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Suresh Siddhadc1e35c2008-07-29 10:29:19 -07001/*
2 * xsave/xrstor support.
3 *
4 * Author: Suresh Siddha <suresh.b.siddha@intel.com>
5 */
Joe Perchesc767a542012-05-21 19:50:07 -07006
7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
Suresh Siddhadc1e35c2008-07-29 10:29:19 -07009#include <linux/bootmem.h>
10#include <linux/compat.h>
11#include <asm/i387.h>
Linus Torvalds1361b832012-02-21 13:19:22 -080012#include <asm/fpu-internal.h>
Suresh Siddha72a671c2012-07-24 16:05:29 -070013#include <asm/sigframe.h>
H. Peter Anvin6152e4b2008-07-29 17:23:16 -070014#include <asm/xcr.h>
Suresh Siddhadc1e35c2008-07-29 10:29:19 -070015
16/*
17 * Supported feature mask by the CPU and the kernel.
18 */
H. Peter Anvin6152e4b2008-07-29 17:23:16 -070019u64 pcntxt_mask;
Suresh Siddhadc1e35c2008-07-29 10:29:19 -070020
Robert Richter45c2d7f2010-07-21 19:03:55 +020021/*
22 * Represents init state for the supported extended state.
23 */
Suresh Siddha304bced2012-08-24 14:13:02 -070024struct xsave_struct *init_xstate_buf;
Robert Richter45c2d7f2010-07-21 19:03:55 +020025
Suresh Siddha72a671c2012-07-24 16:05:29 -070026static struct _fpx_sw_bytes fx_sw_reserved, fx_sw_reserved_ia32;
Suresh Siddhaa1488f82010-07-19 16:05:48 -070027static unsigned int *xstate_offsets, *xstate_sizes, xstate_features;
28
Suresh Siddhac37b5ef2008-07-29 10:29:25 -070029/*
Suresh Siddha29104e12010-07-19 16:05:49 -070030 * If a processor implementation discern that a processor state component is
31 * in its initialized state it may modify the corresponding bit in the
32 * xsave_hdr.xstate_bv as '0', with out modifying the corresponding memory
33 * layout in the case of xsaveopt. While presenting the xstate information to
34 * the user, we always ensure that the memory layout of a feature will be in
35 * the init state if the corresponding header bit is zero. This is to ensure
36 * that the user doesn't see some stale state in the memory layout during
37 * signal handling, debugging etc.
38 */
39void __sanitize_i387_state(struct task_struct *tsk)
40{
Suresh Siddha29104e12010-07-19 16:05:49 -070041 struct i387_fxsave_struct *fx = &tsk->thread.fpu.state->fxsave;
Suresh Siddha72a671c2012-07-24 16:05:29 -070042 int feature_bit = 0x2;
43 u64 xstate_bv;
Suresh Siddha29104e12010-07-19 16:05:49 -070044
45 if (!fx)
46 return;
47
Suresh Siddha29104e12010-07-19 16:05:49 -070048 xstate_bv = tsk->thread.fpu.state->xsave.xsave_hdr.xstate_bv;
49
50 /*
51 * None of the feature bits are in init state. So nothing else
Lucas De Marchi0d2eb442011-03-17 16:24:16 -030052 * to do for us, as the memory layout is up to date.
Suresh Siddha29104e12010-07-19 16:05:49 -070053 */
54 if ((xstate_bv & pcntxt_mask) == pcntxt_mask)
55 return;
56
57 /*
58 * FP is in init state
59 */
60 if (!(xstate_bv & XSTATE_FP)) {
61 fx->cwd = 0x37f;
62 fx->swd = 0;
63 fx->twd = 0;
64 fx->fop = 0;
65 fx->rip = 0;
66 fx->rdp = 0;
67 memset(&fx->st_space[0], 0, 128);
68 }
69
70 /*
71 * SSE is in init state
72 */
73 if (!(xstate_bv & XSTATE_SSE))
74 memset(&fx->xmm_space[0], 0, 256);
75
76 xstate_bv = (pcntxt_mask & ~xstate_bv) >> 2;
77
78 /*
79 * Update all the other memory layouts for which the corresponding
80 * header bit is in the init state.
