1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * linux/arch/unicore32/mm/alignment.c
4 *
5 * Code specific to PKUnity SoC and UniCore ISA
6 *
7 * Copyright (C) 2001-2010 GUAN Xue-tao
8 */
9 /*
10 * TODO:
11 * FPU ldm/stm not handling
12 */
13 #include <linux/compiler.h>
14 #include <linux/kernel.h>
15 #include <linux/sched/debug.h>
16 #include <linux/errno.h>
17 #include <linux/string.h>
18 #include <linux/init.h>
19 #include <linux/sched.h>
20 #include <linux/uaccess.h>
21
22 #include <asm/pgtable.h>
23 #include <asm/tlbflush.h>
24 #include <asm/unaligned.h>
25
26 #include "mm.h"
27
28 #define CODING_BITS(i) (i & 0xe0000120)
29
30 #define LDST_P_BIT(i) (i & (1 << 28)) /* Preindex */
31 #define LDST_U_BIT(i) (i & (1 << 27)) /* Add offset */
32 #define LDST_W_BIT(i) (i & (1 << 25)) /* Writeback */
33 #define LDST_L_BIT(i) (i & (1 << 24)) /* Load */
34
35 #define LDST_P_EQ_U(i) ((((i) ^ ((i) >> 1)) & (1 << 27)) == 0)
36
37 #define LDSTH_I_BIT(i) (i & (1 << 26)) /* half-word immed */
38 #define LDM_S_BIT(i) (i & (1 << 26)) /* write ASR from BSR */
39 #define LDM_H_BIT(i) (i & (1 << 6)) /* select r0-r15 or r16-r31 */
40
41 #define RN_BITS(i) ((i >> 19) & 31) /* Rn */
42 #define RD_BITS(i) ((i >> 14) & 31) /* Rd */
43 #define RM_BITS(i) (i & 31) /* Rm */
44
45 #define REGMASK_BITS(i) (((i & 0x7fe00) >> 3) | (i & 0x3f))
46 #define OFFSET_BITS(i) (i & 0x03fff)
47
48 #define SHIFT_BITS(i) ((i >> 9) & 0x1f)
49 #define SHIFT_TYPE(i) (i & 0xc0)
50 #define SHIFT_LSL 0x00
51 #define SHIFT_LSR 0x40
52 #define SHIFT_ASR 0x80
53 #define SHIFT_RORRRX 0xc0
54
55 union offset_union {
56 unsigned long un;
57 signed long sn;
58 };
59
60 #define TYPE_ERROR 0
61 #define TYPE_FAULT 1
62 #define TYPE_LDST 2
63 #define TYPE_DONE 3
64 #define TYPE_SWAP 4
65 #define TYPE_COLS 5 /* Coprocessor load/store */
66
67 #define get8_unaligned_check(val, addr, err) \
68 __asm__( \
69 "1: ldb.u %1, [%2], #1\n" \
70 "2:\n" \
71 " .pushsection .fixup,\"ax\"\n" \
72 " .align 2\n" \
73 "3: mov %0, #1\n" \
74 " b 2b\n" \
75 " .popsection\n" \
76 " .pushsection __ex_table,\"a\"\n" \
77 " .align 3\n" \
78 " .long 1b, 3b\n" \
79 " .popsection\n" \
80 : "=r" (err), "=&r" (val), "=r" (addr) \
81 : "0" (err), "2" (addr))
82
83 #define get8t_unaligned_check(val, addr, err) \
84 __asm__( \
85 "1: ldb.u %1, [%2], #1\n" \
86 "2:\n" \
87 " .pushsection .fixup,\"ax\"\n" \
88 " .align 2\n" \
89 "3: mov %0, #1\n" \
90 " b 2b\n" \
91 " .popsection\n" \
92 " .pushsection __ex_table,\"a\"\n" \
93 " .align 3\n" \
94 " .long 1b, 3b\n" \
95 " .popsection\n" \
96 : "=r" (err), "=&r" (val), "=r" (addr) \
97 : "0" (err), "2" (addr))
98
99 #define get16_unaligned_check(val, addr) \
100 do { \
101 unsigned int err = 0, v, a = addr; \
102 get8_unaligned_check(val, a, err); \
103 get8_unaligned_check(v, a, err); \
104 val |= v << 8; \
105 if (err) \
106 goto fault; \
