Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
1da177e4 LT |
2 | * Copyright (C) 1994 Linus Torvalds |
3 | * | |
4 | * Pentium III FXSR, SSE support | |
5 | * General FPU state handling cleanups | |
6 | * Gareth Hughes <gareth@valinux.com>, May 2000 | |
7 | */ | |
78f7f1e5 | 8 | #include <asm/fpu/internal.h> |
91066588 | 9 | #include <linux/hardirq.h> |
1da177e4 | 10 | |
085cc281 IM |
11 | /* |
12 | * Track whether the kernel is using the FPU state | |
13 | * currently. | |
14 | * | |
15 | * This flag is used: | |
16 | * | |
17 | * - by IRQ context code to potentially use the FPU | |
18 | * if it's unused. | |
19 | * | |
20 | * - to debug kernel_fpu_begin()/end() correctness | |
21 | */ | |
14e153ef ON |
22 | static DEFINE_PER_CPU(bool, in_kernel_fpu); |
23 | ||
b0c050c5 | 24 | /* |
36b544dc | 25 | * Track which context is using the FPU on the CPU: |
b0c050c5 | 26 | */ |
36b544dc | 27 | DEFINE_PER_CPU(struct fpu *, fpu_fpregs_owner_ctx); |
b0c050c5 | 28 | |
416d49ac | 29 | static void kernel_fpu_disable(void) |
7575637a ON |
30 | { |
31 | WARN_ON(this_cpu_read(in_kernel_fpu)); | |
32 | this_cpu_write(in_kernel_fpu, true); | |
33 | } | |
34 | ||
416d49ac | 35 | static void kernel_fpu_enable(void) |
7575637a | 36 | { |
3103ae3a | 37 | WARN_ON_ONCE(!this_cpu_read(in_kernel_fpu)); |
7575637a ON |
38 | this_cpu_write(in_kernel_fpu, false); |
39 | } | |
40 | ||
085cc281 IM |
41 | static bool kernel_fpu_disabled(void) |
42 | { | |
43 | return this_cpu_read(in_kernel_fpu); | |
44 | } | |
45 | ||
8546c008 LT |
46 | /* |
47 | * Were we in an interrupt that interrupted kernel mode? | |
48 | * | |
304bceda | 49 | * On others, we can do a kernel_fpu_begin/end() pair *ONLY* if that |
8546c008 LT |
50 | * pair does nothing at all: the thread must not have fpu (so |
51 | * that we don't try to save the FPU state), and TS must | |
52 | * be set (so that the clts/stts pair does nothing that is | |
53 | * visible in the interrupted kernel thread). | |
5187b28f | 54 | * |
4b2e762e ON |
55 | * Except for the eagerfpu case when we return true; in the likely case |
56 | * the thread has FPU but we are not going to set/clear TS. | |
8546c008 | 57 | */ |
416d49ac | 58 | static bool interrupted_kernel_fpu_idle(void) |
8546c008 | 59 | { |
085cc281 | 60 | if (kernel_fpu_disabled()) |
14e153ef ON |
61 | return false; |
62 | ||
5d2bd700 | 63 | if (use_eager_fpu()) |
4b2e762e | 64 | return true; |
304bceda | 65 | |
d5cea9b0 | 66 | return !current->thread.fpu.fpregs_active && (read_cr0() & X86_CR0_TS); |
8546c008 LT |
67 | } |
68 | ||
69 | /* | |
70 | * Were we in user mode (or vm86 mode) when we were | |
71 | * interrupted? | |
72 | * | |
73 | * Doing kernel_fpu_begin/end() is ok if we are running | |
74 | * in an interrupt context from user mode - we'll just | |
75 | * save the FPU state as required. | |
76 | */ | |
416d49ac | 77 | static bool interrupted_user_mode(void) |
8546c008 LT |
78 | { |
79 | struct pt_regs *regs = get_irq_regs(); | |
f39b6f0e | 80 | return regs && user_mode(regs); |
8546c008 LT |
81 | } |
82 | ||
83 | /* | |
84 | * Can we use the FPU in kernel mode with the | |
85 | * whole "kernel_fpu_begin/end()" sequence? | |
86 | * | |
87 | * It's always ok in process context (ie "not interrupt") | |
88 | * but it is sometimes ok even from an irq. | |
89 | */ | |
90 | bool irq_fpu_usable(void) | |
91 | { | |
92 | return !in_interrupt() || | |
93 | interrupted_user_mode() || | |
94 | interrupted_kernel_fpu_idle(); | |
