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-rw-r--r--arch/ppc64/kernel/align.c396
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diff --git a/arch/ppc64/kernel/align.c b/arch/ppc64/kernel/align.c
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1/* align.c - handle alignment exceptions for the Power PC.
2 *
3 * Copyright (c) 1996 Paul Mackerras <paulus@cs.anu.edu.au>
4 * Copyright (c) 1998-1999 TiVo, Inc.
5 * PowerPC 403GCX modifications.
6 * Copyright (c) 1999 Grant Erickson <grant@lcse.umn.edu>
7 * PowerPC 403GCX/405GP modifications.
8 * Copyright (c) 2001-2002 PPC64 team, IBM Corp
9 * 64-bit and Power4 support
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; either version
14 * 2 of the License, or (at your option) any later version.
15 */
16
17#include <linux/kernel.h>
18#include <linux/mm.h>
19#include <asm/processor.h>
20#include <asm/uaccess.h>
21#include <asm/system.h>
22#include <asm/cache.h>
23#include <asm/cputable.h>
24
25struct aligninfo {
26 unsigned char len;
27 unsigned char flags;
28};
29
30#define IS_XFORM(inst) (((inst) >> 26) == 31)
31#define IS_DSFORM(inst) (((inst) >> 26) >= 56)
32
33#define INVALID { 0, 0 }
34
35#define LD 1 /* load */
36#define ST 2 /* store */
37#define SE 4 /* sign-extend value */
38#define F 8 /* to/from fp regs */
39#define U 0x10 /* update index register */
40#define M 0x20 /* multiple load/store */
41#define SW 0x40 /* byte swap */
42
43#define DCBZ 0x5f /* 8xx/82xx dcbz faults when cache not enabled */
44
45/*
46 * The PowerPC stores certain bits of the instruction that caused the
47 * alignment exception in the DSISR register. This array maps those
48 * bits to information about the operand length and what the
49 * instruction would do.
50 */
51static struct aligninfo aligninfo[128] = {
52 { 4, LD }, /* 00 0 0000: lwz / lwarx */
53 INVALID, /* 00 0 0001 */
54 { 4, ST }, /* 00 0 0010: stw */
55 INVALID, /* 00 0 0011 */
56 { 2, LD }, /* 00 0 0100: lhz */
57 { 2, LD+SE }, /* 00 0 0101: lha */
58 { 2, ST }, /* 00 0 0110: sth */
59 { 4, LD+M }, /* 00 0 0111: lmw */
60 { 4, LD+F }, /* 00 0 1000: lfs */
61 { 8, LD+F }, /* 00 0 1001: lfd */
62 { 4, ST+F }, /* 00 0 1010: stfs */
63 { 8, ST+F }, /* 00 0 1011: stfd */
64 INVALID, /* 00 0 1100 */
65 { 8, LD }, /* 00 0 1101: ld */
66 INVALID, /* 00 0 1110 */
67 { 8, ST }, /* 00 0 1111: std */
68 { 4, LD+U }, /* 00 1 0000: lwzu */
69 INVALID, /* 00 1 0001 */
70 { 4, ST+U }, /* 00 1 0010: stwu */
71 INVALID, /* 00 1 0011 */
72 { 2, LD+U }, /* 00 1 0100: lhzu */
73 { 2, LD+SE+U }, /* 00 1 0101: lhau */
74 { 2, ST+U }, /* 00 1 0110: sthu */
75 { 4, ST+M }, /* 00 1 0111: stmw */
76 { 4, LD+F+U }, /* 00 1 1000: lfsu */
77 { 8, LD+F+U }, /* 00 1 1001: lfdu */
78 { 4, ST+F+U }, /* 00 1 1010: stfsu */
79 { 8, ST+F+U }, /* 00 1 1011: stfdu */
80 INVALID, /* 00 1 1100 */
81 INVALID, /* 00 1 1101 */
82 INVALID, /* 00 1 1110 */
83 INVALID, /* 00 1 1111 */
84 { 8, LD }, /* 01 0 0000: ldx */
