9081eec1fb
have successfully built, booted, and run a number of different ELF kernel configurations, including GENERIC. LINT also builds and links cleanly, though I have not tried to boot it. The impact on developers is virtually nil, except for two things. All linker sets that might possibly be present in the kernel must be listed in "sys/i386/i386/setdefs.h". And all C symbols that are also referenced from assembly language code must be listed in "sys/i386/include/asnames.h". It so happens that failure to do these things will have no impact on the a.out kernel. But it will break the build of the ELF kernel. The ELF bootloader works, but it is not ready to commit quite yet.
611 lines
18 KiB
C
611 lines
18 KiB
C
/*-
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* Copyright (c) 1990 William Jolitz.
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* Copyright (c) 1991 The Regents of the University of California.
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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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* 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: @(#)npx.c 7.2 (Berkeley) 5/12/91
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* $Id: npx.c,v 1.40 1997/03/24 11:23:58 bde Exp $
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*/
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#include "npx.h"
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#if NNPX > 0
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#include "opt_cpu.h"
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#include "opt_math_emulate.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/sysctl.h>
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#include <sys/conf.h>
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#include <sys/file.h>
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#include <sys/proc.h>
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#ifdef NPX_DEBUG
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#include <sys/syslog.h>
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#endif
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#include <sys/signalvar.h>
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#include <machine/asmacros.h>
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#include <machine/cpu.h>
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#include <machine/pcb.h>
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#include <machine/md_var.h>
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#include <machine/trap.h>
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#include <machine/clock.h>
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#include <machine/specialreg.h>
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#include <i386/isa/icu.h>
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#include <i386/isa/isa_device.h>
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#include <i386/isa/isa.h>
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/*
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* 387 and 287 Numeric Coprocessor Extension (NPX) Driver.
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*/
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/* Configuration flags. */
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#define NPX_DISABLE_I586_OPTIMIZED_BCOPY (1 << 0)
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#define NPX_DISABLE_I586_OPTIMIZED_BZERO (1 << 1)
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#define NPX_DISABLE_I586_OPTIMIZED_COPYIO (1 << 2)
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/* XXX - should be in header file. */
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extern void (*bcopy_vector) __P((const void *from, void *to, size_t len));
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extern void (*ovbcopy_vector) __P((const void *from, void *to, size_t len));
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extern int (*copyin_vector) __P((const void *udaddr, void *kaddr, size_t len));
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extern int (*copyout_vector) __P((const void *kaddr, void *udaddr, size_t len));
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void i586_bcopy __P((const void *from, void *to, size_t len));
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void i586_bzero __P((void *buf, size_t len));
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int i586_copyin __P((const void *udaddr, void *kaddr, size_t len));
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int i586_copyout __P((const void *kaddr, void *udaddr, size_t len));
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#ifdef __GNUC__
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#define fldcw(addr) __asm("fldcw %0" : : "m" (*(addr)))
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#define fnclex() __asm("fnclex")
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#define fninit() __asm("fninit")
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#define fnop() __asm("fnop")
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#define fnsave(addr) __asm("fnsave %0" : "=m" (*(addr)))
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#define fnstcw(addr) __asm("fnstcw %0" : "=m" (*(addr)))
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#define fnstsw(addr) __asm("fnstsw %0" : "=m" (*(addr)))
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#define fp_divide_by_0() __asm("fldz; fld1; fdiv %st,%st(1); fnop")
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#define frstor(addr) __asm("frstor %0" : : "m" (*(addr)))
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#define start_emulating() __asm("smsw %%ax; orb %0,%%al; lmsw %%ax" \
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: : "n" (CR0_TS) : "ax")
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#define stop_emulating() __asm("clts")
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#else /* not __GNUC__ */
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void fldcw __P((caddr_t addr));
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void fnclex __P((void));
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void fninit __P((void));
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void fnop __P((void));
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void fnsave __P((caddr_t addr));
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void fnstcw __P((caddr_t addr));
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void fnstsw __P((caddr_t addr));
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void fp_divide_by_0 __P((void));
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void frstor __P((caddr_t addr));
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void start_emulating __P((void));
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void stop_emulating __P((void));
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#endif /* __GNUC__ */
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typedef u_char bool_t;
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static int npxattach __P((struct isa_device *dvp));
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static int npxprobe __P((struct isa_device *dvp));
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static int npxprobe1 __P((struct isa_device *dvp));
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struct isa_driver npxdriver = {
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npxprobe, npxattach, "npx",
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};
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int hw_float; /* XXX currently just alias for npx_exists */
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SYSCTL_INT(_hw,HW_FLOATINGPT, floatingpoint,
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CTLFLAG_RD, &hw_float, 0,
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"Floatingpoint instructions executed in hardware");
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static u_int npx0_imask = SWI_CLOCK_MASK;
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struct proc *npxproc;
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static bool_t npx_ex16;
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static bool_t npx_exists;
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static struct gate_descriptor npx_idt_probeintr;
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static int npx_intrno;
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static volatile u_int npx_intrs_while_probing;
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static bool_t npx_irq13;
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static volatile u_int npx_traps_while_probing;
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/*
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* Special interrupt handlers. Someday intr0-intr15 will be used to count
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* interrupts. We'll still need a special exception 16 handler. The busy
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* latch stuff in probeintr() can be moved to npxprobe().
