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17#include <linux/init.h>
18#include <linux/linkage.h>
19#include <asm/thread_info.h>
20#include <asm/vfpmacros.h>
21#include <linux/kern_levels.h>
22#include <asm/assembler.h>
23#include <asm/asm-offsets.h>
24
25 .macro DBGSTR, str
26#ifdef DEBUG
27 stmfd sp!, {r0-r3, ip, lr}
28 ldr r0, =1f
29 bl printk
30 ldmfd sp!, {r0-r3, ip, lr}
31
32 .pushsection .rodata, "a"
331: .ascii KERN_DEBUG "VFP: \str\n"
34 .byte 0
35 .previous
36#endif
37 .endm
38
39 .macro DBGSTR1, str, arg
40#ifdef DEBUG
41 stmfd sp!, {r0-r3, ip, lr}
42 mov r1, \arg
43 ldr r0, =1f
44 bl printk
45 ldmfd sp!, {r0-r3, ip, lr}
46
47 .pushsection .rodata, "a"
481: .ascii KERN_DEBUG "VFP: \str\n"
49 .byte 0
50 .previous
51#endif
52 .endm
53
54 .macro DBGSTR3, str, arg1, arg2, arg3
55#ifdef DEBUG
56 stmfd sp!, {r0-r3, ip, lr}
57 mov r3, \arg3
58 mov r2, \arg2
59 mov r1, \arg1
60 ldr r0, =1f
61 bl printk
62 ldmfd sp!, {r0-r3, ip, lr}
63
64 .pushsection .rodata, "a"
651: .ascii KERN_DEBUG "VFP: \str\n"
66 .byte 0
67 .previous
68#endif
69 .endm
70
71
72@ VFP hardware support entry point.
73@
74@ r0 = instruction opcode (32-bit ARM or two 16-bit Thumb)
75@ r2 = PC value to resume execution after successful emulation
76@ r9 = normal "successful" return address
77@ r10 = vfp_state union
78@ r11 = CPU number
79@ lr = unrecognised instruction return address
80@ IRQs enabled.
81ENTRY(vfp_support_entry)
82 DBGSTR3 "instr %08x pc %08x state %p", r0, r2, r10
83
84 ldr r3, [sp,
85 and r3, r3,
86 teq r3,
87 bne vfp_kmode_exception @ Returns through lr
88
89 VFPFMRX r1, FPEXC @ Is the VFP enabled?
90 DBGSTR1 "fpexc %08x", r1
91 tst r1,
92 bne look_for_VFP_exceptions @ VFP is already enabled
93
94 DBGSTR1 "enable %x", r10
95 ldr r3, vfp_current_hw_state_address
96 orr r1, r1,
97 ldr r4, [r3, r11, lsl
98 bic r5, r1,
99 cmp r4, r10 @ this thread owns the hw context?
100#ifndef CONFIG_SMP
101 @ For UP, checking that this thread owns the hw context is
102 @ sufficient to determine that the hardware state is valid.
103 beq vfp_hw_state_valid
104
105 @ On UP, we lazily save the VFP context. As a different
106 @ thread wants ownership of the VFP hardware, save the old
107 @ state if there was a previous (valid) owner.
108
109 VFPFMXR FPEXC, r5 @ enable VFP, disable any pending
110 @ exceptions, so we can get at the
111 @ rest of it
112
113 DBGSTR1 "save old state %p", r4
114 cmp r4,
115 beq vfp_reload_hw @ then the hw state needs reloading
116 VFPFSTMIA r4, r5 @ save the working registers
117 VFPFMRX r5, FPSCR @ current status
118#ifndef CONFIG_CPU_FEROCEON
119 tst r1,
120 beq 1f
121 VFPFMRX r6, FPINST @ FPINST (only if FPEXC.EX is set)
122 tst r1,
123 beq 1f
124 VFPFMRX r8, FPINST2 @ FPINST2 if needed (and present)
1251:
126#endif
127 stmia r4, {r1, r5, r6, r8} @ save FPEXC, FPSCR, FPINST, FPINST2
128vfp_reload_hw:
129
130#else
131 @ For SMP, if this thread does not own the hw context, then we
132 @ need to reload it. No need to save the old state as on SMP,
133 @ we always save the state when we switch away from a thread.
134 bne vfp_reload_hw
135
136 @ This thread has ownership of the current hardware context.
137 @ However, it may have been migrated to another CPU, in which
138 @ case the saved state is newer than the hardware context.
139 @ Check this by looking at the CPU number which the state was
140 @ last loaded onto.
141 ldr ip, [r10,
142 teq ip, r11
143 beq vfp_hw_state_valid
144
145vfp_reload_hw:
146 @ We're loading this threads state into the VFP hardware. Update
147 @ the CPU number which contains the most up to date VFP context.