95 | } | |
96 | EXPORT_SYMBOL(irq_fpu_usable); | |
97 | ||
b1a74bf8 | 98 | void __kernel_fpu_begin(void) |
8546c008 | 99 | { |
36b544dc | 100 | struct fpu *fpu = ¤t->thread.fpu; |
8546c008 | 101 | |
3103ae3a | 102 | kernel_fpu_disable(); |
14e153ef | 103 | |
d5cea9b0 | 104 | if (fpu->fpregs_active) { |
4f836347 | 105 | copy_fpregs_to_fpstate(fpu); |
7aeccb83 | 106 | } else { |
36b544dc | 107 | this_cpu_write(fpu_fpregs_owner_ctx, NULL); |
32b49b3c | 108 | __fpregs_activate_hw(); |
8546c008 LT |
109 | } |
110 | } | |
b1a74bf8 | 111 | EXPORT_SYMBOL(__kernel_fpu_begin); |
8546c008 | 112 | |
b1a74bf8 | 113 | void __kernel_fpu_end(void) |
8546c008 | 114 | { |
af2d94fd | 115 | struct fpu *fpu = ¤t->thread.fpu; |
33a3ebdc | 116 | |
d5cea9b0 | 117 | if (fpu->fpregs_active) { |
11f2d50b | 118 | if (WARN_ON(restore_fpu_checking(fpu))) |
af2d94fd | 119 | fpu_reset_state(fpu); |
32b49b3c IM |
120 | } else { |
121 | __fpregs_deactivate_hw(); | |
731bd6a9 | 122 | } |
14e153ef | 123 | |
3103ae3a | 124 | kernel_fpu_enable(); |
8546c008 | 125 | } |
b1a74bf8 | 126 | EXPORT_SYMBOL(__kernel_fpu_end); |
8546c008 | 127 | |
d63e79b1 IM |
128 | void kernel_fpu_begin(void) |
129 | { | |
130 | preempt_disable(); | |
131 | WARN_ON_ONCE(!irq_fpu_usable()); | |
132 | __kernel_fpu_begin(); | |
133 | } | |
134 | EXPORT_SYMBOL_GPL(kernel_fpu_begin); | |
135 | ||
136 | void kernel_fpu_end(void) | |
137 | { | |
138 | __kernel_fpu_end(); | |
139 | preempt_enable(); | |
140 | } | |
141 | EXPORT_SYMBOL_GPL(kernel_fpu_end); | |
142 | ||
91066588 IM |
143 | /* |
144 | * CR0::TS save/restore functions: | |
145 | */ | |
146 | int irq_ts_save(void) | |
147 | { | |
148 | /* | |
149 | * If in process context and not atomic, we can take a spurious DNA fault. | |
150 | * Otherwise, doing clts() in process context requires disabling preemption | |
151 | * or some heavy lifting like kernel_fpu_begin() | |
152 | */ | |
153 | if (!in_atomic()) | |
154 | return 0; | |
155 | ||
156 | if (read_cr0() & X86_CR0_TS) { | |
157 | clts(); | |
158 | return 1; | |
159 | } | |
160 | ||
161 | return 0; | |
162 | } | |
163 | EXPORT_SYMBOL_GPL(irq_ts_save); | |
164 | ||
165 | void irq_ts_restore(int TS_state) | |
166 | { | |
167 | if (TS_state) | |
168 | stts(); | |
169 | } | |
170 | EXPORT_SYMBOL_GPL(irq_ts_restore); | |
171 | ||
4af08f2f | 172 | /* |
48c4717f | 173 | * Save the FPU state (mark it for reload if necessary): |
87cdb98a IM |
174 | * |
175 | * This only ever gets called for the current task. | |
4af08f2f | 176 | */ |
0c070595 | 177 | void fpu__save(struct fpu *fpu) |
8546c008 | 178 | { |
0c070595 | 179 | WARN_ON(fpu != ¤t->thread.fpu); |
87cdb98a | 180 | |
8546c008 | 181 | preempt_disable(); |
d5cea9b0 | 182 | if (fpu->fpregs_active) { |
48c4717f | 183 | if (!copy_fpregs_to_fpstate(fpu)) |
66af8e27 | 184 | fpregs_deactivate(fpu); |
a9241ea5 | 185 | } |
8546c008 LT |
186 | preempt_enable(); |
187 | } | |
4af08f2f | 188 | EXPORT_SYMBOL_GPL(fpu__save); |
8546c008 | 189 | |
c0ee2cf6 | 190 | void fpstate_init(struct fpu *fpu) |
1da177e4 | 191 | { |
60e019eb | 192 | if (!cpu_has_fpu) { |
7366ed77 | 193 | finit_soft_fpu(&fpu->state.soft); |
86603283 | 194 | return; |
e8a496ac | 195 | } |
e8a496ac | 196 | |
7366ed77 | 197 | memset(&fpu->state, 0, xstate_size); |
1d23c451 | 198 | |
1da177e4 | 199 | if (cpu_has_fxsr) { |
7366ed77 | 200 | fx_finit(&fpu->state.fxsave); |
1da177e4 | 201 | } else { |
7366ed77 | 202 | struct i387_fsave_struct *fp = &fpu->state.fsave; |
