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/pgtable.h>
25 #include <asm/tlbflush.h>
26 #include <asm/unaligned.h>
27
28 #include "mm.h"
29
30 #define CODING_BITS(i) (i & 0xe0000120)
31
32 #define LDST_P_BIT(i) (i & (1 << 28)) /* Preindex */
33 #define LDST_U_BIT(i) (i & (1 << 27)) /* Add offset */
34 #define LDST_W_BIT(i) (i & (1 << 25)) /* Writeback */
35 #define LDST_L_BIT(i) (i & (1 << 24)) /* Load */
36
37 #define LDST_P_EQ_U(i) ((((i) ^ ((i) >> 1)) & (1 << 27)) == 0)
38
39 #define LDSTH_I_BIT(i) (i & (1 << 26)) /* half-word immed */
40 #define LDM_S_BIT(i) (i & (1 << 26)) /* write ASR from BSR */
41 #define LDM_H_BIT(i) (i & (1 << 6)) /* select r0-r15 or r16-r31 */
42
43 #define RN_BITS(i) ((i >> 19) & 31) /* Rn */
44 #define RD_BITS(i) ((i >> 14) & 31) /* Rd */
45 #define RM_BITS(i) (i & 31) /* Rm */
46
47 #define REGMASK_BITS(i) (((i & 0x7fe00) >> 3) | (i & 0x3f))
48 #define OFFSET_BITS(i) (i & 0x03fff)
49
50 #define SHIFT_BITS(i) ((i >> 9) & 0x1f)
51 #define SHIFT_TYPE(i) (i & 0xc0)
52 #define SHIFT_LSL 0x00
53 #define SHIFT_LSR 0x40
54 #define SHIFT_ASR 0x80
55 #define SHIFT_RORRRX 0xc0
56
57 union offset_union {
58 unsigned long un;
59 signed long sn;
60 };
61
62 #define TYPE_ERROR 0
63 #define TYPE_FAULT 1
64 #define TYPE_LDST 2
65 #define TYPE_DONE 3
66 #define TYPE_SWAP 4
67 #define TYPE_COLS 5 /* Coprocessor load/store */
68
69 #define get8_unaligned_check(val, addr, err) \
70 __asm__( \
71 "1: ldb.u %1, [%2], #1\n" \
72 "2:\n" \
73 " .pushsection .fixup,\"ax\"\n" \
74 " .align 2\n" \
75 "3: mov %0, #1\n" \
76 " b 2b\n" \
77 " .popsection\n" \
78 " .pushsection __ex_table,\"a\"\n" \
79 " .align 3\n" \
80 " .long 1b, 3b\n" \
81 " .popsection\n" \
82 : "=r" (err), "=&r" (val), "=r" (addr) \
83 : "0" (err), "2" (addr))
84
85 #define get8t_unaligned_check(val, addr, err) \
86 __asm__( \
87 "1: ldb.u %1, [%2], #1\n" \
88 "2:\n" \
89 " .pushsection .fixup,\"ax\"\n" \
90 " .align 2\n" \
91 "3: mov %0, #1\n" \
92 " b 2b\n" \
93 " .popsection\n" \
94 " .pushsection __ex_table,\"a\"\n" \
95 " .align 3\n" \
96 " .long 1b, 3b\n" \
97 " .popsection\n" \
98 : "=r" (err), "=&r" (val), "=r" (addr) \
99 : "0" (err), "2" (addr))
100
101 #define get16_unaligned_check(val, addr) \
102 do { \
103 unsigned int err = 0, v, a = addr; \
104 get8_unaligned_check(val, a, err); \
105 get8_unaligned_check(v, a, err); \
106 val |= v << 8; \
107 if (err) \
108 goto fault; \
109 } while (0)
110
111 #define put16_unaligned_check(val, addr) \
112 do { \
113 unsigned int err = 0, v = val, a = addr; \
114 __asm__( \
115 "1: stb.u %1, [%2], #1\n" \
116 " mov %1, %1 >> #8\n" \
117 "2: stb.u %1, [%2]\n" \
118 "3:\n" \
119 " .pushsection .fixup,\"ax\"\n" \
120 " .align 2\n" \
