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2e651ea1 VG |
1 | /* |
2 | * Copyright (C) 2011-2012 Synopsys (www.synopsys.com) | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | * vineetg : May 2011 | |
9 | * -Adapted (from .26 to .35) | |
10 | * -original contribution by Tim.yao@amlogic.com | |
11 | * | |
12 | */ | |
13 | ||
14 | #include <linux/types.h> | |
15 | #include <linux/ptrace.h> | |
16 | #include <linux/uaccess.h> | |
17 | #include <asm/disasm.h> | |
18 | ||
19 | #define __get8_unaligned_check(val, addr, err) \ | |
20 | __asm__( \ | |
21 | "1: ldb.ab %1, [%2, 1]\n" \ | |
22 | "2:\n" \ | |
23 | " .section .fixup,\"ax\"\n" \ | |
24 | " .align 4\n" \ | |
25 | "3: mov %0, 1\n" \ | |
26 | " b 2b\n" \ | |
27 | " .previous\n" \ | |
28 | " .section __ex_table,\"a\"\n" \ | |
29 | " .align 4\n" \ | |
30 | " .long 1b, 3b\n" \ | |
31 | " .previous\n" \ | |
32 | : "=r" (err), "=&r" (val), "=r" (addr) \ | |
33 | : "0" (err), "2" (addr)) | |
34 | ||
35 | #define get16_unaligned_check(val, addr) \ | |
36 | do { \ | |
37 | unsigned int err = 0, v, a = addr; \ | |
38 | __get8_unaligned_check(v, a, err); \ | |
39 | val = v ; \ | |
40 | __get8_unaligned_check(v, a, err); \ | |
41 | val |= v << 8; \ | |
42 | if (err) \ | |
43 | goto fault; \ | |
44 | } while (0) | |
45 | ||
46 | #define get32_unaligned_check(val, addr) \ | |
47 | do { \ | |
48 | unsigned int err = 0, v, a = addr; \ | |
49 | __get8_unaligned_check(v, a, err); \ | |
50 | val = v << 0; \ | |
51 | __get8_unaligned_check(v, a, err); \ | |
52 | val |= v << 8; \ | |
53 | __get8_unaligned_check(v, a, err); \ | |
54 | val |= v << 16; \ | |
55 | __get8_unaligned_check(v, a, err); \ | |
56 | val |= v << 24; \ | |
57 | if (err) \ | |
58 | goto fault; \ | |
59 | } while (0) | |
60 | ||
61 | #define put16_unaligned_check(val, addr) \ | |
62 | do { \ | |
63 | unsigned int err = 0, v = val, a = addr;\ | |
64 | \ | |
65 | __asm__( \ | |
66 | "1: stb.ab %1, [%2, 1]\n" \ | |
67 | " lsr %1, %1, 8\n" \ | |
68 | "2: stb %1, [%2]\n" \ | |
69 | "3:\n" \ | |
70 | " .section .fixup,\"ax\"\n" \ | |
71 | " .align 4\n" \ | |
72 | "4: mov %0, 1\n" \ | |
73 | " b 3b\n" \ | |
74 | " .previous\n" \ | |
75 | " .section __ex_table,\"a\"\n" \ | |
76 | " .align 4\n" \ | |
77 | " .long 1b, 4b\n" \ | |
78 | " .long 2b, 4b\n" \ | |
79 | " .previous\n" \ | |
80 | : "=r" (err), "=&r" (v), "=&r" (a) \ | |
81 | : "0" (err), "1" (v), "2" (a)); \ | |
82 | \ | |
83 | if (err) \ | |
84 | goto fault; \ | |
85 | } while (0) | |
86 | ||
87 | #define put32_unaligned_check(val, addr) \ | |
88 | do { \ | |
89 | unsigned int err = 0, v = val, a = addr;\ | |
90 | __asm__( \ | |
91 | \ | |
92 | "1: stb.ab %1, [%2, 1]\n" \ | |
93 | " lsr %1, %1, 8\n" \ | |
94 | "2: stb.ab %1, [%2, 1]\n" \ | |
95 | " lsr %1, %1, 8\n" \ | |
96 | "3: stb.ab %1, [%2, 1]\n" \ | |
97 | " lsr %1, %1, 8\n" \ | |
98 | "4: stb %1, [%2]\n" \ | |
99 | "5:\n" \ | |
100 | " .section .fixup,\"ax\"\n" \ | |
101 | " .align 4\n" \ | |
102 | "6: mov %0, 1\n" \ | |
103 | " b 5b\n" \ | |
104 | " .previous\n" \ | |
105 | " .section __ex_table,\"a\"\n" \ | |
106 | " .align 4\n" \ | |
107 | " .long 1b, 6b\n" \ | |
108 | " .long 2b, 6b\n" \ | |
109 | " .long 3b, 6b\n" \ | |
110 | " .long 4b, 6b\n" \ | |
111 | " .previous\n" \ | |
112 | : "=r" (err), "=&r" (v), "=&r" (a) \ | |
113 | : "0" (err), "1" (v), "2" (a)); \ | |
114 | \ | |
115 | if (err) \ | |
116 | goto fault; \ | |
117 | } while (0) | |
118 | ||
119 | /* sysctl hooks */ | |
120 | int unaligned_enabled __read_mostly = 1; /* Enabled by default */ | |
121 | int no_unaligned_warning __read_mostly = 1; /* Only 1 warning by default */ | |
122 | ||
123 | static void fixup_load(struct disasm_state *state, struct pt_regs *regs, | |
124 | struct callee_regs *cregs) | |
125 | { | |
126 | int val; | |