85 INVALID, /* 01 0 0001 */
86 { 8, ST }, /* 01 0 0010: stdx */
87 INVALID, /* 01 0 0011 */
88 INVALID, /* 01 0 0100 */
89 { 4, LD+SE }, /* 01 0 0101: lwax */
90 INVALID, /* 01 0 0110 */
91 INVALID, /* 01 0 0111 */
92 { 0, LD }, /* 01 0 1000: lswx */
93 { 0, LD }, /* 01 0 1001: lswi */
94 { 0, ST }, /* 01 0 1010: stswx */
95 { 0, ST }, /* 01 0 1011: stswi */
96 INVALID, /* 01 0 1100 */
97 { 8, LD+U }, /* 01 0 1101: ldu */
98 INVALID, /* 01 0 1110 */
99 { 8, ST+U }, /* 01 0 1111: stdu */
100 { 8, LD+U }, /* 01 1 0000: ldux */
101 INVALID, /* 01 1 0001 */
102 { 8, ST+U }, /* 01 1 0010: stdux */
103 INVALID, /* 01 1 0011 */
104 INVALID, /* 01 1 0100 */
105 { 4, LD+SE+U }, /* 01 1 0101: lwaux */
106 INVALID, /* 01 1 0110 */
107 INVALID, /* 01 1 0111 */
108 INVALID, /* 01 1 1000 */
109 INVALID, /* 01 1 1001 */
110 INVALID, /* 01 1 1010 */
111 INVALID, /* 01 1 1011 */
112 INVALID, /* 01 1 1100 */
113 INVALID, /* 01 1 1101 */
114 INVALID, /* 01 1 1110 */
115 INVALID, /* 01 1 1111 */
116 INVALID, /* 10 0 0000 */
117 INVALID, /* 10 0 0001 */
118 { 0, ST }, /* 10 0 0010: stwcx. */
119 INVALID, /* 10 0 0011 */
120 INVALID, /* 10 0 0100 */
121 INVALID, /* 10 0 0101 */
122 INVALID, /* 10 0 0110 */
123 INVALID, /* 10 0 0111 */
124 { 4, LD+SW }, /* 10 0 1000: lwbrx */
125 INVALID, /* 10 0 1001 */
126 { 4, ST+SW }, /* 10 0 1010: stwbrx */
127 INVALID, /* 10 0 1011 */
128 { 2, LD+SW }, /* 10 0 1100: lhbrx */
129 { 4, LD+SE }, /* 10 0 1101 lwa */
130 { 2, ST+SW }, /* 10 0 1110: sthbrx */
131 INVALID, /* 10 0 1111 */
132 INVALID, /* 10 1 0000 */
133 INVALID, /* 10 1 0001 */
134 INVALID, /* 10 1 0010 */
135 INVALID, /* 10 1 0011 */
136 INVALID, /* 10 1 0100 */
137 INVALID, /* 10 1 0101 */
138 INVALID, /* 10 1 0110 */
139 INVALID, /* 10 1 0111 */
140 INVALID, /* 10 1 1000 */
141 INVALID, /* 10 1 1001 */
142 INVALID, /* 10 1 1010 */
143 INVALID, /* 10 1 1011 */
144 INVALID, /* 10 1 1100 */
145 INVALID, /* 10 1 1101 */
146 INVALID, /* 10 1 1110 */
147 { L1_CACHE_BYTES, ST }, /* 10 1 1111: dcbz */
148 { 4, LD }, /* 11 0 0000: lwzx */
149 INVALID, /* 11 0 0001 */
150 { 4, ST }, /* 11 0 0010: stwx */
151 INVALID, /* 11 0 0011 */
152 { 2, LD }, /* 11 0 0100: lhzx */
153 { 2, LD+SE }, /* 11 0 0101: lhax */
154 { 2, ST }, /* 11 0 0110: sthx */
155 INVALID, /* 11 0 0111 */
156 { 4, LD+F }, /* 11 0 1000: lfsx */
157 { 8, LD+F }, /* 11 0 1001: lfdx */
158 { 4, ST+F }, /* 11 0 1010: stfsx */
159 { 8, ST+F }, /* 11 0 1011: stfdx */
160 INVALID, /* 11 0 1100 */
161 { 8, LD+M }, /* 11 0 1101: lmd */
162 INVALID, /* 11 0 1110 */
163 { 8, ST+M }, /* 11 0 1111: stmd */
164 { 4, LD+U }, /* 11 1 0000: lwzux */
165 INVALID, /* 11 1 0001 */
166 { 4, ST+U }, /* 11 1 0010: stwux */
167 INVALID, /* 11 1 0011 */
168 { 2, LD+U }, /* 11 1 0100: lhzux */
169 { 2, LD+SE+U }, /* 11 1 0101: lhaux */
170 { 2, ST+U }, /* 11 1 0110: sthux */
171 INVALID, /* 11 1 0111 */
172 { 4, LD+F+U }, /* 11 1 1000: lfsux */