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*/
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inthand_t probeintr;
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asm
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("
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.text
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.p2align 2,0x90
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" __XSTRING(CNAME(probeintr)) ":
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ss
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incl " __XSTRING(CNAME(npx_intrs_while_probing)) "
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pushl %eax
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movb $0x20,%al # EOI (asm in strings loses cpp features)
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outb %al,$0xa0 # IO_ICU2
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outb %al,$0x20 # IO_ICU1
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movb $0,%al
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outb %al,$0xf0 # clear BUSY# latch
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popl %eax
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iret
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");
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inthand_t probetrap;
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asm
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("
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.text
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.p2align 2,0x90
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" __XSTRING(CNAME(probetrap)) ":
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ss
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incl " __XSTRING(CNAME(npx_traps_while_probing)) "
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fnclex
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iret
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");
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/*
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* Probe routine. Initialize cr0 to give correct behaviour for [f]wait
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* whether the device exists or not (XXX should be elsewhere). Set flags
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* to tell npxattach() what to do. Modify device struct if npx doesn't
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* need to use interrupts. Return 1 if device exists.
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*/
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static int
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npxprobe(dvp)
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struct isa_device *dvp;
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{
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int result;
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u_long save_eflags;
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u_char save_icu1_mask;
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u_char save_icu2_mask;
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struct gate_descriptor save_idt_npxintr;
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struct gate_descriptor save_idt_npxtrap;
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/*
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* This routine is now just a wrapper for npxprobe1(), to install
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* special npx interrupt and trap handlers, to enable npx interrupts
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* and to disable other interrupts. Someday isa_configure() will
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* install suitable handlers and run with interrupts enabled so we
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* won't need to do so much here.
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*/
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npx_intrno = NRSVIDT + ffs(dvp->id_irq) - 1;
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save_eflags = read_eflags();
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disable_intr();
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save_icu1_mask = inb(IO_ICU1 + 1);
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save_icu2_mask = inb(IO_ICU2 + 1);
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save_idt_npxintr = idt[npx_intrno];
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save_idt_npxtrap = idt[16];
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outb(IO_ICU1 + 1, ~(IRQ_SLAVE | dvp->id_irq));
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outb(IO_ICU2 + 1, ~(dvp->id_irq >> 8));
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setidt(16, probetrap, SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
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setidt(npx_intrno, probeintr, SDT_SYS386IGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
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npx_idt_probeintr = idt[npx_intrno];
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enable_intr();
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result = npxprobe1(dvp);
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disable_intr();
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outb(IO_ICU1 + 1, save_icu1_mask);
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outb(IO_ICU2 + 1, save_icu2_mask);
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idt[npx_intrno] = save_idt_npxintr;
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idt[16] = save_idt_npxtrap;
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write_eflags(save_eflags);
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return (result);
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}
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static int
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npxprobe1(dvp)
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struct isa_device *dvp;
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{
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u_short control;
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u_short status;
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/*
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* Partially reset the coprocessor, if any. Some BIOS's don't reset
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* it after a warm boot.
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*/
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outb(0xf1, 0); /* full reset on some systems, NOP on others */
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outb(0xf0, 0); /* clear BUSY# latch */
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/*
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* Prepare to trap all ESC (i.e., NPX) instructions and all WAIT
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* instructions. We must set the CR0_MP bit and use the CR0_TS
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* bit to control the trap, because setting the CR0_EM bit does
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* not cause WAIT instructions to trap. It's important to trap
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* WAIT instructions - otherwise the "wait" variants of no-wait
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* control instructions would degenerate to the "no-wait" variants
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* after FP context switches but work correctly otherwise. It's
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* particularly important to trap WAITs when there is no NPX -
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* otherwise the "wait" variants would always degenerate.
