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1 | /* |
2 | * linux/arch/arm/vfp/vfphw.S | |
3 | * | |
4 | * Copyright (C) 2004 ARM Limited. | |
5 | * Written by Deep Blue Solutions Limited. | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | * | |
11 | * This code is called from the kernel's undefined instruction trap. | |
12 | * r9 holds the return address for successful handling. | |
13 | * lr holds the return address for unrecognised instructions. | |
14 | * r10 points at the start of the private FP workspace in the thread structure | |
15 | * sp points to a struct pt_regs (as defined in include/asm/proc/ptrace.h) | |
16 | */ | |
17 | #include <asm/thread_info.h> | |
18 | #include <asm/vfpmacros.h> | |
19 | #include "../kernel/entry-header.S" | |
20 | ||
21 | .macro DBGSTR, str | |
22 | #ifdef DEBUG | |
23 | stmfd sp!, {r0-r3, ip, lr} | |
24 | add r0, pc, #4 | |
25 | bl printk | |
26 | b 1f | |
27 | .asciz "<7>VFP: \str\n" | |
28 | .balign 4 | |
29 | 1: ldmfd sp!, {r0-r3, ip, lr} | |
30 | #endif | |
31 | .endm | |
32 | ||
33 | .macro DBGSTR1, str, arg | |
34 | #ifdef DEBUG | |
35 | stmfd sp!, {r0-r3, ip, lr} | |
36 | mov r1, \arg | |
37 | add r0, pc, #4 | |
38 | bl printk | |
39 | b 1f | |
40 | .asciz "<7>VFP: \str\n" | |
41 | .balign 4 | |
42 | 1: ldmfd sp!, {r0-r3, ip, lr} | |
43 | #endif | |
44 | .endm | |
45 | ||
46 | .macro DBGSTR3, str, arg1, arg2, arg3 | |
47 | #ifdef DEBUG | |
48 | stmfd sp!, {r0-r3, ip, lr} | |
49 | mov r3, \arg3 | |
50 | mov r2, \arg2 | |
51 | mov r1, \arg1 | |
52 | add r0, pc, #4 | |
53 | bl printk | |
54 | b 1f | |
55 | .asciz "<7>VFP: \str\n" | |
56 | .balign 4 | |
57 | 1: ldmfd sp!, {r0-r3, ip, lr} | |
58 | #endif | |
59 | .endm | |
60 | ||
61 | ||
62 | @ VFP hardware support entry point. | |
63 | @ | |
64 | @ r0 = faulted instruction | |
65 | @ r2 = faulted PC+4 | |
66 | @ r9 = successful return | |
67 | @ r10 = vfp_state union | |
68 | @ lr = failure return | |
69 | ||
70 | .globl vfp_support_entry | |
71 | vfp_support_entry: | |
72 | DBGSTR3 "instr %08x pc %08x state %p", r0, r2, r10 | |
73 | ||
74 | VFPFMRX r1, FPEXC @ Is the VFP enabled? | |
75 | DBGSTR1 "fpexc %08x", r1 | |
76 | tst r1, #FPEXC_ENABLE | |
77 | bne look_for_VFP_exceptions @ VFP is already enabled | |
78 | ||
79 | DBGSTR1 "enable %x", r10 | |
80 | ldr r3, last_VFP_context_address | |
81 | orr r1, r1, #FPEXC_ENABLE @ user FPEXC has the enable bit set | |
82 | ldr r4, [r3] @ last_VFP_context pointer | |
83 | bic r5, r1, #FPEXC_EXCEPTION @ make sure exceptions are disabled | |
84 | cmp r4, r10 | |
85 | beq check_for_exception @ we are returning to the same | |
86 | @ process, so the registers are | |
87 | @ still there. In this case, we do | |
88 | @ not want to drop a pending exception. | |
89 | ||
90 | VFPFMXR FPEXC, r5 @ enable VFP, disable any pending | |
91 | @ exceptions, so we can get at the | |
92 | @ rest of it | |
93 | ||
94 | @ Save out the current registers to the old thread state | |
95 | ||
96 | DBGSTR1 "save old state %p", r4 | |
97 | cmp r4, #0 | |
98 | beq no_old_VFP_process | |
99 | VFPFMRX r5, FPSCR @ current status | |
100 | VFPFMRX r6, FPINST @ FPINST (always there, rev0 onwards) | |
101 | tst r1, #FPEXC_FPV2 @ is there an FPINST2 to read? | |
102 | VFPFMRX r8, FPINST2, NE @ FPINST2 if needed - avoids reading | |
103 | @ nonexistant reg on rev0 | |
104 | VFPFSTMIA r4 @ save the working registers | |
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105 | stmia r4, {r1, r5, r6, r8} @ save FPEXC, FPSCR, FPINST, FPINST2 |
106 | @ and point r4 at the word at the | |
107 | @ start of the register dump | |
108 | ||
109 | no_old_VFP_process: | |
110 | DBGSTR1 "load state %p", r10 | |
111 | str r10, [r3] @ update the last_VFP_context pointer | |
112 | @ Load the saved state back into the VFP | |
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113 | VFPFLDMIA r10 @ reload the working registers while |