121 "4: mov %0, #1\n" \
122 " b 3b\n" \
123 " .popsection\n" \
124 " .pushsection __ex_table,\"a\"\n" \
125 " .align 3\n" \
126 " .long 1b, 4b\n" \
127 " .long 2b, 4b\n" \
128 " .popsection\n" \
129 : "=r" (err), "=&r" (v), "=&r" (a) \
130 : "0" (err), "1" (v), "2" (a)); \
131 if (err) \
132 goto fault; \
133 } while (0)
134
135 #define __put32_unaligned_check(ins, val, addr) \
136 do { \
137 unsigned int err = 0, v = val, a = addr; \
138 __asm__( \
139 "1: "ins" %1, [%2], #1\n" \
140 " mov %1, %1 >> #8\n" \
141 "2: "ins" %1, [%2], #1\n" \
142 " mov %1, %1 >> #8\n" \
143 "3: "ins" %1, [%2], #1\n" \
144 " mov %1, %1 >> #8\n" \
145 "4: "ins" %1, [%2]\n" \
146 "5:\n" \
147 " .pushsection .fixup,\"ax\"\n" \
148 " .align 2\n" \
149 "6: mov %0, #1\n" \
150 " b 5b\n" \
151 " .popsection\n" \
152 " .pushsection __ex_table,\"a\"\n" \
153 " .align 3\n" \
154 " .long 1b, 6b\n" \
155 " .long 2b, 6b\n" \
156 " .long 3b, 6b\n" \
157 " .long 4b, 6b\n" \
158 " .popsection\n" \
159 : "=r" (err), "=&r" (v), "=&r" (a) \
160 : "0" (err), "1" (v), "2" (a)); \
161 if (err) \
162 goto fault; \
163 } while (0)
164
165 #define get32_unaligned_check(val, addr) \
166 do { \
167 unsigned int err = 0, v, a = addr; \
168 get8_unaligned_check(val, a, err); \
169 get8_unaligned_check(v, a, err); \
170 val |= v << 8; \
171 get8_unaligned_check(v, a, err); \
172 val |= v << 16; \
173 get8_unaligned_check(v, a, err); \
174 val |= v << 24; \
175 if (err) \
176 goto fault; \
177 } while (0)
178
179 #define put32_unaligned_check(val, addr) \
180 __put32_unaligned_check("stb.u", val, addr)
181
182 #define get32t_unaligned_check(val, addr) \
183 do { \
184 unsigned int err = 0, v, a = addr; \
185 get8t_unaligned_check(val, a, err); \
186 get8t_unaligned_check(v, a, err); \
187 val |= v << 8; \
188 get8t_unaligned_check(v, a, err); \
189 val |= v << 16; \
190 get8t_unaligned_check(v, a, err); \
191 val |= v << 24; \
192 if (err) \
193 goto fault; \
194 } while (0)
195
196 #define put32t_unaligned_check(val, addr) \
197 __put32_unaligned_check("stb.u", val, addr)
198
199 static void
do_alignment_finish_ldst(unsigned long addr,unsigned long instr,struct pt_regs * regs,union offset_union offset)200 do_alignment_finish_ldst(unsigned long addr, unsigned long instr,
201 struct pt_regs *regs, union offset_union offset)
202 {
203 if (!LDST_U_BIT(instr))
204 offset.un = -offset.un;
205
206 if (!LDST_P_BIT(instr))
207 addr += offset.un;
208
209 if (!LDST_P_BIT(instr) || LDST_W_BIT(instr))
210 regs->uregs[RN_BITS(instr)] = addr;
211 }
212
213 static int
do_alignment_ldrhstrh(unsigned long addr,unsigned long instr,struct pt_regs * regs)214 do_alignment_ldrhstrh(unsigned long addr, unsigned long instr,
