ARM: fix scheduling while atomic warning in alignment handling code
[deliverable/linux.git] / arch / arm / vfp / vfphw.S
CommitLineData
1da177e4
LT
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>
0cc41e4a 19#include <linux/kern_levels.h>
1da177e4
LT
20#include "../kernel/entry-header.S"
21
22 .macro DBGSTR, str
23#ifdef DEBUG
24 stmfd sp!, {r0-r3, ip, lr}
25 add r0, pc, #4
26 bl printk
27 b 1f
0cc41e4a 28 .asciz KERN_DEBUG "VFP: \str\n"
1da177e4
LT
29 .balign 4
301: ldmfd sp!, {r0-r3, ip, lr}
31#endif
32 .endm
33
34 .macro DBGSTR1, str, arg
35#ifdef DEBUG
36 stmfd sp!, {r0-r3, ip, lr}
37 mov r1, \arg
38 add r0, pc, #4
39 bl printk
40 b 1f
0cc41e4a 41 .asciz KERN_DEBUG "VFP: \str\n"
1da177e4
LT
42 .balign 4
431: ldmfd sp!, {r0-r3, ip, lr}
44#endif
45 .endm
46
47 .macro DBGSTR3, str, arg1, arg2, arg3
48#ifdef DEBUG
49 stmfd sp!, {r0-r3, ip, lr}
50 mov r3, \arg3
51 mov r2, \arg2
52 mov r1, \arg1
53 add r0, pc, #4
54 bl printk
55 b 1f
0cc41e4a 56 .asciz KERN_DEBUG "VFP: \str\n"
1da177e4
LT
57 .balign 4
581: ldmfd sp!, {r0-r3, ip, lr}
59#endif
60 .endm
61
62
63@ VFP hardware support entry point.
64@
15ac49b6
RK
65@ r0 = instruction opcode (32-bit ARM or two 16-bit Thumb)
66@ r2 = PC value to resume execution after successful emulation
67@ r9 = normal "successful" return address
1da177e4 68@ r10 = vfp_state union
c6428464 69@ r11 = CPU number
15ac49b6
RK
70@ lr = unrecognised instruction return address
71@ IRQs enabled.
93ed3970 72ENTRY(vfp_support_entry)
1da177e4
LT
73 DBGSTR3 "instr %08x pc %08x state %p", r0, r2, r10
74
75 VFPFMRX r1, FPEXC @ Is the VFP enabled?
76 DBGSTR1 "fpexc %08x", r1
228adef1 77 tst r1, #FPEXC_EN
1da177e4
LT
78 bne look_for_VFP_exceptions @ VFP is already enabled
79
80 DBGSTR1 "enable %x", r10
af61bdf0 81 ldr r3, vfp_current_hw_state_address
228adef1 82 orr r1, r1, #FPEXC_EN @ user FPEXC has the enable bit set
af61bdf0 83 ldr r4, [r3, r11, lsl #2] @ vfp_current_hw_state pointer
228adef1 84 bic r5, r1, #FPEXC_EX @ make sure exceptions are disabled
08409c33 85 cmp r4, r10 @ this thread owns the hw context?
f8f2a852
RK
86#ifndef CONFIG_SMP
87 @ For UP, checking that this thread owns the hw context is
88 @ sufficient to determine that the hardware state is valid.
08409c33 89 beq vfp_hw_state_valid
1da177e4 90
f8f2a852
RK
91 @ On UP, we lazily save the VFP context. As a different
92 @ thread wants ownership of the VFP hardware, save the old
93 @ state if there was a previous (valid) owner.
94
1da177e4
LT
95 VFPFMXR FPEXC, r5 @ enable VFP, disable any pending
96 @ exceptions, so we can get at the
97 @ rest of it
98
1da177e4 99 DBGSTR1 "save old state %p", r4
f8f2a852
RK
100 cmp r4, #0 @ if the vfp_current_hw_state is NULL
101 beq vfp_reload_hw @ then the hw state needs reloading
25ebee02 102 VFPFSTMIA r4, r5 @ save the working registers
1da177e4 103 VFPFMRX r5, FPSCR @ current status
85d6943a 104#ifndef CONFIG_CPU_FEROCEON
c98929c0 105 tst r1, #FPEXC_EX @ is there additional state to save?
24b647a0
CM
106 beq 1f
107 VFPFMRX r6, FPINST @ FPINST (only if FPEXC.EX is set)
108 tst r1, #FPEXC_FP2V @ is there an FPINST2 to read?
109 beq 1f
110 VFPFMRX r8, FPINST2 @ FPINST2 if needed (and present)
1111:
85d6943a 112#endif
1da177e4 113 stmia r4, {r1, r5, r6, r8} @ save FPEXC, FPSCR, FPINST, FPINST2
f8f2a852
RK
114vfp_reload_hw:
115
116#else
117 @ For SMP, if this thread does not own the hw context, then we
118 @ need to reload it. No need to save the old state as on SMP,
119 @ we always save the state when we switch away from a thread.
