freebsd-skq/sys/i386/include/cpu.h
jhb ed96335a07 Add a custom implementation of cpu_lock_delay() for x86.
Avoid using DELAY() since it can try to use spin locks on CPUs without
a P-state invariant TSC.  For cpu_lock_delay(), always use the TSC if
it exists (even if it is not P-state invariant) to delay for a
microsecond.  If the TSC does not exist, read from I/O port 0x84 to
delay instead.

PR:		228768
Reported by:	Roger Hammerstein <cheeky.m@live.com>
Reviewed by:	kib
MFC after:	3 days
Differential Revision:	https://reviews.freebsd.org/D17851
2018-11-05 22:54:03 +00:00

94 lines
3.0 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* William Jolitz.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: @(#)cpu.h 5.4 (Berkeley) 5/9/91
* $FreeBSD$
*/
#ifndef _MACHINE_CPU_H_
#define _MACHINE_CPU_H_
/*
* Definitions unique to i386 cpu support.
*/
#include <machine/psl.h>
#include <machine/frame.h>
#include <machine/segments.h>
#define cpu_exec(p) /* nothing */
#define cpu_swapin(p) /* nothing */
#define cpu_getstack(td) ((td)->td_frame->tf_esp)
#define cpu_setstack(td, ap) ((td)->td_frame->tf_esp = (ap))
#define cpu_spinwait() ia32_pause()
#define TRAPF_USERMODE(framep) \
((ISPL((framep)->tf_cs) == SEL_UPL) || ((framep)->tf_eflags & PSL_VM))
#define TRAPF_PC(framep) ((framep)->tf_eip)
#ifdef _KERNEL
/*
* Struct containing pointers to CPU management functions whose
* implementation is run time selectable. Selection can be made,
* for example, based on detection of a particular CPU variant or
* hypervisor environment.
*/
struct cpu_ops {
void (*cpu_init)(void);
void (*cpu_resume)(void);
};
extern struct cpu_ops cpu_ops;
extern char btext[];
extern char etext[];
void cpu_halt(void);
void cpu_lock_delay(void);
void cpu_reset(void);
void fork_trampoline(void);
void swi_vm(void *);
/*
* Return contents of in-cpu fast counter as a sort of "bogo-time"
* for random-harvesting purposes.
*/
static __inline uint64_t
get_cyclecount(void)
{
return (cpu_ticks());
}
#endif
#endif /* !_MACHINE_CPU_H_ */