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/sched/debug.h>
19 #include <linux/errno.h>
20 #include <linux/string.h>
21 #include <linux/init.h>
22 #include <linux/sched.h>
23 #include <linux/uaccess.h>
24
25 #include <asm/pgtable.h>
26 #include <asm/tlbflush.h>
27 #include <asm/unaligned.h>
28
29 #include "mm.h"
30
31 #define CODING_BITS(i) (i & 0xe0000120)
32
33 #define LDST_P_BIT(i) (i & (1 << 28)) /* Preindex */
34 #define LDST_U_BIT(i) (i & (1 << 27)) /* Add offset */
35 #define LDST_W_BIT(i) (i & (1 << 25)) /* Writeback */
36 #define LDST_L_BIT(i) (i & (1 << 24)) /* Load */
37
38 #define LDST_P_EQ_U(i) ((((i) ^ ((i) >> 1)) & (1 << 27)) == 0)
39
40 #define LDSTH_I_BIT(i) (i & (1 << 26)) /* half-word immed */
41 #define LDM_S_BIT(i) (i & (1 << 26)) /* write ASR from BSR */
42 #define LDM_H_BIT(i) (i & (1 << 6)) /* select r0-r15 or r16-r31 */
43
44 #define RN_BITS(i) ((i >> 19) & 31) /* Rn */
45 #define RD_BITS(i) ((i >> 14) & 31) /* Rd */
46 #define RM_BITS(i) (i & 31) /* Rm */
47
48 #define REGMASK_BITS(i) (((i & 0x7fe00) >> 3) | (i & 0x3f))
49 #define OFFSET_BITS(i) (i & 0x03fff)
50
51 #define SHIFT_BITS(i) ((i >> 9) & 0x1f)
52 #define SHIFT_TYPE(i) (i & 0xc0)
53 #define SHIFT_LSL 0x00
54 #define SHIFT_LSR 0x40
55 #define SHIFT_ASR 0x80
56 #define SHIFT_RORRRX 0xc0
57
58 union offset_union {
59 unsigned long un;
60 signed long sn;
61 };
62
63 #define TYPE_ERROR 0
64 #define TYPE_FAULT 1
65 #define TYPE_LDST 2
66 #define TYPE_DONE 3
67 #define TYPE_SWAP 4
68 #define TYPE_COLS 5 /* Coprocessor load/store */
69
70 #define get8_unaligned_check(val, addr, err) \
71 __asm__( \
72 "1: ldb.u %1, [%2], #1\n" \
73 "2:\n" \
74 " .pushsection .fixup,\"ax\"\n" \
75 " .align 2\n" \
76 "3: mov %0, #1\n" \
77 " b 2b\n" \
78 " .popsection\n" \
79 " .pushsection __ex_table,\"a\"\n" \
80 " .align 3\n" \
81 " .long 1b, 3b\n" \
82 " .popsection\n" \
83 : "=r" (err), "=&r" (val), "=r" (addr) \
84 : "0" (err), "2" (addr))
85
86 #define get8t_unaligned_check(val, addr, err) \
87 __asm__( \
88 "1: ldb.u %1, [%2], #1\n" \
89 "2:\n" \
90 " .pushsection .fixup,\"ax\"\n" \
91 " .align 2\n" \
92 "3: mov %0, #1\n" \
93 " b 2b\n" \
94 " .popsection\n" \
95 " .pushsection __ex_table,\"a\"\n" \
96 " .align 3\n" \
97 " .long 1b, 3b\n" \
98 " .popsection\n" \
99 : "=r" (err), "=&r" (val), "=r" (addr) \
100 : "0" (err), "2" (addr))
101
102 #define get16_unaligned_check(val, addr) \
103 do { \
104 unsigned int err = 0, v, a = addr; \
105 get8_unaligned_check(val, a, err); \
106 get8_unaligned_check(v, a, err); \
107 val |= v << 8; \
108 if (err) \
109 goto fault; \
110 } while (0)
111
112 #define put16_unaligned_check(val, addr) \
113 do { \
114 unsigned int err = 0, v = val, a = addr; \
115 __asm__( \
116 "1: stb.u %1, [%2], #1\n" \
