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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> | |
16 | #include <linux/kernel.h> | |
17 | #include <linux/kprobes.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/reboot.h> | |
20 | #include <linux/uaccess.h> | |
21 | #include <linux/ptrace.h> | |
22 | #include <asm/opcode-tile.h> | |
0707ad30 CM |
23 | #include <asm/opcode_constants.h> |
24 | #include <asm/stack.h> | |
25 | #include <asm/traps.h> | |
867e359b CM |
26 | |
27 | #include <arch/interrupts.h> | |
28 | #include <arch/spr_def.h> | |
29 | ||
30 | void __init trap_init(void) | |
31 | { | |
32 | /* Nothing needed here since we link code at .intrpt1 */ | |
33 | } | |
34 | ||
35 | int unaligned_fixup = 1; | |
36 | ||
37 | static int __init setup_unaligned_fixup(char *str) | |
38 | { | |
39 | /* | |
40 | * Say "=-1" to completely disable it. If you just do "=0", we | |
41 | * will still parse the instruction, then fire a SIGBUS with | |
42 | * the correct address from inside the single_step code. | |
43 | */ | |
44 | long val; | |
45 | if (strict_strtol(str, 0, &val) != 0) | |
46 | return 0; | |
47 | unaligned_fixup = val; | |
0707ad30 | 48 | pr_info("Fixups for unaligned data accesses are %s\n", |
867e359b CM |
49 | unaligned_fixup >= 0 ? |
50 | (unaligned_fixup ? "enabled" : "disabled") : | |
51 | "completely disabled"); | |
52 | return 1; | |
53 | } | |
54 | __setup("unaligned_fixup=", setup_unaligned_fixup); | |
55 | ||
56 | #if CHIP_HAS_TILE_DMA() | |
57 | ||
58 | static int dma_disabled; | |
59 | ||
60 | static int __init nodma(char *str) | |
61 | { | |
0707ad30 | 62 | pr_info("User-space DMA is disabled\n"); |
867e359b CM |
63 | dma_disabled = 1; |
64 | return 1; | |
65 | } | |
66 | __setup("nodma", nodma); | |
67 | ||
68 | /* How to decode SPR_GPV_REASON */ | |
69 | #define IRET_ERROR (1U << 31) | |
70 | #define MT_ERROR (1U << 30) | |
71 | #define MF_ERROR (1U << 29) | |
72 | #define SPR_INDEX ((1U << 15) - 1) | |
73 | #define SPR_MPL_SHIFT 9 /* starting bit position for MPL encoded in SPR */ | |
74 | ||
75 | /* | |
76 | * See if this GPV is just to notify the kernel of SPR use and we can | |
77 | * retry the user instruction after adjusting some MPLs suitably. | |
78 | */ | |
79 | static int retry_gpv(unsigned int gpv_reason) | |
80 | { | |
81 | int mpl; | |
82 | ||
83 | if (gpv_reason & IRET_ERROR) | |
84 | return 0; | |
85 | ||
86 | BUG_ON((gpv_reason & (MT_ERROR|MF_ERROR)) == 0); | |
87 | mpl = (gpv_reason & SPR_INDEX) >> SPR_MPL_SHIFT; | |
88 | if (mpl == INT_DMA_NOTIFY && !dma_disabled) { | |
89 | /* User is turning on DMA. Allow it and retry. */ | |
90 | printk(KERN_DEBUG "Process %d/%s is now enabled for DMA\n", | |
91 | current->pid, current->comm); | |
92 | BUG_ON(current->thread.tile_dma_state.enabled); | |
93 | current->thread.tile_dma_state.enabled = 1; | |
94 | grant_dma_mpls(); | |
95 | return 1; | |
96 | } | |
97 | ||
98 | return 0; | |
99 | } | |
100 | ||
101 | #endif /* CHIP_HAS_TILE_DMA() */ | |
102 | ||
867e359b | 103 | #ifdef __tilegx__ |
0707ad30 | 104 | #define bundle_bits tilegx_bundle_bits |
867e359b | 105 | #else |
0707ad30 | 106 | #define bundle_bits tile_bundle_bits |
867e359b CM |
107 | #endif |
108 | ||
0707ad30 CM |
109 | extern bundle_bits bpt_code; |
110 | ||
111 | asm(".pushsection .rodata.bpt_code,\"a\";" | |
112 | ".align 8;" | |
113 | "bpt_code: bpt;" | |
114 | ".size bpt_code,.-bpt_code;" | |
115 | ".popsection"); | |
116 | ||
