1 /*
2 * linux/arch/unicore32/mm/alignment.c
3 *
4 * Code specific to PKUnity SoC and UniCore ISA
5 *
6 * Copyright (C) 2001-2010 GUAN Xue-tao
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12 /*
13 * TODO:
14 * FPU ldm/stm not handling
15 */
16 #include <linux/compiler.h>
17 #include <linux/kernel.h>
18 #include <linux/errno.h>
19 #include <linux/string.h>
20 #include <linux/init.h>
21 #include <linux/sched.h>
22 #include <linux/uaccess.h>
23
24 #include <asm/tlbflush.h>
25 #include <asm/unaligned.h>
26
27 #define CODING_BITS(i) (i & 0xe0000120)
28
29 #define LDST_P_BIT(i) (i & (1 << 28)) /* Preindex */
30 #define LDST_U_BIT(i) (i & (1 << 27)) /* Add offset */
31 #define LDST_W_BIT(i) (i & (1 << 25)) /* Writeback */
32 #define LDST_L_BIT(i) (i & (1 << 24)) /* Load */
33
34 #define LDST_P_EQ_U(i) ((((i) ^ ((i) >> 1)) & (1 << 27)) == 0)
35
36 #define LDSTH_I_BIT(i) (i & (1 << 26)) /* half-word immed */
37 #define LDM_S_BIT(i) (i & (1 << 26)) /* write ASR from BSR */
38 #define LDM_H_BIT(i) (i & (1 << 6)) /* select r0-r15 or r16-r31 */
39
40 #define RN_BITS(i) ((i >> 19) & 31) /* Rn */
41 #define RD_BITS(i) ((i >> 14) & 31) /* Rd */
42 #define RM_BITS(i) (i & 31) /* Rm */
43
44 #define REGMASK_BITS(i) (((i & 0x7fe00) >> 3) | (i & 0x3f))
45 #define OFFSET_BITS(i) (i & 0x03fff)
46
47 #define SHIFT_BITS(i) ((i >> 9) & 0x1f)
48 #define SHIFT_TYPE(i) (i & 0xc0)
49 #define SHIFT_LSL 0x00
50 #define SHIFT_LSR 0x40
51 #define SHIFT_ASR 0x80
52 #define SHIFT_RORRRX 0xc0
53
54 union offset_union {
55 unsigned long un;
56 signed long sn;
57 };
58
59 #define TYPE_ERROR 0
60 #define TYPE_FAULT 1
61 #define TYPE_LDST 2
62 #define TYPE_DONE 3
63 #define TYPE_SWAP 4
64 #define TYPE_COLS 5 /* Coprocessor load/store */
65
66 #define get8_unaligned_check(val, addr, err) \
67 __asm__( \
68 "1: ldb.u %1, [%2], #1\n" \
69 "2:\n" \
70 " .pushsection .fixup,\"ax\"\n" \
71 " .align 2\n" \
72 "3: mov %0, #1\n" \
73 " b 2b\n" \
74 " .popsection\n" \
75 " .pushsection __ex_table,\"a\"\n" \
76 " .align 3\n" \
77 " .long 1b, 3b\n" \
78 " .popsection\n" \
79 : "=r" (err), "=&r" (val), "=r" (addr) \
80 : "0" (err), "2" (addr))
81
82 #define get8t_unaligned_check(val, addr, err) \
83 __asm__( \
84 "1: ldb.u %1, [%2], #1\n" \
85 "2:\n" \
86 " .pushsection .fixup,\"ax\"\n" \
87 " .align 2\n" \
88 "3: mov %0, #1\n" \
89 " b 2b\n" \
90 " .popsection\n" \
91 " .pushsection __ex_table,\"a\"\n" \
92 " .align 3\n" \
93 " .long 1b, 3b\n" \
94 " .popsection\n" \
95 : "=r" (err), "=&r" (val), "=r" (addr) \
96 : "0" (err), "2" (addr))
97
98 #define get16_unaligned_check(val, addr) \
99 do { \
100 unsigned int err = 0, v, a = addr; \
101 get8_unaligned_check(val, a, err); \
102 get8_unaligned_check(v, a, err); \
103 val |= v << 8; \
104 if (err) \
105 goto fault; \
106 } while (0)
107
108 #define put16_unaligned_check(val, addr) \