81 */
82 while (xstate_bv) {
83 if (xstate_bv & 0x1) {
84 int offset = xstate_offsets[feature_bit];
85 int size = xstate_sizes[feature_bit];
86
87 memcpy(((void *) fx) + offset,
88 ((void *) init_xstate_buf) + offset,
89 size);
90 }
91
92 xstate_bv >>= 1;
93 feature_bit++;
94 }
95}
96
Suresh Siddhac37b5ef2008-07-29 10:29:25 -070097/*
98 * Check for the presence of extended state information in the
99 * user fpstate pointer in the sigcontext.
100 */
Suresh Siddha72a671c2012-07-24 16:05:29 -0700101static inline int check_for_xstate(struct i387_fxsave_struct __user *buf,
102 void __user *fpstate,
103 struct _fpx_sw_bytes *fx_sw)
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700104{
105 int min_xstate_size = sizeof(struct i387_fxsave_struct) +
106 sizeof(struct xsave_hdr_struct);
107 unsigned int magic2;
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700108
Suresh Siddha72a671c2012-07-24 16:05:29 -0700109 if (__copy_from_user(fx_sw, &buf->sw_reserved[0], sizeof(*fx_sw)))
110 return -1;
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700111
Suresh Siddha72a671c2012-07-24 16:05:29 -0700112 /* Check for the first magic field and other error scenarios. */
113 if (fx_sw->magic1 != FP_XSTATE_MAGIC1 ||
114 fx_sw->xstate_size < min_xstate_size ||
115 fx_sw->xstate_size > xstate_size ||
116 fx_sw->xstate_size > fx_sw->extended_size)
117 return -1;
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700118
119 /*
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700120 * Check for the presence of second magic word at the end of memory
121 * layout. This detects the case where the user just copied the legacy
122 * fpstate layout with out copying the extended state information
123 * in the memory layout.
124 */
Suresh Siddha72a671c2012-07-24 16:05:29 -0700125 if (__get_user(magic2, (__u32 __user *)(fpstate + fx_sw->xstate_size))
126 || magic2 != FP_XSTATE_MAGIC2)
127 return -1;
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700128
129 return 0;
130}
131
Suresh Siddhaab513702008-07-29 10:29:22 -0700132/*
133 * Signal frame handlers.
134 */
Suresh Siddha72a671c2012-07-24 16:05:29 -0700135static inline int save_fsave_header(struct task_struct *tsk, void __user *buf)
Suresh Siddhaab513702008-07-29 10:29:22 -0700136{
Suresh Siddha72a671c2012-07-24 16:05:29 -0700137 if (use_fxsr()) {
138 struct xsave_struct *xsave = &tsk->thread.fpu.state->xsave;
139 struct user_i387_ia32_struct env;
140 struct _fpstate_ia32 __user *fp = buf;
Suresh Siddhaab513702008-07-29 10:29:22 -0700141
Suresh Siddha72a671c2012-07-24 16:05:29 -0700142 convert_from_fxsr(&env, tsk);
Suresh Siddhaab513702008-07-29 10:29:22 -0700143
Suresh Siddha72a671c2012-07-24 16:05:29 -0700144 if (__copy_to_user(buf, &env, sizeof(env)) ||
145 __put_user(xsave->i387.swd, &fp->status) ||
146 __put_user(X86_FXSR_MAGIC, &fp->magic))
147 return -1;
Suresh Siddhaab513702008-07-29 10:29:22 -0700148 } else {
Suresh Siddha72a671c2012-07-24 16:05:29 -0700149 struct i387_fsave_struct __user *fp = buf;
150 u32 swd;
151 if (__get_user(swd, &fp->swd) || __put_user(swd, &fp->status))
Suresh Siddhaab513702008-07-29 10:29:22 -0700152 return -1;
153 }
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700154
Suresh Siddha72a671c2012-07-24 16:05:29 -0700155 return 0;
Suresh Siddhaab513702008-07-29 10:29:22 -0700156}
157
Suresh Siddha72a671c2012-07-24 16:05:29 -0700158static inline int save_xstate_epilog(void __user *buf, int ia32_frame)
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700159{
Suresh Siddha72a671c2012-07-24 16:05:29 -0700160 struct xsave_struct __user *x = buf;
161 struct _fpx_sw_bytes *sw_bytes;
162 u32 xstate_bv;
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700163 int err;
164
Suresh Siddha72a671c2012-07-24 16:05:29 -0700165 /* Setup the bytes not touched by the [f]xsave and reserved for SW. */
166 sw_bytes = ia32_frame ? &fx_sw_reserved_ia32 : &fx_sw_reserved;
167 err = __copy_to_user(&x->i387.sw_reserved, sw_bytes, sizeof(*sw_bytes));
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700168
Suresh Siddha72a671c2012-07-24 16:05:29 -0700169 if (!use_xsave())
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700170 return err;
171
Suresh Siddha72a671c2012-07-24 16:05:29 -0700172 err |= __put_user(FP_XSTATE_MAGIC2, (__u32 *)(buf + xstate_size));
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700173
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700174 /*
Suresh Siddha72a671c2012-07-24 16:05:29 -0700175 * Read the xstate_bv which we copied (directly from the cpu or
176 * from the state in task struct) to the user buffers.
