/arch/unicore32/mm/alignment.c

  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
 54union 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
196static void
197do_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
210static int
211do_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
234swp:
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
241fault:
242	return TYPE_FAULT;
243}
244
245static int
246do_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
260trans:
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
267fault:
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 */
284static int
285do_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
343fault:
344	regs->UCreg_pc -= pc_correction;
345	return TYPE_FAULT;
346
347bad:
348	printk(KERN_ERR "Alignment trap: not handling ldm with s-bit set\n");
349	return TYPE_ERROR;
350}
351
352static int
353do_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
441bad_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
451bad:
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	}
502fault:
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 */
515static 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
523fs_initcall(alignment_init);