1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* align.c - handle alignment exceptions for the Power PC.
3 *
4 * Copyright (c) 1996 Paul Mackerras <paulus@cs.anu.edu.au>
5 * Copyright (c) 1998-1999 TiVo, Inc.
6 * PowerPC 403GCX modifications.
7 * Copyright (c) 1999 Grant Erickson <grant@lcse.umn.edu>
8 * PowerPC 403GCX/405GP modifications.
9 * Copyright (c) 2001-2002 PPC64 team, IBM Corp
10 * 64-bit and Power4 support
11 * Copyright (c) 2005 Benjamin Herrenschmidt, IBM Corp
12 * <benh@kernel.crashing.org>
13 * Merge ppc32 and ppc64 implementations
14 */
15
16 #include <linux/kernel.h>
17 #include <linux/mm.h>
18 #include <asm/processor.h>
19 #include <linux/uaccess.h>
20 #include <asm/cache.h>
21 #include <asm/cputable.h>
22 #include <asm/emulated_ops.h>
23 #include <asm/switch_to.h>
24 #include <asm/disassemble.h>
25 #include <asm/cpu_has_feature.h>
26 #include <asm/sstep.h>
27
28 struct aligninfo {
29 unsigned char len;
30 unsigned char flags;
31 };
32
33
34 #define INVALID { 0, 0 }
35
36 /* Bits in the flags field */
37 #define LD 0 /* load */
38 #define ST 1 /* store */
39 #define SE 2 /* sign-extend value, or FP ld/st as word */
40 #define SW 0x20 /* byte swap */
41 #define E4 0x40 /* SPE endianness is word */
42 #define E8 0x80 /* SPE endianness is double word */
43
44 #ifdef CONFIG_SPE
45
46 static struct aligninfo spe_aligninfo[32] = {
47 { 8, LD+E8 }, /* 0 00 00: evldd[x] */
48 { 8, LD+E4 }, /* 0 00 01: evldw[x] */
49 { 8, LD }, /* 0 00 10: evldh[x] */
50 INVALID, /* 0 00 11 */
51 { 2, LD }, /* 0 01 00: evlhhesplat[x] */
52 INVALID, /* 0 01 01 */
53 { 2, LD }, /* 0 01 10: evlhhousplat[x] */
54 { 2, LD+SE }, /* 0 01 11: evlhhossplat[x] */
55 { 4, LD }, /* 0 10 00: evlwhe[x] */
56 INVALID, /* 0 10 01 */
57 { 4, LD }, /* 0 10 10: evlwhou[x] */
58 { 4, LD+SE }, /* 0 10 11: evlwhos[x] */
59 { 4, LD+E4 }, /* 0 11 00: evlwwsplat[x] */
60 INVALID, /* 0 11 01 */
61 { 4, LD }, /* 0 11 10: evlwhsplat[x] */
62 INVALID, /* 0 11 11 */
63
64 { 8, ST+E8 }, /* 1 00 00: evstdd[x] */
65 { 8, ST+E4 }, /* 1 00 01: evstdw[x] */
66 { 8, ST }, /* 1 00 10: evstdh[x] */
67 INVALID, /* 1 00 11 */
68 INVALID, /* 1 01 00 */
69 INVALID, /* 1 01 01 */
70 INVALID, /* 1 01 10 */
71 INVALID, /* 1 01 11 */
72 { 4, ST }, /* 1 10 00: evstwhe[x] */
73 INVALID, /* 1 10 01 */
74 { 4, ST }, /* 1 10 10: evstwho[x] */
75 INVALID, /* 1 10 11 */
76 { 4, ST+E4 }, /* 1 11 00: evstwwe[x] */
77 INVALID, /* 1 11 01 */
78 { 4, ST+E4 }, /* 1 11 10: evstwwo[x] */
79 INVALID, /* 1 11 11 */
80 };
81
82 #define EVLDD 0x00
83 #define EVLDW 0x01
84 #define EVLDH 0x02
85 #define EVLHHESPLAT 0x04
86 #define EVLHHOUSPLAT 0x06
87 #define EVLHHOSSPLAT 0x07
88 #define EVLWHE 0x08
89 #define EVLWHOU 0x0A
90 #define EVLWHOS 0x0B
91 #define EVLWWSPLAT 0x0C
92 #define EVLWHSPLAT 0x0E
93 #define EVSTDD 0x10
94 #define EVSTDW 0x11
95 #define EVSTDH 0x12
96 #define EVSTWHE 0x18
97 #define EVSTWHO 0x1A
98 #define EVSTWWE 0x1C
99 #define EVSTWWO 0x1E
100
101 /*
102 * Emulate SPE loads and stores.
