x86/retpoline/xen: Convert Xen hypercall indirect jumps
[sfrench/cifs-2.6.git] / arch / x86 / include / asm / xen / hypercall.h
1 /******************************************************************************
2  * hypercall.h
3  *
4  * Linux-specific hypervisor handling.
5  *
6  * Copyright (c) 2002-2004, K A Fraser
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License version 2
10  * as published by the Free Software Foundation; or, when distributed
11  * separately from the Linux kernel or incorporated into other
12  * software packages, subject to the following license:
13  *
14  * Permission is hereby granted, free of charge, to any person obtaining a copy
15  * of this source file (the "Software"), to deal in the Software without
16  * restriction, including without limitation the rights to use, copy, modify,
17  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
18  * and to permit persons to whom the Software is furnished to do so, subject to
19  * the following conditions:
20  *
21  * The above copyright notice and this permission notice shall be included in
22  * all copies or substantial portions of the Software.
23  *
24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
25  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
26  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
27  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
28  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
29  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
30  * IN THE SOFTWARE.
31  */
32
33 #ifndef _ASM_X86_XEN_HYPERCALL_H
34 #define _ASM_X86_XEN_HYPERCALL_H
35
36 #include <linux/kernel.h>
37 #include <linux/spinlock.h>
38 #include <linux/errno.h>
39 #include <linux/string.h>
40 #include <linux/types.h>
41
42 #include <trace/events/xen.h>
43
44 #include <asm/page.h>
45 #include <asm/pgtable.h>
46 #include <asm/smap.h>
47 #include <asm/nospec-branch.h>
48
49 #include <xen/interface/xen.h>
50 #include <xen/interface/sched.h>
51 #include <xen/interface/physdev.h>
52 #include <xen/interface/platform.h>
53 #include <xen/interface/xen-mca.h>
54
55 struct xen_dm_op_buf;
56
57 /*
58  * The hypercall asms have to meet several constraints:
59  * - Work on 32- and 64-bit.
60  *    The two architectures put their arguments in different sets of
61  *    registers.
62  *
63  * - Work around asm syntax quirks
64  *    It isn't possible to specify one of the rNN registers in a
65  *    constraint, so we use explicit register variables to get the
66  *    args into the right place.
67  *
68  * - Mark all registers as potentially clobbered
69  *    Even unused parameters can be clobbered by the hypervisor, so we
70  *    need to make sure gcc knows it.
71  *
72  * - Avoid compiler bugs.
73  *    This is the tricky part.  Because x86_32 has such a constrained
74  *    register set, gcc versions below 4.3 have trouble generating
75  *    code when all the arg registers and memory are trashed by the
76  *    asm.  There are syntactically simpler ways of achieving the
77  *    semantics below, but they cause the compiler to crash.
78  *
79  *    The only combination I found which works is:
80  *     - assign the __argX variables first
81  *     - list all actually used parameters as "+r" (__argX)
82  *     - clobber the rest
83  *
84  * The result certainly isn't pretty, and it really shows up cpp's
85  * weakness as as macro language.  Sorry.  (But let's just give thanks
86  * there aren't more than 5 arguments...)
