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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 | ||
7d669a19 NC |
19 | #ifdef CONFIG_CPU_BIG_ENDIAN |
20 | #define BE 1 | |
21 | #define FIRST_BYTE_16 "swap %1, %1\n swape %1, %1\n" | |
22 | #define FIRST_BYTE_32 "swape %1, %1\n" | |
23 | #else | |
24 | #define BE 0 | |
25 | #define FIRST_BYTE_16 | |
26 | #define FIRST_BYTE_32 | |
27 | #endif | |
28 | ||
2e651ea1 VG |
29 | #define __get8_unaligned_check(val, addr, err) \ |
30 | __asm__( \ | |
31 | "1: ldb.ab %1, [%2, 1]\n" \ | |
32 | "2:\n" \ | |
33 | " .section .fixup,\"ax\"\n" \ | |
34 | " .align 4\n" \ | |
35 | "3: mov %0, 1\n" \ | |
36 | " b 2b\n" \ | |
37 | " .previous\n" \ | |
38 | " .section __ex_table,\"a\"\n" \ | |
39 | " .align 4\n" \ | |
40 | " .long 1b, 3b\n" \ | |
41 | " .previous\n" \ | |
42 | : "=r" (err), "=&r" (val), "=r" (addr) \ | |
43 | : "0" (err), "2" (addr)) | |
44 | ||
45 | #define get16_unaligned_check(val, addr) \ | |
46 | do { \ | |
47 | unsigned int err = 0, v, a = addr; \ | |
48 | __get8_unaligned_check(v, a, err); \ | |
7d669a19 | 49 | val = v << ((BE) ? 8 : 0); \ |
2e651ea1 | 50 | __get8_unaligned_check(v, a, err); \ |
7d669a19 | 51 | val |= v << ((BE) ? 0 : 8); \ |
2e651ea1 VG |
52 | if (err) \ |
53 | goto fault; \ | |
54 | } while (0) | |
55 | ||
56 | #define get32_unaligned_check(val, addr) \ | |
57 | do { \ | |
58 | unsigned int err = 0, v, a = addr; \ | |
59 | __get8_unaligned_check(v, a, err); \ | |
7d669a19 | 60 | val = v << ((BE) ? 24 : 0); \ |
2e651ea1 | 61 | __get8_unaligned_check(v, a, err); \ |
7d669a19 | 62 | val |= v << ((BE) ? 16 : 8); \ |
2e651ea1 | 63 | __get8_unaligned_check(v, a, err); \ |
7d669a19 | 64 | val |= v << ((BE) ? 8 : 16); \ |
2e651ea1 | 65 | __get8_unaligned_check(v, a, err); \ |
7d669a19 | 66 | val |= v << ((BE) ? 0 : 24); \ |
2e651ea1 VG |
67 | if (err) \ |
68 | goto fault; \ | |
69 | } while (0) | |
70 | ||
71 | #define put16_unaligned_check(val, addr) \ | |
72 | do { \ | |
73 | unsigned int err = 0, v = val, a = addr;\ | |
74 | \ | |
75 | __asm__( \ | |
7d669a19 | 76 | FIRST_BYTE_16 \ |
2e651ea1 VG |
77 | "1: stb.ab %1, [%2, 1]\n" \ |
78 | " lsr %1, %1, 8\n" \ | |
79 | "2: stb %1, [%2]\n" \ | |
80 | "3:\n" \ | |
81 | " .section .fixup,\"ax\"\n" \ | |
82 | " .align 4\n" \ | |
83 | "4: mov %0, 1\n" \ | |
84 | " b 3b\n" \ | |
85 | " .previous\n" \ | |
86 | " .section __ex_table,\"a\"\n" \ | |
87 | " .align 4\n" \ | |
88 | " .long 1b, 4b\n" \ | |
89 | " .long 2b, 4b\n" \ | |
90 | " .previous\n" \ | |
91 | : "=r" (err), "=&r" (v), "=&r" (a) \ | |
92 | : "0" (err), "1" (v), "2" (a)); \ | |
93 | \ | |
94 | if (err) \ | |
95 | goto fault; \ | |
96 | } while (0) | |
97 | ||
98 | #define put32_unaligned_check(val, addr) \ | |
99 | do { \ | |
100 | unsigned int err = 0, v = val, a = addr;\ | |
2e651ea1 | 101 | \ |
7d669a19 NC |
102 | __asm__( \ |
103 | FIRST_BYTE_32 \ | |
2e651ea1 VG |
104 | "1: stb.ab %1, [%2, 1]\n" \ |
105 | " lsr %1, %1, 8\n" \ | |
106 | "2: stb.ab %1, [%2, 1]\n" \ | |
107 | " lsr %1, %1, 8\n" \ | |
108 | "3: stb.ab %1, [%2, 1]\n" \ | |
109 | " lsr %1, %1, 8\n" \ | |
110 | "4: stb %1, [%2]\n" \ | |
111 | "5:\n" \ | |
112 | " .section .fixup,\"ax\"\n" \ | |
113 | " .align 4\n" \ | |
114 | "6: mov %0, 1\n" \ | |
115 | " b 5b\n" \ | |
116 | " .previous\n" \ | |
117 | " .section __ex_table,\"a\"\n" \ | |
118 | " .align 4\n" \ | |
119 | " .long 1b, 6b\n" \ | |
120 | " .long 2b, 6b\n" \ | |
121 | " .long 3b, 6b\n" \ | |
122 | " .long 4b, 6b\n" \ | |
123 | " .previous\n" \ | |
124 | : "=r" (err), "=&r" (v), "=&r" (a) \ | |
125 | : "0" (err), "1" (v), "2" (a)); \ | |
126 | \ | |
127 | if (err) \ | |
128 | goto fault; \ | |
129 | } while (0) | |
130 | ||
131 | /* sysctl hooks */ | |
132 | int unaligned_enabled __read_mostly = 1; /* Enabled by default */ | |
133 | int no_unaligned_warning __read_mostly = 1; /* Only 1 warning by default */ | |
134 | ||
