arch/x86/kernel/platform/i86pc/include/sys/comm_page.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 2016 Joyent, Inc.
  14  */
  15
  16 #ifndef _COMM_PAGE_H
  17 #define _COMM_PAGE_H
  18
  19 #ifndef _ASM
  20 #include <sys/types.h>
  21 #include <sys/param.h>
  22 #include <sys/time.h>
  23 #endif /* _ASM */
  24
  25 #ifdef __cplusplus
  26 extern "C" {
  27 #endif
  28
  29 #define COMM_PAGE_SIZE  PAGESIZE
  30
  31 #ifndef _ASM
  32
  33 /*
  34  * x86 comm page
  35  *
  36  * This struct defines the data format for the "comm page": kernel data made
  37  * directly available to userspace for read-only operations.  This enables
  38  * facilities such as clock_gettime to operate entirely in userspace without
  39  * the need for a trap or fasttrap.
  40  *
  41  * A note about 32-bit/64-bit compatibility:
  42  * The current format of the comm page is designed to be consistent for both
  43  * 32-bit and 64-bit programs running in a 64-bit kernel.  On 32-bit kernels,
  44  * the comm page is not exposed to userspace due to the difference in
  45  * timespec_t sizing.
  46  *
  47  * This struct is instantiated "by hand" in assembly to preserve the global
  48  * symbols it contains.  That layout must be kept in sync with the structure
  49  * defined here.
  50  * See: "uts/i86pc/ml/comm_page.s"
  51  */
  52 typedef struct comm_page_s {
  53         hrtime_t                cp_tsc_last;
  54         hrtime_t                cp_tsc_hrtime_base;
  55         hrtime_t                cp_tsc_resume_cap;
  56         uint32_t                cp_tsc_type;
  57         uint32_t                cp_tsc_max_delta;
  58
  59         volatile uint32_t       cp_hres_lock;   /* must be 8-byte aligned */
  60         uint32_t                cp_nsec_scale;
  61         int64_t                 cp_hrestime_adj;
  62         hrtime_t                cp_hres_last_tick;
  63         uint32_t                cp_tsc_ncpu;
  64         uint32_t                _cp_pad;
  65         volatile int64_t        cp_hrestime[2];
  66 #if defined(_MACHDEP)
  67         hrtime_t                cp_tsc_sync_tick_delta[NCPU];
  68 #else
  69         /* length resides in cp_ncpu */
  70         hrtime_t                cp_tsc_sync_tick_delta[];
  71 #endif /* defined(_MACHDEP) */
  72 } comm_page_t;
  73
  74 #if defined(_KERNEL)
  75 extern comm_page_t comm_page;
  76
  77 #if defined(_MACHDEP)
  78 extern hrtime_t tsc_last;
  79 extern hrtime_t tsc_hrtime_base;
  80 extern hrtime_t tsc_resume_cap;
  81 extern uint32_t tsc_type;
  82 extern uint32_t tsc_max_delta;
  83 extern volatile uint32_t hres_lock;
  84 extern uint32_t nsec_scale;
  85 extern int64_t hrestime_adj;
  86 extern hrtime_t hres_last_tick;
  87 extern uint32_t tsc_ncpu;
  88 extern volatile timestruc_t hrestime;
  89 extern hrtime_t tsc_sync_tick_delta[NCPU];
  90 #endif /* defined(_MACHDEP) */
  91 #endif /* defined(_KERNEL) */
  92
  93 #endif  /* _ASM */
  94
  95 #ifdef __cplusplus
  96 }
  97 #endif
  98
  99 #endif /* _COMM_PAGE_H */