127 | ||
128 | /* register write back */ | |
129 | if ((state->aa == 1) || (state->aa == 2)) { | |
130 | set_reg(state->wb_reg, state->src1 + state->src2, regs, cregs); | |
131 | ||
132 | if (state->aa == 2) | |
133 | state->src2 = 0; | |
134 | } | |
135 | ||
136 | if (state->zz == 0) { | |
137 | get32_unaligned_check(val, state->src1 + state->src2); | |
138 | } else { | |
139 | get16_unaligned_check(val, state->src1 + state->src2); | |
140 | ||
141 | if (state->x) | |
142 | val = (val << 16) >> 16; | |
143 | } | |
144 | ||
145 | if (state->pref == 0) | |
146 | set_reg(state->dest, val, regs, cregs); | |
147 | ||
148 | return; | |
149 | ||
150 | fault: state->fault = 1; | |
151 | } | |
152 | ||
153 | static void fixup_store(struct disasm_state *state, struct pt_regs *regs, | |
154 | struct callee_regs *cregs) | |
155 | { | |
156 | /* register write back */ | |
157 | if ((state->aa == 1) || (state->aa == 2)) { | |
158 | set_reg(state->wb_reg, state->src2 + state->src3, regs, cregs); | |
159 | ||
160 | if (state->aa == 3) | |
161 | state->src3 = 0; | |
162 | } else if (state->aa == 3) { | |
163 | if (state->zz == 2) { | |
164 | set_reg(state->wb_reg, state->src2 + (state->src3 << 1), | |
165 | regs, cregs); | |
166 | } else if (!state->zz) { | |
167 | set_reg(state->wb_reg, state->src2 + (state->src3 << 2), | |
168 | regs, cregs); | |
169 | } else { | |
170 | goto fault; | |
171 | } | |
172 | } | |
173 | ||
174 | /* write fix-up */ | |
175 | if (!state->zz) | |
176 | put32_unaligned_check(state->src1, state->src2 + state->src3); | |
177 | else | |
178 | put16_unaligned_check(state->src1, state->src2 + state->src3); | |
179 | ||
180 | return; | |
181 | ||
182 | fault: state->fault = 1; | |
183 | } | |
184 | ||
185 | /* | |
186 | * Handle an unaligned access | |
187 | * Returns 0 if successfully handled, 1 if some error happened | |
188 | */ | |
189 | int misaligned_fixup(unsigned long address, struct pt_regs *regs, | |
38a9ff6d | 190 | struct callee_regs *cregs) |
2e651ea1 VG |
191 | { |
192 | struct disasm_state state; | |
193 | char buf[TASK_COMM_LEN]; | |
194 | ||
195 | /* handle user mode only and only if enabled by sysadmin */ | |
196 | if (!user_mode(regs) || !unaligned_enabled) | |
197 | return 1; | |
198 | ||
199 | if (no_unaligned_warning) { | |
200 | pr_warn_once("%s(%d) made unaligned access which was emulated" | |
201 | " by kernel assist\n. This can degrade application" | |
202 | " performance significantly\n. To enable further" | |
203 | " logging of such instances, please \n" | |
204 | " echo 0 > /proc/sys/kernel/ignore-unaligned-usertrap\n", | |
205 | get_task_comm(buf, current), task_pid_nr(current)); | |
206 | } else { | |
207 | /* Add rate limiting if it gets down to it */ | |
208 | pr_warn("%s(%d): unaligned access to/from 0x%lx by PC: 0x%lx\n", | |
209 | get_task_comm(buf, current), task_pid_nr(current), | |
210 | address, regs->ret); | |
211 | ||
212 | } | |
213 | ||
214 | disasm_instr(regs->ret, &state, 1, regs, cregs); | |
215 | ||
216 | if (state.fault) | |
217 | goto fault; | |
218 | ||
219 | /* ldb/stb should not have unaligned exception */ | |
220 | if ((state.zz == 1) || (state.di)) | |
221 | goto fault; | |
222 | ||
223 | if (!state.write) | |
224 | fixup_load(&state, regs, cregs); | |
225 | else | |
226 | fixup_store(&state, regs, cregs); | |
227 | ||
228 | if (state.fault) | |
229 | goto fault; | |
230 | ||
231 | if (delay_mode(regs)) { | |
232 | regs->ret = regs->bta; | |
233 | regs->status32 &= ~STATUS_DE_MASK; | |
234 | } else { | |
235 | regs->ret += state.instr_len; | |
236 | } | |
237 | ||
238 | return 0; | |
239 | ||
240 | fault: | |
241 | pr_err("Alignment trap: fault in fix-up %08lx at [<%08lx>]\n", | |
242 | state.words[0], address); | |
243 | ||
244 | return 1; | |
245 | } |