107 } while (0)
108
109 #define put16_unaligned_check(val, addr) \
110 do { \
111 unsigned int err = 0, v = val, a = addr; \
112 __asm__( \
113 "1: stb.u %1, [%2], #1\n" \
114 " mov %1, %1 >> #8\n" \
115 "2: stb.u %1, [%2]\n" \
116 "3:\n" \
117 " .pushsection .fixup,\"ax\"\n" \
118 " .align 2\n" \
119 "4: mov %0, #1\n" \
120 " b 3b\n" \
121 " .popsection\n" \
122 " .pushsection __ex_table,\"a\"\n" \
123 " .align 3\n" \
124 " .long 1b, 4b\n" \
125 " .long 2b, 4b\n" \
126 " .popsection\n" \
127 : "=r" (err), "=&r" (v), "=&r" (a) \
128 : "0" (err), "1" (v), "2" (a)); \
129 if (err) \
130 goto fault; \
131 } while (0)
132
133 #define __put32_unaligned_check(ins, val, addr) \
134 do { \
135 unsigned int err = 0, v = val, a = addr; \
136 __asm__( \
137 "1: "ins" %1, [%2], #1\n" \
138 " mov %1, %1 >> #8\n" \
139 "2: "ins" %1, [%2], #1\n" \
140 " mov %1, %1 >> #8\n" \
141 "3: "ins" %1, [%2], #1\n" \
142 " mov %1, %1 >> #8\n" \
143 "4: "ins" %1, [%2]\n" \
144 "5:\n" \
145 " .pushsection .fixup,\"ax\"\n" \
146 " .align 2\n" \
147 "6: mov %0, #1\n" \
148 " b 5b\n" \
149 " .popsection\n" \
150 " .pushsection __ex_table,\"a\"\n" \
151 " .align 3\n" \
152 " .long 1b, 6b\n" \
153 " .long 2b, 6b\n" \
154 " .long 3b, 6b\n" \
155 " .long 4b, 6b\n" \
156 " .popsection\n" \
157 : "=r" (err), "=&r" (v), "=&r" (a) \
158 : "0" (err), "1" (v), "2" (a)); \
159 if (err) \
160 goto fault; \
161 } while (0)
162
163 #define get32_unaligned_check(val, addr) \
164 do { \
165 unsigned int err = 0, v, a = addr; \
166 get8_unaligned_check(val, a, err); \
167 get8_unaligned_check(v, a, err); \
168 val |= v << 8; \
169 get8_unaligned_check(v, a, err); \
170 val |= v << 16; \
171 get8_unaligned_check(v, a, err); \
172 val |= v << 24; \
173 if (err) \
174 goto fault; \
175 } while (0)
176
177 #define put32_unaligned_check(val, addr) \
178 __put32_unaligned_check("stb.u", val, addr)
179
180 #define get32t_unaligned_check(val, addr) \
181 do { \
182 unsigned int err = 0, v, a = addr; \
183 get8t_unaligned_check(val, a, err); \
184 get8t_unaligned_check(v, a, err); \
185 val |= v << 8; \
186 get8t_unaligned_check(v, a, err); \
187 val |= v << 16; \
188 get8t_unaligned_check(v, a, err); \
189 val |= v << 24; \
190 if (err) \
191 goto fault; \
192 } while (0)
193
194 #define put32t_unaligned_check(val, addr) \
195 __put32_unaligned_check("stb.u", val, addr)
196
197 static void
do_alignment_finish_ldst(unsigned long addr,unsigned long instr,struct pt_regs * regs,union offset_union offset)198 do_alignment_finish_ldst(unsigned long addr, unsigned long instr,
199 struct pt_regs *regs, union offset_union offset)
200 {
201 if (!LDST_U_BIT(instr))
202 offset.un = -offset.un;
203
204 if (!LDST_P_BIT(instr))
205 addr += offset.un;
206
207 if (!LDST_P_BIT(instr) || LDST_W_BIT(instr))
208 regs->uregs[RN_BITS(instr)] = addr;
209 }
210
211 static int