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*
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* Try setting CR0_NE to get correct error reporting on 486DX's.
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* Setting it should fail or do nothing on lesser processors.
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*/
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load_cr0(rcr0() | CR0_MP | CR0_NE);
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/*
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* But don't trap while we're probing.
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*/
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stop_emulating();
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/*
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* Finish resetting the coprocessor, if any. If there is an error
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* pending, then we may get a bogus IRQ13, but probeintr() will handle
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* it OK. Bogus halts have never been observed, but we enabled
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* IRQ13 and cleared the BUSY# latch early to handle them anyway.
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*/
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fninit();
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/*
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* Don't use fwait here because it might hang.
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* Don't use fnop here because it usually hangs if there is no FPU.
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*/
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DELAY(1000); /* wait for any IRQ13 */
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#ifdef DIAGNOSTIC
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if (npx_intrs_while_probing != 0)
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printf("fninit caused %u bogus npx interrupt(s)\n",
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npx_intrs_while_probing);
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if (npx_traps_while_probing != 0)
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printf("fninit caused %u bogus npx trap(s)\n",
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npx_traps_while_probing);
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#endif
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/*
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* Check for a status of mostly zero.
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*/
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status = 0x5a5a;
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fnstsw(&status);
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if ((status & 0xb8ff) == 0) {
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/*
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* Good, now check for a proper control word.
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*/
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control = 0x5a5a;
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fnstcw(&control);
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if ((control & 0x1f3f) == 0x033f) {
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hw_float = npx_exists = 1;
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/*
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* We have an npx, now divide by 0 to see if exception
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* 16 works.
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*/
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control &= ~(1 << 2); /* enable divide by 0 trap */
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fldcw(&control);
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npx_traps_while_probing = npx_intrs_while_probing = 0;
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fp_divide_by_0();
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if (npx_traps_while_probing != 0) {
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/*
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* Good, exception 16 works.
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*/
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npx_ex16 = 1;
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dvp->id_irq = 0; /* zap the interrupt */
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/*
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* special return value to flag that we do not
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* actually use any I/O registers
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*/
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return (-1);
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}
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if (npx_intrs_while_probing != 0) {
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/*
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* Bad, we are stuck with IRQ13.
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*/
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npx_irq13 = 1;
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/*
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* npxattach would be too late to set npx0_imask.
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*/
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npx0_imask |= dvp->id_irq;
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return (IO_NPXSIZE);
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}
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/*
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* Worse, even IRQ13 is broken. Use emulator.
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*/
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}
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}
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/*
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* Probe failed, but we want to get to npxattach to initialize the
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* emulator and say that it has been installed. XXX handle devices
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* that aren't really devices better.
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*/
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dvp->id_irq = 0;
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/*
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* special return value to flag that we do not
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* actually use any I/O registers
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*/
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return (-1);
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}
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/*
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* Attach routine - announce which it is, and wire into system
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*/
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int
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npxattach(dvp)
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struct isa_device *dvp;
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{
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/* The caller has printed "irq 13" for the npx_irq13 case. */
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if (!npx_irq13) {
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printf("npx%d: ", dvp->id_unit);
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if (npx_ex16)
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printf("INT 16 interface\n");
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#if defined(MATH_EMULATE) || defined(GPL_MATH_EMULATE)
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else if (npx_exists) {
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printf("error reporting broken; using 387 emulator\n");
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hw_float = npx_exists = 0;
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} else
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printf("387 emulator\n");
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#else
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else
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printf("no 387 emulator in kernel!\n");
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#endif
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}
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npxinit(__INITIAL_NPXCW__);
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#ifdef I586_CPU
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if (cpu_class == CPUCLASS_586 && npx_ex16) {
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if (!(dvp->id_flags & NPX_DISABLE_I586_OPTIMIZED_BCOPY)) {
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bcopy_vector = i586_bcopy;
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ovbcopy_vector = i586_bcopy;
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}
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if (!(dvp->id_flags & NPX_DISABLE_I586_OPTIMIZED_BZERO))
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bzero = i586_bzero;
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if (!(dvp->id_flags & NPX_DISABLE_I586_OPTIMIZED_COPYIO)) {
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copyin_vector = i586_copyin;
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copyout_vector = i586_copyout;
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}
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}
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#endif
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return (1); /* XXX unused */
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}
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/*
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* Initialize floating point unit.
