a2a1c95c10
space. (!) Have each process use the kernel stack and pcb in the kvm space. Since the stacks are at a different address, we cannot copy the stack at fork() and allow the child to return up through the function call tree to return to user mode - create a new execution context and have the new process begin executing from cpu_switch() and go to user mode directly. In theory this should speed up fork a bit. Context switch the tss_esp0 pointer in the common tss. This is a lot simpler since than swithching the gdt[GPROC0_SEL].sd.sd_base pointer to each process's tss since the esp0 pointer is a 32 bit pointer, and the sd_base setting is split into three different bit sections at non-aligned boundaries and requires a lot of twiddling to reset. The 8K of memory at the top of the process space is now empty, and unmapped (and unmappable, it's higher than VM_MAXUSER_ADDRESS). Simplity the pmap code to manage process contexts, we no longer have to double map the UPAGES, this simplifies and should measuably speed up fork(). The following parts came from John Dyson: Set PG_G on the UPAGES that are now in kernel context, and invalidate them when swapping them out. Move the upages object (upobj) from the vmspace to the proc structure. Now that the UPAGES (pcb and kernel stack) are out of user space, make rfork(..RFMEM..) do what was intended by sharing the vmspace entirely via reference counting rather than simply inheriting the mappings.
144 lines
5.0 KiB
C
144 lines
5.0 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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* $Id: cpu.h,v 1.28 1997/02/22 09:34:04 peter Exp $
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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/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) (ISPL((framep)->cf_cs) == SEL_UPL)
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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_AST
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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 & ~SWI_AST_MASK) == 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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#define need_resched() { want_resched = 1; aston(); }
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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) { (p)->p_flag |= P_OWEUPC; aston(); }
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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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#define signotify(p) aston()
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#define aston() setsoftast()
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#define astoff()
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/*
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* pull in #defines for kinds of processors
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*/
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#include <machine/cputypes.h>
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struct cpu_nameclass {
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char *cpu_name;
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int cpu_class;
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};
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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 int cpu;
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extern int cpu_class;
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extern u_char intr_nesting_level;
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extern int want_resched; /* resched was called */
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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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void cpu_set_fork_handler __P((struct proc *, void (*pc)(void *), void *));
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#endif
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#endif /* !_MACHINE_CPU_H_ */
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