135 | static void fixup_load(struct disasm_state *state, struct pt_regs *regs, | |
136 | struct callee_regs *cregs) | |
137 | { | |
138 | int val; | |
139 | ||
140 | /* register write back */ | |
141 | if ((state->aa == 1) || (state->aa == 2)) { | |
142 | set_reg(state->wb_reg, state->src1 + state->src2, regs, cregs); | |
143 | ||
144 | if (state->aa == 2) | |
145 | state->src2 = 0; | |
146 | } | |
147 | ||
148 | if (state->zz == 0) { | |
149 | get32_unaligned_check(val, state->src1 + state->src2); | |
150 | } else { | |
151 | get16_unaligned_check(val, state->src1 + state->src2); | |
152 | ||
153 | if (state->x) | |
154 | val = (val << 16) >> 16; | |
155 | } | |
156 | ||
157 | if (state->pref == 0) | |
158 | set_reg(state->dest, val, regs, cregs); | |
159 | ||
160 | return; | |
161 | ||
162 | fault: state->fault = 1; | |
163 | } | |
164 | ||
165 | static void fixup_store(struct disasm_state *state, struct pt_regs *regs, | |
166 | struct callee_regs *cregs) | |
167 | { | |
168 | /* register write back */ | |
169 | if ((state->aa == 1) || (state->aa == 2)) { | |
170 | set_reg(state->wb_reg, state->src2 + state->src3, regs, cregs); | |
171 | ||
172 | if (state->aa == 3) | |
173 | state->src3 = 0; | |
174 | } else if (state->aa == 3) { | |
175 | if (state->zz == 2) { | |
176 | set_reg(state->wb_reg, state->src2 + (state->src3 << 1), | |
177 | regs, cregs); | |
178 | } else if (!state->zz) { | |
179 | set_reg(state->wb_reg, state->src2 + (state->src3 << 2), | |
180 | regs, cregs); | |
181 | } else { | |
182 | goto fault; | |
183 | } | |
184 | } | |
185 | ||
186 | /* write fix-up */ | |
187 | if (!state->zz) | |
188 | put32_unaligned_check(state->src1, state->src2 + state->src3); | |
189 | else | |
190 | put16_unaligned_check(state->src1, state->src2 + state->src3); | |
191 | ||
192 | return; | |
193 | ||
194 | fault: state->fault = 1; | |
195 | } | |
196 | ||
197 | /* | |
198 | * Handle an unaligned access | |
199 | * Returns 0 if successfully handled, 1 if some error happened | |
200 | */ | |
201 | int misaligned_fixup(unsigned long address, struct pt_regs *regs, | |
38a9ff6d | 202 | struct callee_regs *cregs) |
2e651ea1 VG |
203 | { |
204 | struct disasm_state state; | |
205 | char buf[TASK_COMM_LEN]; | |
206 | ||
207 | /* handle user mode only and only if enabled by sysadmin */ | |
208 | if (!user_mode(regs) || !unaligned_enabled) | |
209 | return 1; | |
210 | ||
211 | if (no_unaligned_warning) { | |
212 | pr_warn_once("%s(%d) made unaligned access which was emulated" | |
213 | " by kernel assist\n. This can degrade application" | |
214 | " performance significantly\n. To enable further" | |
215 | " logging of such instances, please \n" | |
216 | " echo 0 > /proc/sys/kernel/ignore-unaligned-usertrap\n", | |
217 | get_task_comm(buf, current), task_pid_nr(current)); | |
218 | } else { | |
219 | /* Add rate limiting if it gets down to it */ | |
220 | pr_warn("%s(%d): unaligned access to/from 0x%lx by PC: 0x%lx\n", | |
221 | get_task_comm(buf, current), task_pid_nr(current), | |
222 | address, regs->ret); | |
223 | ||
224 | } | |
225 | ||
226 | disasm_instr(regs->ret, &state, 1, regs, cregs); | |
227 | ||
228 | if (state.fault) | |
229 | goto fault; | |
230 | ||
231 | /* ldb/stb should not have unaligned exception */ | |
232 | if ((state.zz == 1) || (state.di)) | |
233 | goto fault; | |
234 | ||
235 | if (!state.write) | |
236 | fixup_load(&state, regs, cregs); | |
237 | else | |
238 | fixup_store(&state, regs, cregs); | |
239 | ||
240 | if (state.fault) | |
241 | goto fault; | |
242 | ||
243 | if (delay_mode(regs)) { | |
244 | regs->ret = regs->bta; | |
245 | regs->status32 &= ~STATUS_DE_MASK; | |
246 | } else { | |
247 | regs->ret += state.instr_len; | |
248 | } | |
249 | ||
250 | return 0; | |
251 | ||
252 | fault: | |
253 | pr_err("Alignment trap: fault in fix-up %08lx at [<%08lx>]\n", | |
254 | state.words[0], address); | |
255 | ||
256 | return 1; | |
257 | } |