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867e359b CM |
1 | /* |
2 | * Copyright 2010 Tilera Corporation. All Rights Reserved. | |
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, version 2. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, but | |
9 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or | |
11 | * NON INFRINGEMENT. See the GNU General Public License for | |
12 | * more details. | |
13 | */ | |
14 | ||
15 | #include <linux/sched.h> | |
b17b0153 | 16 | #include <linux/sched/debug.h> |
867e359b CM |
17 | #include <linux/kernel.h> |
18 | #include <linux/kprobes.h> | |
3fa17c39 | 19 | #include <linux/kdebug.h> |
867e359b CM |
20 | #include <linux/module.h> |
21 | #include <linux/reboot.h> | |
22 | #include <linux/uaccess.h> | |
23 | #include <linux/ptrace.h> | |
511f8389 CM |
24 | #include <linux/hardirq.h> |
25 | #include <linux/nmi.h> | |
0707ad30 CM |
26 | #include <asm/stack.h> |
27 | #include <asm/traps.h> | |
bd119c69 | 28 | #include <asm/setup.h> |
867e359b CM |
29 | |
30 | #include <arch/interrupts.h> | |
31 | #include <arch/spr_def.h> | |
eb7c792d | 32 | #include <arch/opcode.h> |
867e359b CM |
33 | |
34 | void __init trap_init(void) | |
35 | { | |
acbde1db | 36 | /* Nothing needed here since we link code at .intrpt */ |
867e359b CM |
37 | } |
38 | ||
39 | int unaligned_fixup = 1; | |
40 | ||
41 | static int __init setup_unaligned_fixup(char *str) | |
42 | { | |
43 | /* | |
44 | * Say "=-1" to completely disable it. If you just do "=0", we | |
45 | * will still parse the instruction, then fire a SIGBUS with | |
46 | * the correct address from inside the single_step code. | |
47 | */ | |
b2dfa048 | 48 | if (kstrtoint(str, 0, &unaligned_fixup) != 0) |
867e359b | 49 | return 0; |
b2dfa048 | 50 | |
0707ad30 | 51 | pr_info("Fixups for unaligned data accesses are %s\n", |
f4743673 JP |
52 | unaligned_fixup >= 0 ? |
53 | (unaligned_fixup ? "enabled" : "disabled") : | |
54 | "completely disabled"); | |
867e359b CM |
55 | return 1; |
56 | } | |
57 | __setup("unaligned_fixup=", setup_unaligned_fixup); | |
58 | ||
59 | #if CHIP_HAS_TILE_DMA() | |
60 | ||
61 | static int dma_disabled; | |
62 | ||
63 | static int __init nodma(char *str) | |
64 | { | |
0707ad30 | 65 | pr_info("User-space DMA is disabled\n"); |
867e359b CM |
66 | dma_disabled = 1; |
67 | return 1; | |
68 | } | |
69 | __setup("nodma", nodma); | |
70 | ||
71 | /* How to decode SPR_GPV_REASON */ | |
72 | #define IRET_ERROR (1U << 31) | |
73 | #define MT_ERROR (1U << 30) | |
74 | #define MF_ERROR (1U << 29) | |
75 | #define SPR_INDEX ((1U << 15) - 1) | |
76 | #define SPR_MPL_SHIFT 9 /* starting bit position for MPL encoded in SPR */ | |
77 | ||
78 | /* | |
79 | * See if this GPV is just to notify the kernel of SPR use and we can | |
80 | * retry the user instruction after adjusting some MPLs suitably. | |
81 | */ | |
82 | static int retry_gpv(unsigned int gpv_reason) | |
83 | { | |
84 | int mpl; | |
