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14#include <linux/types.h>
15#include <linux/perf_event.h>
16#include <linux/ptrace.h>
17#include <linux/uaccess.h>
18#include <asm/disasm.h>
19
20#ifdef CONFIG_CPU_BIG_ENDIAN
21#define BE 1
22#define FIRST_BYTE_16 "swap %1, %1\n swape %1, %1\n"
23#define FIRST_BYTE_32 "swape %1, %1\n"
24#else
25#define BE 0
26#define FIRST_BYTE_16
27#define FIRST_BYTE_32
28#endif
29
30#define __get8_unaligned_check(val, addr, err) \
31 __asm__( \
32 "1: ldb.ab %1, [%2, 1]\n" \
33 "2:\n" \
34 " .section .fixup,\"ax\"\n" \
35 " .align 4\n" \
36 "3: mov %0, 1\n" \
37 " j 2b\n" \
38 " .previous\n" \
39 " .section __ex_table,\"a\"\n" \
40 " .align 4\n" \
41 " .long 1b, 3b\n" \
42 " .previous\n" \
43 : "=r" (err), "=&r" (val), "=r" (addr) \
44 : "0" (err), "2" (addr))
45
46#define get16_unaligned_check(val, addr) \
47 do { \
48 unsigned int err = 0, v, a = addr; \
49 __get8_unaligned_check(v, a, err); \
50 val = v << ((BE) ? 8 : 0); \
51 __get8_unaligned_check(v, a, err); \
52 val |= v << ((BE) ? 0 : 8); \
53 if (err) \
54 goto fault; \
55 } while (0)
56
57#define get32_unaligned_check(val, addr) \
58 do { \
59 unsigned int err = 0, v, a = addr; \
60 __get8_unaligned_check(v, a, err); \
61 val = v << ((BE) ? 24 : 0); \
62 __get8_unaligned_check(v, a, err); \
63 val |= v << ((BE) ? 16 : 8); \
64 __get8_unaligned_check(v, a, err); \
65 val |= v << ((BE) ? 8 : 16); \
66 __get8_unaligned_check(v, a, err); \
67 val |= v << ((BE) ? 0 : 24); \
68 if (err) \
69 goto fault; \
70 } while (0)
71
72#define put16_unaligned_check(val, addr) \
73 do { \
74 unsigned int err = 0, v = val, a = addr;\
75 \
76 __asm__( \
77 FIRST_BYTE_16 \
78 "1: stb.ab %1, [%2, 1]\n" \
79 " lsr %1, %1, 8\n" \
80 "2: stb %1, [%2]\n" \
81 "3:\n" \
82 " .section .fixup,\"ax\"\n" \
83 " .align 4\n" \
84 "4: mov %0, 1\n" \
85 " j 3b\n" \
86 " .previous\n" \
87 " .section __ex_table,\"a\"\n" \
88 " .align 4\n" \
89 " .long 1b, 4b\n" \
90 " .long 2b, 4b\n" \
91 " .previous\n" \
92 : "=r" (err), "=&r" (v), "=&r" (a) \
93 : "0" (err), "1" (v), "2" (a)); \
94 \
95 if (err) \
96 goto fault; \
97 } while (0)
98
99#define put32_unaligned_check(val, addr) \
100 do { \
101 unsigned int err = 0, v = val, a = addr;\
102 \
103 __asm__( \
104 FIRST_BYTE_32 \
105 "1: stb.ab %1, [%2, 1]\n" \
106 " lsr %1, %1, 8\n" \
107 "2: stb.ab %1, [%2, 1]\n" \
108 " lsr %1, %1, 8\n" \
109 "3: stb.ab %1, [%2, 1]\n" \
110 " lsr %1, %1, 8\n" \
111 "4: stb %1, [%2]\n" \
112 "5:\n" \
113 " .section .fixup,\"ax\"\n" \
114 " .align 4\n" \
115 "6: mov %0, 1\n" \
116 " j 5b\n" \
117 " .previous\n" \
118 " .section __ex_table,\"a\"\n" \
119 " .align 4\n" \
120 " .long 1b, 6b\n" \
121 " .long 2b, 6b\n" \
122 " .long 3b, 6b\n" \
123 " .long 4b, 6b\n" \
124 " .previous\n" \
125 : "=r" (err), "=&r" (v), "=&r" (a) \
126 : "0" (err), "1" (v), "2" (a)); \
127 \
128 if (err) \
129 goto fault; \
130 } while (0)
131
132
133int unaligned_enabled __read_mostly = 1;
134int no_unaligned_warning __read_mostly = 1;
135
