usr/src/uts/common/sys/kfpu.h

   1 /*
   2  * This file and its contents are supplied under the terms of the
   3  * Common Development and Distribution License ("CDDL"), version 1.0.
   4  * You may only use this file in accordance with the terms of version
   5  * 1.0 of the CDDL.
   6  *
   7  * A full copy of the text of the CDDL should have accompanied this
   8  * source.  A copy of the CDDL is also available via the Internet at
   9  * http://www.illumos.org/license/CDDL.
  10  */
  11
  12 /*
  13  * Copyright 2020 Joyent, Inc.
  14  */
  15
  16 #ifndef _SYS_KFPU_H
  17 #define _SYS_KFPU_H
  18
  19 /*
  20  * This header file provides a means for the kernel to opt into using the FPU.
  21  * Care should be exercised when using the FPU.
  22  */
  23
  24 #include <sys/types.h>
  25
  26 #ifdef __cplusplus
  27 extern "C" {
  28 #endif
  29
  30 typedef struct kfpu_state kfpu_state_t;
  31
  32 /*
  33  * Allocate a new kernel FPU state. This may be allocated at a time independent
  34  * from its use. It will stay around until such a time as kernel_fpu_free() is
  35  * called. A given kernel FPU state may only be used by a single thread at any
  36  * time; however, it is not bound to a given thread.
  37  */
  38 extern kfpu_state_t *kernel_fpu_alloc(int);
  39 extern void kernel_fpu_free(kfpu_state_t *);
  40
  41 /*
  42  * These functions begin and end the use of the kernel FPU. Once this is called,
  43  * a given kernel thread will be allowed to use the FPU. This will be saved and
  44  * restored across context switches.
  45  */
  46 extern void kernel_fpu_begin(kfpu_state_t *, uint_t);
  47 extern void kernel_fpu_end(kfpu_state_t *, uint_t);
  48
  49 /*
  50  * Internal validation function.
  51  */
  52 extern void kernel_fpu_no_swtch(void);
  53
  54 /*
  55  * Flag definitions for kernel_fpu_begin and kernel_fpu_end.
  56  */
  57 #define KFPU_NO_STATE   0x01    /* kfpu_state_t not passed; use preemption */
  58 #define KFPU_USE_LWP    0x02    /* kfpu_state_t not passed; use lwp */
  59
  60 #ifdef __cplusplus
  61 }
  62 #endif
  63
  64 #endif /* _SYS_KFPU_H */