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700177 */
Suresh Siddha72a671c2012-07-24 16:05:29 -0700178 err |= __get_user(xstate_bv, (__u32 *)&x->xsave_hdr.xstate_bv);
179
180 /*
181 * For legacy compatible, we always set FP/SSE bits in the bit
182 * vector while saving the state to the user context. This will
183 * enable us capturing any changes(during sigreturn) to
184 * the FP/SSE bits by the legacy applications which don't touch
185 * xstate_bv in the xsave header.
186 *
187 * xsave aware apps can change the xstate_bv in the xsave
188 * header as well as change any contents in the memory layout.
189 * xrestore as part of sigreturn will capture all the changes.
190 */
191 xstate_bv |= XSTATE_FPSSE;
192
193 err |= __put_user(xstate_bv, (__u32 *)&x->xsave_hdr.xstate_bv);
194
195 return err;
196}
197
198static inline int save_user_xstate(struct xsave_struct __user *buf)
199{
200 int err;
201
202 if (use_xsave())
203 err = xsave_user(buf);
204 else if (use_fxsr())
205 err = fxsave_user((struct i387_fxsave_struct __user *) buf);
206 else
207 err = fsave_user((struct i387_fsave_struct __user *) buf);
208
209 if (unlikely(err) && __clear_user(buf, xstate_size))
210 err = -EFAULT;
211 return err;
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700212}
213
214/*
Suresh Siddha72a671c2012-07-24 16:05:29 -0700215 * Save the fpu, extended register state to the user signal frame.
216 *
217 * 'buf_fx' is the 64-byte aligned pointer at which the [f|fx|x]save
218 * state is copied.
219 * 'buf' points to the 'buf_fx' or to the fsave header followed by 'buf_fx'.
220 *
221 * buf == buf_fx for 64-bit frames and 32-bit fsave frame.
222 * buf != buf_fx for 32-bit frames with fxstate.
223 *
224 * If the fpu, extended register state is live, save the state directly
225 * to the user frame pointed by the aligned pointer 'buf_fx'. Otherwise,
226 * copy the thread's fpu state to the user frame starting at 'buf_fx'.
227 *
228 * If this is a 32-bit frame with fxstate, put a fsave header before
229 * the aligned state at 'buf_fx'.
230 *
231 * For [f]xsave state, update the SW reserved fields in the [f]xsave frame
232 * indicating the absence/presence of the extended state to the user.