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*/
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void
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npxinit(control)
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u_short control;
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{
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struct save87 dummy;
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if (!npx_exists)
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return;
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/*
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* fninit has the same h/w bugs as fnsave. Use the detoxified
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* fnsave to throw away any junk in the fpu. npxsave() initializes
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* the fpu and sets npxproc = NULL as important side effects.
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*/
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npxsave(&dummy);
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stop_emulating();
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fldcw(&control);
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if (curpcb != NULL)
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fnsave(&curpcb->pcb_savefpu);
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start_emulating();
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}
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/*
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* Free coprocessor (if we have it).
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*/
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void
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npxexit(p)
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struct proc *p;
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{
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if (p == npxproc)
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npxsave(&curpcb->pcb_savefpu);
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#ifdef NPX_DEBUG
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if (npx_exists) {
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u_int masked_exceptions;
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masked_exceptions = curpcb->pcb_savefpu.sv_env.en_cw
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& curpcb->pcb_savefpu.sv_env.en_sw & 0x7f;
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/*
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* Log exceptions that would have trapped with the old
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* control word (overflow, divide by 0, and invalid operand).
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*/
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if (masked_exceptions & 0x0d)
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log(LOG_ERR,
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"pid %d (%s) exited with masked floating point exceptions 0x%02x\n",
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p->p_pid, p->p_comm, masked_exceptions);
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}
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#endif
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}
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/*
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* Preserve the FP status word, clear FP exceptions, then generate a SIGFPE.
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*
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* Clearing exceptions is necessary mainly to avoid IRQ13 bugs. We now
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* depend on longjmp() restoring a usable state. Restoring the state
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* or examining it might fail if we didn't clear exceptions.
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*
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* XXX there is no standard way to tell SIGFPE handlers about the error
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* state. The old interface:
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*
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* void handler(int sig, int code, struct sigcontext *scp);
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*
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* is broken because it is non-ANSI and because the FP state is not in
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* struct sigcontext.
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*
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* XXX the FP state is not preserved across signal handlers. So signal
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* handlers cannot afford to do FP unless they preserve the state or
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* longjmp() out. Both preserving the state and longjmp()ing may be
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* destroyed by IRQ13 bugs. Clearing FP exceptions is not an acceptable
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* solution for signals other than SIGFPE.
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*/
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void
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npxintr(unit)
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int unit;
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{
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int code;
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struct intrframe *frame;
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if (npxproc == NULL || !npx_exists) {
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printf("npxintr: npxproc = %p, curproc = %p, npx_exists = %d\n",
|
|
npxproc, curproc, npx_exists);
|
|
panic("npxintr from nowhere");
|
|
}
|
|
if (npxproc != curproc) {
|
|
printf("npxintr: npxproc = %p, curproc = %p, npx_exists = %d\n",
|
|
npxproc, curproc, npx_exists);
|
|
panic("npxintr from non-current process");
|
|
}
|
|
|
|
outb(0xf0, 0);
|
|
fnstsw(&curpcb->pcb_savefpu.sv_ex_sw);
|
|
fnclex();
|
|
fnop();
|
|
|
|
/*
|
|
* Pass exception to process.
|
|
*/
|
|
frame = (struct intrframe *)&unit; /* XXX */
|
|
if (ISPL(frame->if_cs) == SEL_UPL) {
|
|
/*
|
|
* Interrupt is essentially a trap, so we can afford to call
|
|
* the SIGFPE handler (if any) as soon as the interrupt
|
|
* returns.
|
|
*
|
|
* XXX little or nothing is gained from this, and plenty is
|
|
* lost - the interrupt frame has to contain the trap frame
|
|
* (this is otherwise only necessary for the rescheduling trap
|
|
* in doreti, and the frame for that could easily be set up
|
|
* just before it is used).
|
|
*/
|
|
curproc->p_md.md_regs = &frame->if_es;
|
|
#ifdef notyet
|
|
/*
|
|
* Encode the appropriate code for detailed information on
|
|
* this exception.
|
|
*/
|
|
code = XXX_ENCODE(curpcb->pcb_savefpu.sv_ex_sw);
|
|
#else
|
|
code = 0; /* XXX */
|
|
#endif
|
|
trapsignal(curproc, SIGFPE, code);
|
|
} else {
|
|
/*
|
|
* Nested interrupt. These losers occur when:
|
|
* o an IRQ13 is bogusly generated at a bogus time, e.g.:
|
|
* o immediately after an fnsave or frstor of an
|
|
* error state.
