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1da177e4 LT |
1 | /* unaligned.c: unalignment fixup handler for CPUs on which it is supported (FR451 only) |
2 | * | |
3 | * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/config.h> | |
13 | #include <linux/sched.h> | |
14 | #include <linux/signal.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/mm.h> | |
17 | #include <linux/types.h> | |
18 | #include <linux/user.h> | |
19 | #include <linux/string.h> | |
20 | #include <linux/linkage.h> | |
21 | #include <linux/init.h> | |
22 | ||
23 | #include <asm/setup.h> | |
24 | #include <asm/system.h> | |
25 | #include <asm/uaccess.h> | |
26 | ||
27 | #if 0 | |
28 | #define kdebug(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ ) | |
29 | #else | |
30 | #define kdebug(fmt, ...) do {} while(0) | |
31 | #endif | |
32 | ||
33 | #define _MA_SIGNED 0x01 | |
34 | #define _MA_HALF 0x02 | |
35 | #define _MA_WORD 0x04 | |
36 | #define _MA_DWORD 0x08 | |
37 | #define _MA_SZ_MASK 0x0e | |
38 | #define _MA_LOAD 0x10 | |
39 | #define _MA_STORE 0x20 | |
40 | #define _MA_UPDATE 0x40 | |
41 | #define _MA_IMM 0x80 | |
42 | ||
43 | #define _MA_LDxU _MA_LOAD | _MA_UPDATE | |
44 | #define _MA_LDxI _MA_LOAD | _MA_IMM | |
45 | #define _MA_STxU _MA_STORE | _MA_UPDATE | |
46 | #define _MA_STxI _MA_STORE | _MA_IMM | |
47 | ||
48 | static const uint8_t tbl_LDGRk_reg[0x40] = { | |
49 | [0x02] = _MA_LOAD | _MA_HALF | _MA_SIGNED, /* LDSH @(GRi,GRj),GRk */ | |
50 | [0x03] = _MA_LOAD | _MA_HALF, /* LDUH @(GRi,GRj),GRk */ | |
51 | [0x04] = _MA_LOAD | _MA_WORD, /* LD @(GRi,GRj),GRk */ | |
52 | [0x05] = _MA_LOAD | _MA_DWORD, /* LDD @(GRi,GRj),GRk */ | |
53 | [0x12] = _MA_LDxU | _MA_HALF | _MA_SIGNED, /* LDSHU @(GRi,GRj),GRk */ | |
54 | [0x13] = _MA_LDxU | _MA_HALF, /* LDUHU @(GRi,GRj),GRk */ | |
55 | [0x14] = _MA_LDxU | _MA_WORD, /* LDU @(GRi,GRj),GRk */ | |
56 | [0x15] = _MA_LDxU | _MA_DWORD, /* LDDU @(GRi,GRj),GRk */ | |
57 | }; | |
58 | ||
59 | static const uint8_t tbl_STGRk_reg[0x40] = { | |
60 | [0x01] = _MA_STORE | _MA_HALF, /* STH @(GRi,GRj),GRk */ | |
61 | [0x02] = _MA_STORE | _MA_WORD, /* ST @(GRi,GRj),GRk */ | |
62 | [0x03] = _MA_STORE | _MA_DWORD, /* STD @(GRi,GRj),GRk */ | |
63 | [0x11] = _MA_STxU | _MA_HALF, /* STHU @(GRi,GRj),GRk */ | |
64 | [0x12] = _MA_STxU | _MA_WORD, /* STU @(GRi,GRj),GRk */ | |
65 | [0x13] = _MA_STxU | _MA_DWORD, /* STDU @(GRi,GRj),GRk */ | |
66 | }; | |
67 | ||
68 | static const uint8_t tbl_LDSTGRk_imm[0x80] = { | |
69 | [0x31] = _MA_LDxI | _MA_HALF | _MA_SIGNED, /* LDSHI @(GRi,d12),GRk */ | |
70 | [0x32] = _MA_LDxI | _MA_WORD, /* LDI @(GRi,d12),GRk */ | |
71 | [0x33] = _MA_LDxI | _MA_DWORD, /* LDDI @(GRi,d12),GRk */ | |
72 | [0x36] = _MA_LDxI | _MA_HALF, /* LDUHI @(GRi,d12),GRk */ | |
73 | [0x51] = _MA_STxI | _MA_HALF, /* STHI @(GRi,d12),GRk */ | |
74 | [0x52] = _MA_STxI | _MA_WORD, /* STI @(GRi,d12),GRk */ | |
75 | [0x53] = _MA_STxI | _MA_DWORD, /* STDI @(GRi,d12),GRk */ | |
76 | }; | |
77 | ||
78 | ||
79 | /*****************************************************************************/ | |
80 | /* | |
81 | * see if we can handle the exception by fixing up a misaligned memory access | |
82 | */ | |
83 | int handle_misalignment(unsigned long esr0, unsigned long ear0, unsigned long epcr0) | |
84 | { | |
85 | unsigned long insn, addr, *greg; | |
86 | int GRi, GRj, GRk, D12, op; | |
87 | ||
88 | union { | |
89 | uint64_t _64; | |
90 | uint32_t _32[2]; | |
91 | uint16_t _16; | |
92 | uint8_t _8[8]; | |
93 | } x; | |
94 | ||
95 | if (!(esr0 & ESR0_EAV) || !(epcr0 & EPCR0_V) || !(ear0 & 7)) | |
96 | return -EAGAIN; | |
97 | ||