61c4628b SS |
203 | fp->cwd = 0xffff037fu; |
204 | fp->swd = 0xffff0000u; | |
205 | fp->twd = 0xffffffffu; | |
206 | fp->fos = 0xffff0000u; | |
1da177e4 | 207 | } |
86603283 | 208 | } |
c0ee2cf6 | 209 | EXPORT_SYMBOL_GPL(fpstate_init); |
86603283 | 210 | |
bfd6fc05 IM |
211 | /* |
212 | * Copy the current task's FPU state to a new task's FPU context. | |
213 | * | |
214 | * In the 'eager' case we just save to the destination context. | |
215 | * | |
216 | * In the 'lazy' case we save to the source context, mark the FPU lazy | |
217 | * via stts() and copy the source context into the destination context. | |
218 | */ | |
f9bc977f | 219 | static void fpu_copy(struct fpu *dst_fpu, struct fpu *src_fpu) |
e102f30f | 220 | { |
f9bc977f | 221 | WARN_ON(src_fpu != ¤t->thread.fpu); |
bfd6fc05 | 222 | |
b1652900 IM |
223 | /* |
224 | * Don't let 'init optimized' areas of the XSAVE area | |
225 | * leak into the child task: | |
226 | */ | |
227 | if (use_eager_fpu()) | |
7366ed77 | 228 | memset(&dst_fpu->state.xsave, 0, xstate_size); |
b1652900 IM |
229 | |
230 | /* | |
231 | * Save current FPU registers directly into the child | |
232 | * FPU context, without any memory-to-memory copying. | |
233 | * | |
234 | * If the FPU context got destroyed in the process (FNSAVE | |
235 | * done on old CPUs) then copy it back into the source | |
236 | * context and mark the current task for lazy restore. | |
237 | * | |
238 | * We have to do all this with preemption disabled, | |
239 | * mostly because of the FNSAVE case, because in that | |
240 | * case we must not allow preemption in the window | |
241 | * between the FNSAVE and us marking the context lazy. | |
242 | * | |
243 | * It shouldn't be an issue as even FNSAVE is plenty | |
244 | * fast in terms of critical section length. | |
245 | */ | |
246 | preempt_disable(); | |
247 | if (!copy_fpregs_to_fpstate(dst_fpu)) { | |
248 | memcpy(&src_fpu->state, &dst_fpu->state, xstate_size); | |
249 | fpregs_deactivate(src_fpu); | |
e102f30f | 250 | } |
b1652900 | 251 | preempt_enable(); |
e102f30f IM |
252 | } |
253 | ||
c69e098b | 254 | int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu) |
a752b53d | 255 | { |
c69e098b | 256 | dst_fpu->counter = 0; |
d5cea9b0 | 257 | dst_fpu->fpregs_active = 0; |
c69e098b | 258 | dst_fpu->last_cpu = -1; |
a752b53d | 259 | |
c4d6ee6e | 260 | if (src_fpu->fpstate_active) |
f9bc977f | 261 | fpu_copy(dst_fpu, src_fpu); |
c4d6ee6e | 262 | |
a752b53d IM |
263 | return 0; |
264 | } | |
265 | ||
97185c95 | 266 | /* |
c4d72e2d IM |
267 | * Activate the current task's in-memory FPU context, |
268 | * if it has not been used before: | |
97185c95 | 269 | */ |
c4d72e2d | 270 | void fpu__activate_curr(struct fpu *fpu) |
97185c95 | 271 | { |
91d93d0e | 272 | WARN_ON_ONCE(fpu != ¤t->thread.fpu); |
97185c95 | 273 | |
c4d72e2d IM |
274 | if (!fpu->fpstate_active) { |
275 | fpstate_init(fpu); | |
97185c95 | 276 | |
c4d72e2d IM |
277 | /* Safe to do for the current task: */ |
278 | fpu->fpstate_active = 1; | |
279 | } | |
97185c95 | 280 | } |
c4d72e2d | 281 | EXPORT_SYMBOL_GPL(fpu__activate_curr); |
97185c95 | 282 | |
86603283 | 283 | /* |
67ee658e IM |
284 | * This function must be called before we modify a stopped child's |
285 | * fpstate. | |
af7f8721 IM |
286 | * |
287 | * If the child has not used the FPU before then initialize its | |
67ee658e | 288 | * fpstate. |
af7f8721 IM |
289 | * |
