317fd0dfa7
syscall path inward. A system call may select whether it needs the MP
lock or not (the default being that it does need it).
A great deal of conditional SMP code for various deadended experiments
has been removed. 'cil' and 'cml' have been removed entirely, and the
locking around the cpl has been removed. The conditional
separately-locked fast-interrupt code has been removed, meaning that
interrupts must hold the CPL now (but they pretty much had to anyway).
Another reason for doing this is that the original separate-lock for
interrupts just doesn't apply to the interrupt thread mechanism being
contemplated.
Modifications to the cpl may now ONLY occur while holding the MP
lock. For example, if an otherwise MP safe syscall needs to mess with
the cpl, it must hold the MP lock for the duration and must (as usual)
save/restore the cpl in a nested fashion.
This is precursor work for the real meat coming later: avoiding having
to hold the MP lock for common syscalls and I/O's and interrupt threads.
It is expected that the spl mechanisms and new interrupt threading
mechanisms will be able to run in tandem, allowing a slow piecemeal
transition to occur.
This patch should result in a moderate performance improvement due to
the considerable amount of code that has been removed from the critical
path, especially the simplification of the spl*() calls. The real
performance gains will come later.
Approved by: jkh
Reviewed by: current, bde (exception.s)
Some work taken from: luoqi's patch
146 lines
5.4 KiB
C
146 lines
5.4 KiB
C
/*-
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* Copyright (c) 1990 The Regents of the University of California.
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* All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* William Jolitz.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: @(#)cpu.h 5.4 (Berkeley) 5/9/91
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* $FreeBSD$
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*/
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#ifndef _MACHINE_CPU_H_
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#define _MACHINE_CPU_H_
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/*
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* Definitions unique to i386 cpu support.
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*/
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#include <machine/psl.h>
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#include <machine/frame.h>
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#include <machine/segments.h>
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/*
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* definitions of cpu-dependent requirements
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* referenced in generic code
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*/
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#undef COPY_SIGCODE /* don't copy sigcode above user stack in exec */
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#define cpu_exec(p) /* nothing */
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#define cpu_swapin(p) /* nothing */
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#define cpu_setstack(p, ap) ((p)->p_md.md_regs[SP] = (ap))
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#define cpu_set_init_frame(p, fp) ((p)->p_md.md_regs = (fp))
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#define CLKF_USERMODE(framep) \
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((ISPL((framep)->cf_cs) == SEL_UPL) || (framep->cf_eflags & PSL_VM))
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#define CLKF_INTR(framep) (intr_nesting_level >= 2)
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#if 0
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/*
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* XXX splsoftclock() is very broken and barely worth fixing. It doesn't
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* turn off the clock bit in imen or in the icu. (This is not a serious
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* problem at 100 Hz but it is serious at 16000 Hz for pcaudio. softclock()
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* can take more than 62.5 usec so clock interrupts are lost.) It doesn't
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* check for pending interrupts being unmasked. clkintr() and Xintr0()
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* assume that the ipl is high when hardclock() returns. Our SWI_CLOCK
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* handling is efficient enough that little is gained by calling
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* softclock() directly.
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*/
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#define CLKF_BASEPRI(framep) ((framep)->cf_ppl == 0)
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#else
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#define CLKF_BASEPRI(framep) (0)
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#endif
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#define CLKF_PC(framep) ((framep)->cf_eip)
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/*
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* Preempt the current process if in interrupt from user mode,
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* or after the current trap/syscall if in system mode.
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*
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* XXX: if astpending is later changed to an |= here due to more flags being
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* added, we will have an atomicy problem. The type of atomicy we need is
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* a non-locked orl.
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*/
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#define need_resched() do { astpending = AST_RESCHED|AST_PENDING; } while (0)
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#define resched_wanted() (astpending & AST_RESCHED)
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/*
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* Arrange to handle pending profiling ticks before returning to user mode.
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*
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* XXX this is now poorly named and implemented. It used to handle only a
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* single tick and the P_OWEUPC flag served as a counter. Now there is a
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* counter in the proc table and flag isn't really necessary.
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*/
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#define need_proftick(p) \
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do { (p)->p_flag |= P_OWEUPC; aston(); } while (0)
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/*
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* Notify the current process (p) that it has a signal pending,
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* process as soon as possible.
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*
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* XXX: aston() really needs to be an atomic (not locked, but an orl),
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* in case need_resched() is set by an interrupt. But with astpending a
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* per-cpu variable this is not trivial to do efficiently. For now we blow
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* it off (asynchronous need_resched() conflicts are not critical).
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*/
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#define signotify(p) aston()
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#define aston() do { astpending |= AST_PENDING; } while (0)
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#define astoff()
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/*
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* CTL_MACHDEP definitions.
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*/
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#define CPU_CONSDEV 1 /* dev_t: console terminal device */
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#define CPU_ADJKERNTZ 2 /* int: timezone offset (seconds) */
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#define CPU_DISRTCSET 3 /* int: disable resettodr() call */
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#define CPU_BOOTINFO 4 /* struct: bootinfo */
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#define CPU_WALLCLOCK 5 /* int: indicates wall CMOS clock */
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#define CPU_MAXID 6 /* number of valid machdep ids */
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#define CTL_MACHDEP_NAMES { \
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{ 0, 0 }, \
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{ "console_device", CTLTYPE_STRUCT }, \
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{ "adjkerntz", CTLTYPE_INT }, \
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{ "disable_rtc_set", CTLTYPE_INT }, \
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{ "bootinfo", CTLTYPE_STRUCT }, \
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{ "wall_cmos_clock", CTLTYPE_INT }, \
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}
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#ifdef _KERNEL
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extern char btext[];
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extern char etext[];
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extern u_char intr_nesting_level;
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void fork_trampoline __P((void));
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void fork_return __P((struct proc *, struct trapframe));
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#endif
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#endif /* !_MACHINE_CPU_H_ */
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