36e9f877df
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
96 lines
3.3 KiB
C
96 lines
3.3 KiB
C
/*-
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* Copyright (c) Peter Wemm <peter@netplex.com.au>
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* All rights reserved.
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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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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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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* $FreeBSD$
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*/
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/*
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* This structure maps out the global data that needs to be kept on a
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* per-cpu basis. genassym uses this to generate offsets for the assembler
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* code, which also provides external symbols so that C can get at them as
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* though they were really globals.
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*
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* The SMP parts are setup in pmap.c and locore.s for the BSP, and
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* mp_machdep.c sets up the data for the AP's to "see" when they awake.
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* The reason for doing it via a struct is so that an array of pointers
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* to each CPU's data can be set up for things like "check curproc on all
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* other processors"
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*/
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struct globaldata {
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struct privatespace *gd_prvspace; /* self-reference */
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struct proc *gd_curproc;
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struct proc *gd_npxproc;
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struct pcb *gd_curpcb;
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struct timeval gd_switchtime;
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struct i386tss gd_common_tss;
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int gd_switchticks;
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struct segment_descriptor gd_common_tssd;
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struct segment_descriptor *gd_tss_gdt;
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#ifdef USER_LDT
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int gd_currentldt;
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#endif
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#ifdef SMP
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u_int gd_cpuid;
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u_int gd_cpu_lockid;
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u_int gd_other_cpus;
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int gd_inside_intr;
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u_int gd_ss_eflags;
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pt_entry_t *gd_prv_CMAP1;
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pt_entry_t *gd_prv_CMAP2;
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pt_entry_t *gd_prv_CMAP3;
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pt_entry_t *gd_prv_PMAP1;
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caddr_t gd_prv_CADDR1;
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caddr_t gd_prv_CADDR2;
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caddr_t gd_prv_CADDR3;
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unsigned *gd_prv_PADDR1;
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#endif
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u_int gd_astpending;
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};
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#ifdef SMP
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/*
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* This is the upper (0xff800000) address space layout that is per-cpu.
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* It is setup in locore.s and pmap.c for the BSP and in mp_machdep.c for
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* each AP. genassym helps export this to the assembler code.
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*/
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struct privatespace {
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/* page 0 - data page */
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struct globaldata globaldata;
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char __filler0[PAGE_SIZE - sizeof(struct globaldata)];
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/* page 1..4 - CPAGE1,CPAGE2,CPAGE3,PPAGE1 */
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char CPAGE1[PAGE_SIZE];
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char CPAGE2[PAGE_SIZE];
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char CPAGE3[PAGE_SIZE];
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char PPAGE1[PAGE_SIZE];
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/* page 5..4+UPAGES - idle stack (UPAGES pages) */
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char idlestack[UPAGES * PAGE_SIZE];
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};
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extern struct privatespace SMP_prvspace[];
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#endif
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