136static void fixup_load(struct disasm_state *state, struct pt_regs *regs,
137 struct callee_regs *cregs)
138{
139 int val;
140
141
142 if ((state->aa == 1) || (state->aa == 2)) {
143 set_reg(state->wb_reg, state->src1 + state->src2, regs, cregs);
144
145 if (state->aa == 2)
146 state->src2 = 0;
147 }
148
149 if (state->zz == 0) {
150 get32_unaligned_check(val, state->src1 + state->src2);
151 } else {
152 get16_unaligned_check(val, state->src1 + state->src2);
153
154 if (state->x)
155 val = (val << 16) >> 16;
156 }
157
158 if (state->pref == 0)
159 set_reg(state->dest, val, regs, cregs);
160
161 return;
162
163fault: state->fault = 1;
164}
165
166static void fixup_store(struct disasm_state *state, struct pt_regs *regs,
167 struct callee_regs *cregs)
168{
169
170 if ((state->aa == 1) || (state->aa == 2)) {
171 set_reg(state->wb_reg, state->src2 + state->src3, regs, cregs);
172
173 if (state->aa == 3)
174 state->src3 = 0;
175 } else if (state->aa == 3) {
176 if (state->zz == 2) {
177 set_reg(state->wb_reg, state->src2 + (state->src3 << 1),
178 regs, cregs);
179 } else if (!state->zz) {
180 set_reg(state->wb_reg, state->src2 + (state->src3 << 2),
181 regs, cregs);
182 } else {
183 goto fault;
184 }
185 }
186
187
188 if (!state->zz)
189 put32_unaligned_check(state->src1, state->src2 + state->src3);
190 else
191 put16_unaligned_check(state->src1, state->src2 + state->src3);
192
193 return;
194
195fault: state->fault = 1;
196}
197
198
199
200
201
202int misaligned_fixup(unsigned long address, struct pt_regs *regs,
203 struct callee_regs *cregs)
204{
205 struct disasm_state state;
206 char buf[TASK_COMM_LEN];
207
208
209 if (!user_mode(regs) || !unaligned_enabled)
210 return 1;
211
212 if (no_unaligned_warning) {
213 pr_warn_once("%s(%d) made unaligned access which was emulated"
214 " by kernel assist\n. This can degrade application"
215 " performance significantly\n. To enable further"
216 " logging of such instances, please \n"
217 " echo 0 > /proc/sys/kernel/ignore-unaligned-usertrap\n",
218 get_task_comm(buf, current), task_pid_nr(current));
219 } else {
220
221 pr_warn("%s(%d): unaligned access to/from 0x%lx by PC: 0x%lx\n",
222 get_task_comm(buf, current), task_pid_nr(current),
223 address, regs->ret);
224
225 }
226
227 disasm_instr(regs->ret, &state, 1, regs, cregs);
228
229 if (state.fault)
230 goto fault;
231
232
233 if ((state.zz == 1) || (state.di))
234 goto fault;
235
236 if (!state.write)
237 fixup_load(&state, regs, cregs);
238 else
239 fixup_store(&state, regs, cregs);
240
241 if (state.fault)
242 goto fault;
243
244
245 if (delay_mode(regs)) {
246 regs->ret = regs->bta & ~1U;
247 regs->status32 &= ~STATUS_DE_MASK;
248 } else {
249 regs->ret += state.instr_len;
250
251
252 if ((regs->ret == regs->lp_end) && (regs->lp_count)) {
253 regs->ret = regs->lp_start;
254 regs->lp_count--;
255 }
256 }
257
258 perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, address);
259 return 0;
260
261fault:
262 pr_err("Alignment trap: fault in fix-up %08lx at [<%08lx>]\n",
263 state.words[0], address);
264
265 return 1;
266}
267