290 | * If the child has used the FPU before then unlazy it. | |
291 | * | |
67ee658e IM |
292 | * [ After this function call, after registers in the fpstate are |
293 | * modified and the child task has woken up, the child task will | |
294 | * restore the modified FPU state from the modified context. If we | |
af7f8721 | 295 | * didn't clear its lazy status here then the lazy in-registers |
67ee658e | 296 | * state pending on its former CPU could be restored, corrupting |
af7f8721 IM |
297 | * the modifications. ] |
298 | * | |
299 | * This function is also called before we read a stopped child's | |
67ee658e IM |
300 | * FPU state - to make sure it's initialized if the child has |
301 | * no active FPU state. | |
af7f8721 IM |
302 | * |
303 | * TODO: A future optimization would be to skip the unlazying in | |
304 | * the read-only case, it's not strictly necessary for | |
305 | * read-only access to the context. | |
86603283 | 306 | */ |
67ee658e | 307 | static void fpu__activate_stopped(struct fpu *child_fpu) |
86603283 | 308 | { |
2fb29fc7 | 309 | WARN_ON_ONCE(child_fpu == ¤t->thread.fpu); |
67e97fc2 | 310 | |
c5bedc68 | 311 | if (child_fpu->fpstate_active) { |
cc08d545 | 312 | child_fpu->last_cpu = -1; |
2fb29fc7 IM |
313 | } else { |
314 | fpstate_init(child_fpu); | |
071ae621 | 315 | |
2fb29fc7 IM |
316 | /* Safe to do for stopped child tasks: */ |
317 | child_fpu->fpstate_active = 1; | |
318 | } | |
1da177e4 LT |
319 | } |
320 | ||
93b90712 | 321 | /* |
be7436d5 IM |
322 | * 'fpu__restore()' is called to copy FPU registers from |
323 | * the FPU fpstate to the live hw registers and to activate | |
324 | * access to the hardware registers, so that FPU instructions | |
325 | * can be used afterwards. | |
93b90712 | 326 | * |
be7436d5 IM |
327 | * Must be called with kernel preemption disabled (for example |
328 | * with local interrupts disabled, as it is in the case of | |
329 | * do_device_not_available()). | |
93b90712 | 330 | */ |
3a0aee48 | 331 | void fpu__restore(void) |
93b90712 IM |
332 | { |
333 | struct task_struct *tsk = current; | |
4540d3fa | 334 | struct fpu *fpu = &tsk->thread.fpu; |
93b90712 | 335 | |
c4d72e2d | 336 | fpu__activate_curr(fpu); |
93b90712 | 337 | |
232f62cd | 338 | /* Avoid __kernel_fpu_begin() right after fpregs_activate() */ |
93b90712 | 339 | kernel_fpu_disable(); |
232f62cd | 340 | fpregs_activate(fpu); |
11f2d50b | 341 | if (unlikely(restore_fpu_checking(fpu))) { |
af2d94fd | 342 | fpu_reset_state(fpu); |
93b90712 IM |
343 | force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk); |
344 | } else { | |
345 | tsk->thread.fpu.counter++; | |
346 | } | |
347 | kernel_fpu_enable(); | |
348 | } | |
3a0aee48 | 349 | EXPORT_SYMBOL_GPL(fpu__restore); |
93b90712 | 350 | |
2e85591a IM |
351 | /* |
352 | * Called by sys_execve() to clear the FPU fpregs, so that FPU state | |
353 | * of the previous binary does not leak over into the exec()ed binary: | |
354 | */ | |
2e8a3102 | 355 | void fpu__clear(struct task_struct *tsk) |
81683cc8 | 356 | { |
c5bedc68 IM |
357 | struct fpu *fpu = &tsk->thread.fpu; |
358 | ||
2e8a3102 | 359 | WARN_ON_ONCE(tsk != current); /* Almost certainly an anomaly */ |
4c138410 | 360 | |
81683cc8 IM |
361 | if (!use_eager_fpu()) { |
362 | /* FPU state will be reallocated lazily at the first use. */ | |
ca6787ba | 363 | drop_fpu(fpu); |
81683cc8 | 364 | } else { |
c5bedc68 | 365 | if (!fpu->fpstate_active) { |
c4d72e2d | 366 | fpu__activate_curr(fpu); |
81683cc8 IM |
