Commit | Line | Data |
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1da177e4 | 1 | /* |
09abbcff | 2 | * Copyright (C) 2003, 2004, 2007 Maciej W. Rozycki |
1da177e4 LT |
3 | * |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation; either version | |
7 | * 2 of the License, or (at your option) any later version. | |
8 | */ | |
1da177e4 LT |
9 | #include <linux/init.h> |
10 | #include <linux/kernel.h> | |
11 | #include <linux/ptrace.h> | |
12 | #include <linux/stddef.h> | |
13 | ||
14 | #include <asm/bugs.h> | |
15 | #include <asm/compiler.h> | |
16 | #include <asm/cpu.h> | |
17 | #include <asm/fpu.h> | |
18 | #include <asm/mipsregs.h> | |
19 | #include <asm/system.h> | |
20 | ||
20d60d99 MR |
21 | static char bug64hit[] __initdata = |
22 | "reliable operation impossible!\n%s"; | |
23 | static char nowar[] __initdata = | |
24 | "Please report to <linux-mips@linux-mips.org>."; | |
25 | static char r4kwar[] __initdata = | |
26 | "Enable CPU_R4000_WORKAROUNDS to rectify."; | |
27 | static char daddiwar[] __initdata = | |
28 | "Enable CPU_DADDI_WORKAROUNDS to rectify."; | |
29 | ||
1da177e4 LT |
30 | static inline void align_mod(const int align, const int mod) |
31 | { | |
32 | asm volatile( | |
33 | ".set push\n\t" | |
34 | ".set noreorder\n\t" | |
35 | ".balign %0\n\t" | |
36 | ".rept %1\n\t" | |
37 | "nop\n\t" | |
38 | ".endr\n\t" | |
39 | ".set pop" | |
40 | : | |
ad1d77a3 | 41 | : GCC_IMM_ASM() (align), GCC_IMM_ASM() (mod)); |
1da177e4 LT |
42 | } |
43 | ||
44 | static inline void mult_sh_align_mod(long *v1, long *v2, long *w, | |
45 | const int align, const int mod) | |
46 | { | |
47 | unsigned long flags; | |
48 | int m1, m2; | |
49 | long p, s, lv1, lv2, lw; | |
50 | ||
51 | /* | |
52 | * We want the multiply and the shift to be isolated from the | |
53 | * rest of the code to disable gcc optimizations. Hence the | |
54 | * asm statements that execute nothing, but make gcc not know | |
55 | * what the values of m1, m2 and s are and what lv2 and p are | |
56 | * used for. | |
57 | */ | |
58 | ||
59 | local_irq_save(flags); | |
60 | /* | |
61 | * The following code leads to a wrong result of the first | |
62 | * dsll32 when executed on R4000 rev. 2.2 or 3.0 (PRId | |
63 | * 00000422 or 00000430, respectively). | |
64 | * | |
65 | * See "MIPS R4000PC/SC Errata, Processor Revision 2.2 and | |
66 | * 3.0" by MIPS Technologies, Inc., errata #16 and #28 for | |
67 | * details. I got no permission to duplicate them here, | |
68 | * sigh... --macro | |
69 | */ | |
70 | asm volatile( | |
71 | "" | |
72 | : "=r" (m1), "=r" (m2), "=r" (s) | |
73 | : "0" (5), "1" (8), "2" (5)); | |
74 | align_mod(align, mod); | |
75 | /* | |
76 | * The trailing nop is needed to fullfill the two-instruction | |
77 | * requirement between reading hi/lo and staring a mult/div. | |
78 | * Leaving it out may cause gas insert a nop itself breaking | |
79 | * the desired alignment of the next chunk. | |
80 | */ | |
81 | asm volatile( | |
82 | ".set push\n\t" | |
83 | ".set noat\n\t" | |
84 | ".set noreorder\n\t" | |
85 | ".set nomacro\n\t" | |
86 | "mult %2, %3\n\t" | |
87 | "dsll32 %0, %4, %5\n\t" | |
88 | "mflo $0\n\t" | |
89 | "dsll32 %1, %4, %5\n\t" | |
90 | "nop\n\t" | |
91 | ".set pop" | |
92 | : "=&r" (lv1), "=r" (lw) | |
93 | : "r" (m1), "r" (m2), "r" (s), "I" (0) | |
94 | : "hi", "lo", GCC_REG_ACCUM); | |
95 | /* We have to use single integers for m1 and m2 and a double | |
96 | * one for p to be sure the mulsidi3 gcc's RTL multiplication | |