117 " mov %1, %1 >> #8\n" \
118 "2: stb.u %1, [%2]\n" \
119 "3:\n" \
120 " .pushsection .fixup,\"ax\"\n" \
121 " .align 2\n" \
122 "4: mov %0, #1\n" \
123 " b 3b\n" \
124 " .popsection\n" \
125 " .pushsection __ex_table,\"a\"\n" \
126 " .align 3\n" \
127 " .long 1b, 4b\n" \
128 " .long 2b, 4b\n" \
129 " .popsection\n" \
130 : "=r" (err), "=&r" (v), "=&r" (a) \
131 : "0" (err), "1" (v), "2" (a)); \
132 if (err) \
133 goto fault; \
134 } while (0)
135
136 #define __put32_unaligned_check(ins, val, addr) \
137 do { \
138 unsigned int err = 0, v = val, a = addr; \
139 __asm__( \
140 "1: "ins" %1, [%2], #1\n" \
141 " mov %1, %1 >> #8\n" \
142 "2: "ins" %1, [%2], #1\n" \
143 " mov %1, %1 >> #8\n" \
144 "3: "ins" %1, [%2], #1\n" \
145 " mov %1, %1 >> #8\n" \
146 "4: "ins" %1, [%2]\n" \
147 "5:\n" \
148 " .pushsection .fixup,\"ax\"\n" \
149 " .align 2\n" \
150 "6: mov %0, #1\n" \
151 " b 5b\n" \
152 " .popsection\n" \
153 " .pushsection __ex_table,\"a\"\n" \
154 " .align 3\n" \
155 " .long 1b, 6b\n" \
156 " .long 2b, 6b\n" \
157 " .long 3b, 6b\n" \
158 " .long 4b, 6b\n" \
159 " .popsection\n" \
160 : "=r" (err), "=&r" (v), "=&r" (a) \
161 : "0" (err), "1" (v), "2" (a)); \
162 if (err) \
163 goto fault; \
164 } while (0)
165
166 #define get32_unaligned_check(val, addr) \
167 do { \
168 unsigned int err = 0, v, a = addr; \
169 get8_unaligned_check(val, a, err); \
170 get8_unaligned_check(v, a, err); \
171 val |= v << 8; \
172 get8_unaligned_check(v, a, err); \
173 val |= v << 16; \
174 get8_unaligned_check(v, a, err); \
175 val |= v << 24; \
176 if (err) \
177 goto fault; \
178 } while (0)
179
180 #define put32_unaligned_check(val, addr) \
181 __put32_unaligned_check("stb.u", val, addr)
182
183 #define get32t_unaligned_check(val, addr) \
184 do { \
185 unsigned int err = 0, v, a = addr; \
186 get8t_unaligned_check(val, a, err); \
187 get8t_unaligned_check(v, a, err); \
188 val |= v << 8; \
189 get8t_unaligned_check(v, a, err); \
190 val |= v << 16; \
191 get8t_unaligned_check(v, a, err); \
192 val |= v << 24; \
193 if (err) \
194 goto fault; \
195 } while (0)
196
197 #define put32t_unaligned_check(val, addr) \
198 __put32_unaligned_check("stb.u", val, addr)
199
200 static void
do_alignment_finish_ldst(unsigned long addr,unsigned long instr,struct pt_regs * regs,union offset_union offset)201 do_alignment_finish_ldst(unsigned long addr, unsigned long instr,
202 struct pt_regs *regs, union offset_union offset)
203 {
204 if (!LDST_U_BIT(instr))
205 offset.un = -offset.un;
206
207 if (!LDST_P_BIT(instr))
208 addr += offset.un;
209
210 if (!LDST_P_BIT(instr) || LDST_W_BIT(instr))
211 regs->uregs[RN_BITS(instr)] = addr;
212 }
213
214 static int
do_alignment_ldrhstrh(unsigned long addr,unsigned long instr,struct pt_regs * regs)215 do_alignment_ldrhstrh(unsigned long addr, unsigned long instr,