117 | static int special_ill(bundle_bits bundle, int *sigp, int *codep) | |
118 | { | |
119 | int sig, code, maxcode; | |
120 | ||
121 | if (bundle == bpt_code) { | |
122 | *sigp = SIGTRAP; | |
123 | *codep = TRAP_BRKPT; | |
124 | return 1; | |
125 | } | |
126 | ||
127 | /* If it's a "raise" bundle, then "ill" must be in pipe X1. */ | |
128 | #ifdef __tilegx__ | |
129 | if ((bundle & TILEGX_BUNDLE_MODE_MASK) != 0) | |
130 | return 0; | |
1fcbe027 CM |
131 | if (get_Opcode_X1(bundle) != RRR_0_OPCODE_X1) |
132 | return 0; | |
133 | if (get_RRROpcodeExtension_X1(bundle) != UNARY_RRR_0_OPCODE_X1) | |
0707ad30 CM |
134 | return 0; |
135 | if (get_UnaryOpcodeExtension_X1(bundle) != ILL_UNARY_OPCODE_X1) | |
136 | return 0; | |
137 | #else | |
138 | if (bundle & TILE_BUNDLE_Y_ENCODING_MASK) | |
139 | return 0; | |
140 | if (get_Opcode_X1(bundle) != SHUN_0_OPCODE_X1) | |
141 | return 0; | |
142 | if (get_UnShOpcodeExtension_X1(bundle) != UN_0_SHUN_0_OPCODE_X1) | |
143 | return 0; | |
144 | if (get_UnOpcodeExtension_X1(bundle) != ILL_UN_0_SHUN_0_OPCODE_X1) | |
145 | return 0; | |
146 | #endif | |
147 | ||
148 | /* Check that the magic distinguishers are set to mean "raise". */ | |
149 | if (get_Dest_X1(bundle) != 29 || get_SrcA_X1(bundle) != 37) | |
150 | return 0; | |
151 | ||
152 | /* There must be an "addli zero, zero, VAL" in X0. */ | |
153 | if (get_Opcode_X0(bundle) != ADDLI_OPCODE_X0) | |
154 | return 0; | |
155 | if (get_Dest_X0(bundle) != TREG_ZERO) | |
156 | return 0; | |
157 | if (get_SrcA_X0(bundle) != TREG_ZERO) | |
158 | return 0; | |
159 | ||
160 | /* | |
161 | * Validate the proposed signal number and si_code value. | |
162 | * Note that we embed these in the static instruction itself | |
163 | * so that we perturb the register state as little as possible | |
164 | * at the time of the actual fault; it's unlikely you'd ever | |
165 | * need to dynamically choose which kind of fault to raise | |
166 | * from user space. | |
167 | */ | |
168 | sig = get_Imm16_X0(bundle) & 0x3f; | |
169 | switch (sig) { | |
170 | case SIGILL: | |
171 | maxcode = NSIGILL; | |
172 | break; | |
173 | case SIGFPE: | |
174 | maxcode = NSIGFPE; | |
175 | break; | |
176 | case SIGSEGV: | |
177 | maxcode = NSIGSEGV; | |
178 | break; | |
179 | case SIGBUS: | |
180 | maxcode = NSIGBUS; | |
181 | break; | |
182 | case SIGTRAP: | |
183 | maxcode = NSIGTRAP; | |
184 | break; | |
185 | default: | |
186 | return 0; | |
187 | } | |
188 | code = (get_Imm16_X0(bundle) >> 6) & 0xf; | |
189 | if (code <= 0 || code > maxcode) | |
190 | return 0; | |
191 | ||
192 | /* Make it the requested signal. */ | |
193 | *sigp = sig; | |
194 | *codep = code | __SI_FAULT; | |
195 | return 1; | |
196 | } | |
197 | ||
867e359b CM |
198 | void __kprobes do_trap(struct pt_regs *regs, int fault_num, |
199 | unsigned long reason) | |
200 | { | |
201 | siginfo_t info = { 0 }; | |
202 | int signo, code; | |
203 | unsigned long address; | |
0707ad30 | 204 | bundle_bits instr; |
867e359b CM |
205 | |
206 | /* Re-enable interrupts. */ | |
207 | local_irq_enable(); | |
208 | ||
209 | /* | |
210 | * If it hits in kernel mode and we can't fix it up, just exit the | |
211 | * current process and hope for the best. | |
212 | */ | |
213 | if (!user_mode(regs)) { | |
214 | if (fixup_exception(regs)) /* only UNALIGN_DATA in practice */ | |
215 | return; | |
0707ad30 | 216 | pr_alert("Kernel took bad trap %d at PC %#lx\n", |
867e359b CM |
217 | fault_num, regs->pc); |
