 *buf = &__copy_page_start;
417 	struct uasm_label *l = labels;
418 	struct uasm_reloc *r = relocs;
419 	int i;
420 	static atomic_t run_once = ATOMIC_INIT(0);
421 
422 	if (atomic_xchg(&run_once, 1)) {
423 		return;
424 	}
425 
426 	memset(labels, 0, sizeof(labels));
427 	memset(relocs, 0, sizeof(relocs));
428 
429 	set_prefetch_parameters();
430 
431 	/*
432 	 * This algorithm makes the following assumptions:
433 	 *   - All prefetch biases are multiples of 8 words.
434 	 *   - The prefetch biases are less than one page.
435 	 *   - The store prefetch bias isn't greater than the load
436 	 *     prefetch bias.
437 	 */
438 	BUG_ON(pref_bias_copy_load % (8 * copy_word_size));
439 	BUG_ON(pref_bias_copy_store % (8 * copy_word_size));
440 	BUG_ON(PAGE_SIZE < pref_bias_copy_load);
441 	BUG_ON(pref_bias_copy_store > pref_bias_copy_load);
442 
443 	off = PAGE_SIZE - pref_bias_copy_load;
444 	if (off > 0xffff || !pref_bias_copy_load)
445 		pg_addiu(&buf, GPR_A2, GPR_A0, off);
446 	else
447 		uasm_i_ori(&buf, GPR_A2, GPR_A0, off);
448 
449 	if (IS_ENABLED(CONFIG_WAR_R4600_V2_HIT_CACHEOP) && cpu_is_r4600_v2_x())
450 		uasm_i_lui(&buf, GPR_AT, uasm_rel_hi(0xa0000000));
451 
452 	off = cache_line_size ? min(8, pref_bias_copy_load / cache_line_size) *
453 				cache_line_size : 0;
454 	while (off) {
455 		build_copy_load_pref(&buf, -off);
456 		off -= cache_line_size;
457 	}
458 	off = cache_line_size ? min(8, pref_bias_copy_store / cache_line_size) *
459 				cache_line_size : 0;
460 	while (off) {
461 		build_copy_store_pref(&buf, -off);
462 		off -= cache_line_size;
463 	}
464 	uasm_l_copy_pref_both(&l, buf);
465 	do {
466 		build_copy_load_pref(&buf, off);
467 		build_copy_load(&buf, GPR_T0, off);
468 		build_copy_load_pref(&buf, off + copy_word_size);
469 		build_copy_load(&buf, GPR_T1, off + copy_word_size);
470 		build_copy_load_pref(&buf, off + 2 * copy_word_size);
471 		build_copy_load(&buf, GPR_T2, off + 2 * copy_word_size);
472 		build_copy_load_pref(&buf, off + 3 * copy_word_size);
473 		build_copy_load(&buf, GPR_T3, off + 3 * copy_word_size);
474 		build_copy_store_pref(&buf, off);
475 		build_copy_store(&buf, GPR_T0, off);
476 		build_copy_store_pref(&buf, off + copy_word_size);
477 		build_copy_store(&buf, GPR_T1, off + copy_word_size);
478 		build_copy_store_pref(&buf, off + 2 * copy_word_size);
479 		build_copy_store(&buf, GPR_T2, off + 2 * copy_word_size);
480 		build_copy_store_pref(&buf, off + 3 * copy_word_size);
481 		build_copy_store(&buf, GPR_T3, off + 3 * copy_word_size);
482 		off += 4 * copy_word_size;
483 	} while (off < half_copy_loop_size);
484 	pg_addiu(&buf, GPR_A1, GPR_A1, 2 * off);
485 	pg_addiu(&buf, GPR_A0, GPR_A0, 2 * off);
486 	off = -off;
487 	do {
488 		build_copy_load_pref(&buf, off);
489 		build_copy_load(&buf, GPR_T0, off);
490 		build_copy_load_pref(&buf, off + copy_word_size);
491 		build_copy_load(&buf, GPR_T1, off + copy_word_size);
492 		build_copy_load_pref(&buf, off + 2 * copy_word_size);
493 		build_copy_load(&buf, GPR_T2, off + 2 * copy_word_size);
494 		build_copy_load_pref(&buf, off + 3 * copy_word_size);
495 		build_copy_load(&buf, GPR_T3, off + 3 * copy_word_size);
496 		build_copy_store_pref(&buf, off);
497 		build_copy_store(&buf, GPR_T0, off);
498 		build_copy_store_pref(&buf, off + copy_word_size);
499 		build_copy_store(&buf, GPR_T1, off + copy_word_size);