103 * Only Book-E has these instructions, and it does true little-endian,
104 * so we don't need the address swizzling.
105 */
106 static int emulate_spe(struct pt_regs *regs, unsigned int reg,
107 unsigned int instr)
108 {
109 int ret;
110 union {
111 u64 ll;
112 u32 w[2];
113 u16 h[4];
114 u8 v[8];
115 } data, temp;
116 unsigned char __user *p, *addr;
117 unsigned long *evr = ¤t->thread.evr[reg];
118 unsigned int nb, flags;
119
120 instr = (instr >> 1) & 0x1f;
121
122 /* DAR has the operand effective address */
123 addr = (unsigned char __user *)regs->dar;
124
125 nb = spe_aligninfo[instr].len;
126 flags = spe_aligninfo[instr].flags;
127
128 /* Verify the address of the operand */
129 if (unlikely(user_mode(regs) &&
130 !access_ok(addr, nb)))
131 return -EFAULT;
132
133 /* userland only */
134 if (unlikely(!user_mode(regs)))
135 return 0;
136
137 flush_spe_to_thread(current);
138
139 /* If we are loading, get the data from user space, else
140 * get it from register values
141 */
142 if (flags & ST) {
143 data.ll = 0;
144 switch (instr) {
145 case EVSTDD:
146 case EVSTDW:
147 case EVSTDH:
148 data.w[0] = *evr;
149 data.w[1] = regs->gpr[reg];
150 break;
151 case EVSTWHE:
152 data.h[2] = *evr >> 16;
153 data.h[3] = regs->gpr[reg] >> 16;
154 break;
155 case EVSTWHO:
156 data.h[2] = *evr & 0xffff;
157 data.h[3] = regs->gpr[reg] & 0xffff;
158 break;
159 case EVSTWWE:
160 data.w[1] = *evr;
161 break;
162 case EVSTWWO:
163 data.w[1] = regs->gpr[reg];
164 break;
165 default:
166 return -EINVAL;
167 }
168 } else {
169 temp.ll = data.ll = 0;
170 ret = 0;
171 p = addr;
172
173 switch (nb) {
174 case 8:
175 ret |= __get_user_inatomic(temp.v[0], p++);
176 ret |= __get_user_inatomic(temp.v[1], p++);
177 ret |= __get_user_inatomic(temp.v[2], p++);
178 ret |= __get_user_inatomic(temp.v[3], p++);
179 /* fall through */
180 case 4:
181 ret |= __get_user_inatomic(temp.v[4], p++);
182 ret |= __get_user_inatomic(temp.v[5], p++);
183 /* fall through */
184 case 2:
185 ret |= __get_user_inatomic(temp.v[6], p++);
186 ret |= __get_user_inatomic(temp.v[7], p++);
187 if (unlikely(ret))
188 return -EFAULT;
189 }
190
191 switch (instr) {
192 case EVLDD:
193 case EVLDW:
194 case EVLDH:
195 data.ll = temp.ll;
196 break;
197 case EVLHHESPLAT:
198 data.h[0] = temp.h[3];
199 data.h[2] = temp.h[3];
200 break;
201 case EVLHHOUSPLAT:
202 case EVLHHOSSPLAT:
203 data.h[1] = temp.h[3];
204 data.h[3] = temp.h[3];
205 break;
206 case EVLWHE:
207 data.h[0] = temp.h[2];
208 data.h[2] = temp.h[3];
209 break;
210 case EVLWHOU:
211 case EVLWHOS:
212 data.h[1] = temp.h[2];
213 data.h[3] = temp.h[3];
214 break;
215 case EVLWWSPLAT:
216 data.w[0] = temp.w[1];
217 data.w[1] = temp.w[1];
218 break;
219 case EVLWHSPLAT:
220 data.h[0] = temp.h[2];
221 data.h[1] = temp.h[2];
222 data.h[2] = temp.h[3];
223 data.h[3] = temp.h[3];
224 break;
225 default:
226 return -EINVAL;
227 }
228 }
229
230 if (flags & SW) {
231 switch (flags & 0xf0) {
232 case E8:
233 data.ll = swab64(data.ll);
234 break;
235 case E4:
236 data.w[0] = swab32(data.w[0]);
237 data.w[1] = swab32(data.w[1]);
238 break;