Suresh Siddhaab513702008-07-29 10:29:22 -0700233 */
Suresh Siddha72a671c2012-07-24 16:05:29 -0700234int save_xstate_sig(void __user *buf, void __user *buf_fx, int size)
Suresh Siddhaab513702008-07-29 10:29:22 -0700235{
Suresh Siddha72a671c2012-07-24 16:05:29 -0700236 struct xsave_struct *xsave = &current->thread.fpu.state->xsave;
Suresh Siddhaab513702008-07-29 10:29:22 -0700237 struct task_struct *tsk = current;
Suresh Siddha72a671c2012-07-24 16:05:29 -0700238 int ia32_fxstate = (buf != buf_fx);
239
240 ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
241 config_enabled(CONFIG_IA32_EMULATION));
242
243 if (!access_ok(VERIFY_WRITE, buf, size))
244 return -EACCES;
245
H. Peter Anvin60e019e2013-04-29 16:04:20 +0200246 if (!static_cpu_has(X86_FEATURE_FPU))
Suresh Siddha72a671c2012-07-24 16:05:29 -0700247 return fpregs_soft_get(current, NULL, 0,
248 sizeof(struct user_i387_ia32_struct), NULL,
249 (struct _fpstate_ia32 __user *) buf) ? -1 : 1;
250
251 if (user_has_fpu()) {
252 /* Save the live register state to the user directly. */
253 if (save_user_xstate(buf_fx))
254 return -1;
255 /* Update the thread's fxstate to save the fsave header. */
256 if (ia32_fxstate)
257 fpu_fxsave(&tsk->thread.fpu);
Suresh Siddha72a671c2012-07-24 16:05:29 -0700258 } else {
259 sanitize_i387_state(tsk);
260 if (__copy_to_user(buf_fx, xsave, xstate_size))
261 return -1;
262 }
263
264 /* Save the fsave header for the 32-bit frames. */
265 if ((ia32_fxstate || !use_fxsr()) && save_fsave_header(tsk, buf))
266 return -1;
267
268 if (use_fxsr() && save_xstate_epilog(buf_fx, ia32_fxstate))
269 return -1;
270
Suresh Siddha304bced2012-08-24 14:13:02 -0700271 drop_init_fpu(tsk); /* trigger finit */
Suresh Siddha72a671c2012-07-24 16:05:29 -0700272
273 return 0;
274}
275
276static inline void
277sanitize_restored_xstate(struct task_struct *tsk,
278 struct user_i387_ia32_struct *ia32_env,
279 u64 xstate_bv, int fx_only)
280{
281 struct xsave_struct *xsave = &tsk->thread.fpu.state->xsave;
282 struct xsave_hdr_struct *xsave_hdr = &xsave->xsave_hdr;
283
284 if (use_xsave()) {
285 /* These bits must be zero. */
286 xsave_hdr->reserved1[0] = xsave_hdr->reserved1[1] = 0;
287
288 /*
289 * Init the state that is not present in the memory
290 * layout and not enabled by the OS.
291 */
292 if (fx_only)
293 xsave_hdr->xstate_bv = XSTATE_FPSSE;
294 else
295 xsave_hdr->xstate_bv &= (pcntxt_mask & xstate_bv);
296 }
297
298 if (use_fxsr()) {
299 /*
300 * mscsr reserved bits must be masked to zero for security
301 * reasons.
302 */
303 xsave->i387.mxcsr &= mxcsr_feature_mask;
304
305 convert_to_fxsr(tsk, ia32_env);
306 }
307}
308
309/*
310 * Restore the extended state if present. Otherwise, restore the FP/SSE state.
311 */
312static inline int restore_user_xstate(void __user *buf, u64 xbv, int fx_only)
313{
314 if (use_xsave()) {
315 if ((unsigned long)buf % 64 || fx_only) {
316 u64 init_bv = pcntxt_mask & ~XSTATE_FPSSE;
317 xrstor_state(init_xstate_buf, init_bv);
H. Peter Anvine139e952012-09-25 15:42:18 -0700318 return fxrstor_user(buf);
Suresh Siddha72a671c2012-07-24 16:05:29 -0700319 } else {
320 u64 init_bv = pcntxt_mask & ~xbv;
321 if (unlikely(init_bv))
322 xrstor_state(init_xstate_buf, init_bv);
323 return xrestore_user(buf, xbv);
324 }
325 } else if (use_fxsr()) {
H. Peter Anvine139e952012-09-25 15:42:18 -0700326 return fxrstor_user(buf);
Suresh Siddha72a671c2012-07-24 16:05:29 -0700327 } else