87  */
88
89 extern struct { char _entry[32]; } hypercall_page[];
90
91 #define __HYPERCALL             "call hypercall_page+%c[offset]"
92 #define __HYPERCALL_ENTRY(x)                                            \
93         [offset] "i" (__HYPERVISOR_##x * sizeof(hypercall_page[0]))
94
95 #ifdef CONFIG_X86_32
96 #define __HYPERCALL_RETREG      "eax"
97 #define __HYPERCALL_ARG1REG     "ebx"
98 #define __HYPERCALL_ARG2REG     "ecx"
99 #define __HYPERCALL_ARG3REG     "edx"
100 #define __HYPERCALL_ARG4REG     "esi"
101 #define __HYPERCALL_ARG5REG     "edi"
102 #else
103 #define __HYPERCALL_RETREG      "rax"
104 #define __HYPERCALL_ARG1REG     "rdi"
105 #define __HYPERCALL_ARG2REG     "rsi"
106 #define __HYPERCALL_ARG3REG     "rdx"
107 #define __HYPERCALL_ARG4REG     "r10"
108 #define __HYPERCALL_ARG5REG     "r8"
109 #endif
110
111 #define __HYPERCALL_DECLS                                               \
112         register unsigned long __res  asm(__HYPERCALL_RETREG);          \
113         register unsigned long __arg1 asm(__HYPERCALL_ARG1REG) = __arg1; \
114         register unsigned long __arg2 asm(__HYPERCALL_ARG2REG) = __arg2; \
115         register unsigned long __arg3 asm(__HYPERCALL_ARG3REG) = __arg3; \
116         register unsigned long __arg4 asm(__HYPERCALL_ARG4REG) = __arg4; \
117         register unsigned long __arg5 asm(__HYPERCALL_ARG5REG) = __arg5;
118
119 #define __HYPERCALL_0PARAM      "=r" (__res), ASM_CALL_CONSTRAINT
120 #define __HYPERCALL_1PARAM      __HYPERCALL_0PARAM, "+r" (__arg1)
121 #define __HYPERCALL_2PARAM      __HYPERCALL_1PARAM, "+r" (__arg2)
122 #define __HYPERCALL_3PARAM      __HYPERCALL_2PARAM, "+r" (__arg3)
123 #define __HYPERCALL_4PARAM      __HYPERCALL_3PARAM, "+r" (__arg4)
124 #define __HYPERCALL_5PARAM      __HYPERCALL_4PARAM, "+r" (__arg5)
125
126 #define __HYPERCALL_0ARG()
127 #define __HYPERCALL_1ARG(a1)                                            \
128         __HYPERCALL_0ARG()              __arg1 = (unsigned long)(a1);
129 #define __HYPERCALL_2ARG(a1,a2)                                         \
130         __HYPERCALL_1ARG(a1)            __arg2 = (unsigned long)(a2);
131 #define __HYPERCALL_3ARG(a1,a2,a3)                                      \
132         __HYPERCALL_2ARG(a1,a2)         __arg3 = (unsigned long)(a3);
133 #define __HYPERCALL_4ARG(a1,a2,a3,a4)                                   \
134         __HYPERCALL_3ARG(a1,a2,a3)      __arg4 = (unsigned long)(a4);
135 #define __HYPERCALL_5ARG(a1,a2,a3,a4,a5)                                \
136         __HYPERCALL_4ARG(a1,a2,a3,a4)   __arg5 = (unsigned long)(a5);
137
138 #define __HYPERCALL_CLOBBER5    "memory"
139 #define __HYPERCALL_CLOBBER4    __HYPERCALL_CLOBBER5, __HYPERCALL_ARG5REG
140 #define __HYPERCALL_CLOBBER3    __HYPERCALL_CLOBBER4, __HYPERCALL_ARG4REG
141 #define __HYPERCALL_CLOBBER2    __HYPERCALL_CLOBBER3, __HYPERCALL_ARG3REG
142 #define __HYPERCALL_CLOBBER1    __HYPERCALL_CLOBBER2, __HYPERCALL_ARG2REG
143 #define __HYPERCALL_CLOBBER0    __HYPERCALL_CLOBBER1, __HYPERCALL_ARG1REG
144
145 #define _hypercall0(type, name)                                         \
146 ({                                                                      \
147         __HYPERCALL_DECLS;                                              \
148         __HYPERCALL_0ARG();                                             \
149         asm volatile (__HYPERCALL                                       \
150                       : __HYPERCALL_0PARAM                              \
151                       : __HYPERCALL_ENTRY(name)                         \
152                       : __HYPERCALL_CLOBBER0);                          \
153         (type)__res;                                                    \
154 })
155
156 #define _hypercall1(type, name, a1)                                     \
157 ({                                                                      \
158         __HYPERCALL_DECLS;                                              \
159         __HYPERCALL_1ARG(a1);                                           \
160         asm volatile (__HYPERCALL                                       \
