summaryrefslogtreecommitdiffstats
path: root/kernel/arch/arm/mm/abort-lv4t.S
blob: f3982580c273057b89a1c025cb52f0f54093014f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
#include <linux/linkage.h>
#include <asm/assembler.h>
/*
 * Function: v4t_late_abort
 *
 * Params  : r2 = pt_regs
 *	   : r4 = aborted context pc
 *	   : r5 = aborted context psr
 *
 * Returns : r4-r5, r10-r11, r13 preserved
 *
 * Purpose : obtain information about current aborted instruction.
 * Note: we read user space.  This means we might cause a data
 * abort here if the I-TLB and D-TLB aren't seeing the same
 * picture.  Unfortunately, this does happen.  We live with it.
 */
ENTRY(v4t_late_abort)
	tst	r5, #PSR_T_BIT			@ check for thumb mode
#ifdef CONFIG_CPU_CP15_MMU
	mrc	p15, 0, r1, c5, c0, 0		@ get FSR
	mrc	p15, 0, r0, c6, c0, 0		@ get FAR
	bic	r1, r1, #1 << 11 | 1 << 10	@ clear bits 11 and 10 of FSR
#else
	mov	r0, #0				@ clear r0, r1 (no FSR/FAR)
	mov	r1, #0
#endif
	bne	.data_thumb_abort
	ldr	r8, [r4]			@ read arm instruction
	tst	r8, #1 << 20			@ L = 1 -> write?
	orreq	r1, r1, #1 << 11		@ yes.
	and	r7, r8, #15 << 24
	add	pc, pc, r7, lsr #22		@ Now branch to the relevant processing routine
	nop

/* 0 */	b	.data_arm_lateldrhpost		@ ldrh	rd, [rn], #m/rm
/* 1 */	b	.data_arm_lateldrhpre		@ ldrh	rd, [rn, #m/rm]
/* 2 */	b	.data_unknown
/* 3 */	b	.data_unknown
/* 4 */	b	.data_arm_lateldrpostconst	@ ldr	rd, [rn], #m
/* 5 */	b	.data_arm_lateldrpreconst	@ ldr	rd, [rn, #m] 
/* 6 */	b	.data_arm_lateldrpostreg	@ ldr	rd, [rn], rm
/* 7 */	b	.data_arm_lateldrprereg		@ ldr	rd, [rn, rm]
/* 8 */	b	.data_arm_ldmstm		@ ldm*a	rn, <rlist>
/* 9 */	b	.data_arm_ldmstm		@ ldm*b	rn, <rlist>
/* a */	b	.data_unknown
/* b */	b	.data_unknown
/* c */	b	do_DataAbort			@ ldc	rd, [rn], #m	@ Same as ldr	rd, [rn], #m
/* d */	b	do_DataAbort			@ ldc	rd, [rn, #m]
/* e */	b	.data_unknown
/* f */
.data_unknown:	@ Part of jumptable
	mov	r0, r4
	mov	r1, r8
	b	baddataabort

.data_arm_ldmstm:
	tst	r8, #1 << 21			@ check writeback bit
	beq	do_DataAbort			@ no writeback -> no fixup
	mov	r7, #0x11
	orr	r7, r7, #0x1100
	and	r6, r8, r7
	and	r9, r8, r7, lsl #1
	add	r6, r6, r9, lsr #1
	and	r9, r8, r7, lsl #2
	add	r6, r6, r9, lsr #2
	and	r9, r8, r7, lsl #3
	add	r6, r6, r9, lsr #3
	add	r6, r6, r6, lsr #8
	add	r6, r6, r6, lsr #4
	and	r6, r6, #15			@ r6 = no. of registers to transfer.
	and	r9, r8, #15 << 16		@ Extract 'n' from instruction
	ldr	r7, [r2, r9, lsr #14]		@ Get register 'Rn'
	tst	r8, #1 << 23			@ Check U bit
	subne	r7, r7, r6, lsl #2		@ Undo increment
	addeq	r7, r7, r6, lsl #2		@ Undo decrement
	str	r7, [r2, r9, lsr #14]		@ Put register 'Rn'
	b	do_DataAbort

.data_arm_lateldrhpre:
	tst	r8, #1 << 21			@ Check writeback bit
	beq	do_DataAbort			@ No writeback -> no fixup
.data_arm_lateldrhpost:
	and	r9, r8, #0x00f			@ get Rm / low nibble of immediate value
	tst	r8, #1 << 22			@ if (immediate offset)
	andne	r6, r8, #0xf00			@ { immediate high nibble
	orrne	r6, r9, r6, lsr #4		@   combine nibbles } else
	ldreq	r6, [r2, r9, lsl #2]		@ { load Rm value }
.data_arm_apply_r6_and_rn:
	and	r9, r8, #15 << 16		@ Extract 'n' from instruction
	ldr	r7, [r2, r9, lsr #14]		@ Get register 'Rn'
	tst	r8, #1 << 23			@ Check U bit
	subne	r7, r7, r6			@ Undo incrmenet
	addeq	r7, r7, r6			@ Undo decrement
	str	r7, [r2, r9, lsr #14]		@ Put register 'Rn'
	b	do_DataAbort