215 struct pt_regs *regs)
216 {
217 unsigned int rd = RD_BITS(instr);
218
219 /* old value 0x40002120, can't judge swap instr correctly */
220 if ((instr & 0x4b003fe0) == 0x40000120)
221 goto swp;
222
223 if (LDST_L_BIT(instr)) {
224 unsigned long val;
225 get16_unaligned_check(val, addr);
226
227 /* signed half-word? */
228 if (instr & 0x80)
229 val = (signed long)((signed short)val);
230
231 regs->uregs[rd] = val;
232 } else
233 put16_unaligned_check(regs->uregs[rd], addr);
234
235 return TYPE_LDST;
236
237 swp:
238 /* only handle swap word
239 * for swap byte should not active this alignment exception */
240 get32_unaligned_check(regs->uregs[RD_BITS(instr)], addr);
241 put32_unaligned_check(regs->uregs[RM_BITS(instr)], addr);
242 return TYPE_SWAP;
243
244 fault:
245 return TYPE_FAULT;
246 }
247
248 static int
do_alignment_ldrstr(unsigned long addr,unsigned long instr,struct pt_regs * regs)249 do_alignment_ldrstr(unsigned long addr, unsigned long instr,
250 struct pt_regs *regs)
251 {
252 unsigned int rd = RD_BITS(instr);
253
254 if (!LDST_P_BIT(instr) && LDST_W_BIT(instr))
255 goto trans;
256
257 if (LDST_L_BIT(instr))
258 get32_unaligned_check(regs->uregs[rd], addr);
259 else
260 put32_unaligned_check(regs->uregs[rd], addr);
261 return TYPE_LDST;
262
263 trans:
264 if (LDST_L_BIT(instr))
265 get32t_unaligned_check(regs->uregs[rd], addr);
266 else
267 put32t_unaligned_check(regs->uregs[rd], addr);
268 return TYPE_LDST;
269
270 fault:
271 return TYPE_FAULT;
272 }
273
274 /*
275 * LDM/STM alignment handler.
276 *
277 * There are 4 variants of this instruction:
278 *
279 * B = rn pointer before instruction, A = rn pointer after instruction
280 * ------ increasing address ----->
281 * | | r0 | r1 | ... | rx | |
282 * PU = 01 B A
283 * PU = 11 B A
284 * PU = 00 A B
285 * PU = 10 A B
286 */
287 static int
do_alignment_ldmstm(unsigned long addr,unsigned long instr,struct pt_regs * regs)288 do_alignment_ldmstm(unsigned long addr, unsigned long instr,
289 struct pt_regs *regs)
290 {
291 unsigned int rd, rn, pc_correction, reg_correction, nr_regs, regbits;
292 unsigned long eaddr, newaddr;
293
294 if (LDM_S_BIT(instr))
295 goto bad;
296
297 pc_correction = 4; /* processor implementation defined */
298
299 /* count the number of registers in the mask to be transferred */
300 nr_regs = hweight16(REGMASK_BITS(instr)) * 4;
301
302 rn = RN_BITS(instr);
303 newaddr = eaddr = regs->uregs[rn];
304
305 if (!LDST_U_BIT(instr))
306 nr_regs = -nr_regs;
307 newaddr += nr_regs;
308 if (!LDST_U_BIT(instr))
309 eaddr = newaddr;
310
311 if (LDST_P_EQ_U(instr)) /* U = P */
312 eaddr += 4;
313
314 /*
315 * This is a "hint" - we already have eaddr worked out by the
316 * processor for us.
