2 * Copyright (C) 2011-2012 Synopsys (www.synopsys.com)
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.
9 * -Adapted (from .26 to .35)
10 * -original contribution by Tim.yao@amlogic.com
14 #include <linux/types.h>
15 #include <linux/ptrace.h>
16 #include <linux/uaccess.h>
17 #include <asm/disasm.h>
19 #define __get8_unaligned_check(val, addr, err) \
21 "1: ldb.ab %1, [%2, 1]\n" \
23 " .section .fixup,\"ax\"\n" \
28 " .section __ex_table,\"a\"\n" \
32 : "=r" (err), "=&r" (val), "=r" (addr) \
33 : "0" (err), "2" (addr))
35 #define get16_unaligned_check(val, addr) \
37 unsigned int err = 0, v, a = addr; \
38 __get8_unaligned_check(v, a, err); \
40 __get8_unaligned_check(v, a, err); \
46 #define get32_unaligned_check(val, addr) \
48 unsigned int err = 0, v, a = addr; \
49 __get8_unaligned_check(v, a, err); \
51 __get8_unaligned_check(v, a, err); \
53 __get8_unaligned_check(v, a, err); \
55 __get8_unaligned_check(v, a, err); \
61 #define put16_unaligned_check(val, addr) \
63 unsigned int err = 0, v = val, a = addr;\
66 "1: stb.ab %1, [%2, 1]\n" \
70 " .section .fixup,\"ax\"\n" \
75 " .section __ex_table,\"a\"\n" \
80 : "=r" (err), "=&r" (v), "=&r" (a) \
81 : "0" (err), "1" (v), "2" (a)); \
87 #define put32_unaligned_check(val, addr) \
89 unsigned int err = 0, v = val, a = addr;\
92 "1: stb.ab %1, [%2, 1]\n" \
94 "2: stb.ab %1, [%2, 1]\n" \
96 "3: stb.ab %1, [%2, 1]\n" \
100 " .section .fixup,\"ax\"\n" \
105 " .section __ex_table,\"a\"\n" \
112 : "=r" (err), "=&r" (v), "=&r" (a) \
113 : "0" (err), "1" (v), "2" (a)); \
120 int unaligned_enabled __read_mostly
= 1; /* Enabled by default */
121 int no_unaligned_warning __read_mostly
= 1; /* Only 1 warning by default */
123 static void fixup_load(struct disasm_state
*state
, struct pt_regs
*regs
,
124 struct callee_regs
*cregs
)
128 /* register write back */
129 if ((state
->aa
== 1) || (state
->aa
== 2)) {
130 set_reg(state
->wb_reg
, state
->src1
+ state
->src2
, regs
, cregs
);
136 if (state
->zz
== 0) {
137 get32_unaligned_check(val
, state
->src1
+ state
->src2
);
139 get16_unaligned_check(val
, state
->src1
+ state
->src2
);
142 val
= (val
<< 16) >> 16;
145 if (state
->pref
== 0)
146 set_reg(state
->dest
, val
, regs
, cregs
);
150 fault
: state
->fault
= 1;
153 static void fixup_store(struct disasm_state
*state
, struct pt_regs
*regs
,
154 struct callee_regs
*cregs
)
156 /* register write back */
157 if ((state
->aa
== 1) || (state
->aa
== 2)) {
158 set_reg(state
->wb_reg
, state
->src2
+ state
->src3
, regs
, cregs
);
162 } else if (state
->aa
== 3) {
163 if (state
->zz
== 2) {
164 set_reg(state
->wb_reg
, state
->src2
+ (state
->src3
<< 1),
166 } else if (!state
->zz
) {
167 set_reg(state
->wb_reg
, state
->src2
+ (state
->src3
<< 2),
176 put32_unaligned_check(state
->src1
, state
->src2
+ state
->src3
);
178 put16_unaligned_check(state
->src1
, state
->src2
+ state
->src3
);
182 fault
: state
->fault
= 1;
186 * Handle an unaligned access
187 * Returns 0 if successfully handled, 1 if some error happened
189 int misaligned_fixup(unsigned long address
, struct pt_regs
*regs
,
190 struct callee_regs
*cregs
)
192 struct disasm_state state
;
193 char buf
[TASK_COMM_LEN
];
195 /* handle user mode only and only if enabled by sysadmin */
196 if (!user_mode(regs
) || !unaligned_enabled
)
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
));
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
),
214 disasm_instr(regs
->ret
, &state
, 1, regs
, cregs
);
219 /* ldb/stb should not have unaligned exception */
220 if ((state
.zz
== 1) || (state
.di
))
224 fixup_load(&state
, regs
, cregs
);
226 fixup_store(&state
, regs
, cregs
);
231 if (delay_mode(regs
)) {
232 regs
->ret
= regs
->bta
;
233 regs
->status32
&= ~STATUS_DE_MASK
;
235 regs
->ret
+= state
.instr_len
;
241 pr_err("Alignment trap: fault in fix-up %08lx at [<%08lx>]\n",
242 state
.words
[0], address
);