109 do { \
110 unsigned int err = 0, v = val, a = addr; \
111 __asm__( \
112 "1: stb.u %1, [%2], #1\n" \
113 " mov %1, %1 >> #8\n" \
114 "2: stb.u %1, [%2]\n" \
115 "3:\n" \
116 " .pushsection .fixup,\"ax\"\n" \
117 " .align 2\n" \
118 "4: mov %0, #1\n" \
119 " b 3b\n" \
120 " .popsection\n" \
121 " .pushsection __ex_table,\"a\"\n" \
122 " .align 3\n" \
123 " .long 1b, 4b\n" \
124 " .long 2b, 4b\n" \
125 " .popsection\n" \
126 : "=r" (err), "=&r" (v), "=&r" (a) \
127 : "0" (err), "1" (v), "2" (a)); \
128 if (err) \
129 goto fault; \
130 } while (0)
131
132 #define __put32_unaligned_check(ins, val, addr) \
133 do { \
134 unsigned int err = 0, v = val, a = addr; \
135 __asm__( \
136 "1: "ins" %1, [%2], #1\n" \
137 " mov %1, %1 >> #8\n" \
138 "2: "ins" %1, [%2], #1\n" \
139 " mov %1, %1 >> #8\n" \
140 "3: "ins" %1, [%2], #1\n" \
141 " mov %1, %1 >> #8\n" \
142 "4: "ins" %1, [%2]\n" \
143 "5:\n" \
144 " .pushsection .fixup,\"ax\"\n" \
145 " .align 2\n" \
146 "6: mov %0, #1\n" \
147 " b 5b\n" \
148 " .popsection\n" \
149 " .pushsection __ex_table,\"a\"\n" \
150 " .align 3\n" \
151 " .long 1b, 6b\n" \
152 " .long 2b, 6b\n" \
153 " .long 3b, 6b\n" \
154 " .long 4b, 6b\n" \
155 " .popsection\n" \
156 : "=r" (err), "=&r" (v), "=&r" (a) \
157 : "0" (err), "1" (v), "2" (a)); \
158 if (err) \
159 goto fault; \
160 } while (0)
161
162 #define get32_unaligned_check(val, addr) \
163 do { \
164 unsigned int err = 0, v, a = addr; \
165 get8_unaligned_check(val, a, err); \
166 get8_unaligned_check(v, a, err); \
167 val |= v << 8; \
168 get8_unaligned_check(v, a, err); \
169 val |= v << 16; \
170 get8_unaligned_check(v, a, err); \
171 val |= v << 24; \
172 if (err) \
173 goto fault; \
174 } while (0)
175
176 #define put32_unaligned_check(val, addr) \
177 __put32_unaligned_check("stb.u", val, addr)
178
179 #define get32t_unaligned_check(val, addr) \
180 do { \
181 unsigned int err = 0, v, a = addr; \
182 get8t_unaligned_check(val, a, err); \
183 get8t_unaligned_check(v, a, err); \
184 val |= v << 8; \
185 get8t_unaligned_check(v, a, err); \
186 val |= v << 16; \
187 get8t_unaligned_check(v, a, err); \
188 val |= v << 24; \
189 if (err) \
190 goto fault; \
191 } while (0)
192
193 #define put32t_unaligned_check(val, addr) \
194 __put32_unaligned_check("stb.u", val, addr)
195
196 static void
do_alignment_finish_ldst(unsigned long addr,unsigned long instr,struct pt_regs * regs,union offset_union offset)197 do_alignment_finish_ldst(unsigned long addr, unsigned long instr,
198 struct pt_regs *regs, union offset_union offset)
199 {
200 if (!LDST_U_BIT(instr))
201 offset.un = -offset.un;
202
203 if (!LDST_P_BIT(instr))
204 addr += offset.un;
205
206 if (!LDST_P_BIT(instr) || LDST_W_BIT(instr))
207 regs->uregs[RN_BITS(instr)] = addr;
208 }
209
210 static int