120 bne vfp_reload_hw
121
122 @ This thread has ownership of the current hardware context.
123 @ However, it may have been migrated to another CPU, in which
124 @ case the saved state is newer than the hardware context.
125 @ Check this by looking at the CPU number which the state was
126 @ last loaded onto.
127 ldr ip, [r10, #VFP_CPU]
128 teq ip, r11
129 beq vfp_hw_state_valid
130
131vfp_reload_hw:
132 @ We're loading this threads state into the VFP hardware. Update
133 @ the CPU number which contains the most up to date VFP context.
134 str r11, [r10, #VFP_CPU]
135
136 VFPFMXR FPEXC, r5 @ enable VFP, disable any pending
137 @ exceptions, so we can get at the
138 @ rest of it
c6428464 139#endif
1da177e4 140
1da177e4 141 DBGSTR1 "load state %p", r10
af61bdf0 142 str r10, [r3, r11, lsl #2] @ update the vfp_current_hw_state pointer
1da177e4 143 @ Load the saved state back into the VFP
25ebee02 144 VFPFLDMIA r10, r5 @ reload the working registers while
1da177e4 145 @ FPEXC is in a safe state
80ed3547 146 ldmia r10, {r1, r5, r6, r8} @ load FPEXC, FPSCR, FPINST, FPINST2
85d6943a 147#ifndef CONFIG_CPU_FEROCEON
c98929c0 148 tst r1, #FPEXC_EX @ is there additional state to restore?
24b647a0
CM
149 beq 1f
150 VFPFMXR FPINST, r6 @ restore FPINST (only if FPEXC.EX is set)
151 tst r1, #FPEXC_FP2V @ is there an FPINST2 to write?
152 beq 1f
153 VFPFMXR FPINST2, r8 @ FPINST2 if needed (and present)
1541:
85d6943a 155#endif
1da177e4
LT
156 VFPFMXR FPSCR, r5 @ restore status
157
08409c33
RK
158@ The context stored in the VFP hardware is up to date with this thread
159vfp_hw_state_valid:
228adef1 160 tst r1, #FPEXC_EX
1da177e4
LT
161 bne process_exception @ might as well handle the pending
162 @ exception before retrying branch
163 @ out before setting an FPEXC that
164 @ stops us reading stuff
15ac49b6
RK
165 VFPFMXR FPEXC, r1 @ Restore FPEXC last
166 sub r2, r2, #4 @ Retry current instruction - if Thumb
167 str r2, [sp, #S_PC] @ mode it's two 16-bit instructions,
168 @ else it's one 32-bit instruction, so
169 @ always subtract 4 from the following
170 @ instruction address.
568dca15 171#ifdef CONFIG_PREEMPT_COUNT
f2255be8
GD
172 get_thread_info r10
173 ldr r4, [r10, #TI_PREEMPT] @ get preempt count
174 sub r11, r4, #1 @ decrement it
175 str r11, [r10, #TI_PREEMPT]
176#endif
1da177e4
LT
177 mov pc, r9 @ we think we have handled things
178
179
180look_for_VFP_exceptions:
c98929c0
CM
181 @ Check for synchronous or asynchronous exception
182 tst r1, #FPEXC_EX | FPEXC_DEX
1da177e4 183 bne process_exception
c98929c0
CM
184 @ On some implementations of the VFP subarch 1, setting FPSCR.IXE
185 @ causes all the CDP instructions to be bounced synchronously without
186 @ setting the FPEXC.EX bit
1da177e4 187 VFPFMRX r5, FPSCR
c98929c0 188 tst r5, #FPSCR_IXE
1da177e4
LT
189 bne process_exception
190
191 @ Fall into hand on to next handler - appropriate coproc instr
192 @ not recognised by VFP
193
194 DBGSTR "not VFP"
568dca15 195#ifdef CONFIG_PREEMPT_COUNT
f2255be8
GD
196 get_thread_info r10
197 ldr r4, [r10, #TI_PREEMPT] @ get preempt count
198 sub r11, r4, #1 @ decrement it
199 str r11, [r10, #TI_PREEMPT]
200#endif
1da177e4
LT
201 mov pc, lr
202
203process_exception:
204 DBGSTR "bounce"
1da177e4
LT
205 mov r2, sp @ nothing stacked - regdump is at TOS
206 mov lr, r9 @ setup for a return to the user code.