85 | ||
86 | if (gpv_reason & IRET_ERROR) | |
87 | return 0; | |
88 | ||
89 | BUG_ON((gpv_reason & (MT_ERROR|MF_ERROR)) == 0); | |
90 | mpl = (gpv_reason & SPR_INDEX) >> SPR_MPL_SHIFT; | |
91 | if (mpl == INT_DMA_NOTIFY && !dma_disabled) { | |
92 | /* User is turning on DMA. Allow it and retry. */ | |
93 | printk(KERN_DEBUG "Process %d/%s is now enabled for DMA\n", | |
94 | current->pid, current->comm); | |
95 | BUG_ON(current->thread.tile_dma_state.enabled); | |
96 | current->thread.tile_dma_state.enabled = 1; | |
97 | grant_dma_mpls(); | |
98 | return 1; | |
99 | } | |
100 | ||
101 | return 0; | |
102 | } | |
103 | ||
104 | #endif /* CHIP_HAS_TILE_DMA() */ | |
105 | ||
a0099303 | 106 | extern tile_bundle_bits bpt_code; |
0707ad30 CM |
107 | |
108 | asm(".pushsection .rodata.bpt_code,\"a\";" | |
109 | ".align 8;" | |
110 | "bpt_code: bpt;" | |
111 | ".size bpt_code,.-bpt_code;" | |
112 | ".popsection"); | |
113 | ||
a0099303 | 114 | static int special_ill(tile_bundle_bits bundle, int *sigp, int *codep) |
0707ad30 CM |
115 | { |
116 | int sig, code, maxcode; | |
117 | ||
118 | if (bundle == bpt_code) { | |
119 | *sigp = SIGTRAP; | |
120 | *codep = TRAP_BRKPT; | |
121 | return 1; | |
122 | } | |
123 | ||
124 | /* If it's a "raise" bundle, then "ill" must be in pipe X1. */ | |
125 | #ifdef __tilegx__ | |
126 | if ((bundle & TILEGX_BUNDLE_MODE_MASK) != 0) | |
127 | return 0; | |
1fcbe027 CM |
128 | if (get_Opcode_X1(bundle) != RRR_0_OPCODE_X1) |
129 | return 0; | |
130 | if (get_RRROpcodeExtension_X1(bundle) != UNARY_RRR_0_OPCODE_X1) | |
0707ad30 CM |
131 | return 0; |
132 | if (get_UnaryOpcodeExtension_X1(bundle) != ILL_UNARY_OPCODE_X1) | |
133 | return 0; | |
134 | #else | |
eb7c792d | 135 | if (bundle & TILEPRO_BUNDLE_Y_ENCODING_MASK) |
0707ad30 CM |
136 | return 0; |
137 | if (get_Opcode_X1(bundle) != SHUN_0_OPCODE_X1) | |
138 | return 0; | |
139 | if (get_UnShOpcodeExtension_X1(bundle) != UN_0_SHUN_0_OPCODE_X1) | |
140 | return 0; | |
141 | if (get_UnOpcodeExtension_X1(bundle) != ILL_UN_0_SHUN_0_OPCODE_X1) | |
142 | return 0; | |
143 | #endif | |
144 | ||
145 | /* Check that the magic distinguishers are set to mean "raise". */ | |
146 | if (get_Dest_X1(bundle) != 29 || get_SrcA_X1(bundle) != 37) | |
147 | return 0; | |
148 | ||
149 | /* There must be an "addli zero, zero, VAL" in X0. */ | |
150 | if (get_Opcode_X0(bundle) != ADDLI_OPCODE_X0) | |
151 | return 0; | |
152 | if (get_Dest_X0(bundle) != TREG_ZERO) | |
153 | return 0; | |
154 | if (get_SrcA_X0(bundle) != TREG_ZERO) | |
155 | return 0; | |
156 | ||
157 | /* | |
158 | * Validate the proposed signal number and si_code value. | |
159 | * Note that we embed these in the static instruction itself | |
160 | * so that we perturb the register state as little as possible | |
161 | * at the time of the actual fault; it's unlikely you'd ever | |
162 | * need to dynamically choose which kind of fault to raise | |
163 | * from user space. | |
