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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> | |
23 | ||
24 | #include <arch/interrupts.h> | |
25 | #include <arch/spr_def.h> | |
26 | ||
27 | void __init trap_init(void) | |
28 | { | |
29 | /* Nothing needed here since we link code at .intrpt1 */ | |
30 | } | |
31 | ||
32 | int unaligned_fixup = 1; | |
33 | ||
34 | static int __init setup_unaligned_fixup(char *str) | |
35 | { | |
36 | /* | |
37 | * Say "=-1" to completely disable it. If you just do "=0", we | |
38 | * will still parse the instruction, then fire a SIGBUS with | |
39 | * the correct address from inside the single_step code. | |
40 | */ | |
41 | long val; | |
42 | if (strict_strtol(str, 0, &val) != 0) | |
43 | return 0; | |
44 | unaligned_fixup = val; | |
45 | printk("Fixups for unaligned data accesses are %s\n", | |
46 | unaligned_fixup >= 0 ? | |
47 | (unaligned_fixup ? "enabled" : "disabled") : | |
48 | "completely disabled"); | |
49 | return 1; | |
50 | } | |
51 | __setup("unaligned_fixup=", setup_unaligned_fixup); | |
52 | ||
53 | #if CHIP_HAS_TILE_DMA() | |
54 | ||
55 | static int dma_disabled; | |
56 | ||
57 | static int __init nodma(char *str) | |
58 | { | |
59 | printk("User-space DMA is disabled\n"); | |
60 | dma_disabled = 1; | |
61 | return 1; | |
62 | } | |
63 | __setup("nodma", nodma); | |
64 | ||
65 | /* How to decode SPR_GPV_REASON */ | |
66 | #define IRET_ERROR (1U << 31) | |
67 | #define MT_ERROR (1U << 30) | |
68 | #define MF_ERROR (1U << 29) | |
69 | #define SPR_INDEX ((1U << 15) - 1) | |
70 | #define SPR_MPL_SHIFT 9 /* starting bit position for MPL encoded in SPR */ | |
71 | ||
72 | /* | |
73 | * See if this GPV is just to notify the kernel of SPR use and we can | |
74 | * retry the user instruction after adjusting some MPLs suitably. | |
75 | */ | |
76 | static int retry_gpv(unsigned int gpv_reason) | |
77 | { | |
78 | int mpl; | |
79 | ||
80 | if (gpv_reason & IRET_ERROR) | |
81 | return 0; | |
82 | ||
83 | BUG_ON((gpv_reason & (MT_ERROR|MF_ERROR)) == 0); | |
84 | mpl = (gpv_reason & SPR_INDEX) >> SPR_MPL_SHIFT; | |
85 | if (mpl == INT_DMA_NOTIFY && !dma_disabled) { | |
86 | /* User is turning on DMA. Allow it and retry. */ | |
87 | printk(KERN_DEBUG "Process %d/%s is now enabled for DMA\n", | |
88 | current->pid, current->comm); | |
89 | BUG_ON(current->thread.tile_dma_state.enabled); | |
90 | current->thread.tile_dma_state.enabled = 1; | |
91 | grant_dma_mpls(); | |
92 | return 1; | |
93 | } | |
94 | ||
95 | return 0; | |
96 | } | |
97 | ||
98 | #endif /* CHIP_HAS_TILE_DMA() */ | |
99 | ||
100 | /* Defined inside do_trap(), below. */ | |
101 | #ifdef __tilegx__ | |
102 | extern tilegx_bundle_bits bpt_code; | |
103 | #else | |
104 | extern tile_bundle_bits bpt_code; | |
105 | #endif | |
106 | ||
107 | void __kprobes do_trap(struct pt_regs *regs, int fault_num, | |
108 | unsigned long reason) | |
109 | { | |
110 | siginfo_t info = { 0 }; | |
111 | int signo, code; | |
112 | unsigned long address; | |
113 | __typeof__(bpt_code) instr; | |
114 | ||
115 | /* Re-enable interrupts. */ | |
116 | local_irq_enable(); | |
117 | ||
118 | /* | |
119 | * If it hits in kernel mode and we can't fix it up, just exit the | |
120 | * current process and hope for the best. | |
121 | */ | |
122 | if (!user_mode(regs)) { | |
123 | if (fixup_exception(regs)) /* only UNALIGN_DATA in practice */ | |
124 | return; | |
125 | printk(KERN_ALERT "Kernel took bad trap %d at PC %#lx\n", | |
126 | fault_num, regs->pc); | |
