570 lines
16 KiB
C
570 lines
16 KiB
C
/*-
|
|
* Copyright (c) 1990 William Jolitz.
|
|
* Copyright (c) 1991 The Regents of the University of California.
|
|
* All rights reserved.
|
|
*
|
|
* 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. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by the University of
|
|
* California, Berkeley and its contributors.
|
|
* 4. 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: @(#)npx.c 7.2 (Berkeley) 5/12/91
|
|
* $Id: npx.c,v 1.30 1996/06/25 20:30:38 bde Exp $
|
|
*/
|
|
|
|
#include "npx.h"
|
|
#if NNPX > 0
|
|
|
|
#include "opt_math_emulate.h"
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/sysctl.h>
|
|
#include <sys/conf.h>
|
|
#include <sys/file.h>
|
|
#include <sys/proc.h>
|
|
#include <sys/ioctl.h>
|
|
#include <sys/syslog.h>
|
|
#include <sys/signalvar.h>
|
|
|
|
#include <machine/cpu.h>
|
|
#include <machine/pcb.h>
|
|
#include <machine/md_var.h>
|
|
#include <machine/trap.h>
|
|
#include <machine/clock.h>
|
|
#include <machine/specialreg.h>
|
|
|
|
#include <i386/isa/icu.h>
|
|
#include <i386/isa/isa_device.h>
|
|
#include <i386/isa/isa.h>
|
|
|
|
/*
|
|
* 387 and 287 Numeric Coprocessor Extension (NPX) Driver.
|
|
*/
|
|
|
|
#ifdef __GNUC__
|
|
|
|
#define fldcw(addr) __asm("fldcw %0" : : "m" (*(addr)))
|
|
#define fnclex() __asm("fnclex")
|
|
#define fninit() __asm("fninit")
|
|
#define fnop() __asm("fnop")
|
|
#define fnsave(addr) __asm("fnsave %0" : "=m" (*(addr)))
|
|
#define fnstcw(addr) __asm("fnstcw %0" : "=m" (*(addr)))
|
|
#define fnstsw(addr) __asm("fnstsw %0" : "=m" (*(addr)))
|
|
#define fp_divide_by_0() __asm("fldz; fld1; fdiv %st,%st(1); fnop")
|
|
#define frstor(addr) __asm("frstor %0" : : "m" (*(addr)))
|
|
#define start_emulating() __asm("smsw %%ax; orb %0,%%al; lmsw %%ax" \
|
|
: : "n" (CR0_TS) : "ax")
|
|
#define stop_emulating() __asm("clts")
|
|
|
|
#else /* not __GNUC__ */
|
|
|
|
void fldcw __P((caddr_t addr));
|
|
void fnclex __P((void));
|
|
void fninit __P((void));
|
|
void fnop __P((void));
|
|
void fnsave __P((caddr_t addr));
|
|
void fnstcw __P((caddr_t addr));
|
|
void fnstsw __P((caddr_t addr));
|
|
void fp_divide_by_0 __P((void));
|
|
void frstor __P((caddr_t addr));
|
|
void start_emulating __P((void));
|
|
void stop_emulating __P((void));
|
|
|
|
#endif /* __GNUC__ */
|
|
|
|
typedef u_char bool_t;
|
|
|
|
static int npxattach __P((struct isa_device *dvp));
|
|
static int npxprobe __P((struct isa_device *dvp));
|
|
static int npxprobe1 __P((struct isa_device *dvp));
|
|
|
|
struct isa_driver npxdriver = {
|
|
npxprobe, npxattach, "npx",
|
|
};
|
|
|
|
int hw_float; /* XXX currently just alias for npx_exists */
|
|
|
|
SYSCTL_INT(_hw,HW_FLOATINGPT, floatingpoint,
|
|
CTLFLAG_RD, &hw_float, 0,
|
|
"Floatingpoint instructions executed in hardware");
|
|
|
|
static u_int npx0_imask = SWI_CLOCK_MASK;
|
|
struct proc *npxproc;
|
|
|
|
static bool_t npx_ex16;
|
|
static bool_t npx_exists;
|
|
static struct gate_descriptor npx_idt_probeintr;
|
|
static int npx_intrno;
|
|
static volatile u_int npx_intrs_while_probing;
|
|
static bool_t npx_irq13;
|
|
static volatile u_int npx_traps_while_probing;
|
|
|
|
/*
|
|
* Special interrupt handlers. Someday intr0-intr15 will be used to count
|
|
* interrupts. We'll still need a special exception 16 handler. The busy
|
|
* latch stuff in probeintr() can be moved to npxprobe().