98 | epcr0 &= EPCR0_PC; | |
99 | ||
100 | if (__frame->pc != epcr0) { | |
101 | kdebug("MISALIGN: Execution not halted on excepting instruction\n"); | |
102 | BUG(); | |
103 | } | |
104 | ||
105 | if (__get_user(insn, (unsigned long *) epcr0) < 0) | |
106 | return -EFAULT; | |
107 | ||
108 | /* determine the instruction type first */ | |
109 | switch ((insn >> 18) & 0x7f) { | |
110 | case 0x2: | |
111 | /* LDx @(GRi,GRj),GRk */ | |
112 | op = tbl_LDGRk_reg[(insn >> 6) & 0x3f]; | |
113 | break; | |
114 | ||
115 | case 0x3: | |
116 | /* STx GRk,@(GRi,GRj) */ | |
117 | op = tbl_STGRk_reg[(insn >> 6) & 0x3f]; | |
118 | break; | |
119 | ||
120 | default: | |
121 | op = tbl_LDSTGRk_imm[(insn >> 18) & 0x7f]; | |
122 | break; | |
123 | } | |
124 | ||
125 | if (!op) | |
126 | return -EAGAIN; | |
127 | ||
128 | kdebug("MISALIGN: pc=%08lx insn=%08lx ad=%08lx op=%02x\n", epcr0, insn, ear0, op); | |
129 | ||
130 | memset(&x, 0xba, 8); | |
131 | ||
132 | /* validate the instruction parameters */ | |
133 | greg = (unsigned long *) &__frame->tbr; | |
134 | ||
135 | GRi = (insn >> 12) & 0x3f; | |
136 | GRk = (insn >> 25) & 0x3f; | |
137 | ||
138 | if (GRi > 31 || GRk > 31) | |
139 | return -ENOENT; | |
140 | ||
141 | if (op & _MA_DWORD && GRk & 1) | |
142 | return -EINVAL; | |
143 | ||
144 | if (op & _MA_IMM) { | |
145 | D12 = insn & 0xfff; | |
146 | asm ("slli %0,#20,%0 ! srai %0,#20,%0" : "=r"(D12) : "0"(D12)); /* sign extend */ | |
147 | addr = (GRi ? greg[GRi] : 0) + D12; | |
148 | } | |
149 | else { | |
150 | GRj = (insn >> 0) & 0x3f; | |
151 | if (GRj > 31) | |
152 | return -ENOENT; | |
153 | addr = (GRi ? greg[GRi] : 0) + (GRj ? greg[GRj] : 0); | |
154 | } | |
155 | ||
156 | if (addr != ear0) { | |
157 | kdebug("MISALIGN: Calculated addr (%08lx) does not match EAR0 (%08lx)\n", | |
158 | addr, ear0); | |
159 | return -EFAULT; | |
160 | } | |
161 | ||
162 | /* check the address is okay */ | |
163 | if (user_mode(__frame) && ___range_ok(ear0, 8) < 0) | |
164 | return -EFAULT; | |
165 | ||
166 | /* perform the memory op */ | |
167 | if (op & _MA_STORE) { | |
168 | /* perform a store */ | |
169 | x._32[0] = 0; | |
170 | if (GRk != 0) { | |
171 | if (op & _MA_HALF) { | |
172 | x._16 = greg[GRk]; | |
173 | } | |
174 | else { | |
175 | x._32[0] = greg[GRk]; | |
176 | } | |
177 | } | |
178 | if (op & _MA_DWORD) | |
179 | x._32[1] = greg[GRk + 1]; | |
180 | ||
181 | kdebug("MISALIGN: Store GR%d { %08x:%08x } -> %08lx (%dB)\n", | |
182 | GRk, x._32[1], x._32[0], addr, op & _MA_SZ_MASK); | |
183 | ||
184 | if (__memcpy_user((void *) addr, &x, op & _MA_SZ_MASK) != 0) | |
185 | return -EFAULT; | |
186 | } | |
187 | else { | |
188 | /* perform a load */ | |
189 | if (__memcpy_user(&x, (void *) addr, op & _MA_SZ_MASK) != 0) | |
190 | return -EFAULT; | |
191 | ||
192 | if (op & _MA_HALF) { | |
193 | if (op & _MA_SIGNED) | |
194 | asm ("slli %0,#16,%0 ! srai %0,#16,%0" | |
195 | : "=r"(x._32[0]) : "0"(x._16)); | |
196 | else | |
197 | asm ("sethi #0,%0" | |
198 | : "=r"(x._32[0]) : "0"(x._16)); | |
199 | } | |
200 | ||
201 | kdebug("MISALIGN: Load %08lx (%dB) -> GR%d, { %08x:%08x }\n", | |
202 | addr, op & _MA_SZ_MASK, GRk, x._32[1], x._32[0]); | |
203 | ||
204 | if (GRk != 0) | |
205 | greg[GRk] = x._32[0]; | |
206 | if (op & _MA_DWORD) | |
207 | greg[GRk + 1] = x._32[1]; | |
208 | } | |
209 | ||
210 | /* update the base pointer if required */ | |
211 | if (op & _MA_UPDATE) | |
212 | greg[GRi] = addr; | |
213 | ||
214 | /* well... we've done that insn */ | |
215 | __frame->pc = __frame->pc + 4; | |
216 | ||
217 | return 0; | |
218 | } /* end handle_misalignment() */ |