do_alignment_ldrhstrh(unsigned long addr,unsigned long instr,struct pt_regs * regs)211 do_alignment_ldrhstrh(unsigned long addr, unsigned long instr,
212 struct pt_regs *regs)
213 {
214 unsigned int rd = RD_BITS(instr);
215
216 /* old value 0x40002120, can't judge swap instr correctly */
217 if ((instr & 0x4b003fe0) == 0x40000120)
218 goto swp;
219
220 if (LDST_L_BIT(instr)) {
221 unsigned long val;
222 get16_unaligned_check(val, addr);
223
224 /* signed half-word? */
225 if (instr & 0x80)
226 val = (signed long)((signed short)val);
227
228 regs->uregs[rd] = val;
229 } else
230 put16_unaligned_check(regs->uregs[rd], addr);
231
232 return TYPE_LDST;
233
234 swp:
235 /* only handle swap word
236 * for swap byte should not active this alignment exception */
237 get32_unaligned_check(regs->uregs[RD_BITS(instr)], addr);
238 put32_unaligned_check(regs->uregs[RM_BITS(instr)], addr);
239 return TYPE_SWAP;
240
241 fault:
242 return TYPE_FAULT;
243 }
244
245 static int
do_alignment_ldrstr(unsigned long addr,unsigned long instr,struct pt_regs * regs)246 do_alignment_ldrstr(unsigned long addr, unsigned long instr,
247 struct pt_regs *regs)
248 {
249 unsigned int rd = RD_BITS(instr);
250
251 if (!LDST_P_BIT(instr) && LDST_W_BIT(instr))
252 goto trans;
253
254 if (LDST_L_BIT(instr))
255 get32_unaligned_check(regs->uregs[rd], addr);
256 else
257 put32_unaligned_check(regs->uregs[rd], addr);
258 return TYPE_LDST;
259
260 trans:
261 if (LDST_L_BIT(instr))
262 get32t_unaligned_check(regs->uregs[rd], addr);
263 else
264 put32t_unaligned_check(regs->uregs[rd], addr);
265 return TYPE_LDST;
266
267 fault:
268 return TYPE_FAULT;
269 }
270
271 /*
272 * LDM/STM alignment handler.
273 *
274 * There are 4 variants of this instruction:
275 *
276 * B = rn pointer before instruction, A = rn pointer after instruction
277 * ------ increasing address ----->
278 * | | r0 | r1 | ... | rx | |
279 * PU = 01 B A
280 * PU = 11 B A
281 * PU = 00 A B
282 * PU = 10 A B
283 */
284 static int
do_alignment_ldmstm(unsigned long addr,unsigned long instr,struct pt_regs * regs)285 do_alignment_ldmstm(unsigned long addr, unsigned long instr,
286 struct pt_regs *regs)
287 {
288 unsigned int rd, rn, pc_correction, reg_correction, nr_regs, regbits;
289 unsigned long eaddr, newaddr;
290
291 if (LDM_S_BIT(instr))
292 goto bad;
293
294 pc_correction = 4; /* processor implementation defined */
295
296 /* count the number of registers in the mask to be transferred */
297 nr_regs = hweight16(REGMASK_BITS(instr)) * 4;
298
299 rn = RN_BITS(instr);
300 newaddr = eaddr = regs->uregs[rn];
301
302 if (!LDST_U_BIT(instr))
303 nr_regs = -nr_regs;
304 newaddr += nr_regs;
305 if (!LDST_U_BIT(instr))
306 eaddr = newaddr;
307
308 if (LDST_P_EQ_U(instr)) /* U = P */
309 eaddr += 4;
310
311 /*
312 * This is a "hint" - we already have eaddr worked out by the
313 * processor for us.