367 | user_fpu_begin(); |
368 | } | |
369 | restore_init_xstate(); | |
370 | } | |
371 | } | |
372 | ||
5b3efd50 | 373 | /* |
678eaf60 | 374 | * The xstateregs_active() routine is the same as the regset_fpregs_active() routine, |
5b3efd50 SS |
375 | * as the "regset->n" for the xstate regset will be updated based on the feature |
376 | * capabilites supported by the xsave. | |
377 | */ | |
678eaf60 | 378 | int regset_fpregs_active(struct task_struct *target, const struct user_regset *regset) |
44210111 | 379 | { |
c5bedc68 IM |
380 | struct fpu *target_fpu = &target->thread.fpu; |
381 | ||
382 | return target_fpu->fpstate_active ? regset->n : 0; | |
44210111 | 383 | } |
1da177e4 | 384 | |
678eaf60 | 385 | int regset_xregset_fpregs_active(struct task_struct *target, const struct user_regset *regset) |
1da177e4 | 386 | { |
c5bedc68 IM |
387 | struct fpu *target_fpu = &target->thread.fpu; |
388 | ||
389 | return (cpu_has_fxsr && target_fpu->fpstate_active) ? regset->n : 0; | |
44210111 | 390 | } |
1da177e4 | 391 | |
44210111 RM |
392 | int xfpregs_get(struct task_struct *target, const struct user_regset *regset, |
393 | unsigned int pos, unsigned int count, | |
394 | void *kbuf, void __user *ubuf) | |
395 | { | |
cc08d545 | 396 | struct fpu *fpu = &target->thread.fpu; |
aa283f49 | 397 | |
44210111 RM |
398 | if (!cpu_has_fxsr) |
399 | return -ENODEV; | |
400 | ||
67ee658e | 401 | fpu__activate_stopped(fpu); |
36e49e7f | 402 | fpstate_sanitize_xstate(fpu); |
29104e10 | 403 | |
44210111 | 404 | return user_regset_copyout(&pos, &count, &kbuf, &ubuf, |
7366ed77 | 405 | &fpu->state.fxsave, 0, -1); |
1da177e4 | 406 | } |
44210111 RM |
407 | |
408 | int xfpregs_set(struct task_struct *target, const struct user_regset *regset, | |
409 | unsigned int pos, unsigned int count, | |
410 | const void *kbuf, const void __user *ubuf) | |
411 | { | |
cc08d545 | 412 | struct fpu *fpu = &target->thread.fpu; |
44210111 RM |
413 | int ret; |
414 | ||
415 | if (!cpu_has_fxsr) | |
416 | return -ENODEV; | |
417 | ||
67ee658e | 418 | fpu__activate_stopped(fpu); |
36e49e7f | 419 | fpstate_sanitize_xstate(fpu); |
29104e10 | 420 | |
44210111 | 421 | ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, |
7366ed77 | 422 | &fpu->state.fxsave, 0, -1); |
44210111 RM |
423 | |
424 | /* | |
425 | * mxcsr reserved bits must be masked to zero for security reasons. | |
426 | */ | |
7366ed77 | 427 | fpu->state.fxsave.mxcsr &= mxcsr_feature_mask; |
44210111 | 428 | |
42deec6f SS |
429 | /* |
430 | * update the header bits in the xsave header, indicating the | |
431 | * presence of FP and SSE state. | |
432 | */ | |
433 | if (cpu_has_xsave) | |
7366ed77 | 434 | fpu->state.xsave.header.xfeatures |= XSTATE_FPSSE; |
42deec6f | 435 | |
44210111 RM |
436 | return ret; |
437 | } | |
438 | ||
5b3efd50 SS |
439 | int xstateregs_get(struct task_struct *target, const struct user_regset *regset, |
440 | unsigned int pos, unsigned int count, | |
441 | void *kbuf, void __user *ubuf) | |
442 | { | |
cc08d545 | 443 | struct fpu *fpu = &target->thread.fpu; |
18ecb3bf | 444 | struct xsave_struct *xsave; |
5b3efd50 SS |
445 | int ret; |
446 | ||
447 | if (!cpu_has_xsave) | |
448 | return -ENODEV; | |
449 | ||
67ee658e | 450 | fpu__activate_stopped(fpu); |
5b3efd50 | 451 | |
7366ed77 | 452 | xsave = &fpu->state.xsave; |
18ecb3bf | 453 | |
5b3efd50 | 454 | /* |
ff7fbc72 SS |
455 | * Copy the 48bytes defined by the software first into the xstate |