500 		build_copy_store_pref(&buf, off + 2 * copy_word_size);
501 		build_copy_store(&buf, GPR_T2, off + 2 * copy_word_size);
502 		build_copy_store_pref(&buf, off + 3 * copy_word_size);
503 		if (off == -(4 * copy_word_size))
504 			uasm_il_bne(&buf, &r, GPR_A2, GPR_A0, label_copy_pref_both);
505 		build_copy_store(&buf, GPR_T3, off + 3 * copy_word_size);
506 		off += 4 * copy_word_size;
507 	} while (off < 0);
508 
509 	if (pref_bias_copy_load - pref_bias_copy_store) {
510 		pg_addiu(&buf, GPR_A2, GPR_A0,
511 			 pref_bias_copy_load - pref_bias_copy_store);
512 		uasm_l_copy_pref_store(&l, buf);
513 		off = 0;
514 		do {
515 			build_copy_load(&buf, GPR_T0, off);
516 			build_copy_load(&buf, GPR_T1, off + copy_word_size);
517 			build_copy_load(&buf, GPR_T2, off + 2 * copy_word_size);
518 			build_copy_load(&buf, GPR_T3, off + 3 * copy_word_size);
519 			build_copy_store_pref(&buf, off);
520 			build_copy_store(&buf, GPR_T0, off);
521 			build_copy_store_pref(&buf, off + copy_word_size);
522 			build_copy_store(&buf, GPR_T1, off + copy_word_size);
523 			build_copy_store_pref(&buf, off + 2 * copy_word_size);
524 			build_copy_store(&buf, GPR_T2, off + 2 * copy_word_size);
525 			build_copy_store_pref(&buf, off + 3 * copy_word_size);
526 			build_copy_store(&buf, GPR_T3, off + 3 * copy_word_size);
527 			off += 4 * copy_word_size;
528 		} while (off < half_copy_loop_size);
529 		pg_addiu(&buf, GPR_A1, GPR_A1, 2 * off);
530 		pg_addiu(&buf, GPR_A0, GPR_A0, 2 * off);
531 		off = -off;
532 		do {
533 			build_copy_load(&buf, GPR_T0, off);
534 			build_copy_load(&buf, GPR_T1, off + copy_word_size);
535 			build_copy_load(&buf, GPR_T2, off + 2 * copy_word_size);
536 			build_copy_load(&buf, GPR_T3, off + 3 * copy_word_size);
537 			build_copy_store_pref(&buf, off);
538 			build_copy_store(&buf, GPR_T0, off);
539 			build_copy_store_pref(&buf, off + copy_word_size);
540 			build_copy_store(&buf, GPR_T1, off + copy_word_size);
541 			build_copy_store_pref(&buf, off + 2 * copy_word_size);
542 			build_copy_store(&buf, GPR_T2, off + 2 * copy_word_size);
543 			build_copy_store_pref(&buf, off + 3 * copy_word_size);
544 			if (off == -(4 * copy_word_size))
545 				uasm_il_bne(&buf, &r, GPR_A2, GPR_A0,
546 					    label_copy_pref_store);
547 			build_copy_store(&buf, GPR_T3, off + 3 * copy_word_size);
548 			off += 4 * copy_word_size;
549 		} while (off < 0);
550 	}
551 
552 	if (pref_bias_copy_store) {
553 		pg_addiu(&buf, GPR_A2, GPR_A0, pref_bias_copy_store);
554 		uasm_l_copy_nopref(&l, buf);
555 		off = 0;
556 		do {
557 			build_copy_load(&buf, GPR_T0, off);
558 			build_copy_load(&buf, GPR_T1, off + copy_word_size);
559 			build_copy_load(&buf, GPR_T2, off + 2 * copy_word_size);
560 			build_copy_load(&buf, GPR_T3, off + 3 * copy_word_size);
561 			build_copy_store(&buf, GPR_T0, off);
562 			build_copy_store(&buf, GPR_T1, off + copy_word_size);
563 			build_copy_store(&buf, GPR_T2, off + 2 * copy_word_size);
564 			build_copy_store(&buf, GPR_T3, off + 3 * copy_word_size);
565 			off += 4 * copy_word_size;
566 		} while (off < half_copy_loop_size);
567 		pg_addiu(&buf, GPR_A1, GPR_A1, 2 * off);
568 		pg_addiu(&buf, GPR_A0, GPR_A0, 2 * off);
569 		off = -off;
570 		do {
571 			build_copy_load(&buf, GPR_T0, off);
572 			build_copy_load(&buf, GPR_T1, off + copy_word_size);
573 			build_copy_load(&buf, GPR_T2, off + 2 * copy_word_size);