H. Peter Anvine139e952012-09-25 15:42:18 -0700328 return frstor_user(buf);
Suresh Siddha72a671c2012-07-24 16:05:29 -0700329}
330
331int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size)
332{
333 int ia32_fxstate = (buf != buf_fx);
334 struct task_struct *tsk = current;
335 int state_size = xstate_size;
336 u64 xstate_bv = 0;
337 int fx_only = 0;
338
339 ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
340 config_enabled(CONFIG_IA32_EMULATION));
Suresh Siddhaab513702008-07-29 10:29:22 -0700341
342 if (!buf) {
Suresh Siddha304bced2012-08-24 14:13:02 -0700343 drop_init_fpu(tsk);
Suresh Siddhaab513702008-07-29 10:29:22 -0700344 return 0;
Suresh Siddhaab513702008-07-29 10:29:22 -0700345 }
346
Suresh Siddha72a671c2012-07-24 16:05:29 -0700347 if (!access_ok(VERIFY_READ, buf, size))
348 return -EACCES;
349
350 if (!used_math() && init_fpu(tsk))
351 return -1;
352
H. Peter Anvin60e019e2013-04-29 16:04:20 +0200353 if (!static_cpu_has(X86_FEATURE_FPU))
Suresh Siddha72a671c2012-07-24 16:05:29 -0700354 return fpregs_soft_set(current, NULL,
355 0, sizeof(struct user_i387_ia32_struct),
356 NULL, buf) != 0;
Suresh Siddha72a671c2012-07-24 16:05:29 -0700357
358 if (use_xsave()) {
359 struct _fpx_sw_bytes fx_sw_user;
360 if (unlikely(check_for_xstate(buf_fx, buf_fx, &fx_sw_user))) {
361 /*
362 * Couldn't find the extended state information in the
363 * memory layout. Restore just the FP/SSE and init all
364 * the other extended state.
365 */
366 state_size = sizeof(struct i387_fxsave_struct);
367 fx_only = 1;
368 } else {
369 state_size = fx_sw_user.xstate_size;
370 xstate_bv = fx_sw_user.xstate_bv;
371 }
372 }
373
374 if (ia32_fxstate) {
Suresh Siddhaab513702008-07-29 10:29:22 -0700375 /*
Suresh Siddha72a671c2012-07-24 16:05:29 -0700376 * For 32-bit frames with fxstate, copy the user state to the
377 * thread's fpu state, reconstruct fxstate from the fsave
378 * header. Sanitize the copied state etc.
Suresh Siddhaab513702008-07-29 10:29:22 -0700379 */
Suresh Siddha72a671c2012-07-24 16:05:29 -0700380 struct xsave_struct *xsave = &tsk->thread.fpu.state->xsave;
381 struct user_i387_ia32_struct env;
Suresh Siddha304bced2012-08-24 14:13:02 -0700382 int err = 0;
Suresh Siddha72a671c2012-07-24 16:05:29 -0700383
Suresh Siddha304bced2012-08-24 14:13:02 -0700384 /*
385 * Drop the current fpu which clears used_math(). This ensures
386 * that any context-switch during the copy of the new state,
387 * avoids the intermediate state from getting restored/saved.
388 * Thus avoiding the new restored state from getting corrupted.
389 * We will be ready to restore/save the state only after
390 * set_used_math() is again set.
391 */
Suresh Siddhae9625912012-08-24 14:12:57 -0700392 drop_fpu(tsk);
Suresh Siddha72a671c2012-07-24 16:05:29 -0700393
394 if (__copy_from_user(xsave, buf_fx, state_size) ||
Suresh Siddha304bced2012-08-24 14:13:02 -0700395 __copy_from_user(&env, buf, sizeof(env))) {
396 err = -1;
397 } else {
398 sanitize_restored_xstate(tsk, &env, xstate_bv, fx_only);
399 set_used_math();
400 }
Suresh Siddha72a671c2012-07-24 16:05:29 -0700401
Suresh Siddha5d2bd702012-09-06 14:58:52 -0700402 if (use_eager_fpu())
Suresh Siddha304bced2012-08-24 14:13:02 -0700403 math_state_restore();
404
405 return err;
Suresh Siddha72a671c2012-07-24 16:05:29 -0700406 } else {
407 /*
408 * For 64-bit frames and 32-bit fsave frames, restore the user
409 * state to the registers directly (with exceptions handled).