do_alignment_ldrhstrh(unsigned long addr,unsigned long instr,struct pt_regs * regs)212 do_alignment_ldrhstrh(unsigned long addr, unsigned long instr,
213 struct pt_regs *regs)
214 {
215 unsigned int rd = RD_BITS(instr);
216
217 /* old value 0x40002120, can't judge swap instr correctly */
218 if ((instr & 0x4b003fe0) == 0x40000120)
219 goto swp;
220
221 if (LDST_L_BIT(instr)) {
222 unsigned long val;
223 get16_unaligned_check(val, addr);
224
225 /* signed half-word? */
226 if (instr & 0x80)
227 val = (signed long)((signed short)val);
228
229 regs->uregs[rd] = val;
230 } else
231 put16_unaligned_check(regs->uregs[rd], addr);
232
233 return TYPE_LDST;
234
235 swp:
236 /* only handle swap word
237 * for swap byte should not active this alignment exception */
238 get32_unaligned_check(regs->uregs[RD_BITS(instr)], addr);
239 put32_unaligned_check(regs->uregs[RM_BITS(instr)], addr);
240 return TYPE_SWAP;
241
242 fault:
243 return TYPE_FAULT;
244 }
245
246 static int
do_alignment_ldrstr(unsigned long addr,unsigned long instr,struct pt_regs * regs)247 do_alignment_ldrstr(unsigned long addr, unsigned long instr,
248 struct pt_regs *regs)
249 {
250 unsigned int rd = RD_BITS(instr);
251
252 if (!LDST_P_BIT(instr) && LDST_W_BIT(instr))
253 goto trans;
254
255 if (LDST_L_BIT(instr))
256 get32_unaligned_check(regs->uregs[rd], addr);
257 else
258 put32_unaligned_check(regs->uregs[rd], addr);
259 return TYPE_LDST;
260
261 trans:
262 if (LDST_L_BIT(instr))
263 get32t_unaligned_check(regs->uregs[rd], addr);
264 else
265 put32t_unaligned_check(regs->uregs[rd], addr);
266 return TYPE_LDST;
267
268 fault:
269 return TYPE_FAULT;
270 }
271
272 /*
273 * LDM/STM alignment handler.
274 *
275 * There are 4 variants of this instruction:
276 *
277 * B = rn pointer before instruction, A = rn pointer after instruction
278 * ------ increasing address ----->
279 * | | r0 | r1 | ... | rx | |
280 * PU = 01 B A
281 * PU = 11 B A
282 * PU = 00 A B
283 * PU = 10 A B
284 */
285 static int
do_alignment_ldmstm(unsigned long addr,unsigned long instr,struct pt_regs * regs)286 do_alignment_ldmstm(unsigned long addr, unsigned long instr,
287 struct pt_regs *regs)
288 {
289 unsigned int rd, rn, pc_correction, reg_correction, nr_regs, regbits;
290 unsigned long eaddr, newaddr;
291
292 if (LDM_S_BIT(instr))
293 goto bad;
294
295 pc_correction = 4; /* processor implementation defined */
296
297 /* count the number of registers in the mask to be transferred */
298 nr_regs = hweight16(REGMASK_BITS(instr)) * 4;
299
300 rn = RN_BITS(instr);
301 newaddr = eaddr = regs->uregs[rn];
302
303 if (!LDST_U_BIT(instr))
304 nr_regs = -nr_regs;
305 newaddr += nr_regs;
306 if (!LDST_U_BIT(instr))
307 eaddr = newaddr;
308
309 if (LDST_P_EQ_U(instr)) /* U = P */
310 eaddr += 4;
311
312 /*
313 * This is a "hint" - we already have eaddr worked out by the
314 * processor for us.