97 | * instruction has the workaround applied. Older versions of | |
98 | * gcc have correct umulsi3 and mulsi3, but other | |
99 | * multiplication variants lack the workaround. | |
100 | */ | |
101 | asm volatile( | |
102 | "" | |
103 | : "=r" (m1), "=r" (m2), "=r" (s) | |
104 | : "0" (m1), "1" (m2), "2" (s)); | |
105 | align_mod(align, mod); | |
106 | p = m1 * m2; | |
107 | lv2 = s << 32; | |
108 | asm volatile( | |
109 | "" | |
110 | : "=r" (lv2) | |
111 | : "0" (lv2), "r" (p)); | |
112 | local_irq_restore(flags); | |
113 | ||
114 | *v1 = lv1; | |
115 | *v2 = lv2; | |
116 | *w = lw; | |
117 | } | |
118 | ||
119 | static inline void check_mult_sh(void) | |
120 | { | |
121 | long v1[8], v2[8], w[8]; | |
122 | int bug, fix, i; | |
123 | ||
124 | printk("Checking for the multiply/shift bug... "); | |
125 | ||
126 | /* | |
127 | * Testing discovered false negatives for certain code offsets | |
128 | * into cache lines. Hence we test all possible offsets for | |
129 | * the worst assumption of an R4000 I-cache line width of 32 | |
130 | * bytes. | |
131 | * | |
132 | * We can't use a loop as alignment directives need to be | |
133 | * immediates. | |
134 | */ | |
135 | mult_sh_align_mod(&v1[0], &v2[0], &w[0], 32, 0); | |
136 | mult_sh_align_mod(&v1[1], &v2[1], &w[1], 32, 1); | |
137 | mult_sh_align_mod(&v1[2], &v2[2], &w[2], 32, 2); | |
138 | mult_sh_align_mod(&v1[3], &v2[3], &w[3], 32, 3); | |
139 | mult_sh_align_mod(&v1[4], &v2[4], &w[4], 32, 4); | |
140 | mult_sh_align_mod(&v1[5], &v2[5], &w[5], 32, 5); | |
141 | mult_sh_align_mod(&v1[6], &v2[6], &w[6], 32, 6); | |
142 | mult_sh_align_mod(&v1[7], &v2[7], &w[7], 32, 7); | |
143 | ||
144 | bug = 0; | |
145 | for (i = 0; i < 8; i++) | |
146 | if (v1[i] != w[i]) | |
147 | bug = 1; | |
42a3b4f2 | 148 | |
1da177e4 LT |
149 | if (bug == 0) { |
150 | printk("no.\n"); | |
151 | return; | |
152 | } | |
153 | ||
154 | printk("yes, workaround... "); | |
155 | ||
156 | fix = 1; | |
157 | for (i = 0; i < 8; i++) | |
158 | if (v2[i] != w[i]) | |
159 | fix = 0; | |
42a3b4f2 | 160 | |
1da177e4 LT |
161 | if (fix == 1) { |
162 | printk("yes.\n"); | |
163 | return; | |
164 | } | |
165 | ||
166 | printk("no.\n"); | |
20d60d99 | 167 | panic(bug64hit, !R4000_WAR ? r4kwar : nowar); |
1da177e4 LT |
168 | } |
169 | ||
234fcd14 | 170 | static volatile int daddi_ov __cpuinitdata = 0; |
1da177e4 LT |
171 | |
172 | asmlinkage void __init do_daddi_ov(struct pt_regs *regs) | |
173 | { | |
174 | daddi_ov = 1; | |
175 | regs->cp0_epc += 4; | |
176 | } | |
177 | ||
178 | static inline void check_daddi(void) | |
179 | { | |
180 | extern asmlinkage void handle_daddi_ov(void); | |
181 | unsigned long flags; | |
182 | void *handler; | |
183 | long v, tmp; | |
184 | ||
185 | printk("Checking for the daddi bug... "); | |
186 | ||
187 | local_irq_save(flags); | |
188 | handler = set_except_vector(12, handle_daddi_ov); | |
189 | /* | |
190 | * The following code fails to trigger an overflow exception | |
191 | * when executed on R4000 rev. 2.2 or 3.0 (PRId 00000422 or | |
192 | * 00000430, respectively). | |
193 | * | |
194 | * See "MIPS R4000PC/SC Errata, Processor Revision 2.2 and | |
195 | * 3.0" by MIPS Technologies, Inc., erratum #23 for details. | |
196 | * I got no permission to duplicate it here, sigh... --macro | |
197 | */ | |
198 | asm volatile( | |
199 | ".set push\n\t" | |
200 | ".set noat\n\t" | |
201 | ".set noreorder\n\t" | |
202 | ".set nomacro\n\t" | |
203 | "addiu %1, $0, %2\n\t" | |
204 | "dsrl %1, %1, 1\n\t" | |
205 | #ifdef HAVE_AS_SET_DADDI | |
206 | ".set daddi\n\t" | |