317 */
318 if (addr != eaddr) {
319 printk(KERN_ERR "LDMSTM: PC = %08lx, instr = %08lx, "
320 "addr = %08lx, eaddr = %08lx\n",
321 instruction_pointer(regs), instr, addr, eaddr);
322 show_regs(regs);
323 }
324
325 if (LDM_H_BIT(instr))
326 reg_correction = 0x10;
327 else
328 reg_correction = 0x00;
329
330 for (regbits = REGMASK_BITS(instr), rd = 0; regbits;
331 regbits >>= 1, rd += 1)
332 if (regbits & 1) {
333 if (LDST_L_BIT(instr))
334 get32_unaligned_check(regs->
335 uregs[rd + reg_correction], eaddr);
336 else
337 put32_unaligned_check(regs->
338 uregs[rd + reg_correction], eaddr);
339 eaddr += 4;
340 }
341
342 if (LDST_W_BIT(instr))
343 regs->uregs[rn] = newaddr;
344 return TYPE_DONE;
345
346 fault:
347 regs->UCreg_pc -= pc_correction;
348 return TYPE_FAULT;
349
350 bad:
351 printk(KERN_ERR "Alignment trap: not handling ldm with s-bit set\n");
352 return TYPE_ERROR;
353 }
354
355 static int
do_alignment(unsigned long addr,unsigned int error_code,struct pt_regs * regs)356 do_alignment(unsigned long addr, unsigned int error_code, struct pt_regs *regs)
357 {
358 union offset_union offset;
359 unsigned long instr, instrptr;
360 int (*handler) (unsigned long addr, unsigned long instr,
361 struct pt_regs *regs);
362 unsigned int type;
363
364 instrptr = instruction_pointer(regs);
365 if (instrptr >= PAGE_OFFSET)
366 instr = *(unsigned long *)instrptr;
367 else {
368 __asm__ __volatile__(
369 "ldw.u %0, [%1]\n"
370 : "=&r"(instr)
371 : "r"(instrptr));
372 }
373
374 regs->UCreg_pc += 4;
375
376 switch (CODING_BITS(instr)) {
377 case 0x40000120: /* ldrh or strh */
378 if (LDSTH_I_BIT(instr))
379 offset.un = (instr & 0x3e00) >> 4 | (instr & 31);
380 else
381 offset.un = regs->uregs[RM_BITS(instr)];
382 handler = do_alignment_ldrhstrh;
383 break;
384
385 case 0x60000000: /* ldr or str immediate */
386 case 0x60000100: /* ldr or str immediate */
387 case 0x60000020: /* ldr or str immediate */
388 case 0x60000120: /* ldr or str immediate */
389 offset.un = OFFSET_BITS(instr);
390 handler = do_alignment_ldrstr;
391 break;
392
393 case 0x40000000: /* ldr or str register */
394 offset.un = regs->uregs[RM_BITS(instr)];
395 {
396 unsigned int shiftval = SHIFT_BITS(instr);
397
398 switch (SHIFT_TYPE(instr)) {
399 case SHIFT_LSL:
400 offset.un <<= shiftval;
401 break;
402
403 case SHIFT_LSR:
404 offset.un >>= shiftval;
405 break;
406
407 case SHIFT_ASR:
408 offset.sn >>= shiftval;
409 break;
410
411 case SHIFT_RORRRX:
412 if (shiftval == 0) {
413 offset.un >>= 1;
414 if (regs->UCreg_asr & PSR_C_BIT)
415 offset.un |= 1 << 31;
416 } else
417 offset.un = offset.un >> shiftval |
418 offset.un << (32 - shiftval);
419 break;
420 }
421 }
422 handler = do_alignment_ldrstr;
423 break;
424
425 case 0x80000000: /* ldm or stm */
426 case 0x80000020: /* ldm or stm */
427 handler = do_alignment_ldmstm;
428 break;
429
430 default:
431 goto bad;
432 }
433
434 type = handler(addr, instr, regs);
435
436 if (type == TYPE_ERROR || type == TYPE_FAULT)
437 goto bad_or_fault;
438
439 if (type == TYPE_LDST)
440 do_alignment_finish_ldst(addr, instr, regs, offset);
441
442 return 0;
443
444 bad_or_fault:
445 if (type == TYPE_ERROR)
446 goto bad;
447 regs->UCreg_pc -= 4;
448 /*
449 * We got a fault - fix it up, or die.