|
|
*/
|
|
inthand_t probeintr;
|
|
asm
|
|
("
|
|
.text
|
|
_probeintr:
|
|
ss
|
|
incl _npx_intrs_while_probing
|
|
pushl %eax
|
|
movb $0x20,%al # EOI (asm in strings loses cpp features)
|
|
outb %al,$0xa0 # IO_ICU2
|
|
outb %al,$0x20 # IO_ICU1
|
|
movb $0,%al
|
|
outb %al,$0xf0 # clear BUSY# latch
|
|
popl %eax
|
|
iret
|
|
");
|
|
|
|
inthand_t probetrap;
|
|
asm
|
|
("
|
|
.text
|
|
_probetrap:
|
|
ss
|
|
incl _npx_traps_while_probing
|
|
fnclex
|
|
iret
|
|
");
|
|
|
|
/*
|
|
* Probe routine. Initialize cr0 to give correct behaviour for [f]wait
|
|
* whether the device exists or not (XXX should be elsewhere). Set flags
|
|
* to tell npxattach() what to do. Modify device struct if npx doesn't
|
|
* need to use interrupts. Return 1 if device exists.
|
|
*/
|
|
static int
|
|
npxprobe(dvp)
|
|
struct isa_device *dvp;
|
|
{
|
|
int result;
|
|
u_long save_eflags;
|
|
u_char save_icu1_mask;
|
|
u_char save_icu2_mask;
|
|
struct gate_descriptor save_idt_npxintr;
|
|
struct gate_descriptor save_idt_npxtrap;
|
|
/*
|
|
* This routine is now just a wrapper for npxprobe1(), to install
|
|
* special npx interrupt and trap handlers, to enable npx interrupts
|
|
* and to disable other interrupts. Someday isa_configure() will
|
|
* install suitable handlers and run with interrupts enabled so we
|
|
* won't need to do so much here.
|
|
*/
|
|
npx_intrno = NRSVIDT + ffs(dvp->id_irq) - 1;
|
|
save_eflags = read_eflags();
|
|
disable_intr();
|
|
save_icu1_mask = inb(IO_ICU1 + 1);
|
|
save_icu2_mask = inb(IO_ICU2 + 1);
|
|
save_idt_npxintr = idt[npx_intrno];
|
|
save_idt_npxtrap = idt[16];
|
|
outb(IO_ICU1 + 1, ~(IRQ_SLAVE | dvp->id_irq));
|
|
outb(IO_ICU2 + 1, ~(dvp->id_irq >> 8));
|
|
setidt(16, probetrap, SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
|
|
setidt(npx_intrno, probeintr, SDT_SYS386IGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL));
|
|
npx_idt_probeintr = idt[npx_intrno];
|
|
enable_intr();
|
|
result = npxprobe1(dvp);
|
|
disable_intr();
|
|
outb(IO_ICU1 + 1, save_icu1_mask);
|
|
outb(IO_ICU2 + 1, save_icu2_mask);
|
|
idt[npx_intrno] = save_idt_npxintr;
|
|
idt[16] = save_idt_npxtrap;
|
|
write_eflags(save_eflags);
|
|
return (result);
|
|
}
|
|
|
|
static int
|
|
npxprobe1(dvp)
|
|
struct isa_device *dvp;
|
|
{
|
|
u_short control;
|
|
u_short status;
|
|
|
|
/*
|
|
* Partially reset the coprocessor, if any. Some BIOS's don't reset
|
|
* it after a warm boot.