207 | #endif | |
208 | "daddi %0, %1, %3\n\t" | |
209 | ".set pop" | |
210 | : "=r" (v), "=&r" (tmp) | |
460c0422 | 211 | : "I" (0xffffffffffffdb9aUL), "I" (0x1234)); |
1da177e4 LT |
212 | set_except_vector(12, handler); |
213 | local_irq_restore(flags); | |
214 | ||
215 | if (daddi_ov) { | |
216 | printk("no.\n"); | |
217 | return; | |
218 | } | |
219 | ||
220 | printk("yes, workaround... "); | |
221 | ||
222 | local_irq_save(flags); | |
223 | handler = set_except_vector(12, handle_daddi_ov); | |
224 | asm volatile( | |
225 | "addiu %1, $0, %2\n\t" | |
226 | "dsrl %1, %1, 1\n\t" | |
227 | "daddi %0, %1, %3" | |
228 | : "=r" (v), "=&r" (tmp) | |
460c0422 | 229 | : "I" (0xffffffffffffdb9aUL), "I" (0x1234)); |
1da177e4 LT |
230 | set_except_vector(12, handler); |
231 | local_irq_restore(flags); | |
232 | ||
233 | if (daddi_ov) { | |
234 | printk("yes.\n"); | |
235 | return; | |
236 | } | |
237 | ||
238 | printk("no.\n"); | |
20d60d99 | 239 | panic(bug64hit, !DADDI_WAR ? daddiwar : nowar); |
1da177e4 LT |
240 | } |
241 | ||
234fcd14 | 242 | int daddiu_bug __cpuinitdata = -1; |
20d60d99 | 243 | |
1da177e4 LT |
244 | static inline void check_daddiu(void) |
245 | { | |
246 | long v, w, tmp; | |
247 | ||
248 | printk("Checking for the daddiu bug... "); | |
249 | ||
250 | /* | |
251 | * The following code leads to a wrong result of daddiu when | |
252 | * executed on R4400 rev. 1.0 (PRId 00000440). | |
253 | * | |
254 | * See "MIPS R4400PC/SC Errata, Processor Revision 1.0" by | |
255 | * MIPS Technologies, Inc., erratum #7 for details. | |
256 | * | |
257 | * According to "MIPS R4000PC/SC Errata, Processor Revision | |
258 | * 2.2 and 3.0" by MIPS Technologies, Inc., erratum #41 this | |
259 | * problem affects R4000 rev. 2.2 and 3.0 (PRId 00000422 and | |
260 | * 00000430, respectively), too. Testing failed to trigger it | |
261 | * so far. | |
262 | * | |
263 | * I got no permission to duplicate the errata here, sigh... | |
264 | * --macro | |
265 | */ | |
266 | asm volatile( | |
267 | ".set push\n\t" | |
268 | ".set noat\n\t" | |
269 | ".set noreorder\n\t" | |
270 | ".set nomacro\n\t" | |
271 | "addiu %2, $0, %3\n\t" | |
272 | "dsrl %2, %2, 1\n\t" | |
273 | #ifdef HAVE_AS_SET_DADDI | |
274 | ".set daddi\n\t" | |
275 | #endif | |
276 | "daddiu %0, %2, %4\n\t" | |
277 | "addiu %1, $0, %4\n\t" | |
278 | "daddu %1, %2\n\t" | |
279 | ".set pop" | |
280 | : "=&r" (v), "=&r" (w), "=&r" (tmp) | |
460c0422 | 281 | : "I" (0xffffffffffffdb9aUL), "I" (0x1234)); |
1da177e4 | 282 | |
20d60d99 MR |
283 | daddiu_bug = v != w; |
284 | ||
285 | if (!daddiu_bug) { | |
1da177e4 LT |
286 | printk("no.\n"); |
287 | return; | |
288 | } | |
289 | ||
290 | printk("yes, workaround... "); | |
291 | ||
292 | asm volatile( | |
293 | "addiu %2, $0, %3\n\t" | |
294 | "dsrl %2, %2, 1\n\t" | |
295 | "daddiu %0, %2, %4\n\t" | |
296 | "addiu %1, $0, %4\n\t" | |
297 | "daddu %1, %2" | |
298 | : "=&r" (v), "=&r" (w), "=&r" (tmp) | |
460c0422 | 299 | : "I" (0xffffffffffffdb9aUL), "I" (0x1234)); |
1da177e4 LT |
300 | |
301 | if (v == w) { | |
302 | printk("yes.\n"); | |
303 | return; | |
304 | } | |
305 | ||
306 | printk("no.\n"); | |
20d60d99 | 307 | panic(bug64hit, !DADDI_WAR ? daddiwar : nowar); |
1da177e4 LT |
308 | } |
309 | ||
20d60d99 | 310 | void __init check_bugs64_early(void) |
1da177e4 LT |
311 | { |
312 | check_mult_sh(); | |
1da177e4 LT |
313 | check_daddiu(); |
314 | } | |
20d60d99 MR |
315 | |
316 | void __init check_bugs64(void) | |
317 | { | |
318 | check_daddi(); | |
319 | } |