450 */
451 do_bad_area(addr, error_code, regs);
452 return 0;
453
454 bad:
455 /*
456 * Oops, we didn't handle the instruction.
457 * However, we must handle fpu instr firstly.
458 */
459 #ifdef CONFIG_UNICORE_FPU_F64
460 /* handle co.load/store */
461 #define CODING_COLS 0xc0000000
462 #define COLS_OFFSET_BITS(i) (i & 0x1FF)
463 #define COLS_L_BITS(i) (i & (1<<24))
464 #define COLS_FN_BITS(i) ((i>>14) & 31)
465 if ((instr & 0xe0000000) == CODING_COLS) {
466 unsigned int fn = COLS_FN_BITS(instr);
467 unsigned long val = 0;
468 if (COLS_L_BITS(instr)) {
469 get32t_unaligned_check(val, addr);
470 switch (fn) {
471 #define ASM_MTF(n) case n: \
472 __asm__ __volatile__("MTF %0, F" __stringify(n) \
473 : : "r"(val)); \
474 break;
475 ASM_MTF(0); ASM_MTF(1); ASM_MTF(2); ASM_MTF(3);
476 ASM_MTF(4); ASM_MTF(5); ASM_MTF(6); ASM_MTF(7);
477 ASM_MTF(8); ASM_MTF(9); ASM_MTF(10); ASM_MTF(11);
478 ASM_MTF(12); ASM_MTF(13); ASM_MTF(14); ASM_MTF(15);
479 ASM_MTF(16); ASM_MTF(17); ASM_MTF(18); ASM_MTF(19);
480 ASM_MTF(20); ASM_MTF(21); ASM_MTF(22); ASM_MTF(23);
481 ASM_MTF(24); ASM_MTF(25); ASM_MTF(26); ASM_MTF(27);
482 ASM_MTF(28); ASM_MTF(29); ASM_MTF(30); ASM_MTF(31);
483 #undef ASM_MTF
484 }
485 } else {
486 switch (fn) {
487 #define ASM_MFF(n) case n: \
488 __asm__ __volatile__("MFF %0, F" __stringify(n) \
489 : : "r"(val)); \
490 break;
491 ASM_MFF(0); ASM_MFF(1); ASM_MFF(2); ASM_MFF(3);
492 ASM_MFF(4); ASM_MFF(5); ASM_MFF(6); ASM_MFF(7);
493 ASM_MFF(8); ASM_MFF(9); ASM_MFF(10); ASM_MFF(11);
494 ASM_MFF(12); ASM_MFF(13); ASM_MFF(14); ASM_MFF(15);
495 ASM_MFF(16); ASM_MFF(17); ASM_MFF(18); ASM_MFF(19);
496 ASM_MFF(20); ASM_MFF(21); ASM_MFF(22); ASM_MFF(23);
497 ASM_MFF(24); ASM_MFF(25); ASM_MFF(26); ASM_MFF(27);
498 ASM_MFF(28); ASM_MFF(29); ASM_MFF(30); ASM_MFF(31);
499 #undef ASM_MFF
500 }
501 put32t_unaligned_check(val, addr);
502 }
503 return TYPE_COLS;
504 }
505 fault:
506 return TYPE_FAULT;
507 #endif
508 printk(KERN_ERR "Alignment trap: not handling instruction "
509 "%08lx at [<%08lx>]\n", instr, instrptr);
510 return 1;
511 }
512
513 /*
514 * This needs to be done after sysctl_init, otherwise sys/ will be
515 * overwritten. Actually, this shouldn't be in sys/ at all since
516 * it isn't a sysctl, and it doesn't contain sysctl information.
517 */
alignment_init(void)518 static int __init alignment_init(void)
519 {
520 hook_fault_code(1, do_alignment, SIGBUS, BUS_ADRALN,
521 "alignment exception");
522
523 return 0;
524 }
525
526 fs_initcall(alignment_init);
527