164 | */ | |
165 | sig = get_Imm16_X0(bundle) & 0x3f; | |
166 | switch (sig) { | |
167 | case SIGILL: | |
168 | maxcode = NSIGILL; | |
169 | break; | |
170 | case SIGFPE: | |
171 | maxcode = NSIGFPE; | |
172 | break; | |
173 | case SIGSEGV: | |
174 | maxcode = NSIGSEGV; | |
175 | break; | |
176 | case SIGBUS: | |
177 | maxcode = NSIGBUS; | |
178 | break; | |
179 | case SIGTRAP: | |
180 | maxcode = NSIGTRAP; | |
181 | break; | |
182 | default: | |
183 | return 0; | |
184 | } | |
185 | code = (get_Imm16_X0(bundle) >> 6) & 0xf; | |
186 | if (code <= 0 || code > maxcode) | |
187 | return 0; | |
188 | ||
189 | /* Make it the requested signal. */ | |
190 | *sigp = sig; | |
cc731525 | 191 | *codep = code; |
0707ad30 CM |
192 | return 1; |
193 | } | |
194 | ||
c6f696f6 CM |
195 | static const char *const int_name[] = { |
196 | [INT_MEM_ERROR] = "Memory error", | |
197 | [INT_ILL] = "Illegal instruction", | |
198 | [INT_GPV] = "General protection violation", | |
199 | [INT_UDN_ACCESS] = "UDN access", | |
200 | [INT_IDN_ACCESS] = "IDN access", | |
201 | #if CHIP_HAS_SN() | |
202 | [INT_SN_ACCESS] = "SN access", | |
203 | #endif | |
204 | [INT_SWINT_3] = "Software interrupt 3", | |
205 | [INT_SWINT_2] = "Software interrupt 2", | |
206 | [INT_SWINT_0] = "Software interrupt 0", | |
207 | [INT_UNALIGN_DATA] = "Unaligned data", | |
208 | [INT_DOUBLE_FAULT] = "Double fault", | |
209 | #ifdef __tilegx__ | |
210 | [INT_ILL_TRANS] = "Illegal virtual address", | |
211 | #endif | |
212 | }; | |
213 | ||
3fa17c39 TL |
214 | static int do_bpt(struct pt_regs *regs) |
215 | { | |
216 | unsigned long bundle, bcode, bpt; | |
217 | ||
218 | bundle = *(unsigned long *)instruction_pointer(regs); | |
219 | ||
220 | /* | |
221 | * bpt shoule be { bpt; nop }, which is 0x286a44ae51485000ULL. | |
222 | * we encode the unused least significant bits for other purpose. | |
223 | */ | |
224 | bpt = bundle & ~((1ULL << 12) - 1); | |
225 | if (bpt != TILE_BPT_BUNDLE) | |
226 | return 0; | |
227 | ||
228 | bcode = bundle & ((1ULL << 12) - 1); | |
229 | /* | |
230 | * notify the kprobe handlers, if instruction is likely to | |
231 | * pertain to them. | |
232 | */ | |
233 | switch (bcode) { | |
234 | /* breakpoint_insn */ | |
235 | case 0: | |
236 | notify_die(DIE_BREAK, "debug", regs, bundle, | |
237 | INT_ILL, SIGTRAP); | |
238 | break; | |
8157107b CM |
239 | /* compiled_bpt */ |
240 | case DIE_COMPILED_BPT: | |
241 | notify_die(DIE_COMPILED_BPT, "debug", regs, bundle, | |
242 | INT_ILL, SIGTRAP); | |
243 | break; | |
3fa17c39 TL |
244 | /* breakpoint2_insn */ |
245 | case DIE_SSTEPBP: | |
246 | notify_die(DIE_SSTEPBP, "single_step", regs, bundle, | |
247 | INT_ILL, SIGTRAP); | |
248 | break; | |
249 | default: | |
250 | return 0; | |
251 | } | |
252 | ||
253 | return 1; | |
254 | } | |
255 | ||
867e359b CM |
256 | void __kprobes do_trap(struct pt_regs *regs, int fault_num, |
257 | unsigned long reason) | |
258 | { | |
