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