207
208 @ Now call the C code to package up the bounce to the support code
209 @ r0 holds the trigger instruction
210 @ r1 holds the FPEXC value
211 @ r2 pointer to register dump
c98929c0 212 b VFP_bounce @ we have handled this - the support
1da177e4
LT
213 @ code will raise an exception if
214 @ required. If not, the user code will
215 @ retry the faulted instruction
93ed3970 216ENDPROC(vfp_support_entry)
1da177e4 217
93ed3970 218ENTRY(vfp_save_state)
c6428464
CM
219 @ Save the current VFP state
220 @ r0 - save location
221 @ r1 - FPEXC
222 DBGSTR1 "save VFP state %p", r0
25ebee02 223 VFPFSTMIA r0, r2 @ save the working registers
c6428464 224 VFPFMRX r2, FPSCR @ current status
c98929c0 225 tst r1, #FPEXC_EX @ is there additional state to save?
24b647a0
CM
226 beq 1f
227 VFPFMRX r3, FPINST @ FPINST (only if FPEXC.EX is set)
228 tst r1, #FPEXC_FP2V @ is there an FPINST2 to read?
229 beq 1f
230 VFPFMRX r12, FPINST2 @ FPINST2 if needed (and present)
2311:
c6428464
CM
232 stmia r0, {r1, r2, r3, r12} @ save FPEXC, FPSCR, FPINST, FPINST2
233 mov pc, lr
93ed3970 234ENDPROC(vfp_save_state)
c6428464 235
7eb25ebe 236 .align
af61bdf0
RK
237vfp_current_hw_state_address:
238 .word vfp_current_hw_state
1da177e4 239
07f33a03
CM
240 .macro tbl_branch, base, tmp, shift
241#ifdef CONFIG_THUMB2_KERNEL
242 adr \tmp, 1f
243 add \tmp, \tmp, \base, lsl \shift
244 mov pc, \tmp
245#else
246 add pc, pc, \base, lsl \shift
1da177e4 247 mov r0, r0
07f33a03
CM
248#endif
2491:
250 .endm
251
252ENTRY(vfp_get_float)
253 tbl_branch r0, r3, #3
1da177e4 254 .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
07f33a03 2551: mrc p10, 0, r0, c\dr, c0, 0 @ fmrs r0, s0
1da177e4 256 mov pc, lr
07f33a03
CM
257 .org 1b + 8
2581: mrc p10, 0, r0, c\dr, c0, 4 @ fmrs r0, s1
1da177e4 259 mov pc, lr
07f33a03 260 .org 1b + 8
1da177e4 261 .endr
93ed3970 262ENDPROC(vfp_get_float)
1da177e4 263
93ed3970 264ENTRY(vfp_put_float)
07f33a03 265 tbl_branch r1, r3, #3
1da177e4 266 .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
07f33a03 2671: mcr p10, 0, r0, c\dr, c0, 0 @ fmsr r0, s0
1da177e4 268 mov pc, lr
07f33a03
CM
269 .org 1b + 8
2701: mcr p10, 0, r0, c\dr, c0, 4 @ fmsr r0, s1
1da177e4 271 mov pc, lr
07f33a03 272 .org 1b + 8
1da177e4 273 .endr
93ed3970 274ENDPROC(vfp_put_float)
1da177e4 275
93ed3970 276ENTRY(vfp_get_double)
07f33a03 277 tbl_branch r0, r3, #3
1da177e4 278 .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
07f33a03 2791: fmrrd r0, r1, d\dr
1da177e4 280 mov pc, lr
07f33a03 281 .org 1b + 8
1da177e4 282 .endr
25ebee02
CM
283#ifdef CONFIG_VFPv3
284 @ d16 - d31 registers
285 .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
07f33a03 2861: mrrc p11, 3, r0, r1, c\dr @ fmrrd r0, r1, d\dr
25ebee02 287 mov pc, lr
07f33a03 288 .org 1b + 8
25ebee02
CM
289 .endr
290#endif
1da177e4 291
25ebee02 292 @ virtual register 16 (or 32 if VFPv3) for compare with zero
1da177e4
LT
293 mov r0, #0
294 mov r1, #0
295 mov pc, lr
93ed3970 296ENDPROC(vfp_get_double)
1da177e4 297
93ed3970 298ENTRY(vfp_put_double)
07f33a03 299 tbl_branch r2, r3, #3
1da177e4 300 .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
07f33a03 3011: fmdrr d\dr, r0, r1
1da177e4 302 mov pc, lr
07f33a03 303 .org 1b + 8
1da177e4 304 .endr
25ebee02
CM
305#ifdef CONFIG_VFPv3
306 @ d16 - d31 registers
307 .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
138de1c4 3081: mcrr p11, 3, r0, r1, c\dr @ fmdrr r0, r1, d\dr
25ebee02 309 mov pc, lr
07f33a03 310 .org 1b + 8
25ebee02
CM
311 .endr
312#endif
93ed3970 313ENDPROC(vfp_put_double)
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