259 | siginfo_t info = { 0 }; | |
260 | int signo, code; | |
a714ffff | 261 | unsigned long address = 0; |
a0099303 | 262 | tile_bundle_bits instr; |
3fa17c39 TL |
263 | int is_kernel = !user_mode(regs); |
264 | ||
265 | /* Handle breakpoints, etc. */ | |
266 | if (is_kernel && fault_num == INT_ILL && do_bpt(regs)) | |
1bb50cad | 267 | return; |
867e359b | 268 | |
70d2b595 CM |
269 | /* Re-enable interrupts, if they were previously enabled. */ |
270 | if (!(regs->flags & PT_FLAGS_DISABLE_IRQ)) | |
271 | local_irq_enable(); | |
867e359b CM |
272 | |
273 | /* | |
274 | * If it hits in kernel mode and we can't fix it up, just exit the | |
275 | * current process and hope for the best. | |
276 | */ | |
3fa17c39 | 277 | if (is_kernel) { |
c6f696f6 | 278 | const char *name; |
70d2b595 CM |
279 | char buf[100]; |
280 | if (fixup_exception(regs)) /* ILL_TRANS or UNALIGN_DATA */ | |
1bb50cad | 281 | return; |
c6f696f6 | 282 | if (fault_num >= 0 && |
367b9380 | 283 | fault_num < ARRAY_SIZE(int_name) && |
c6f696f6 CM |
284 | int_name[fault_num] != NULL) |
285 | name = int_name[fault_num]; | |
286 | else | |
287 | name = "Unknown interrupt"; | |
867e359b | 288 | if (fault_num == INT_GPV) |
70d2b595 CM |
289 | snprintf(buf, sizeof(buf), "; GPV_REASON %#lx", reason); |
290 | #ifdef __tilegx__ | |
291 | else if (fault_num == INT_ILL_TRANS) | |
292 | snprintf(buf, sizeof(buf), "; address %#lx", reason); | |
293 | #endif | |
294 | else | |
295 | buf[0] = '\0'; | |
296 | pr_alert("Kernel took bad trap %d (%s) at PC %#lx%s\n", | |
297 | fault_num, name, regs->pc, buf); | |
867e359b CM |
298 | show_regs(regs); |
299 | do_exit(SIGKILL); /* FIXME: implement i386 die() */ | |
867e359b CM |
300 | } |
301 | ||
302 | switch (fault_num) { | |
a714ffff CM |
303 | case INT_MEM_ERROR: |
304 | signo = SIGBUS; | |
305 | code = BUS_OBJERR; | |
306 | break; | |
867e359b | 307 | case INT_ILL: |
0707ad30 CM |
308 | if (copy_from_user(&instr, (void __user *)regs->pc, |
309 | sizeof(instr))) { | |
f4743673 JP |
310 | pr_err("Unreadable instruction for INT_ILL: %#lx\n", |
311 | regs->pc); | |
867e359b | 312 | do_exit(SIGKILL); |
867e359b | 313 | } |
0707ad30 | 314 | if (!special_ill(instr, &signo, &code)) { |
867e359b CM |
315 | signo = SIGILL; |
316 | code = ILL_ILLOPC; | |
317 | } | |
318 | address = regs->pc; | |
319 | break; | |
320 | case INT_GPV: | |
321 | #if CHIP_HAS_TILE_DMA() | |
322 | if (retry_gpv(reason)) | |
1bb50cad | 323 | return; |
867e359b CM |
324 | #endif |
325 | /*FALLTHROUGH*/ | |
326 | case INT_UDN_ACCESS: | |
327 | case INT_IDN_ACCESS: | |
328 | #if CHIP_HAS_SN() | |
329 | case INT_SN_ACCESS: | |
330 | #endif | |
331 | signo = SIGILL; | |
332 | code = ILL_PRVREG; | |
333 | address = regs->pc; | |
334 | break; | |
335 | case INT_SWINT_3: | |
336 | case INT_SWINT_2: | |
337 | case INT_SWINT_0: | |
338 | signo = SIGILL; | |
339 | code = ILL_ILLTRP; | |
340 | address = regs->pc; | |
341 | break; | |