218 | if (fault_num == INT_GPV) | |
0707ad30 | 219 | pr_alert("GPV_REASON is %#lx\n", reason); |
867e359b CM |
220 | show_regs(regs); |
221 | do_exit(SIGKILL); /* FIXME: implement i386 die() */ | |
222 | return; | |
223 | } | |
224 | ||
225 | switch (fault_num) { | |
226 | case INT_ILL: | |
0707ad30 CM |
227 | if (copy_from_user(&instr, (void __user *)regs->pc, |
228 | sizeof(instr))) { | |
229 | pr_err("Unreadable instruction for INT_ILL:" | |
867e359b CM |
230 | " %#lx\n", regs->pc); |
231 | do_exit(SIGKILL); | |
232 | return; | |
233 | } | |
0707ad30 | 234 | if (!special_ill(instr, &signo, &code)) { |
867e359b CM |
235 | signo = SIGILL; |
236 | code = ILL_ILLOPC; | |
237 | } | |
238 | address = regs->pc; | |
239 | break; | |
240 | case INT_GPV: | |
241 | #if CHIP_HAS_TILE_DMA() | |
242 | if (retry_gpv(reason)) | |
243 | return; | |
244 | #endif | |
245 | /*FALLTHROUGH*/ | |
246 | case INT_UDN_ACCESS: | |
247 | case INT_IDN_ACCESS: | |
248 | #if CHIP_HAS_SN() | |
249 | case INT_SN_ACCESS: | |
250 | #endif | |
251 | signo = SIGILL; | |
252 | code = ILL_PRVREG; | |
253 | address = regs->pc; | |
254 | break; | |
255 | case INT_SWINT_3: | |
256 | case INT_SWINT_2: | |
257 | case INT_SWINT_0: | |
258 | signo = SIGILL; | |
259 | code = ILL_ILLTRP; | |
260 | address = regs->pc; | |
261 | break; | |
262 | case INT_UNALIGN_DATA: | |
233325b9 | 263 | #ifndef __tilegx__ /* Emulated support for single step debugging */ |
867e359b CM |
264 | if (unaligned_fixup >= 0) { |
265 | struct single_step_state *state = | |
266 | current_thread_info()->step_state; | |
0707ad30 CM |
267 | if (!state || |
268 | (void __user *)(regs->pc) != state->buffer) { | |
867e359b CM |
269 | single_step_once(regs); |
270 | return; | |
271 | } | |
272 | } | |
273 | #endif | |
274 | signo = SIGBUS; | |
275 | code = BUS_ADRALN; | |
276 | address = 0; | |
277 | break; | |
278 | case INT_DOUBLE_FAULT: | |
279 | /* | |
280 | * For double fault, "reason" is actually passed as | |
a78c942d | 281 | * SYSTEM_SAVE_K_2, the hypervisor's double-fault info, so |
867e359b CM |
282 | * we can provide the original fault number rather than |
283 | * the uninteresting "INT_DOUBLE_FAULT" so the user can | |
284 | * learn what actually struck while PL0 ICS was set. | |
285 | */ | |
286 | fault_num = reason; | |
287 | signo = SIGILL; | |
288 | code = ILL_DBLFLT; | |
289 | address = regs->pc; | |
290 | break; | |
291 | #ifdef __tilegx__ | |
292 | case INT_ILL_TRANS: | |
293 | signo = SIGSEGV; | |
294 | code = SEGV_MAPERR; | |
295 | if (reason & SPR_ILL_TRANS_REASON__I_STREAM_VA_RMASK) | |
296 | address = regs->pc; | |
297 | else | |
298 | address = 0; /* FIXME: GX: single-step for address */ | |
299 | break; | |
300 | #endif | |
301 | default: | |
302 | panic("Unexpected do_trap interrupt number %d", fault_num); | |
303 | return; | |
304 | } | |
305 | ||
306 | info.si_signo = signo; | |
307 | info.si_code = code; | |
0707ad30 | 308 | info.si_addr = (void __user *)address; |
867e359b CM |
309 | if (signo == SIGILL) |
310 | info.si_trapno = fault_num; | |
571d76ac | 311 | trace_unhandled_signal("trap", regs, address, signo); |
867e359b CM |
312 | force_sig_info(signo, &info, current); |
313 | } | |
314 | ||
867e359b CM |
315 | void kernel_double_fault(int dummy, ulong pc, ulong lr, ulong sp, ulong r52) |
316 | { | |
317 | _dump_stack(dummy, pc, lr, sp, r52); | |
0707ad30 | 318 | pr_emerg("Double fault: exiting\n"); |
867e359b CM |
319 | machine_halt(); |
320 | } |