315 */
316 if (addr != eaddr) {
317 printk(KERN_ERR "LDMSTM: PC = %08lx, instr = %08lx, "
318 "addr = %08lx, eaddr = %08lx\n",
319 instruction_pointer(regs), instr, addr, eaddr);
320 show_regs(regs);
321 }
322
323 if (LDM_H_BIT(instr))
324 reg_correction = 0x10;
325 else
326 reg_correction = 0x00;
327
328 for (regbits = REGMASK_BITS(instr), rd = 0; regbits;
329 regbits >>= 1, rd += 1)
330 if (regbits & 1) {
331 if (LDST_L_BIT(instr))
332 get32_unaligned_check(regs->
333 uregs[rd + reg_correction], eaddr);
334 else
335 put32_unaligned_check(regs->
336 uregs[rd + reg_correction], eaddr);
337 eaddr += 4;
338 }
339
340 if (LDST_W_BIT(instr))
341 regs->uregs[rn] = newaddr;
342 return TYPE_DONE;
343
344 fault:
345 regs->UCreg_pc -= pc_correction;
346 return TYPE_FAULT;
347
348 bad:
349 printk(KERN_ERR "Alignment trap: not handling ldm with s-bit set\n");
350 return TYPE_ERROR;
351 }
352
353 static int
do_alignment(unsigned long addr,unsigned int error_code,struct pt_regs * regs)354 do_alignment(unsigned long addr, unsigned int error_code, struct pt_regs *regs)
355 {
356 union offset_union offset;
357 unsigned long instr, instrptr;
358 int (*handler) (unsigned long addr, unsigned long instr,
359 struct pt_regs *regs);
360 unsigned int type;
361
362 instrptr = instruction_pointer(regs);
363 if (instrptr >= PAGE_OFFSET)
364 instr = *(unsigned long *)instrptr;
365 else {
366 __asm__ __volatile__(
367 "ldw.u %0, [%1]\n"
368 : "=&r"(instr)
369 : "r"(instrptr));
370 }
371
372 regs->UCreg_pc += 4;
373
374 switch (CODING_BITS(instr)) {
375 case 0x40000120: /* ldrh or strh */
376 if (LDSTH_I_BIT(instr))
377 offset.un = (instr & 0x3e00) >> 4 | (instr & 31);
378 else
379 offset.un = regs->uregs[RM_BITS(instr)];
380 handler = do_alignment_ldrhstrh;
381 break;
382
383 case 0x60000000: /* ldr or str immediate */
384 case 0x60000100: /* ldr or str immediate */
385 case 0x60000020: /* ldr or str immediate */
386 case 0x60000120: /* ldr or str immediate */
387 offset.un = OFFSET_BITS(instr);
388 handler = do_alignment_ldrstr;
389 break;
390
391 case 0x40000000: /* ldr or str register */
392 offset.un = regs->uregs[RM_BITS(instr)];
393 {
394 unsigned int shiftval = SHIFT_BITS(instr);
395
396 switch (SHIFT_TYPE(instr)) {
397 case SHIFT_LSL:
398 offset.un <<= shiftval;
399 break;
400
401 case SHIFT_LSR:
402 offset.un >>= shiftval;
403 break;
404
405 case SHIFT_ASR:
406 offset.sn >>= shiftval;
407 break;
408
409 case SHIFT_RORRRX:
410 if (shiftval == 0) {
411 offset.un >>= 1;
412 if (regs->UCreg_asr & PSR_C_BIT)
413 offset.un |= 1 << 31;
414 } else
415 offset.un = offset.un >> shiftval |
416 offset.un << (32 - shiftval);
417 break;
418 }
419 }
420 handler = do_alignment_ldrstr;
421 break;
422
423 case 0x80000000: /* ldm or stm */
424 case 0x80000020: /* ldm or stm */
425 handler = do_alignment_ldmstm;
426 break;
427
428 default:
429 goto bad;
430 }
431
432 type = handler(addr, instr, regs);
433
434 if (type == TYPE_ERROR || type == TYPE_FAULT)
435 goto bad_or_fault;
436
437 if (type == TYPE_LDST)
438 do_alignment_finish_ldst(addr, instr, regs, offset);
439
440 return 0;
441
442 bad_or_fault:
443 if (type == TYPE_ERROR)
444 goto bad;
445 regs->UCreg_pc -= 4;
446 /*
447 * We got a fault - fix it up, or die.