410 */
411 user_fpu_begin();
412 if (restore_user_xstate(buf_fx, xstate_bv, fx_only)) {
Suresh Siddha304bced2012-08-24 14:13:02 -0700413 drop_init_fpu(tsk);
Suresh Siddha72a671c2012-07-24 16:05:29 -0700414 return -1;
415 }
Suresh Siddhaab513702008-07-29 10:29:22 -0700416 }
Suresh Siddha72a671c2012-07-24 16:05:29 -0700417
418 return 0;
Suresh Siddhaab513702008-07-29 10:29:22 -0700419}
Suresh Siddhaab513702008-07-29 10:29:22 -0700420
Suresh Siddhadc1e35c2008-07-29 10:29:19 -0700421/*
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700422 * Prepare the SW reserved portion of the fxsave memory layout, indicating
423 * the presence of the extended state information in the memory layout
424 * pointed by the fpstate pointer in the sigcontext.
425 * This will be saved when ever the FP and extended state context is
426 * saved on the user stack during the signal handler delivery to the user.
427 */
roel kluin8bcad302008-10-21 19:49:09 -0400428static void prepare_fx_sw_frame(void)
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700429{
Suresh Siddha72a671c2012-07-24 16:05:29 -0700430 int fsave_header_size = sizeof(struct i387_fsave_struct);
431 int size = xstate_size + FP_XSTATE_MAGIC2_SIZE;
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700432
Suresh Siddha72a671c2012-07-24 16:05:29 -0700433 if (config_enabled(CONFIG_X86_32))
434 size += fsave_header_size;
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700435
436 fx_sw_reserved.magic1 = FP_XSTATE_MAGIC1;
Suresh Siddha72a671c2012-07-24 16:05:29 -0700437 fx_sw_reserved.extended_size = size;
H. Peter Anvin6152e4b2008-07-29 17:23:16 -0700438 fx_sw_reserved.xstate_bv = pcntxt_mask;
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700439 fx_sw_reserved.xstate_size = xstate_size;
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700440
Suresh Siddha72a671c2012-07-24 16:05:29 -0700441 if (config_enabled(CONFIG_IA32_EMULATION)) {
442 fx_sw_reserved_ia32 = fx_sw_reserved;
443 fx_sw_reserved_ia32.extended_size += fsave_header_size;
444 }
445}
Suresh Siddha3c1c7f12008-07-29 10:29:21 -0700446
Suresh Siddhadc1e35c2008-07-29 10:29:19 -0700447/*
448 * Enable the extended processor state save/restore feature
449 */
H. Peter Anvin1cff92d2010-07-21 14:23:10 -0700450static inline void xstate_enable(void)
Suresh Siddhadc1e35c2008-07-29 10:29:19 -0700451{
Suresh Siddhadc1e35c2008-07-29 10:29:19 -0700452 set_in_cr4(X86_CR4_OSXSAVE);
H. Peter Anvin6152e4b2008-07-29 17:23:16 -0700453 xsetbv(XCR_XFEATURE_ENABLED_MASK, pcntxt_mask);
Suresh Siddhadc1e35c2008-07-29 10:29:19 -0700454}
455
456/*
Suresh Siddhaa1488f82010-07-19 16:05:48 -0700457 * Record the offsets and sizes of different state managed by the xsave
458 * memory layout.