216 struct pt_regs *regs)
217 {
218 unsigned int rd = RD_BITS(instr);
219
220 /* old value 0x40002120, can't judge swap instr correctly */
221 if ((instr & 0x4b003fe0) == 0x40000120)
222 goto swp;
223
224 if (LDST_L_BIT(instr)) {
225 unsigned long val;
226 get16_unaligned_check(val, addr);
227
228 /* signed half-word? */
229 if (instr & 0x80)
230 val = (signed long)((signed short)val);
231
232 regs->uregs[rd] = val;
233 } else
234 put16_unaligned_check(regs->uregs[rd], addr);
235
236 return TYPE_LDST;
237
238 swp:
239 /* only handle swap word
240 * for swap byte should not active this alignment exception */
241 get32_unaligned_check(regs->uregs[RD_BITS(instr)], addr);
242 put32_unaligned_check(regs->uregs[RM_BITS(instr)], addr);
243 return TYPE_SWAP;
244
245 fault:
246 return TYPE_FAULT;
247 }
248
249 static int
do_alignment_ldrstr(unsigned long addr,unsigned long instr,struct pt_regs * regs)250 do_alignment_ldrstr(unsigned long addr, unsigned long instr,
251 struct pt_regs *regs)
252 {
253 unsigned int rd = RD_BITS(instr);
254
255 if (!LDST_P_BIT(instr) && LDST_W_BIT(instr))
256 goto trans;
257
258 if (LDST_L_BIT(instr))
259 get32_unaligned_check(regs->uregs[rd], addr);
260 else
261 put32_unaligned_check(regs->uregs[rd], addr);
262 return TYPE_LDST;
263
264 trans:
265 if (LDST_L_BIT(instr))
266 get32t_unaligned_check(regs->uregs[rd], addr);
267 else
268 put32t_unaligned_check(regs->uregs[rd], addr);
269 return TYPE_LDST;
270
271 fault:
272 return TYPE_FAULT;
273 }
274
275 /*
276 * LDM/STM alignment handler.
277 *
278 * There are 4 variants of this instruction:
279 *
280 * B = rn pointer before instruction, A = rn pointer after instruction
281 * ------ increasing address ----->
282 * | | r0 | r1 | ... | rx | |
283 * PU = 01 B A
284 * PU = 11 B A
285 * PU = 00 A B
286 * PU = 10 A B
287 */
288 static int
do_alignment_ldmstm(unsigned long addr,unsigned long instr,struct pt_regs * regs)289 do_alignment_ldmstm(unsigned long addr, unsigned long instr,
290 struct pt_regs *regs)
291 {
292 unsigned int rd, rn, pc_correction, reg_correction, nr_regs, regbits;
293 unsigned long eaddr, newaddr;
294
295 if (LDM_S_BIT(instr))
296 goto bad;
297
298 pc_correction = 4; /* processor implementation defined */
299
300 /* count the number of registers in the mask to be transferred */
301 nr_regs = hweight16(REGMASK_BITS(instr)) * 4;
302
303 rn = RN_BITS(instr);
304 newaddr = eaddr = regs->uregs[rn];
305
306 if (!LDST_U_BIT(instr))
307 nr_regs = -nr_regs;
308 newaddr += nr_regs;
309 if (!LDST_U_BIT(instr))
310 eaddr = newaddr;
311
312 if (LDST_P_EQ_U(instr)) /* U = P */
313 eaddr += 4;
314
315 /*
316 * This is a "hint" - we already have eaddr worked out by the
317 * processor for us.