456 | * memory layout in the thread struct, so that we can copy the entire | |
457 | * xstateregs to the user using one user_regset_copyout(). | |
5b3efd50 | 458 | */ |
e7f180dc ON |
459 | memcpy(&xsave->i387.sw_reserved, |
460 | xstate_fx_sw_bytes, sizeof(xstate_fx_sw_bytes)); | |
5b3efd50 | 461 | /* |
ff7fbc72 | 462 | * Copy the xstate memory layout. |
5b3efd50 | 463 | */ |
e7f180dc | 464 | ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, xsave, 0, -1); |
5b3efd50 SS |
465 | return ret; |
466 | } | |
467 | ||
468 | int xstateregs_set(struct task_struct *target, const struct user_regset *regset, | |
469 | unsigned int pos, unsigned int count, | |
470 | const void *kbuf, const void __user *ubuf) | |
471 | { | |
cc08d545 | 472 | struct fpu *fpu = &target->thread.fpu; |
18ecb3bf | 473 | struct xsave_struct *xsave; |
5b3efd50 | 474 | int ret; |
5b3efd50 SS |
475 | |
476 | if (!cpu_has_xsave) | |
477 | return -ENODEV; | |
478 | ||
67ee658e | 479 | fpu__activate_stopped(fpu); |
5b3efd50 | 480 | |
7366ed77 | 481 | xsave = &fpu->state.xsave; |
18ecb3bf | 482 | |
e7f180dc | 483 | ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, xsave, 0, -1); |
5b3efd50 SS |
484 | /* |
485 | * mxcsr reserved bits must be masked to zero for security reasons. | |
486 | */ | |
e7f180dc | 487 | xsave->i387.mxcsr &= mxcsr_feature_mask; |
400e4b20 | 488 | xsave->header.xfeatures &= xfeatures_mask; |
5b3efd50 SS |
489 | /* |
490 | * These bits must be zero. | |
491 | */ | |
3a54450b | 492 | memset(&xsave->header.reserved, 0, 48); |
8dcea8db | 493 | |
5b3efd50 SS |
494 | return ret; |
495 | } | |
496 | ||
44210111 | 497 | #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION |
1da177e4 | 498 | |
1da177e4 LT |
499 | /* |
500 | * FPU tag word conversions. | |
501 | */ | |
502 | ||
3b095a04 | 503 | static inline unsigned short twd_i387_to_fxsr(unsigned short twd) |
1da177e4 LT |
504 | { |
505 | unsigned int tmp; /* to avoid 16 bit prefixes in the code */ | |
3b095a04 | 506 | |
1da177e4 | 507 | /* Transform each pair of bits into 01 (valid) or 00 (empty) */ |
3b095a04 | 508 | tmp = ~twd; |
44210111 | 509 | tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */ |
3b095a04 CG |
510 | /* and move the valid bits to the lower byte. */ |
511 | tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */ | |
512 | tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */ | |
513 | tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */ | |
f668964e | 514 | |
3b095a04 | 515 | return tmp; |
1da177e4 LT |
516 | } |
517 | ||
497888cf | 518 | #define FPREG_ADDR(f, n) ((void *)&(f)->st_space + (n) * 16) |
44210111 RM |
519 | #define FP_EXP_TAG_VALID 0 |
520 | #define FP_EXP_TAG_ZERO 1 | |
521 | #define FP_EXP_TAG_SPECIAL 2 | |
522 | #define FP_EXP_TAG_EMPTY 3 | |
523 | ||
524 | static inline u32 twd_fxsr_to_i387(struct i387_fxsave_struct *fxsave) | |
525 | { | |
526 | struct _fpxreg *st; | |
527 | u32 tos = (fxsave->swd >> 11) & 7; | |
528 | u32 twd = (unsigned long) fxsave->twd; | |
529 | u32 tag; | |
530 | u32 ret = 0xffff0000u; | |
531 | int i; | |
1da177e4 | 532 | |
44210111 | 533 | for (i = 0; i < 8; i++, twd >>= 1) { |
3b095a04 CG |
534 | if (twd & 0x1) { |
535 | st = FPREG_ADDR(fxsave, (i - tos) & 7); | |
1da177e4 | 536 | |
3b095a04 | 537 | switch (st->exponent & 0x7fff) { |
1da177e4 | 538 | case 0x7fff: |
44210111 | 539 | tag = FP_EXP_TAG_SPECIAL; |
1da177e4 LT |
540 | break; |
541 | case 0x0000: | |
3b095a04 CG |
542 | if (!st->significand[0] && |