459 */
Robert Richter4995b9d2010-07-21 19:03:56 +0200460static void __init setup_xstate_features(void)
Suresh Siddhaa1488f82010-07-19 16:05:48 -0700461{
462 int eax, ebx, ecx, edx, leaf = 0x2;
463
464 xstate_features = fls64(pcntxt_mask);
465 xstate_offsets = alloc_bootmem(xstate_features * sizeof(int));
466 xstate_sizes = alloc_bootmem(xstate_features * sizeof(int));
467
468 do {
Robert Richteree813d52010-07-21 19:03:54 +0200469 cpuid_count(XSTATE_CPUID, leaf, &eax, &ebx, &ecx, &edx);
Suresh Siddhaa1488f82010-07-19 16:05:48 -0700470
471 if (eax == 0)
472 break;
473
474 xstate_offsets[leaf] = ebx;
475 xstate_sizes[leaf] = eax;
476
477 leaf++;
478 } while (1);
479}
480
481/*
Suresh Siddhadc1e35c2008-07-29 10:29:19 -0700482 * setup the xstate image representing the init state
483 */
Suresh Siddha5d2bd702012-09-06 14:58:52 -0700484static void __init setup_init_fpu_buf(void)
Suresh Siddhadc1e35c2008-07-29 10:29:19 -0700485{
Suresh Siddha29104e12010-07-19 16:05:49 -0700486 /*
487 * Setup init_xstate_buf to represent the init state of
488 * all the features managed by the xsave
489 */
Suresh Siddha10340ae2010-11-16 13:23:51 -0800490 init_xstate_buf = alloc_bootmem_align(xstate_size,
491 __alignof__(struct xsave_struct));
Suresh Siddha5d2bd702012-09-06 14:58:52 -0700492 fx_finit(&init_xstate_buf->i387);
493
494 if (!cpu_has_xsave)
495 return;
496
497 setup_xstate_features();
Suresh Siddhaa1488f82010-07-19 16:05:48 -0700498
Suresh Siddha29104e12010-07-19 16:05:49 -0700499 /*
500 * Init all the features state with header_bv being 0x0
501 */
502 xrstor_state(init_xstate_buf, -1);
503 /*
504 * Dump the init state again. This is to identify the init state
505 * of any feature which is not represented by all zero's.
506 */
507 xsave_state(init_xstate_buf, -1);
Suresh Siddhadc1e35c2008-07-29 10:29:19 -0700508}
509
Suresh Siddhae0022982012-09-10 10:32:32 -0700510static enum { AUTO, ENABLE, DISABLE } eagerfpu = AUTO;
Suresh Siddha5d2bd702012-09-06 14:58:52 -0700511static int __init eager_fpu_setup(char *s)
512{
513 if (!strcmp(s, "on"))
Suresh Siddhae0022982012-09-10 10:32:32 -0700514 eagerfpu = ENABLE;
Suresh Siddha5d2bd702012-09-06 14:58:52 -0700515 else if (!strcmp(s, "off"))
Suresh Siddhae0022982012-09-10 10:32:32 -0700516 eagerfpu = DISABLE;
517 else if (!strcmp(s, "auto"))
518 eagerfpu = AUTO;
Suresh Siddha5d2bd702012-09-06 14:58:52 -0700519 return 1;
520}
521__setup("eagerfpu=", eager_fpu_setup);
522
Suresh Siddhadc1e35c2008-07-29 10:29:19 -0700523/*
524 * Enable and initialize the xsave feature.
525 */
H. Peter Anvin1cff92d2010-07-21 14:23:10 -0700526static void __init xstate_enable_boot_cpu(void)
Suresh Siddhadc1e35c2008-07-29 10:29:19 -0700527{
528 unsigned int eax, ebx, ecx, edx;
529
Robert Richteree813d52010-07-21 19:03:54 +0200530 if (boot_cpu_data.cpuid_level < XSTATE_CPUID) {
531 WARN(1, KERN_ERR "XSTATE_CPUID missing\n");
532 return;
533 }
534
535 cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
H. Peter Anvin6152e4b2008-07-29 17:23:16 -0700536 pcntxt_mask = eax + ((u64)edx << 32);
Suresh Siddhadc1e35c2008-07-29 10:29:19 -0700537
H. Peter Anvin6152e4b2008-07-29 17:23:16 -0700538 if ((pcntxt_mask & XSTATE_FPSSE) != XSTATE_FPSSE) {
Joe Perchesc767a542012-05-21 19:50:07 -0700539 pr_err("FP/SSE not shown under xsave features 0x%llx\n",
H. Peter Anvin6152e4b2008-07-29 17:23:16 -0700540 pcntxt_mask);
Suresh Siddhadc1e35c2008-07-29 10:29:19 -0700541 BUG();
542 }
543
544 /*
Suresh Siddhaa30469e2009-04-10 15:21:24 -0700545 * Support only the state known to OS.