318 */
319 if (addr != eaddr) {
320 printk(KERN_ERR "LDMSTM: PC = %08lx, instr = %08lx, "
321 "addr = %08lx, eaddr = %08lx\n",
322 instruction_pointer(regs), instr, addr, eaddr);
323 show_regs(regs);
324 }
325
326 if (LDM_H_BIT(instr))
327 reg_correction = 0x10;
328 else
329 reg_correction = 0x00;
330
331 for (regbits = REGMASK_BITS(instr), rd = 0; regbits;
332 regbits >>= 1, rd += 1)
333 if (regbits & 1) {
334 if (LDST_L_BIT(instr))
335 get32_unaligned_check(regs->
336 uregs[rd + reg_correction], eaddr);
337 else
338 put32_unaligned_check(regs->
339 uregs[rd + reg_correction], eaddr);
340 eaddr += 4;
341 }
342
343 if (LDST_W_BIT(instr))
344 regs->uregs[rn] = newaddr;
345 return TYPE_DONE;
346
347 fault:
348 regs->UCreg_pc -= pc_correction;
349 return TYPE_FAULT;
350
351 bad:
352 printk(KERN_ERR "Alignment trap: not handling ldm with s-bit set\n");
353 return TYPE_ERROR;
354 }
355
356 static int
do_alignment(unsigned long addr,unsigned int error_code,struct pt_regs * regs)357 do_alignment(unsigned long addr, unsigned int error_code, struct pt_regs *regs)
358 {
359 union offset_union offset;
360 unsigned long instr, instrptr;
361 int (*handler) (unsigned long addr, unsigned long instr,
362 struct pt_regs *regs);
363 unsigned int type;
364
365 instrptr = instruction_pointer(regs);
366 if (instrptr >= PAGE_OFFSET)
367 instr = *(unsigned long *)instrptr;
368 else {
369 __asm__ __volatile__(
370 "ldw.u %0, [%1]\n"
371 : "=&r"(instr)
372 : "r"(instrptr));
373 }
374
375 regs->UCreg_pc += 4;
376
377 switch (CODING_BITS(instr)) {
378 case 0x40000120: /* ldrh or strh */
379 if (LDSTH_I_BIT(instr))
380 offset.un = (instr & 0x3e00) >> 4 | (instr & 31);
381 else
382 offset.un = regs->uregs[RM_BITS(instr)];
383 handler = do_alignment_ldrhstrh;
384 break;
385
386 case 0x60000000: /* ldr or str immediate */
387 case 0x60000100: /* ldr or str immediate */
388 case 0x60000020: /* ldr or str immediate */
389 case 0x60000120: /* ldr or str immediate */
390 offset.un = OFFSET_BITS(instr);
391 handler = do_alignment_ldrstr;
392 break;
393
394 case 0x40000000: /* ldr or str register */
395 offset.un = regs->uregs[RM_BITS(instr)];
396 {
397 unsigned int shiftval = SHIFT_BITS(instr);
398
399 switch (SHIFT_TYPE(instr)) {
400 case SHIFT_LSL:
401 offset.un <<= shiftval;
402 break;
403
404 case SHIFT_LSR:
405 offset.un >>= shiftval;
406 break;
407
408 case SHIFT_ASR:
409 offset.sn >>= shiftval;
410 break;
411
412 case SHIFT_RORRRX:
413 if (shiftval == 0) {
414 offset.un >>= 1;
415 if (regs->UCreg_asr & PSR_C_BIT)
416 offset.un |= 1 << 31;
417 } else
418 offset.un = offset.un >> shiftval |
419 offset.un << (32 - shiftval);
420 break;
421 }
422 }
423 handler = do_alignment_ldrstr;
424 break;
425
426 case 0x80000000: /* ldm or stm */
427 case 0x80000020: /* ldm or stm */
428 handler = do_alignment_ldmstm;
429 break;
430
431 default:
432 goto bad;
433 }
434
435 type = handler(addr, instr, regs);
436
437 if (type == TYPE_ERROR || type == TYPE_FAULT)
438 goto bad_or_fault;
439
440 if (type == TYPE_LDST)
441 do_alignment_finish_ldst(addr, instr, regs, offset);
442
443 return 0;
444
445 bad_or_fault:
446 if (type == TYPE_ERROR)
447 goto bad;
448 regs->UCreg_pc -= 4;
449 /*
450 * We got a fault - fix it up, or die.