543 | !st->significand[1] && | |
544 | !st->significand[2] && | |
44210111 RM |
545 | !st->significand[3]) |
546 | tag = FP_EXP_TAG_ZERO; | |
547 | else | |
548 | tag = FP_EXP_TAG_SPECIAL; | |
1da177e4 LT |
549 | break; |
550 | default: | |
44210111 RM |
551 | if (st->significand[3] & 0x8000) |
552 | tag = FP_EXP_TAG_VALID; | |
553 | else | |
554 | tag = FP_EXP_TAG_SPECIAL; | |
1da177e4 LT |
555 | break; |
556 | } | |
557 | } else { | |
44210111 | 558 | tag = FP_EXP_TAG_EMPTY; |
1da177e4 | 559 | } |
44210111 | 560 | ret |= tag << (2 * i); |
1da177e4 LT |
561 | } |
562 | return ret; | |
563 | } | |
564 | ||
565 | /* | |
44210111 | 566 | * FXSR floating point environment conversions. |
1da177e4 LT |
567 | */ |
568 | ||
72a671ce | 569 | void |
f668964e | 570 | convert_from_fxsr(struct user_i387_ia32_struct *env, struct task_struct *tsk) |
1da177e4 | 571 | { |
7366ed77 | 572 | struct i387_fxsave_struct *fxsave = &tsk->thread.fpu.state.fxsave; |
44210111 RM |
573 | struct _fpreg *to = (struct _fpreg *) &env->st_space[0]; |
574 | struct _fpxreg *from = (struct _fpxreg *) &fxsave->st_space[0]; | |
575 | int i; | |
1da177e4 | 576 | |
44210111 RM |
577 | env->cwd = fxsave->cwd | 0xffff0000u; |
578 | env->swd = fxsave->swd | 0xffff0000u; | |
579 | env->twd = twd_fxsr_to_i387(fxsave); | |
580 | ||
581 | #ifdef CONFIG_X86_64 | |
582 | env->fip = fxsave->rip; | |
583 | env->foo = fxsave->rdp; | |
10c11f30 BG |
584 | /* |
585 | * should be actually ds/cs at fpu exception time, but | |
586 | * that information is not available in 64bit mode. | |
587 | */ | |
588 | env->fcs = task_pt_regs(tsk)->cs; | |
44210111 | 589 | if (tsk == current) { |
10c11f30 | 590 | savesegment(ds, env->fos); |
1da177e4 | 591 | } else { |
10c11f30 | 592 | env->fos = tsk->thread.ds; |
1da177e4 | 593 | } |
10c11f30 | 594 | env->fos |= 0xffff0000; |
44210111 RM |
595 | #else |
596 | env->fip = fxsave->fip; | |
609b5297 | 597 | env->fcs = (u16) fxsave->fcs | ((u32) fxsave->fop << 16); |
44210111 RM |
598 | env->foo = fxsave->foo; |
599 | env->fos = fxsave->fos; | |
600 | #endif | |
1da177e4 | 601 | |
44210111 RM |
602 | for (i = 0; i < 8; ++i) |
603 | memcpy(&to[i], &from[i], sizeof(to[0])); | |
1da177e4 LT |
604 | } |
605 | ||
72a671ce SS |
606 | void convert_to_fxsr(struct task_struct *tsk, |
607 | const struct user_i387_ia32_struct *env) | |
1da177e4 | 608 | |
1da177e4 | 609 | { |
7366ed77 | 610 | struct i387_fxsave_struct *fxsave = &tsk->thread.fpu.state.fxsave; |
44210111 RM |
611 | struct _fpreg *from = (struct _fpreg *) &env->st_space[0]; |
612 | struct _fpxreg *to = (struct _fpxreg *) &fxsave->st_space[0]; | |
613 | int i; | |
1da177e4 | 614 | |
44210111 RM |
615 | fxsave->cwd = env->cwd; |
616 | fxsave->swd = env->swd; | |
617 | fxsave->twd = twd_i387_to_fxsr(env->twd); | |
618 | fxsave->fop = (u16) ((u32) env->fcs >> 16); | |
619 | #ifdef CONFIG_X86_64 | |
620 | fxsave->rip = env->fip; | |
621 | fxsave->rdp = env->foo; | |
622 | /* cs and ds ignored */ | |
623 | #else | |
624 | fxsave->fip = env->fip; | |
625 | fxsave->fcs = (env->fcs & 0xffff); | |
626 | fxsave->foo = env->foo; | |
627 | fxsave->fos = env->fos; | |
628 | #endif | |
1da177e4 | 629 | |
44210111 RM |
630 | for (i = 0; i < 8; ++i) |
631 | memcpy(&to[i], &from[i], sizeof(from[0])); | |
1da177e4 LT |
632 | } |
633 | ||
44210111 RM |
634 | int fpregs_get(struct task_struct *target, const struct user_regset *regset, |
635 | unsigned int pos, unsigned int count, | |