173 { 8, LD+F+U }, /* 11 1 1001: lfdux */
174 { 4, ST+F+U }, /* 11 1 1010: stfsux */
175 { 8, ST+F+U }, /* 11 1 1011: stfdux */
176 INVALID, /* 11 1 1100 */
177 INVALID, /* 11 1 1101 */
178 INVALID, /* 11 1 1110 */
179 INVALID, /* 11 1 1111 */
180};
181
182#define SWAP(a, b) (t = (a), (a) = (b), (b) = t)
183
184static inline unsigned make_dsisr(unsigned instr)
185{
186 unsigned dsisr;
187
188 /* create a DSISR value from the instruction */
189 dsisr = (instr & 0x03ff0000) >> 16; /* bits 6:15 --> 22:31 */
190
191 if ( IS_XFORM(instr) ) {
192 dsisr |= (instr & 0x00000006) << 14; /* bits 29:30 --> 15:16 */
193 dsisr |= (instr & 0x00000040) << 8; /* bit 25 --> 17 */
194 dsisr |= (instr & 0x00000780) << 3; /* bits 21:24 --> 18:21 */
195 }
196 else {
197 dsisr |= (instr & 0x04000000) >> 12; /* bit 5 --> 17 */
198 dsisr |= (instr & 0x78000000) >> 17; /* bits 1: 4 --> 18:21 */
199 if ( IS_DSFORM(instr) ) {
200 dsisr |= (instr & 0x00000003) << 18; /* bits 30:31 --> 12:13 */
201 }
202 }
203
204 return dsisr;
205}
206
207int
208fix_alignment(struct pt_regs *regs)
209{
210 unsigned int instr, nb, flags;
211 int t;
212 unsigned long reg, areg;
213 unsigned long i;
214 int ret;
215 unsigned dsisr;
216 unsigned char __user *addr;
217 unsigned char __user *p;
218 unsigned long __user *lp;
219 union {
220 long ll;
221 double dd;
222 unsigned char v[8];
223 struct {
224 unsigned hi32;
225 int low32;
226 } x32;
227 struct {
228 unsigned char hi48[6];
229 short low16;
230 } x16;
231 } data;
232
233 /*
234 * Return 1 on success
235 * Return 0 if unable to handle the interrupt
236 * Return -EFAULT if data address is bad
237 */
238
239 dsisr = regs->dsisr;
240
241 if (cpu_has_feature(CPU_FTR_NODSISRALIGN)) {
242 unsigned int real_instr;
243 if (__get_user(real_instr, (unsigned int __user *)regs->nip))
244 return 0;
245 dsisr = make_dsisr(real_instr);
246 }
247
248 /* extract the operation and registers from the dsisr */
249 reg = (dsisr >> 5) & 0x1f; /* source/dest register */
250 areg = dsisr & 0x1f; /* register to update */
251 instr = (dsisr >> 10) & 0x7f;
252 instr |= (dsisr >> 13) & 0x60;
253
254 /* Lookup the operation in our table */
255 nb = aligninfo[instr].len;
256 flags = aligninfo[instr].flags;
257
258 /* DAR has the operand effective address */
259 addr = (unsigned char __user *)regs->dar;
260
261 /* A size of 0 indicates an instruction we don't support */
262 /* we also don't support the multiples (lmw, stmw, lmd, stmd) */
263 if ((nb == 0) || (flags & M))
264 return 0; /* too hard or invalid instruction */
265
266 /*
267 * Special handling for dcbz
268 * dcbz may give an alignment exception for accesses to caching inhibited
269 * storage
270 */
271 if (instr == DCBZ)
272 addr = (unsigned char __user *) ((unsigned long)addr & -L1_CACHE_BYTES);
273
274 /* Verify the address of the operand */
275 if (user_mode(regs)) {
276 if (!access_ok((flags & ST? VERIFY_WRITE: VERIFY_READ), addr, nb))