161                       : __HYPERCALL_1PARAM                              \
162                       : __HYPERCALL_ENTRY(name)                         \
163                       : __HYPERCALL_CLOBBER1);                          \
164         (type)__res;                                                    \
165 })
166
167 #define _hypercall2(type, name, a1, a2)                                 \
168 ({                                                                      \
169         __HYPERCALL_DECLS;                                              \
170         __HYPERCALL_2ARG(a1, a2);                                       \
171         asm volatile (__HYPERCALL                                       \
172                       : __HYPERCALL_2PARAM                              \
173                       : __HYPERCALL_ENTRY(name)                         \
174                       : __HYPERCALL_CLOBBER2);                          \
175         (type)__res;                                                    \
176 })
177
178 #define _hypercall3(type, name, a1, a2, a3)                             \
179 ({                                                                      \
180         __HYPERCALL_DECLS;                                              \
181         __HYPERCALL_3ARG(a1, a2, a3);                                   \
182         asm volatile (__HYPERCALL                                       \
183                       : __HYPERCALL_3PARAM                              \
184                       : __HYPERCALL_ENTRY(name)                         \
185                       : __HYPERCALL_CLOBBER3);                          \
186         (type)__res;                                                    \
187 })
188
189 #define _hypercall4(type, name, a1, a2, a3, a4)                         \
190 ({                                                                      \
191         __HYPERCALL_DECLS;                                              \
192         __HYPERCALL_4ARG(a1, a2, a3, a4);                               \
193         asm volatile (__HYPERCALL                                       \
194                       : __HYPERCALL_4PARAM                              \
195                       : __HYPERCALL_ENTRY(name)                         \
196                       : __HYPERCALL_CLOBBER4);                          \
197         (type)__res;                                                    \
198 })
199
200 #define _hypercall5(type, name, a1, a2, a3, a4, a5)                     \
201 ({                                                                      \
202         __HYPERCALL_DECLS;                                              \
203         __HYPERCALL_5ARG(a1, a2, a3, a4, a5);                           \
204         asm volatile (__HYPERCALL                                       \
205                       : __HYPERCALL_5PARAM                              \
206                       : __HYPERCALL_ENTRY(name)                         \
207                       : __HYPERCALL_CLOBBER5);                          \
208         (type)__res;                                                    \
209 })
210
211 static inline long
212 privcmd_call(unsigned call,
213              unsigned long a1, unsigned long a2,
214              unsigned long a3, unsigned long a4,
215              unsigned long a5)
216 {
217         __HYPERCALL_DECLS;
218         __HYPERCALL_5ARG(a1, a2, a3, a4, a5);
219
220         stac();
221         asm volatile(CALL_NOSPEC
222                      : __HYPERCALL_5PARAM
223                      : [thunk_target] "a" (&hypercall_page[call])
224                      : __HYPERCALL_CLOBBER5);
225         clac();
226
227         return (long)__res;
228 }
229
230 static inline int
231 HYPERVISOR_set_trap_table(struct trap_info *table)
232 {
233         return _hypercall1(int, set_trap_table, table);
234 }
235
236 static inline int
237 HYPERVISOR_mmu_update(struct mmu_update *req, int count,
238                       int *success_count, domid_t domid)
239 {
240         return _hypercall4(int, mmu_update, req, count, success_count, domid);