|
|
*/
|
|
outb(0xf1, 0); /* full reset on some systems, NOP on others */
|
|
outb(0xf0, 0); /* clear BUSY# latch */
|
|
/*
|
|
* Prepare to trap all ESC (i.e., NPX) instructions and all WAIT
|
|
* instructions. We must set the CR0_MP bit and use the CR0_TS
|
|
* bit to control the trap, because setting the CR0_EM bit does
|
|
* not cause WAIT instructions to trap. It's important to trap
|
|
* WAIT instructions - otherwise the "wait" variants of no-wait
|
|
* control instructions would degenerate to the "no-wait" variants
|
|
* after FP context switches but work correctly otherwise. It's
|
|
* particularly important to trap WAITs when there is no NPX -
|
|
* otherwise the "wait" variants would always degenerate.
|
|
*
|
|
* Try setting CR0_NE to get correct error reporting on 486DX's.
|
|
* Setting it should fail or do nothing on lesser processors.
|
|
*/
|
|
load_cr0(rcr0() | CR0_MP | CR0_NE);
|
|
/*
|
|
* But don't trap while we're probing.
|
|
*/
|
|
stop_emulating();
|
|
/*
|
|
* Finish resetting the coprocessor, if any. If there is an error
|
|
* pending, then we may get a bogus IRQ13, but probeintr() will handle
|
|
* it OK. Bogus halts have never been observed, but we enabled
|
|
* IRQ13 and cleared the BUSY# latch early to handle them anyway.
|
|
*/
|
|
fninit();
|
|
/*
|
|
* Don't use fwait here because it might hang.
|
|
* Don't use fnop here because it usually hangs if there is no FPU.
|
|
*/
|
|
DELAY(1000); /* wait for any IRQ13 */
|
|
#ifdef DIAGNOSTIC
|
|
if (npx_intrs_while_probing != 0)
|
|
printf("fninit caused %u bogus npx interrupt(s)\n",
|
|
npx_intrs_while_probing);
|
|
if (npx_traps_while_probing != 0)
|
|
printf("fninit caused %u bogus npx trap(s)\n",
|
|
npx_traps_while_probing);
|
|
#endif
|
|
/*
|
|
* Check for a status of mostly zero.
|
|
*/
|
|
status = 0x5a5a;
|
|
fnstsw(&status);
|
|
if ((status & 0xb8ff) == 0) {
|
|
/*
|
|
* Good, now check for a proper control word.
|
|
*/
|
|
control = 0x5a5a;
|
|
fnstcw(&control);
|
|
if ((control & 0x1f3f) == 0x033f) {
|
|
hw_float = npx_exists = 1;
|
|
/*
|
|
* We have an npx, now divide by 0 to see if exception
|
|
* 16 works.
|
|
*/
|
|
control &= ~(1 << 2); /* enable divide by 0 trap */
|
|
fldcw(&control);
|
|
npx_traps_while_probing = npx_intrs_while_probing = 0;
|
|
fp_divide_by_0();
|
|
if (npx_traps_while_probing != 0) {
|
|
/*
|
|
* Good, exception 16 works.
|
|
*/
|
|
npx_ex16 = 1;
|
|
dvp->id_irq = 0; /* zap the interrupt */
|
|
/*
|
|
* special return value to flag that we do not
|
|
* actually use any I/O registers
|
|
*/
|
|
return (-1);
|
|
}
|
|
if (npx_intrs_while_probing != 0) {
|
|
/*
|
|
* Bad, we are stuck with IRQ13.
|
|
*/
|
|
npx_irq13 = 1;
|
|
/*
|
|
* npxattach would be too late to set npx0_imask.
|
|
*/
|
|
npx0_imask |= dvp->id_irq;
|
|
return (IO_NPXSIZE);
|
|
}
|
|
/*
|
|
* Worse, even IRQ13 is broken. Use emulator.
|
|
*/
|
|
}
|
|
}
|
|
/*
|
|
* Probe failed, but we want to get to npxattach to initialize the
|
|
* emulator and say that it has been installed. XXX handle devices
|
|
* that aren't really devices better.