.data_arm_lateldrpreconst:
	tst	r8, #1 << 21			@ check writeback bit
	beq	do_DataAbort			@ no writeback -> no fixup
.data_arm_lateldrpostconst:
	movs	r6, r8, lsl #20			@ Get offset
	beq	do_DataAbort			@ zero -> no fixup
	and	r9, r8, #15 << 16		@ Extract 'n' from instruction
	ldr	r7, [r2, r9, lsr #14]		@ Get register 'Rn'
	tst	r8, #1 << 23			@ Check U bit
	subne	r7, r7, r6, lsr #20		@ Undo increment
	addeq	r7, r7, r6, lsr #20		@ Undo decrement
	str	r7, [r2, r9, lsr #14]		@ Put register 'Rn'
	b	do_DataAbort

.data_arm_lateldrprereg:
	tst	r8, #1 << 21			@ check writeback bit
	beq	do_DataAbort			@ no writeback -> no fixup
.data_arm_lateldrpostreg:
	and	r7, r8, #15			@ Extract 'm' from instruction
	ldr	r6, [r2, r7, lsl #2]		@ Get register 'Rm'
	mov	r9, r8, lsr #7			@ get shift count
	ands	r9, r9, #31
	and	r7, r8, #0x70			@ get shift type
	orreq	r7, r7, #8			@ shift count = 0
	add	pc, pc, r7
	nop

	mov	r6, r6, lsl r9			@ 0: LSL #!0
	b	.data_arm_apply_r6_and_rn
	b	.data_arm_apply_r6_and_rn	@ 1: LSL #0
	nop
	b	.data_unknown			@ 2: MUL?
	nop
	b	.data_unknown			@ 3: MUL?
	nop
	mov	r6, r6, lsr r9			@ 4: LSR #!0
	b	.data_arm_apply_r6_and_rn
	mov	r6, r6, lsr #32			@ 5: LSR #32
	b	.data_arm_apply_r6_and_rn
	b	.data_unknown			@ 6: MUL?
	nop
	b	.data_unknown			@ 7: MUL?
	nop
	mov	r6, r6, asr r9			@ 8: ASR #!0
	b	.data_arm_apply_r6_and_rn
	mov	r6, r6, asr #32			@ 9: ASR #32
	b	.data_arm_apply_r6_and_rn
	b	.data_unknown			@ A: MUL?
	nop
	b	.data_unknown			@ B: MUL?
	nop
	mov	r6, r6, ror r9			@ C: ROR #!0
	b	.data_arm_apply_r6_and_rn
	mov	r6, r6, rrx			@ D: RRX
	b	.data_arm_apply_r6_and_rn
	b	.data_unknown			@ E: MUL?
	nop
	b	.data_unknown			@ F: MUL?

.data_thumb_abort:
	ldrh	r8, [r4]			@ read instruction
	tst	r8, #1 << 11			@ L = 1 -> write?
	orreq	r1, r1, #1 << 8			@ yes
	and	r7, r8, #15 << 12
	add	pc, pc, r7, lsr #10		@ lookup in table
	nop

/* 0 */	b	.data_unknown
/* 1 */	b	.data_unknown
/* 2 */	b	.data_unknown
/* 3 */	b	.data_unknown
/* 4 */	b	.data_unknown
/* 5 */	b	.data_thumb_reg
/* 6 */	b	do_DataAbort
/* 7 */	b	do_DataAbort
/* 8 */	b	do_DataAbort
/* 9 */	b	do_DataAbort
/* A */	b	.data_unknown
/* B */	b	.data_thumb_pushpop
/* C */	b	.data_thumb_ldmstm
/* D */	b	.data_unknown
/* E */	b	.data_unknown
/* F */	b	.data_unknown

.data_thumb_reg:
	tst	r8, #1 << 9
	beq	do_DataAbort
	tst	r8, #1 << 10			@ If 'S' (signed) bit is set
	movne	r1, #0				@ it must be a load instr
	b	do_DataAbort

.data_thumb_pushpop:
	tst	r8, #1 << 10
	beq	.data_unknown
	and	r6, r8, #0x55			@ hweight8(r8) + R bit
	and	r9, r8, #0xaa
	add	r6, r6, r9, lsr #1
	and	r9, r6, #0xcc
	and	r6, r6, #0x33
	add	r6, r6, r9, lsr #2
	movs	r7, r8, lsr #9			@ C = r8 bit 8 (R bit)
	adc	r6, r6, r6, lsr #4		@ high + low nibble + R bit
	and	r6, r6, #15			@ number of regs to transfer
	ldr	r7, [r2, #13 << 2]
	tst	r8, #1 << 11
	addeq	r7, r7, r6, lsl #2		@ increment SP if PUSH
	subne	r7, r7, r6, lsl #2		@ decrement SP if POP
	str	r7, [r2, #13 << 2]
	b	do_DataAbort

.data_thumb_ldmstm:
	and	r6, r8, #0x55			@ hweight8(r8)
	and	r9, r8, #0xaa
	add	r6, r6, r9, lsr #1
	and	r9, r6, #0xcc
	and	r6, r6, #0x33
	add	r6, r6, r9, lsr #2
	add	r6, r6, r6, lsr #4
	and	r9, r8, #7 << 8
	ldr	r7, [r2, r9, lsr #6]
	and	r6, r6, #15			@ number of regs to transfer
	sub	r7, r7, r6, lsl #2		@ always decrement
	str	r7, [r2, r9, lsr #6]
	b	do_DataAbort