241 }
242
243 static inline int
244 HYPERVISOR_mmuext_op(struct mmuext_op *op, int count,
245                      int *success_count, domid_t domid)
246 {
247         return _hypercall4(int, mmuext_op, op, count, success_count, domid);
248 }
249
250 static inline int
251 HYPERVISOR_set_gdt(unsigned long *frame_list, int entries)
252 {
253         return _hypercall2(int, set_gdt, frame_list, entries);
254 }
255
256 static inline int
257 HYPERVISOR_stack_switch(unsigned long ss, unsigned long esp)
258 {
259         return _hypercall2(int, stack_switch, ss, esp);
260 }
261
262 #ifdef CONFIG_X86_32
263 static inline int
264 HYPERVISOR_set_callbacks(unsigned long event_selector,
265                          unsigned long event_address,
266                          unsigned long failsafe_selector,
267                          unsigned long failsafe_address)
268 {
269         return _hypercall4(int, set_callbacks,
270                            event_selector, event_address,
271                            failsafe_selector, failsafe_address);
272 }
273 #else  /* CONFIG_X86_64 */
274 static inline int
275 HYPERVISOR_set_callbacks(unsigned long event_address,
276                         unsigned long failsafe_address,
277                         unsigned long syscall_address)
278 {
279         return _hypercall3(int, set_callbacks,
280                            event_address, failsafe_address,
281                            syscall_address);
282 }
283 #endif  /* CONFIG_X86_{32,64} */
284
285 static inline int
286 HYPERVISOR_callback_op(int cmd, void *arg)
287 {
288         return _hypercall2(int, callback_op, cmd, arg);
289 }
290
291 static inline int
292 HYPERVISOR_fpu_taskswitch(int set)
293 {
294         return _hypercall1(int, fpu_taskswitch, set);
295 }
296
297 static inline int
298 HYPERVISOR_sched_op(int cmd, void *arg)
299 {
300         return _hypercall2(int, sched_op, cmd, arg);
301 }
302
303 static inline long
304 HYPERVISOR_set_timer_op(u64 timeout)
305 {
306         unsigned long timeout_hi = (unsigned long)(timeout>>32);
307         unsigned long timeout_lo = (unsigned long)timeout;
308         return _hypercall2(long, set_timer_op, timeout_lo, timeout_hi);
309 }
310
311 static inline int
312 HYPERVISOR_mca(struct xen_mc *mc_op)
313 {
314         mc_op->interface_version = XEN_MCA_INTERFACE_VERSION;
315         return _hypercall1(int, mca, mc_op);
316 }
317
318 static inline int
319 HYPERVISOR_platform_op(struct xen_platform_op *op)
320 {
321         op->interface_version = XENPF_INTERFACE_VERSION;
322         return _hypercall1(int, platform_op, op);
323 }
324
325 static inline int
326 HYPERVISOR_set_debugreg(int reg, unsigned long value)
327 {
328         return _hypercall2(int, set_debugreg, reg, value);
329 }
330
331 static inline unsigned long
332 HYPERVISOR_get_debugreg(int reg)
333 {
334         return _hypercall1(unsigned long, get_debugreg, reg);
335 }
336
337 static inline int
338 HYPERVISOR_update_descriptor(u64 ma, u64 desc)
339 {
340         if (sizeof(u64) == sizeof(long))
341                 return _hypercall2(int, update_descriptor, ma, desc);
342         return _hypercall4(int, update_descriptor, ma, ma>>32, desc, desc>>32);
343 }
344
345 static inline long
346 HYPERVISOR_memory_op(unsigned int cmd, void *arg)
347 {
348         return _hypercall2(long, memory_op, cmd, arg);
349 }
350
351 static inline int
352 HYPERVISOR_multicall(void *call_list, uint32_t nr_calls)
353 {
354         return _hypercall2(int, multicall, call_list, nr_calls);
355 }
356
357 static inline int
358 HYPERVISOR_update_va_mapping(unsigned long va, pte_t new_val,
359                              unsigned long flags)
360 {
361         if (sizeof(new_val) == sizeof(long))
362                 return _hypercall3(int, update_va_mapping, va,
363                                    new_val.pte, flags);
364         else
365                 return _hypercall4(int, update_va_mapping, va,
366                                    new_val.pte, new_val.pte >> 32, flags);
367 }
368 extern int __must_check xen_event_channel_op_compat(int, void *);
369
370 static inline int