114 | @ FPEXC is in a safe state | |
80ed3547 | 115 | ldmia r10, {r1, r5, r6, r8} @ load FPEXC, FPSCR, FPINST, FPINST2 |
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116 | tst r1, #FPEXC_FPV2 @ is there an FPINST2 to write? |
117 | VFPFMXR FPINST2, r8, NE @ FPINST2 if needed - avoids writing | |
118 | @ nonexistant reg on rev0 | |
119 | VFPFMXR FPINST, r6 | |
120 | VFPFMXR FPSCR, r5 @ restore status | |
121 | ||
122 | check_for_exception: | |
123 | tst r1, #FPEXC_EXCEPTION | |
124 | bne process_exception @ might as well handle the pending | |
125 | @ exception before retrying branch | |
126 | @ out before setting an FPEXC that | |
127 | @ stops us reading stuff | |
128 | VFPFMXR FPEXC, r1 @ restore FPEXC last | |
129 | sub r2, r2, #4 | |
130 | str r2, [sp, #S_PC] @ retry the instruction | |
131 | mov pc, r9 @ we think we have handled things | |
132 | ||
133 | ||
134 | look_for_VFP_exceptions: | |
135 | tst r1, #FPEXC_EXCEPTION | |
136 | bne process_exception | |
137 | VFPFMRX r5, FPSCR | |
138 | tst r5, #FPSCR_IXE @ IXE doesn't set FPEXC_EXCEPTION ! | |
139 | bne process_exception | |
140 | ||
141 | @ Fall into hand on to next handler - appropriate coproc instr | |
142 | @ not recognised by VFP | |
143 | ||
144 | DBGSTR "not VFP" | |
145 | mov pc, lr | |
146 | ||
147 | process_exception: | |
148 | DBGSTR "bounce" | |
149 | sub r2, r2, #4 | |
150 | str r2, [sp, #S_PC] @ retry the instruction on exit from | |
151 | @ the imprecise exception handling in | |
152 | @ the support code | |
153 | mov r2, sp @ nothing stacked - regdump is at TOS | |
154 | mov lr, r9 @ setup for a return to the user code. | |
155 | ||
156 | @ Now call the C code to package up the bounce to the support code | |
157 | @ r0 holds the trigger instruction | |
158 | @ r1 holds the FPEXC value | |
159 | @ r2 pointer to register dump | |
160 | b VFP9_bounce @ we have handled this - the support | |
161 | @ code will raise an exception if | |
162 | @ required. If not, the user code will | |
163 | @ retry the faulted instruction | |
164 | ||
165 | last_VFP_context_address: | |
166 | .word last_VFP_context | |
167 | ||
168 | .globl vfp_get_float | |
169 | vfp_get_float: | |
170 | add pc, pc, r0, lsl #3 | |
171 | mov r0, r0 | |
172 | .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 | |
173 | mrc p10, 0, r0, c\dr, c0, 0 @ fmrs r0, s0 | |
174 | mov pc, lr | |
175 | mrc p10, 0, r0, c\dr, c0, 4 @ fmrs r0, s1 | |
176 | mov pc, lr | |
177 | .endr | |
178 | ||
179 | .globl vfp_put_float | |
180 | vfp_put_float: | |
0355b3e0 | 181 | add pc, pc, r1, lsl #3 |
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182 | mov r0, r0 |
183 | .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 | |
0355b3e0 | 184 | mcr p10, 0, r0, c\dr, c0, 0 @ fmsr r0, s0 |
1da177e4 | 185 | mov pc, lr |
0355b3e0 | 186 | mcr p10, 0, r0, c\dr, c0, 4 @ fmsr r0, s1 |
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187 | mov pc, lr |
188 | .endr | |
189 | ||
190 | .globl vfp_get_double | |
191 | vfp_get_double: | |
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192 | add pc, pc, r0, lsl #3 |
193 | mov r0, r0 | |
194 | .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 | |
1a6be26d | 195 | fmrrd r0, r1, d\dr |
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196 | mov pc, lr |
197 | .endr | |
198 | ||
199 | @ virtual register 16 for compare with zero | |
200 | mov r0, #0 | |
201 | mov r1, #0 | |
202 | mov pc, lr | |
203 | ||
204 | .globl vfp_put_double | |
205 | vfp_put_double: | |
0355b3e0 | 206 | add pc, pc, r2, lsl #3 |
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207 | mov r0, r0 |
208 | .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 | |
0355b3e0 | 209 | fmdrr d\dr, r0, r1 |
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210 | mov pc, lr |
211 | .endr |