127 | if (fault_num == INT_GPV) | |
128 | printk(KERN_ALERT "GPV_REASON is %#lx\n", reason); | |
129 | show_regs(regs); | |
130 | do_exit(SIGKILL); /* FIXME: implement i386 die() */ | |
131 | return; | |
132 | } | |
133 | ||
134 | switch (fault_num) { | |
135 | case INT_ILL: | |
136 | asm(".pushsection .rodata.bpt_code,\"a\";" | |
137 | ".align 8;" | |
138 | "bpt_code: bpt;" | |
139 | ".size bpt_code,.-bpt_code;" | |
140 | ".popsection"); | |
141 | ||
142 | if (copy_from_user(&instr, (void *)regs->pc, sizeof(instr))) { | |
143 | printk(KERN_ERR "Unreadable instruction for INT_ILL:" | |
144 | " %#lx\n", regs->pc); | |
145 | do_exit(SIGKILL); | |
146 | return; | |
147 | } | |
148 | if (instr == bpt_code) { | |
149 | signo = SIGTRAP; | |
150 | code = TRAP_BRKPT; | |
151 | } else { | |
152 | signo = SIGILL; | |
153 | code = ILL_ILLOPC; | |
154 | } | |
155 | address = regs->pc; | |
156 | break; | |
157 | case INT_GPV: | |
158 | #if CHIP_HAS_TILE_DMA() | |
159 | if (retry_gpv(reason)) | |
160 | return; | |
161 | #endif | |
162 | /*FALLTHROUGH*/ | |
163 | case INT_UDN_ACCESS: | |
164 | case INT_IDN_ACCESS: | |
165 | #if CHIP_HAS_SN() | |
166 | case INT_SN_ACCESS: | |
167 | #endif | |
168 | signo = SIGILL; | |
169 | code = ILL_PRVREG; | |
170 | address = regs->pc; | |
171 | break; | |
172 | case INT_SWINT_3: | |
173 | case INT_SWINT_2: | |
174 | case INT_SWINT_0: | |
175 | signo = SIGILL; | |
176 | code = ILL_ILLTRP; | |
177 | address = regs->pc; | |
178 | break; | |
179 | case INT_UNALIGN_DATA: | |
180 | #ifndef __tilegx__ /* FIXME: GX: no single-step yet */ | |
181 | if (unaligned_fixup >= 0) { | |
182 | struct single_step_state *state = | |
183 | current_thread_info()->step_state; | |
184 | if (!state || (void *)(regs->pc) != state->buffer) { | |
185 | single_step_once(regs); | |
186 | return; | |
187 | } | |
188 | } | |
189 | #endif | |
190 | signo = SIGBUS; | |
191 | code = BUS_ADRALN; | |
192 | address = 0; | |
193 | break; | |
194 | case INT_DOUBLE_FAULT: | |
195 | /* | |
196 | * For double fault, "reason" is actually passed as | |
197 | * SYSTEM_SAVE_1_2, the hypervisor's double-fault info, so | |
198 | * we can provide the original fault number rather than | |
199 | * the uninteresting "INT_DOUBLE_FAULT" so the user can | |
200 | * learn what actually struck while PL0 ICS was set. | |
201 | */ | |
202 | fault_num = reason; | |
203 | signo = SIGILL; | |
204 | code = ILL_DBLFLT; | |
205 | address = regs->pc; | |
206 | break; | |
207 | #ifdef __tilegx__ | |
208 | case INT_ILL_TRANS: | |
209 | signo = SIGSEGV; | |
210 | code = SEGV_MAPERR; | |
211 | if (reason & SPR_ILL_TRANS_REASON__I_STREAM_VA_RMASK) | |
212 | address = regs->pc; | |
213 | else | |
214 | address = 0; /* FIXME: GX: single-step for address */ | |
215 | break; | |
216 | #endif | |
217 | default: | |
218 | panic("Unexpected do_trap interrupt number %d", fault_num); | |
219 | return; | |
220 | } | |
221 | ||
222 | info.si_signo = signo; | |
223 | info.si_code = code; | |
224 | info.si_addr = (void *)address; | |
225 | if (signo == SIGILL) | |
226 | info.si_trapno = fault_num; | |
227 | force_sig_info(signo, &info, current); | |
228 | } | |
229 | ||
230 | extern void _dump_stack(int dummy, ulong pc, ulong lr, ulong sp, ulong r52); | |
231 | ||
232 | void kernel_double_fault(int dummy, ulong pc, ulong lr, ulong sp, ulong r52) | |
233 | { | |
234 | _dump_stack(dummy, pc, lr, sp, r52); | |
235 | printk("Double fault: exiting\n"); | |
236 | machine_halt(); | |
237 | } |