|
|
* o a couple of 386 instructions after
|
|
* "fstpl _memvar" causes a stack overflow.
|
|
* These are especially nasty when combined with a
|
|
* trace trap.
|
|
* o an IRQ13 occurs at the same time as another higher-
|
|
* priority interrupt.
|
|
*
|
|
* Treat them like a true async interrupt.
|
|
*/
|
|
psignal(curproc, SIGFPE);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Implement device not available (DNA) exception
|
|
*
|
|
* It would be better to switch FP context here (if curproc != npxproc)
|
|
* and not necessarily for every context switch, but it is too hard to
|
|
* access foreign pcb's.
|
|
*/
|
|
int
|
|
npxdna()
|
|
{
|
|
if (!npx_exists)
|
|
return (0);
|
|
if (npxproc != NULL) {
|
|
printf("npxdna: npxproc = %p, curproc = %p\n",
|
|
npxproc, curproc);
|
|
panic("npxdna");
|
|
}
|
|
stop_emulating();
|
|
/*
|
|
* Record new context early in case frstor causes an IRQ13.
|
|
*/
|
|
npxproc = curproc;
|
|
curpcb->pcb_savefpu.sv_ex_sw = 0;
|
|
/*
|
|
* The following frstor may cause an IRQ13 when the state being
|
|
* restored has a pending error. The error will appear to have been
|
|
* triggered by the current (npx) user instruction even when that
|
|
* instruction is a no-wait instruction that should not trigger an
|
|
* error (e.g., fnclex). On at least one 486 system all of the
|
|
* no-wait instructions are broken the same as frstor, so our
|
|
* treatment does not amplify the breakage. On at least one
|
|
* 386/Cyrix 387 system, fnclex works correctly while frstor and
|
|
* fnsave are broken, so our treatment breaks fnclex if it is the
|
|
* first FPU instruction after a context switch.
|
|
*/
|
|
frstor(&curpcb->pcb_savefpu);
|
|
|
|
return (1);
|
|
}
|
|
|
|
/*
|
|
* Wrapper for fnsave instruction to handle h/w bugs. If there is an error
|
|
* pending, then fnsave generates a bogus IRQ13 on some systems. Force
|
|
* any IRQ13 to be handled immediately, and then ignore it. This routine is
|
|
* often called at splhigh so it must not use many system services. In
|
|
* particular, it's much easier to install a special handler than to
|
|
* guarantee that it's safe to use npxintr() and its supporting code.
|
|
*/
|
|
void
|
|
npxsave(addr)
|
|
struct save87 *addr;
|
|
{
|
|
u_char icu1_mask;
|
|
u_char icu2_mask;
|
|
u_char old_icu1_mask;
|
|
u_char old_icu2_mask;
|
|
struct gate_descriptor save_idt_npxintr;
|
|
|
|
disable_intr();
|
|
old_icu1_mask = inb(IO_ICU1 + 1);
|
|
old_icu2_mask = inb(IO_ICU2 + 1);
|
|
save_idt_npxintr = idt[npx_intrno];
|
|
outb(IO_ICU1 + 1, old_icu1_mask & ~(IRQ_SLAVE | npx0_imask));
|
|
outb(IO_ICU2 + 1, old_icu2_mask & ~(npx0_imask >> 8));
|
|
idt[npx_intrno] = npx_idt_probeintr;
|
|
enable_intr();
|
|
stop_emulating();
|
|
fnsave(addr);
|
|
fnop();
|
|
start_emulating();
|
|
npxproc = NULL;
|
|
disable_intr();
|
|
icu1_mask = inb(IO_ICU1 + 1); /* masks may have changed */
|
|
icu2_mask = inb(IO_ICU2 + 1);
|
|
outb(IO_ICU1 + 1,
|
|
(icu1_mask & ~npx0_imask) | (old_icu1_mask & npx0_imask));
|
|
outb(IO_ICU2 + 1,
|
|
(icu2_mask & ~(npx0_imask >> 8))
|
|
| (old_icu2_mask & (npx0_imask >> 8)));
|
|
idt[npx_intrno] = save_idt_npxintr;
|
|
enable_intr(); /* back to usual state */
|
|
}
|
|
|
|
#endif /* NNPX > 0 */
|