451 */
452 do_bad_area(addr, error_code, regs);
453 return 0;
454
455 bad:
456 /*
457 * Oops, we didn't handle the instruction.
458 * However, we must handle fpu instr firstly.
459 */
460 #ifdef CONFIG_UNICORE_FPU_F64
461 /* handle co.load/store */
462 #define CODING_COLS 0xc0000000
463 #define COLS_OFFSET_BITS(i) (i & 0x1FF)
464 #define COLS_L_BITS(i) (i & (1<<24))
465 #define COLS_FN_BITS(i) ((i>>14) & 31)
466 if ((instr & 0xe0000000) == CODING_COLS) {
467 unsigned int fn = COLS_FN_BITS(instr);
468 unsigned long val = 0;
469 if (COLS_L_BITS(instr)) {
470 get32t_unaligned_check(val, addr);
471 switch (fn) {
472 #define ASM_MTF(n) case n: \
473 __asm__ __volatile__("MTF %0, F" __stringify(n) \
474 : : "r"(val)); \
475 break;
476 ASM_MTF(0); ASM_MTF(1); ASM_MTF(2); ASM_MTF(3);
477 ASM_MTF(4); ASM_MTF(5); ASM_MTF(6); ASM_MTF(7);
478 ASM_MTF(8); ASM_MTF(9); ASM_MTF(10); ASM_MTF(11);
479 ASM_MTF(12); ASM_MTF(13); ASM_MTF(14); ASM_MTF(15);
480 ASM_MTF(16); ASM_MTF(17); ASM_MTF(18); ASM_MTF(19);
481 ASM_MTF(20); ASM_MTF(21); ASM_MTF(22); ASM_MTF(23);
482 ASM_MTF(24); ASM_MTF(25); ASM_MTF(26); ASM_MTF(27);
483 ASM_MTF(28); ASM_MTF(29); ASM_MTF(30); ASM_MTF(31);
484 #undef ASM_MTF
485 }
486 } else {
487 switch (fn) {
488 #define ASM_MFF(n) case n: \
489 __asm__ __volatile__("MFF %0, F" __stringify(n) \
490 : : "r"(val)); \
491 break;
492 ASM_MFF(0); ASM_MFF(1); ASM_MFF(2); ASM_MFF(3);
493 ASM_MFF(4); ASM_MFF(5); ASM_MFF(6); ASM_MFF(7);
494 ASM_MFF(8); ASM_MFF(9); ASM_MFF(10); ASM_MFF(11);
495 ASM_MFF(12); ASM_MFF(13); ASM_MFF(14); ASM_MFF(15);
496 ASM_MFF(16); ASM_MFF(17); ASM_MFF(18); ASM_MFF(19);
497 ASM_MFF(20); ASM_MFF(21); ASM_MFF(22); ASM_MFF(23);
498 ASM_MFF(24); ASM_MFF(25); ASM_MFF(26); ASM_MFF(27);
499 ASM_MFF(28); ASM_MFF(29); ASM_MFF(30); ASM_MFF(31);
500 #undef ASM_MFF
501 }
502 put32t_unaligned_check(val, addr);
503 }
504 return TYPE_COLS;
505 }
506 fault:
507 return TYPE_FAULT;
508 #endif
509 printk(KERN_ERR "Alignment trap: not handling instruction "
510 "%08lx at [<%08lx>]\n", instr, instrptr);
511 return 1;
512 }
513
514 /*
515 * This needs to be done after sysctl_init, otherwise sys/ will be
516 * overwritten. Actually, this shouldn't be in sys/ at all since
517 * it isn't a sysctl, and it doesn't contain sysctl information.
518 */
alignment_init(void)519 static int __init alignment_init(void)
520 {
521 hook_fault_code(1, do_alignment, SIGBUS, BUS_ADRALN,
522 "alignment exception");
523
524 return 0;
525 }
526
527 fs_initcall(alignment_init);
528