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