|
|
*/
|
|
dvp->id_irq = 0;
|
|
/*
|
|
* special return value to flag that we do not
|
|
* actually use any I/O registers
|
|
*/
|
|
return (-1);
|
|
}
|
|
|
|
/*
|
|
* Attach routine - announce which it is, and wire into system
|
|
*/
|
|
int
|
|
npxattach(dvp)
|
|
struct isa_device *dvp;
|
|
{
|
|
if (npx_ex16)
|
|
printf("npx%d: INT 16 interface\n", dvp->id_unit);
|
|
else if (npx_irq13)
|
|
; /* higher level has printed "irq 13" */
|
|
#if defined(MATH_EMULATE) || defined(GPL_MATH_EMULATE)
|
|
else if (npx_exists) {
|
|
printf("npx%d: error reporting broken; using 387 emulator\n",
|
|
dvp->id_unit);
|
|
npx_exists = 0;
|
|
} else
|
|
printf("npx%d: 387 emulator\n",dvp->id_unit);
|
|
#else
|
|
else
|
|
printf("npx%d: no 387 emulator in kernel!\n", dvp->id_unit);
|
|
#endif
|
|
npxinit(__INITIAL_NPXCW__);
|
|
return (1); /* XXX unused */
|
|
}
|
|
|
|
/*
|
|
* Initialize floating point unit.
|
|
*/
|
|
void
|
|
npxinit(control)
|
|
u_short control;
|
|
{
|
|
struct save87 dummy;
|
|
|
|
if (!npx_exists)
|
|
return;
|
|
/*
|
|
* fninit has the same h/w bugs as fnsave. Use the detoxified
|
|
* fnsave to throw away any junk in the fpu. npxsave() initializes
|
|
* the fpu and sets npxproc = NULL as important side effects.
|
|
*/
|
|
npxsave(&dummy);
|
|
stop_emulating();
|
|
fldcw(&control);
|
|
if (curpcb != NULL)
|
|
fnsave(&curpcb->pcb_savefpu);
|
|
start_emulating();
|
|
}
|
|
|
|
/*
|
|
* Free coprocessor (if we have it).
|
|
*/
|
|
void
|
|
npxexit(p)
|
|
struct proc *p;
|
|
{
|
|
|
|
if (p == npxproc)
|
|
npxsave(&curpcb->pcb_savefpu);
|
|
if (npx_exists) {
|
|
u_int masked_exceptions;
|
|
|
|
masked_exceptions = curpcb->pcb_savefpu.sv_env.en_cw
|
|
& curpcb->pcb_savefpu.sv_env.en_sw & 0x7f;
|
|
/*
|
|
* Overflow, divde by 0, and invalid operand would have
|
|
* caused a trap in 1.1.5.
|
|
*/
|
|
if (masked_exceptions & 0x0d)
|
|
log(LOG_ERR,
|
|
"pid %d (%s) exited with masked floating point exceptions 0x%02x\n",
|
|
p->p_pid, p->p_comm, masked_exceptions);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Preserve the FP status word, clear FP exceptions, then generate a SIGFPE.
|
|
*
|
|
* Clearing exceptions is necessary mainly to avoid IRQ13 bugs. We now
|
|
* depend on longjmp() restoring a usable state. Restoring the state
|
|
* or examining it might fail if we didn't clear exceptions.
|
|
*
|
|
* XXX there is no standard way to tell SIGFPE handlers about the error
|
|
* state. The old interface:
|
|
*
|
|
* void handler(int sig, int code, struct sigcontext *scp);
|
|
*
|
|
* is broken because it is non-ANSI and because the FP state is not in
|
|
* struct sigcontext.
|
|
*
|
|
* XXX the FP state is not preserved across signal handlers. So signal
|
|
* handlers cannot afford to do FP unless they preserve the state or
|
|
* longjmp() out. Both preserving the state and longjmp()ing may be
|
|
* destroyed by IRQ13 bugs. Clearing FP exceptions is not an acceptable
|
|
* solution for signals other than SIGFPE.
|
|
*/
|
|
void
|
|
npxintr(unit)
|
|
int unit;
|
|
{
|
|
int code;
|
|
struct intrframe *frame;
|
|
|
|
if (npxproc == NULL || !npx_exists) {
|
|
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 */
|