277 return -EFAULT; /* bad address */
278 }
279
280 /* Force the fprs into the save area so we can reference them */
281 if (flags & F) {
282 if (!user_mode(regs))
283 return 0;
284 flush_fp_to_thread(current);
285 }
286
287 /* If we are loading, get the data from user space */
288 if (flags & LD) {
289 data.ll = 0;
290 ret = 0;
291 p = addr;
292 switch (nb) {
293 case 8:
294 ret |= __get_user(data.v[0], p++);
295 ret |= __get_user(data.v[1], p++);
296 ret |= __get_user(data.v[2], p++);
297 ret |= __get_user(data.v[3], p++);
298 case 4:
299 ret |= __get_user(data.v[4], p++);
300 ret |= __get_user(data.v[5], p++);
301 case 2:
302 ret |= __get_user(data.v[6], p++);
303 ret |= __get_user(data.v[7], p++);
304 if (ret)
305 return -EFAULT;
306 }
307 }
308
309 /* If we are storing, get the data from the saved gpr or fpr */
310 if (flags & ST) {
311 if (flags & F) {
312 if (nb == 4) {
313 /* Doing stfs, have to convert to single */
314 preempt_disable();
315 enable_kernel_fp();
316 cvt_df(&current->thread.fpr[reg], (float *)&data.v[4], &current->thread.fpscr);
317 disable_kernel_fp();
318 preempt_enable();
319 }
320 else
321 data.dd = current->thread.fpr[reg];
322 }
323 else
324 data.ll = regs->gpr[reg];
325 }
326
327 /* Swap bytes as needed */
328 if (flags & SW) {
329 if (nb == 2)
330 SWAP(data.v[6], data.v[7]);
331 else { /* nb must be 4 */
332 SWAP(data.v[4], data.v[7]);
333 SWAP(data.v[5], data.v[6]);
334 }
335 }
336
337 /* Sign extend as needed */
338 if (flags & SE) {
339 if ( nb == 2 )
340 data.ll = data.x16.low16;
341 else /* nb must be 4 */
342 data.ll = data.x32.low32;
343 }
344
345 /* If we are loading, move the data to the gpr or fpr */
346 if (flags & LD) {
347 if (flags & F) {
348 if (nb == 4) {
349 /* Doing lfs, have to convert to double */
350 preempt_disable();
351 enable_kernel_fp();
352 cvt_fd((float *)&data.v[4], &current->thread.fpr[reg], &current->thread.fpscr);
353 disable_kernel_fp();
354 preempt_enable();
355 }
356 else
357 current->thread.fpr[reg] = data.dd;
358 }
359 else
360 regs->gpr[reg] = data.ll;
361 }
362
363 /* If we are storing, copy the data to the user */
364 if (flags & ST) {
365 ret = 0;
366 p = addr;
367 switch (nb) {
368 case 128: /* Special case - must be dcbz */
369 lp = (unsigned long __user *)p;
370 for (i = 0; i < L1_CACHE_BYTES / sizeof(long); ++i)
371 ret |= __put_user(0, lp++);
372 break;
373 case 8:
374 ret |= __put_user(data.v[0], p++);
375 ret |= __put_user(data.v[1], p++);
376 ret |= __put_user(data.v[2], p++);
377 ret |= __put_user(data.v[3], p++);
378 case 4:
379 ret |= __put_user(data.v[4], p++);
380 ret |= __put_user(data.v[5], p++);
381 case 2:
382 ret |= __put_user(data.v[6], p++);
383 ret |= __put_user(data.v[7], p++);
384 }
385 if (ret)
386 return -EFAULT;
387 }
388
389 /* Update RA as needed */
390 if (flags & U) {
391 regs->gpr[areg] = regs->dar;
392 }
393
394 return 1;
395}
396
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