Suresh Siddhadc1e35c2008-07-29 10:29:19 -0700546 */
H. Peter Anvin6152e4b2008-07-29 17:23:16 -0700547 pcntxt_mask = pcntxt_mask & XCNTXT_MASK;
Robert Richter97e80a72010-07-21 19:03:53 +0200548
H. Peter Anvin1cff92d2010-07-21 14:23:10 -0700549 xstate_enable();
Suresh Siddhadc1e35c2008-07-29 10:29:19 -0700550
551 /*
552 * Recompute the context size for enabled features
553 */
Robert Richteree813d52010-07-21 19:03:54 +0200554 cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
Suresh Siddhadc1e35c2008-07-29 10:29:19 -0700555 xstate_size = ebx;
556
Suresh Siddha5b3efd52010-02-11 11:50:59 -0800557 update_regset_xstate_info(xstate_size, pcntxt_mask);
Suresh Siddhac37b5ef2008-07-29 10:29:25 -0700558 prepare_fx_sw_frame();
Suresh Siddha5d2bd702012-09-06 14:58:52 -0700559 setup_init_fpu_buf();
Suresh Siddhadc1e35c2008-07-29 10:29:19 -0700560
Suresh Siddhae0022982012-09-10 10:32:32 -0700561 /* Auto enable eagerfpu for xsaveopt */
562 if (cpu_has_xsaveopt && eagerfpu != DISABLE)
563 eagerfpu = ENABLE;
Suresh Siddha212b0212012-09-06 15:05:18 -0700564
Joe Perchesc767a542012-05-21 19:50:07 -0700565 pr_info("enabled xstate_bv 0x%llx, cntxt size 0x%x\n",
566 pcntxt_mask, xstate_size);
Suresh Siddhadc1e35c2008-07-29 10:29:19 -0700567}
Robert Richter82d41502010-07-20 20:50:51 +0200568
H. Peter Anvin1cff92d2010-07-21 14:23:10 -0700569/*
570 * For the very first instance, this calls xstate_enable_boot_cpu();
571 * for all subsequent instances, this calls xstate_enable().
572 *
573 * This is somewhat obfuscated due to the lack of powerful enough
574 * overrides for the section checks.
575 */
Robert Richter82d41502010-07-20 20:50:51 +0200576void __cpuinit xsave_init(void)
577{
H. Peter Anvin1cff92d2010-07-21 14:23:10 -0700578 static __refdata void (*next_func)(void) = xstate_enable_boot_cpu;
579 void (*this_func)(void);
580
Robert Richter0e49bf62010-07-21 19:03:52 +0200581 if (!cpu_has_xsave)
582 return;
583
H. Peter Anvin1cff92d2010-07-21 14:23:10 -0700584 this_func = next_func;
Suresh Siddha5d2bd702012-09-06 14:58:52 -0700585 next_func = xstate_enable;
H. Peter Anvin1cff92d2010-07-21 14:23:10 -0700586 this_func();
Robert Richter82d41502010-07-20 20:50:51 +0200587}
Suresh Siddha5d2bd702012-09-06 14:58:52 -0700588
589static inline void __init eager_fpu_init_bp(void)
590{
591 current->thread.fpu.state =
592 alloc_bootmem_align(xstate_size, __alignof__(struct xsave_struct));
593 if (!init_xstate_buf)
594 setup_init_fpu_buf();
595}
596
597void __cpuinit eager_fpu_init(void)
598{
599 static __refdata void (*boot_func)(void) = eager_fpu_init_bp;
600
601 clear_used_math();
602 current_thread_info()->status = 0;
Suresh Siddhae0022982012-09-10 10:32:32 -0700603
604 if (eagerfpu == ENABLE)
605 setup_force_cpu_cap(X86_FEATURE_EAGER_FPU);
606
Suresh Siddha5d2bd702012-09-06 14:58:52 -0700607 if (!cpu_has_eager_fpu) {
608 stts();
609 return;
610 }
611
612 if (boot_func) {
613 boot_func();
614 boot_func = NULL;
615 }
616
617 /*
618 * This is same as math_state_restore(). But use_xsave() is
619 * not yet patched to use math_state_restore().
620 */
621 init_fpu(current);
622 __thread_fpu_begin(current);
623 if (cpu_has_xsave)
624 xrstor_state(init_xstate_buf, -1);
625 else
626 fxrstor_checking(&init_xstate_buf->i387);
627}