371 HYPERVISOR_event_channel_op(int cmd, void *arg)
372 {
373         int rc = _hypercall2(int, event_channel_op, cmd, arg);
374         if (unlikely(rc == -ENOSYS))
375                 rc = xen_event_channel_op_compat(cmd, arg);
376         return rc;
377 }
378
379 static inline int
380 HYPERVISOR_xen_version(int cmd, void *arg)
381 {
382         return _hypercall2(int, xen_version, cmd, arg);
383 }
384
385 static inline int
386 HYPERVISOR_console_io(int cmd, int count, char *str)
387 {
388         return _hypercall3(int, console_io, cmd, count, str);
389 }
390
391 extern int __must_check xen_physdev_op_compat(int, void *);
392
393 static inline int
394 HYPERVISOR_physdev_op(int cmd, void *arg)
395 {
396         int rc = _hypercall2(int, physdev_op, cmd, arg);
397         if (unlikely(rc == -ENOSYS))
398                 rc = xen_physdev_op_compat(cmd, arg);
399         return rc;
400 }
401
402 static inline int
403 HYPERVISOR_grant_table_op(unsigned int cmd, void *uop, unsigned int count)
404 {
405         return _hypercall3(int, grant_table_op, cmd, uop, count);
406 }
407
408 static inline int
409 HYPERVISOR_update_va_mapping_otherdomain(unsigned long va, pte_t new_val,
410                                          unsigned long flags, domid_t domid)
411 {
412         if (sizeof(new_val) == sizeof(long))
413                 return _hypercall4(int, update_va_mapping_otherdomain, va,
414                                    new_val.pte, flags, domid);
415         else
416                 return _hypercall5(int, update_va_mapping_otherdomain, va,
417                                    new_val.pte, new_val.pte >> 32,
418                                    flags, domid);
419 }
420
421 static inline int
422 HYPERVISOR_vm_assist(unsigned int cmd, unsigned int type)
423 {
424         return _hypercall2(int, vm_assist, cmd, type);
425 }
426
427 static inline int
428 HYPERVISOR_vcpu_op(int cmd, int vcpuid, void *extra_args)
429 {
430         return _hypercall3(int, vcpu_op, cmd, vcpuid, extra_args);
431 }
432
433 #ifdef CONFIG_X86_64
434 static inline int
435 HYPERVISOR_set_segment_base(int reg, unsigned long value)
436 {
437         return _hypercall2(int, set_segment_base, reg, value);
438 }
439 #endif
440
441 static inline int
442 HYPERVISOR_suspend(unsigned long start_info_mfn)
443 {
444         struct sched_shutdown r = { .reason = SHUTDOWN_suspend };
445
446         /*
447          * For a PV guest the tools require that the start_info mfn be
448          * present in rdx/edx when the hypercall is made. Per the
449          * hypercall calling convention this is the third hypercall
450          * argument, which is start_info_mfn here.
451          */
452         return _hypercall3(int, sched_op, SCHEDOP_shutdown, &r, start_info_mfn);
453 }
454
455 static inline int
456 HYPERVISOR_nmi_op(unsigned long op, unsigned long arg)
457 {
458         return _hypercall2(int, nmi_op, op, arg);
459 }
460
461 static inline unsigned long __must_check
462 HYPERVISOR_hvm_op(int op, void *arg)
463 {
464        return _hypercall2(unsigned long, hvm_op, op, arg);
465 }
466
467 static inline int
468 HYPERVISOR_tmem_op(
469         struct tmem_op *op)
470 {
471         return _hypercall1(int, tmem_op, op);
472 }
473
474 static inline int
475 HYPERVISOR_xenpmu_op(unsigned int op, void *arg)
476 {
477         return _hypercall2(int, xenpmu_op, op, arg);
478 }
479
480 static inline int
481 HYPERVISOR_dm_op(
482         domid_t dom, unsigned int nr_bufs, struct xen_dm_op_buf *bufs)
483 {
484         int ret;
485         stac();
486         ret = _hypercall3(int, dm_op, dom, nr_bufs, bufs);
487         clac();
488         return ret;
489 }
490
491 static inline void
492 MULTI_fpu_taskswitch(struct multicall_entry *mcl, int set)
493 {
494         mcl->op = __HYPERVISOR_fpu_taskswitch;
495         mcl->args[0] = set;
496
497         trace_xen_mc_entry(mcl, 1);
498 }
499
500 static inline void
501 MULTI_update_va_mapping(struct multicall_entry *mcl, unsigned long va,
502                         pte_t new_val, unsigned long flags)
503 {
504         mcl->op = __HYPERVISOR_update_va_mapping;
505         mcl->args[0] = va;