636 | void *kbuf, void __user *ubuf) | |
1da177e4 | 637 | { |
cc08d545 | 638 | struct fpu *fpu = &target->thread.fpu; |
44210111 | 639 | struct user_i387_ia32_struct env; |
1da177e4 | 640 | |
67ee658e | 641 | fpu__activate_stopped(fpu); |
1da177e4 | 642 | |
60e019eb | 643 | if (!static_cpu_has(X86_FEATURE_FPU)) |
e8a496ac SS |
644 | return fpregs_soft_get(target, regset, pos, count, kbuf, ubuf); |
645 | ||
60e019eb | 646 | if (!cpu_has_fxsr) |
44210111 | 647 | return user_regset_copyout(&pos, &count, &kbuf, &ubuf, |
7366ed77 | 648 | &fpu->state.fsave, 0, |
61c4628b | 649 | -1); |
1da177e4 | 650 | |
36e49e7f | 651 | fpstate_sanitize_xstate(fpu); |
29104e10 | 652 | |
44210111 RM |
653 | if (kbuf && pos == 0 && count == sizeof(env)) { |
654 | convert_from_fxsr(kbuf, target); | |
655 | return 0; | |
1da177e4 | 656 | } |
44210111 RM |
657 | |
658 | convert_from_fxsr(&env, target); | |
f668964e | 659 | |
44210111 | 660 | return user_regset_copyout(&pos, &count, &kbuf, &ubuf, &env, 0, -1); |
1da177e4 LT |
661 | } |
662 | ||
44210111 RM |
663 | int fpregs_set(struct task_struct *target, const struct user_regset *regset, |
664 | unsigned int pos, unsigned int count, | |
665 | const void *kbuf, const void __user *ubuf) | |
1da177e4 | 666 | { |
cc08d545 | 667 | struct fpu *fpu = &target->thread.fpu; |
44210111 RM |
668 | struct user_i387_ia32_struct env; |
669 | int ret; | |
1da177e4 | 670 | |
67ee658e | 671 | fpu__activate_stopped(fpu); |
36e49e7f | 672 | fpstate_sanitize_xstate(fpu); |
29104e10 | 673 | |
60e019eb | 674 | if (!static_cpu_has(X86_FEATURE_FPU)) |
e8a496ac SS |
675 | return fpregs_soft_set(target, regset, pos, count, kbuf, ubuf); |
676 | ||
60e019eb | 677 | if (!cpu_has_fxsr) |
44210111 | 678 | return user_regset_copyin(&pos, &count, &kbuf, &ubuf, |
7366ed77 | 679 | &fpu->state.fsave, 0, |
60e019eb | 680 | -1); |
44210111 RM |
681 | |
682 | if (pos > 0 || count < sizeof(env)) | |
683 | convert_from_fxsr(&env, target); | |
684 | ||
685 | ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &env, 0, -1); | |
686 | if (!ret) | |
687 | convert_to_fxsr(target, &env); | |
688 | ||
42deec6f SS |
689 | /* |
690 | * update the header bit in the xsave header, indicating the | |
691 | * presence of FP. | |
692 | */ | |
693 | if (cpu_has_xsave) | |
7366ed77 | 694 | fpu->state.xsave.header.xfeatures |= XSTATE_FP; |
44210111 | 695 | return ret; |
1da177e4 LT |
696 | } |
697 | ||
1da177e4 LT |
698 | /* |
699 | * FPU state for core dumps. | |
60b3b9af RM |
700 | * This is only used for a.out dumps now. |
701 | * It is declared generically using elf_fpregset_t (which is | |
702 | * struct user_i387_struct) but is in fact only used for 32-bit | |
703 | * dumps, so on 64-bit it is really struct user_i387_ia32_struct. | |
1da177e4 | 704 | */ |
c5bedc68 | 705 | int dump_fpu(struct pt_regs *regs, struct user_i387_struct *ufpu) |
1da177e4 | 706 | { |
1da177e4 | 707 | struct task_struct *tsk = current; |
c5bedc68 | 708 | struct fpu *fpu = &tsk->thread.fpu; |
f668964e | 709 | int fpvalid; |
1da177e4 | 710 | |
c5bedc68 | 711 | fpvalid = fpu->fpstate_active; |
60b3b9af RM |
712 | if (fpvalid) |
713 | fpvalid = !fpregs_get(tsk, NULL, | |
714 | 0, sizeof(struct user_i387_ia32_struct), | |
c5bedc68 | 715 | ufpu, NULL); |
1da177e4 LT |
716 | |
717 | return fpvalid; | |
718 | } | |
129f6946 | 719 | EXPORT_SYMBOL(dump_fpu); |
1da177e4 | 720 | |
60b3b9af | 721 | #endif /* CONFIG_X86_32 || CONFIG_IA32_EMULATION */ |