342 | case INT_UNALIGN_DATA: | |
233325b9 | 343 | #ifndef __tilegx__ /* Emulated support for single step debugging */ |
867e359b CM |
344 | if (unaligned_fixup >= 0) { |
345 | struct single_step_state *state = | |
346 | current_thread_info()->step_state; | |
0707ad30 CM |
347 | if (!state || |
348 | (void __user *)(regs->pc) != state->buffer) { | |
867e359b | 349 | single_step_once(regs); |
1bb50cad | 350 | return; |
867e359b CM |
351 | } |
352 | } | |
353 | #endif | |
354 | signo = SIGBUS; | |
355 | code = BUS_ADRALN; | |
356 | address = 0; | |
357 | break; | |
358 | case INT_DOUBLE_FAULT: | |
359 | /* | |
360 | * For double fault, "reason" is actually passed as | |
a78c942d | 361 | * SYSTEM_SAVE_K_2, the hypervisor's double-fault info, so |
867e359b CM |
362 | * we can provide the original fault number rather than |
363 | * the uninteresting "INT_DOUBLE_FAULT" so the user can | |
364 | * learn what actually struck while PL0 ICS was set. | |
365 | */ | |
366 | fault_num = reason; | |
367 | signo = SIGILL; | |
368 | code = ILL_DBLFLT; | |
369 | address = regs->pc; | |
370 | break; | |
371 | #ifdef __tilegx__ | |
e1723538 CM |
372 | case INT_ILL_TRANS: { |
373 | /* Avoid a hardware erratum with the return address stack. */ | |
374 | fill_ra_stack(); | |
375 | ||
867e359b | 376 | signo = SIGSEGV; |
70d2b595 | 377 | address = reason; |
867e359b | 378 | code = SEGV_MAPERR; |
867e359b | 379 | break; |
e1723538 | 380 | } |
867e359b CM |
381 | #endif |
382 | default: | |
383 | panic("Unexpected do_trap interrupt number %d", fault_num); | |
867e359b CM |
384 | } |
385 | ||
386 | info.si_signo = signo; | |
387 | info.si_code = code; | |
0707ad30 | 388 | info.si_addr = (void __user *)address; |
867e359b CM |
389 | if (signo == SIGILL) |
390 | info.si_trapno = fault_num; | |
a714ffff CM |
391 | if (signo != SIGTRAP) |
392 | trace_unhandled_signal("trap", regs, address, signo); | |
867e359b CM |
393 | force_sig_info(signo, &info, current); |
394 | } | |
395 | ||
e5701b74 CM |
396 | void do_nmi(struct pt_regs *regs, int fault_num, unsigned long reason) |
397 | { | |
511f8389 | 398 | nmi_enter(); |
e5701b74 | 399 | switch (reason) { |
511f8389 | 400 | #ifdef arch_trigger_cpumask_backtrace |
e5701b74 | 401 | case TILE_NMI_DUMP_STACK: |
511f8389 | 402 | nmi_cpu_backtrace(regs); |
e5701b74 | 403 | break; |
511f8389 | 404 | #endif |
e5701b74 CM |
405 | default: |
406 | panic("Unexpected do_nmi type %ld", reason); | |
e5701b74 | 407 | } |
511f8389 | 408 | nmi_exit(); |
e5701b74 CM |
409 | } |
410 | ||
47ad7b9b CM |
411 | /* Deprecated function currently only used here. */ |
412 | extern void _dump_stack(int dummy, ulong pc, ulong lr, ulong sp, ulong r52); | |
413 | ||
867e359b CM |
414 | void kernel_double_fault(int dummy, ulong pc, ulong lr, ulong sp, ulong r52) |
415 | { | |
416 | _dump_stack(dummy, pc, lr, sp, r52); | |
0707ad30 | 417 | pr_emerg("Double fault: exiting\n"); |
867e359b CM |
418 | machine_halt(); |
419 | } |