239 /* Its half word endian */
240 default:
241 data.h[0] = swab16(data.h[0]);
242 data.h[1] = swab16(data.h[1]);
243 data.h[2] = swab16(data.h[2]);
244 data.h[3] = swab16(data.h[3]);
245 break;
246 }
247 }
248
249 if (flags & SE) {
250 data.w[0] = (s16)data.h[1];
251 data.w[1] = (s16)data.h[3];
252 }
253
254 /* Store result to memory or update registers */
255 if (flags & ST) {
256 ret = 0;
257 p = addr;
258 switch (nb) {
259 case 8:
260 ret |= __put_user_inatomic(data.v[0], p++);
261 ret |= __put_user_inatomic(data.v[1], p++);
262 ret |= __put_user_inatomic(data.v[2], p++);
263 ret |= __put_user_inatomic(data.v[3], p++);
264 /* fall through */
265 case 4:
266 ret |= __put_user_inatomic(data.v[4], p++);
267 ret |= __put_user_inatomic(data.v[5], p++);
268 /* fall through */
269 case 2:
270 ret |= __put_user_inatomic(data.v[6], p++);
271 ret |= __put_user_inatomic(data.v[7], p++);
272 }
273 if (unlikely(ret))
274 return -EFAULT;
275 } else {
276 *evr = data.w[0];
277 regs->gpr[reg] = data.w[1];
278 }
279
280 return 1;
281 }
282 #endif /* CONFIG_SPE */
283
284 /*
285 * Called on alignment exception. Attempts to fixup
286 *
287 * Return 1 on success
288 * Return 0 if unable to handle the interrupt
289 * Return -EFAULT if data address is bad
290 * Other negative return values indicate that the instruction can't
291 * be emulated, and the process should be given a SIGBUS.
292 */
293
294 int fix_alignment(struct pt_regs *regs)
295 {
296 unsigned int instr;
297 struct instruction_op op;
298 int r, type;
299
300 /*
301 * We require a complete register set, if not, then our assembly
302 * is broken
303 */
304 CHECK_FULL_REGS(regs);
305
306 if (unlikely(__get_user(instr, (unsigned int __user *)regs->nip)))
307 return -EFAULT;
308 if ((regs->msr & MSR_LE) != (MSR_KERNEL & MSR_LE)) {
309 /* We don't handle PPC little-endian any more... */
310 if (cpu_has_feature(CPU_FTR_PPC_LE))
311 return -EIO;
312 instr = swab32(instr);
313 }
314
315 #ifdef CONFIG_SPE
316 if ((instr >> 26) == 0x4) {
317 int reg = (instr >> 21) & 0x1f;
318 PPC_WARN_ALIGNMENT(spe, regs);
319 return emulate_spe(regs, reg, instr);
320 }
321 #endif
322
323
324 /*
325 * ISA 3.0 (such as P9) copy, copy_first, paste and paste_last alignment
326 * check.
327 *
328 * Send a SIGBUS to the process that caused the fault.
329 *
330 * We do not emulate these because paste may contain additional metadata
331 * when pasting to a co-processor. Furthermore, paste_last is the
332 * synchronisation point for preceding copy/paste sequences.
333 */
334 if ((instr & 0xfc0006fe) == (PPC_INST_COPY & 0xfc0006fe))
335 return -EIO;
336
337 r = analyse_instr(&op, regs, instr);
338 if (r < 0)
339 return -EINVAL;
340
341 type = GETTYPE(op.type);
342 if (!OP_IS_LOAD_STORE(type)) {
343 if (op.type != CACHEOP + DCBZ)
344 return -EINVAL;
345 PPC_WARN_ALIGNMENT(dcbz, regs);
346 r = emulate_dcbz(op.ea, regs);
347 } else {
348 if (type == LARX || type == STCX)
349 return -EIO;
350 PPC_WARN_ALIGNMENT(unaligned, regs);
351 r = emulate_loadstore(regs, &op);
352 }
353
354 if (!r)
355 return 1;
356 return r;
357 }