1 /* unaligned.c: unalignment fixup handler for CPUs on which it is supported (FR451 only)
3 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
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.
12 #include <linux/config.h>
13 #include <linux/sched.h>
14 #include <linux/signal.h>
15 #include <linux/kernel.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>
23 #include <asm/setup.h>
24 #include <asm/system.h>
25 #include <asm/uaccess.h>
28 #define kdebug(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
30 #define kdebug(fmt, ...) do {} while(0)
33 #define _MA_SIGNED 0x01
36 #define _MA_DWORD 0x08
37 #define _MA_SZ_MASK 0x0e
39 #define _MA_STORE 0x20
40 #define _MA_UPDATE 0x40
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
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 */
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 */
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 */
79 /*****************************************************************************/
81 * see if we can handle the exception by fixing up a misaligned memory access
83 int handle_misalignment(unsigned long esr0
, unsigned long ear0
, unsigned long epcr0
)
85 unsigned long insn
, addr
, *greg
;
86 int GRi
, GRj
, GRk
, D12
, op
;
95 if (!(esr0
& ESR0_EAV
) || !(epcr0
& EPCR0_V
) || !(ear0
& 7))
100 if (__frame
->pc
!= epcr0
) {
101 kdebug("MISALIGN: Execution not halted on excepting instruction\n");
105 if (__get_user(insn
, (unsigned long *) epcr0
) < 0)
108 /* determine the instruction type first */
109 switch ((insn
>> 18) & 0x7f) {
111 /* LDx @(GRi,GRj),GRk */
112 op
= tbl_LDGRk_reg
[(insn
>> 6) & 0x3f];
116 /* STx GRk,@(GRi,GRj) */
117 op
= tbl_STGRk_reg
[(insn
>> 6) & 0x3f];
121 op
= tbl_LDSTGRk_imm
[(insn
>> 18) & 0x7f];
128 kdebug("MISALIGN: pc=%08lx insn=%08lx ad=%08lx op=%02x\n", epcr0
, insn
, ear0
, op
);
132 /* validate the instruction parameters */
133 greg
= (unsigned long *) &__frame
->tbr
;
135 GRi
= (insn
>> 12) & 0x3f;
136 GRk
= (insn
>> 25) & 0x3f;
138 if (GRi
> 31 || GRk
> 31)
141 if (op
& _MA_DWORD
&& GRk
& 1)
146 asm ("slli %0,#20,%0 ! srai %0,#20,%0" : "=r"(D12
) : "0"(D12
)); /* sign extend */
147 addr
= (GRi
? greg
[GRi
] : 0) + D12
;
150 GRj
= (insn
>> 0) & 0x3f;
153 addr
= (GRi
? greg
[GRi
] : 0) + (GRj
? greg
[GRj
] : 0);
157 kdebug("MISALIGN: Calculated addr (%08lx) does not match EAR0 (%08lx)\n",
162 /* check the address is okay */
163 if (user_mode(__frame
) && ___range_ok(ear0
, 8) < 0)
166 /* perform the memory op */
167 if (op
& _MA_STORE
) {
168 /* perform a store */
175 x
._32
[0] = greg
[GRk
];
179 x
._32
[1] = greg
[GRk
+ 1];
181 kdebug("MISALIGN: Store GR%d { %08x:%08x } -> %08lx (%dB)\n",
182 GRk
, x
._32
[1], x
._32
[0], addr
, op
& _MA_SZ_MASK
);
184 if (__memcpy_user((void *) addr
, &x
, op
& _MA_SZ_MASK
) != 0)
189 if (__memcpy_user(&x
, (void *) addr
, op
& _MA_SZ_MASK
) != 0)
194 asm ("slli %0,#16,%0 ! srai %0,#16,%0"
195 : "=r"(x
._32
[0]) : "0"(x
._16
));
198 : "=r"(x
._32
[0]) : "0"(x
._16
));
201 kdebug("MISALIGN: Load %08lx (%dB) -> GR%d, { %08x:%08x }\n",
202 addr
, op
& _MA_SZ_MASK
, GRk
, x
._32
[1], x
._32
[0]);
205 greg
[GRk
] = x
._32
[0];
207 greg
[GRk
+ 1] = x
._32
[1];
210 /* update the base pointer if required */
214 /* well... we've done that insn */
215 __frame
->pc
= __frame
->pc
+ 4;
218 } /* end handle_misalignment() */