314 */
315 if (addr != eaddr) {
316 printk(KERN_ERR "LDMSTM: PC = %08lx, instr = %08lx, "
317 "addr = %08lx, eaddr = %08lx\n",
318 instruction_pointer(regs), instr, addr, eaddr);
319 show_regs(regs);
320 }
321
322 if (LDM_H_BIT(instr))
323 reg_correction = 0x10;
324 else
325 reg_correction = 0x00;
326
327 for (regbits = REGMASK_BITS(instr), rd = 0; regbits;
328 regbits >>= 1, rd += 1)
329 if (regbits & 1) {
330 if (LDST_L_BIT(instr))
331 get32_unaligned_check(regs->
332 uregs[rd + reg_correction], eaddr);
333 else
334 put32_unaligned_check(regs->
335 uregs[rd + reg_correction], eaddr);
336 eaddr += 4;
337 }
338
339 if (LDST_W_BIT(instr))
340 regs->uregs[rn] = newaddr;
341 return TYPE_DONE;
342
343 fault:
344 regs->UCreg_pc -= pc_correction;
345 return TYPE_FAULT;
346
347 bad:
348 printk(KERN_ERR "Alignment trap: not handling ldm with s-bit set\n");
349 return TYPE_ERROR;
350 }
351
352 static int
do_alignment(unsigned long addr,unsigned int error_code,struct pt_regs * regs)353 do_alignment(unsigned long addr, unsigned int error_code, struct pt_regs *regs)
354 {
355 union offset_union offset;
356 unsigned long instr, instrptr;
357 int (*handler) (unsigned long addr, unsigned long instr,
358 struct pt_regs *regs);
359 unsigned int type;
360
361 instrptr = instruction_pointer(regs);
362 if (instrptr >= PAGE_OFFSET)
363 instr = *(unsigned long *)instrptr;
364 else {
365 __asm__ __volatile__(
366 "ldw.u %0, [%1]\n"
367 : "=&r"(instr)
368 : "r"(instrptr));
369 }
370
371 regs->UCreg_pc += 4;
372
373 switch (CODING_BITS(instr)) {
374 case 0x40000120: /* ldrh or strh */
375 if (LDSTH_I_BIT(instr))
376 offset.un = (instr & 0x3e00) >> 4 | (instr & 31);
377 else
378 offset.un = regs->uregs[RM_BITS(instr)];
379 handler = do_alignment_ldrhstrh;
380 break;
381
382 case 0x60000000: /* ldr or str immediate */
383 case 0x60000100: /* ldr or str immediate */
384 case 0x60000020: /* ldr or str immediate */
385 case 0x60000120: /* ldr or str immediate */
386 offset.un = OFFSET_BITS(instr);
387 handler = do_alignment_ldrstr;
388 break;
389
390 case 0x40000000: /* ldr or str register */
391 offset.un = regs->uregs[RM_BITS(instr)];
392 {
393 unsigned int shiftval = SHIFT_BITS(instr);
394
395 switch (SHIFT_TYPE(instr)) {
396 case SHIFT_LSL:
397 offset.un <<= shiftval;
398 break;
399
400 case SHIFT_LSR:
401 offset.un >>= shiftval;
402 break;
403
404 case SHIFT_ASR:
405 offset.sn >>= shiftval;
406 break;
407
408 case SHIFT_RORRRX:
409 if (shiftval == 0) {
410 offset.un >>= 1;
411 if (regs->UCreg_asr & PSR_C_BIT)
412 offset.un |= 1 << 31;
413 } else
414 offset.un = offset.un >> shiftval |
415 offset.un << (32 - shiftval);
416 break;
417 }
418 }
419 handler = do_alignment_ldrstr;
420 break;
421
422 case 0x80000000: /* ldm or stm */
423 case 0x80000020: /* ldm or stm */
424 handler = do_alignment_ldmstm;
425 break;
426
427 default:
428 goto bad;
429 }
430
431 type = handler(addr, instr, regs);
432
433 if (type == TYPE_ERROR || type == TYPE_FAULT)
434 goto bad_or_fault;
435
436 if (type == TYPE_LDST)
437 do_alignment_finish_ldst(addr, instr, regs, offset);
438
439 return 0;
440
441 bad_or_fault:
442 if (type == TYPE_ERROR)
443 goto bad;
444 regs->UCreg_pc -= 4;
445 /*
446 * We got a fault - fix it up, or die.