148 str r11, [r10,
149
150 VFPFMXR FPEXC, r5 @ enable VFP, disable any pending
151 @ exceptions, so we can get at the
152 @ rest of it
153#endif
154
155 DBGSTR1 "load state %p", r10
156 str r10, [r3, r11, lsl
157 @ Load the saved state back into the VFP
158 VFPFLDMIA r10, r5 @ reload the working registers while
159 @ FPEXC is in a safe state
160 ldmia r10, {r1, r5, r6, r8} @ load FPEXC, FPSCR, FPINST, FPINST2
161#ifndef CONFIG_CPU_FEROCEON
162 tst r1,
163 beq 1f
164 VFPFMXR FPINST, r6 @ restore FPINST (only if FPEXC.EX is set)
165 tst r1,
166 beq 1f
167 VFPFMXR FPINST2, r8 @ FPINST2 if needed (and present)
1681:
169#endif
170 VFPFMXR FPSCR, r5 @ restore status
171
172@ The context stored in the VFP hardware is up to date with this thread
173vfp_hw_state_valid:
174 tst r1,
175 bne process_exception @ might as well handle the pending
176 @ exception before retrying branch
177 @ out before setting an FPEXC that
178 @ stops us reading stuff
179 VFPFMXR FPEXC, r1 @ Restore FPEXC last
180 sub r2, r2,
181 str r2, [sp,
182 @ else it's one 32-bit instruction, so
183 @ always subtract 4 from the following
184 @ instruction address.
185 dec_preempt_count_ti r10, r4
186 ret r9 @ we think we have handled things
187
188
189look_for_VFP_exceptions:
190 @ Check for synchronous or asynchronous exception
191 tst r1,
192 bne process_exception
193 @ On some implementations of the VFP subarch 1, setting FPSCR.IXE
194 @ causes all the CDP instructions to be bounced synchronously without
195 @ setting the FPEXC.EX bit
196 VFPFMRX r5, FPSCR
197 tst r5,
198 bne process_exception
199
200 tst r5,
201 beq skip
202 orr r1, r1,
203 b process_exception
204skip:
205
206 @ Fall into hand on to next handler - appropriate coproc instr
207 @ not recognised by VFP
208
209 DBGSTR "not VFP"
210 dec_preempt_count_ti r10, r4
211 ret lr
212
213process_exception:
214 DBGSTR "bounce"
215 mov r2, sp @ nothing stacked - regdump is at TOS
216 mov lr, r9 @ setup for a return to the user code.
217
218 @ Now call the C code to package up the bounce to the support code
219 @ r0 holds the trigger instruction
220 @ r1 holds the FPEXC value
221 @ r2 pointer to register dump
222 b VFP_bounce @ we have handled this - the support
223 @ code will raise an exception if
224 @ required. If not, the user code will
225 @ retry the faulted instruction
226ENDPROC(vfp_support_entry)
227
228ENTRY(vfp_save_state)
229 @ Save the current VFP state
230 @ r0 - save location
231 @ r1 - FPEXC
232 DBGSTR1 "save VFP state %p", r0
233 VFPFSTMIA r0, r2 @ save the working registers
234 VFPFMRX r2, FPSCR @ current status
235 tst r1,
236 beq 1f
237 VFPFMRX r3, FPINST @ FPINST (only if FPEXC.EX is set)
238 tst r1,
239 beq 1f
240 VFPFMRX r12, FPINST2 @ FPINST2 if needed (and present)
2411:
242 stmia r0, {r1, r2, r3, r12} @ save FPEXC, FPSCR, FPINST, FPINST2
243 ret lr
244ENDPROC(vfp_save_state)
245
246 .align
247vfp_current_hw_state_address:
248 .word vfp_current_hw_state
249
250 .macro tbl_branch, base, tmp, shift
251#ifdef CONFIG_THUMB2_KERNEL
252 adr \tmp, 1f
253 add \tmp, \tmp, \base, lsl \shift
254 ret \tmp
255#else
256 add pc, pc, \base, lsl \shift
257 mov r0, r0
258#endif
2591:
260 .endm
261
262ENTRY(vfp_get_float)
263 tbl_branch r0, r3,
264 .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
2651: mrc p10, 0, r0, c\dr, c0, 0 @ fmrs r0, s0
266 ret lr
267 .org 1b + 8
2681: mrc p10, 0, r0, c\dr, c0, 4 @ fmrs r0, s1
269 ret lr
270 .org 1b + 8
271 .endr
272ENDPROC(vfp_get_float)
273
274ENTRY(vfp_put_float)
275 tbl_branch r1, r3,
276 .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
2771: mcr p10, 0, r0, c\dr, c0, 0 @ fmsr r0, s0
278 ret lr
279 .org 1b + 8
2801: mcr p10, 0, r0, c\dr, c0, 4 @ fmsr r0, s1
281 ret lr
282 .org 1b + 8
283 .endr
284ENDPROC(vfp_put_float)
285
286ENTRY(vfp_get_double)
287 tbl_branch r0, r3,
288 .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
2891: fmrrd r0, r1, d\dr
290 ret lr
291 .org 1b + 8
292 .endr
293#ifdef CONFIG_VFPv3
294 @ d16 - d31 registers
295 .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
2961: mrrc p11, 3, r0, r1, c\dr @ fmrrd r0, r1, d\dr
297 ret lr
298 .org 1b + 8
299 .endr
300#endif
301
302 @ virtual register 16 (or 32 if VFPv3) for compare with zero
303 mov r0,
304 mov r1,
305 ret lr
306ENDPROC(vfp_get_double)
307
308ENTRY(vfp_put_double)
309 tbl_branch r2, r3,
310 .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
3111: fmdrr d\dr, r0, r1
312 ret lr
313 .org 1b + 8
314 .endr
315#ifdef CONFIG_VFPv3
316 @ d16 - d31 registers
317 .irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
3181: mcrr p11, 3, r0, r1, c\dr @ fmdrr r0, r1, d\dr
319 ret lr
320 .org 1b + 8
321 .endr
322#endif
323ENDPROC(vfp_put_double)
324