448 */
449 do_bad_area(addr, error_code, regs);
450 return 0;
451
452 bad:
453 /*
454 * Oops, we didn't handle the instruction.
455 * However, we must handle fpu instr firstly.
456 */
457 #ifdef CONFIG_UNICORE_FPU_F64
458 /* handle co.load/store */
459 #define CODING_COLS 0xc0000000
460 #define COLS_OFFSET_BITS(i) (i & 0x1FF)
461 #define COLS_L_BITS(i) (i & (1<<24))
462 #define COLS_FN_BITS(i) ((i>>14) & 31)
463 if ((instr & 0xe0000000) == CODING_COLS) {
464 unsigned int fn = COLS_FN_BITS(instr);
465 unsigned long val = 0;
466 if (COLS_L_BITS(instr)) {
467 get32t_unaligned_check(val, addr);
468 switch (fn) {
469 #define ASM_MTF(n) case n: \
470 __asm__ __volatile__("MTF %0, F" __stringify(n) \
471 : : "r"(val)); \
472 break;
473 ASM_MTF(0); ASM_MTF(1); ASM_MTF(2); ASM_MTF(3);
474 ASM_MTF(4); ASM_MTF(5); ASM_MTF(6); ASM_MTF(7);
475 ASM_MTF(8); ASM_MTF(9); ASM_MTF(10); ASM_MTF(11);
476 ASM_MTF(12); ASM_MTF(13); ASM_MTF(14); ASM_MTF(15);
477 ASM_MTF(16); ASM_MTF(17); ASM_MTF(18); ASM_MTF(19);
478 ASM_MTF(20); ASM_MTF(21); ASM_MTF(22); ASM_MTF(23);
479 ASM_MTF(24); ASM_MTF(25); ASM_MTF(26); ASM_MTF(27);
480 ASM_MTF(28); ASM_MTF(29); ASM_MTF(30); ASM_MTF(31);
481 #undef ASM_MTF
482 }
483 } else {
484 switch (fn) {
485 #define ASM_MFF(n) case n: \
486 __asm__ __volatile__("MFF %0, F" __stringify(n) \
487 : : "r"(val)); \
488 break;
489 ASM_MFF(0); ASM_MFF(1); ASM_MFF(2); ASM_MFF(3);
490 ASM_MFF(4); ASM_MFF(5); ASM_MFF(6); ASM_MFF(7);
491 ASM_MFF(8); ASM_MFF(9); ASM_MFF(10); ASM_MFF(11);
492 ASM_MFF(12); ASM_MFF(13); ASM_MFF(14); ASM_MFF(15);
493 ASM_MFF(16); ASM_MFF(17); ASM_MFF(18); ASM_MFF(19);
494 ASM_MFF(20); ASM_MFF(21); ASM_MFF(22); ASM_MFF(23);
495 ASM_MFF(24); ASM_MFF(25); ASM_MFF(26); ASM_MFF(27);
496 ASM_MFF(28); ASM_MFF(29); ASM_MFF(30); ASM_MFF(31);
497 #undef ASM_MFF
498 }
499 put32t_unaligned_check(val, addr);
500 }
501 return TYPE_COLS;
502 }
503 fault:
504 return TYPE_FAULT;
505 #endif
506 printk(KERN_ERR "Alignment trap: not handling instruction "
507 "%08lx at [<%08lx>]\n", instr, instrptr);
508 return 1;
509 }
510
511 /*
512 * This needs to be done after sysctl_init, otherwise sys/ will be
513 * overwritten. Actually, this shouldn't be in sys/ at all since
514 * it isn't a sysctl, and it doesn't contain sysctl information.
515 */
alignment_init(void)516 static int __init alignment_init(void)
517 {
518 hook_fault_code(1, do_alignment, SIGBUS, BUS_ADRALN,
519 "alignment exception");
520
521 return 0;
522 }
523
524 fs_initcall(alignment_init);
525