447 */
448 do_bad_area(addr, error_code, regs);
449 return 0;
450
451 bad:
452 /*
453 * Oops, we didn't handle the instruction.
454 * However, we must handle fpu instr firstly.
455 */
456 #ifdef CONFIG_UNICORE_FPU_F64
457 /* handle co.load/store */
458 #define CODING_COLS 0xc0000000
459 #define COLS_OFFSET_BITS(i) (i & 0x1FF)
460 #define COLS_L_BITS(i) (i & (1<<24))
461 #define COLS_FN_BITS(i) ((i>>14) & 31)
462 if ((instr & 0xe0000000) == CODING_COLS) {
463 unsigned int fn = COLS_FN_BITS(instr);
464 unsigned long val = 0;
465 if (COLS_L_BITS(instr)) {
466 get32t_unaligned_check(val, addr);
467 switch (fn) {
468 #define ASM_MTF(n) case n: \
469 __asm__ __volatile__("MTF %0, F" __stringify(n) \
470 : : "r"(val)); \
471 break;
472 ASM_MTF(0); ASM_MTF(1); ASM_MTF(2); ASM_MTF(3);
473 ASM_MTF(4); ASM_MTF(5); ASM_MTF(6); ASM_MTF(7);
474 ASM_MTF(8); ASM_MTF(9); ASM_MTF(10); ASM_MTF(11);
475 ASM_MTF(12); ASM_MTF(13); ASM_MTF(14); ASM_MTF(15);
476 ASM_MTF(16); ASM_MTF(17); ASM_MTF(18); ASM_MTF(19);
477 ASM_MTF(20); ASM_MTF(21); ASM_MTF(22); ASM_MTF(23);
478 ASM_MTF(24); ASM_MTF(25); ASM_MTF(26); ASM_MTF(27);
479 ASM_MTF(28); ASM_MTF(29); ASM_MTF(30); ASM_MTF(31);
480 #undef ASM_MTF
481 }
482 } else {
483 switch (fn) {
484 #define ASM_MFF(n) case n: \
485 __asm__ __volatile__("MFF %0, F" __stringify(n) \
486 : : "r"(val)); \
487 break;
488 ASM_MFF(0); ASM_MFF(1); ASM_MFF(2); ASM_MFF(3);
489 ASM_MFF(4); ASM_MFF(5); ASM_MFF(6); ASM_MFF(7);
490 ASM_MFF(8); ASM_MFF(9); ASM_MFF(10); ASM_MFF(11);
491 ASM_MFF(12); ASM_MFF(13); ASM_MFF(14); ASM_MFF(15);
492 ASM_MFF(16); ASM_MFF(17); ASM_MFF(18); ASM_MFF(19);
493 ASM_MFF(20); ASM_MFF(21); ASM_MFF(22); ASM_MFF(23);
494 ASM_MFF(24); ASM_MFF(25); ASM_MFF(26); ASM_MFF(27);
495 ASM_MFF(28); ASM_MFF(29); ASM_MFF(30); ASM_MFF(31);
496 #undef ASM_MFF
497 }
498 put32t_unaligned_check(val, addr);
499 }
500 return TYPE_COLS;
501 }
502 fault:
503 return TYPE_FAULT;
504 #endif
505 printk(KERN_ERR "Alignment trap: not handling instruction "
506 "%08lx at [<%08lx>]\n", instr, instrptr);
507 return 1;
508 }
509
510 /*
511 * This needs to be done after sysctl_init, otherwise sys/ will be
512 * overwritten. Actually, this shouldn't be in sys/ at all since
513 * it isn't a sysctl, and it doesn't contain sysctl information.
514 */
alignment_init(void)515 static int __init alignment_init(void)
516 {
517 hook_fault_code(1, do_alignment, SIGBUS, BUS_ADRALN,
518 "alignment exception");
519
520 return 0;
521 }
522
523 fs_initcall(alignment_init);
524