506         if (sizeof(new_val) == sizeof(long)) {
507                 mcl->args[1] = new_val.pte;
508                 mcl->args[2] = flags;
509         } else {
510                 mcl->args[1] = new_val.pte;
511                 mcl->args[2] = new_val.pte >> 32;
512                 mcl->args[3] = flags;
513         }
514
515         trace_xen_mc_entry(mcl, sizeof(new_val) == sizeof(long) ? 3 : 4);
516 }
517
518 static inline void
519 MULTI_grant_table_op(struct multicall_entry *mcl, unsigned int cmd,
520                      void *uop, unsigned int count)
521 {
522         mcl->op = __HYPERVISOR_grant_table_op;
523         mcl->args[0] = cmd;
524         mcl->args[1] = (unsigned long)uop;
525         mcl->args[2] = count;
526
527         trace_xen_mc_entry(mcl, 3);
528 }
529
530 static inline void
531 MULTI_update_va_mapping_otherdomain(struct multicall_entry *mcl, unsigned long va,
532                                     pte_t new_val, unsigned long flags,
533                                     domid_t domid)
534 {
535         mcl->op = __HYPERVISOR_update_va_mapping_otherdomain;
536         mcl->args[0] = va;
537         if (sizeof(new_val) == sizeof(long)) {
538                 mcl->args[1] = new_val.pte;
539                 mcl->args[2] = flags;
540                 mcl->args[3] = domid;
541         } else {
542                 mcl->args[1] = new_val.pte;
543                 mcl->args[2] = new_val.pte >> 32;
544                 mcl->args[3] = flags;
545                 mcl->args[4] = domid;
546         }
547
548         trace_xen_mc_entry(mcl, sizeof(new_val) == sizeof(long) ? 4 : 5);
549 }
550
551 static inline void
552 MULTI_update_descriptor(struct multicall_entry *mcl, u64 maddr,
553                         struct desc_struct desc)
554 {
555         mcl->op = __HYPERVISOR_update_descriptor;
556         if (sizeof(maddr) == sizeof(long)) {
557                 mcl->args[0] = maddr;
558                 mcl->args[1] = *(unsigned long *)&desc;
559         } else {
560                 u32 *p = (u32 *)&desc;
561
562                 mcl->args[0] = maddr;
563                 mcl->args[1] = maddr >> 32;
564                 mcl->args[2] = *p++;
565                 mcl->args[3] = *p;
566         }
567
568         trace_xen_mc_entry(mcl, sizeof(maddr) == sizeof(long) ? 2 : 4);
569 }
570
571 static inline void
572 MULTI_memory_op(struct multicall_entry *mcl, unsigned int cmd, void *arg)
573 {
574         mcl->op = __HYPERVISOR_memory_op;
575         mcl->args[0] = cmd;
576         mcl->args[1] = (unsigned long)arg;
577
578         trace_xen_mc_entry(mcl, 2);
579 }
580
581 static inline void
582 MULTI_mmu_update(struct multicall_entry *mcl, struct mmu_update *req,
583                  int count, int *success_count, domid_t domid)
584 {
585         mcl->op = __HYPERVISOR_mmu_update;
586         mcl->args[0] = (unsigned long)req;
587         mcl->args[1] = count;
588         mcl->args[2] = (unsigned long)success_count;
589         mcl->args[3] = domid;
590
591         trace_xen_mc_entry(mcl, 4);
592 }
593
594 static inline void
595 MULTI_mmuext_op(struct multicall_entry *mcl, struct mmuext_op *op, int count,
596                 int *success_count, domid_t domid)
597 {
598         mcl->op = __HYPERVISOR_mmuext_op;
599         mcl->args[0] = (unsigned long)op;
600         mcl->args[1] = count;
601         mcl->args[2] = (unsigned long)success_count;
602         mcl->args[3] = domid;
603
604         trace_xen_mc_entry(mcl, 4);
605 }
606
607 static inline void
608 MULTI_set_gdt(struct multicall_entry *mcl, unsigned long *frames, int entries)
609 {
610         mcl->op = __HYPERVISOR_set_gdt;
611         mcl->args[0] = (unsigned long)frames;
612         mcl->args[1] = entries;
613
614         trace_xen_mc_entry(mcl, 2);
615 }
616
617 static inline void
618 MULTI_stack_switch(struct multicall_entry *mcl,
619                    unsigned long ss, unsigned long esp)
620 {
621         mcl->op = __HYPERVISOR_stack_switch;
622         mcl->args[0] = ss;
623         mcl->args[1] = esp;
624
625         trace_xen_mc_entry(mcl, 2);
626 }
627
628 #endif /* _ASM_X86_XEN_HYPERCALL_H */