574 			build_copy_load(&buf, GPR_T3, off + 3 * copy_word_size);
575 			build_copy_store(&buf, GPR_T0, off);
576 			build_copy_store(&buf, GPR_T1, off + copy_word_size);
577 			build_copy_store(&buf, GPR_T2, off + 2 * copy_word_size);
578 			if (off == -(4 * copy_word_size))
579 				uasm_il_bne(&buf, &r, GPR_A2, GPR_A0,
580 					    label_copy_nopref);
581 			build_copy_store(&buf, GPR_T3, off + 3 * copy_word_size);
582 			off += 4 * copy_word_size;
583 		} while (off < 0);
584 	}
585 
586 	uasm_i_jr(&buf, GPR_RA);
587 	uasm_i_nop(&buf);
588 
589 	BUG_ON(buf > &__copy_page_end);
590 
591 	uasm_resolve_relocs(relocs, labels);
592 
593 	pr_debug("Synthesized copy page handler (%u instructions).\n",
594 		 (u32)(buf - &__copy_page_start));
595 
596 	pr_debug("\t.set push\n");
597 	pr_debug("\t.set noreorder\n");
598 	for (i = 0; i < (buf - &__copy_page_start); i++)
599 		pr_debug("\t.word 0x%08x\n", (&__copy_page_start)[i]);
600 	pr_debug("\t.set pop\n");
601 }
602 
603 #ifdef CONFIG_SIBYTE_DMA_PAGEOPS
604 extern void clear_page_cpu(void *page);
605 extern void copy_page_cpu(void *to, void *from);
606 
607 /*
608  * Pad descriptors to cacheline, since each is exclusively owned by a
609  * particular CPU.
610  */
611 struct dmadscr {
612 	u64 dscr_a;
613 	u64 dscr_b;
614 	u64 pad_a;
615 	u64 pad_b;
616 } ____cacheline_aligned_in_smp page_descr[DM_NUM_CHANNELS];
617 
618 void clear_page(void *page)
619 {
620 	u64 to_phys = CPHYSADDR((unsigned long)page);
621 	unsigned int cpu = smp_processor_id();
622 
623 	/* if the page is not in KSEG0, use old way */
624 	if ((long)KSEGX((unsigned long)page) != (long)CKSEG0)
625 		return clear_page_cpu(page);
626 
627 	page_descr[cpu].dscr_a = to_phys | M_DM_DSCRA_ZERO_MEM |
628 				 M_DM_DSCRA_L2C_DEST | M_DM_DSCRA_INTERRUPT;
629 	page_descr[cpu].dscr_b = V_DM_DSCRB_SRC_LENGTH(PAGE_SIZE);
630 	__raw_writeq(1, IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_COUNT)));
631 
632 	/*
633 	 * Don't really want to do it this way, but there's no
634 	 * reliable way to delay completion detection.
635 	 */
636 	while (!(__raw_readq(IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_BASE_DEBUG)))
637 		 & M_DM_DSCR_BASE_INTERRUPT))
638 		;
639 	__raw_readq(IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_BASE)));
640 }
641 EXPORT_SYMBOL(clear_page);
642 
643 void copy_page(void *to, void *from)
644 {
645 	u64 from_phys = CPHYSADDR((unsigned long)from);
646 	u64 to_phys = CPHYSADDR((unsigned long)to);
647 	unsigned int cpu = smp_processor_id();
648 
649 	/* if any page is not in KSEG0, use old way */
650 	if ((long)KSEGX((unsigned long)to) != (long)CKSEG0
651 	    || (long)KSEGX((unsigned long)from) != (long)CKSEG0)
652 		return copy_page_cpu(to, from);
653 
654 	page_descr[cpu].dscr_a = to_phys | M_DM_DSCRA_L2C_DEST |
655 				 M_DM_DSCRA_INTERRUPT;
656 	page_descr[cpu].dscr_b = from_phys | V_DM_DSCRB_SRC_LENGTH(PAGE_SIZE);
657 	__raw_writeq(1, IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_COUNT)));
658 
659 	/*
660 	 * Don't really want to do it this way, but there's no
661 	 * reliable way to delay completion detection.
662 	 */
663 	while (!(__raw_readq(IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_BASE_DEBUG)))
664 		 & M_DM_DSCR_BASE_INTERRUPT))
665 		;
666 	__raw_readq(IOADDR(A_DM_REGISTER(cpu, R_DM_DSCR_BASE)));
667 }
668 EXPORT_SYMBOL(copy_page);
669 
670 #endif /* CONFIG_SIBYTE_DMA_PAGEOPS */
671