/*- * 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 1.55 1998/01/31 07:23:09 eivind Exp $ */ #include "npx.h" #if NNPX > 0 #include "opt_debug_npx.h" #include "opt_math_emulate.h" #include #include #include #include #include #include #include #ifdef NPX_DEBUG #include #endif #include #ifndef SMP #include #endif #include #include #include #ifndef SMP #include #endif #include #include #ifndef SMP #include #endif #include #include #ifndef SMP #include #include #include #endif #include /* * 387 and 287 Numeric Coprocessor Extension (NPX) Driver. */ /* Configuration flags. */ #define NPX_DISABLE_I586_OPTIMIZED_BCOPY (1 << 0) #define NPX_DISABLE_I586_OPTIMIZED_BZERO (1 << 1) #define NPX_DISABLE_I586_OPTIMIZED_COPYIO (1 << 2) /* XXX - should be in header file. */ extern void (*bcopy_vector) __P((const void *from, void *to, size_t len)); extern void (*ovbcopy_vector) __P((const void *from, void *to, size_t len)); extern int (*copyin_vector) __P((const void *udaddr, void *kaddr, size_t len)); extern int (*copyout_vector) __P((const void *kaddr, void *udaddr, size_t len)); void i586_bcopy __P((const void *from, void *to, size_t len)); void i586_bzero __P((void *buf, size_t len)); int i586_copyin __P((const void *udaddr, void *kaddr, size_t len)); int i586_copyout __P((const void *kaddr, void *udaddr, size_t len)); #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)); static long timezero __P((const char *funcname, void (*func)(void *buf, size_t len))); 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; #ifndef SMP /* XXX per-cpu on smp */ struct proc *npxproc; #endif 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; #ifndef SMP /* * 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 .p2align 2,0x90 " __XSTRING(CNAME(probeintr)) ": ss incl " __XSTRING(CNAME(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 .p2align 2,0x90 " __XSTRING(CNAME(probetrap)) ": ss incl " __XSTRING(CNAME(npx_traps_while_probing)) " fnclex iret "); #endif /* SMP */ /* * 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; { #ifdef SMP return npxprobe1(dvp); #else /* SMP */ 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); #endif /* SMP */ } 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(); #ifdef SMP /* * Exception 16 MUST work for SMP. */ npx_irq13 = 0; npx_ex16 = hw_float = npx_exists = 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); #else /* SMP */ /* * 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); #endif /* SMP */ } /* * Attach routine - announce which it is, and wire into system */ int npxattach(dvp) struct isa_device *dvp; { /* The caller has printed "irq 13" for the npx_irq13 case. */ if (!npx_irq13) { printf("npx%d: ", dvp->id_unit); if (npx_ex16) printf("INT 16 interface\n"); #if defined(MATH_EMULATE) || defined(GPL_MATH_EMULATE) else if (npx_exists) { printf("error reporting broken; using 387 emulator\n"); hw_float = npx_exists = 0; } else printf("387 emulator\n"); #else else printf("no 387 emulator in kernel!\n"); #endif } npxinit(__INITIAL_NPXCW__); #ifdef I586_CPU if (cpu_class == CPUCLASS_586 && npx_ex16 && timezero("i586_bzero()", i586_bzero) < timezero("bzero()", bzero) * 4 / 5) { if (!(dvp->id_flags & NPX_DISABLE_I586_OPTIMIZED_BCOPY)) { bcopy_vector = i586_bcopy; ovbcopy_vector = i586_bcopy; } if (!(dvp->id_flags & NPX_DISABLE_I586_OPTIMIZED_BZERO)) bzero = i586_bzero; if (!(dvp->id_flags & NPX_DISABLE_I586_OPTIMIZED_COPYIO)) { copyin_vector = i586_copyin; copyout_vector = i586_copyout; } } #endif 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); #ifdef NPX_DEBUG if (npx_exists) { u_int masked_exceptions; masked_exceptions = curpcb->pcb_savefpu.sv_env.en_cw & curpcb->pcb_savefpu.sv_env.en_sw & 0x7f; /* * Log exceptions that would have trapped with the old * control word (overflow, divide by 0, and invalid operand). */ 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); } #endif } /* * 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) || (frame->if_eflags & PSL_VM)) { /* * 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 = (struct trapframe *)&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; { #ifdef SMP stop_emulating(); fnsave(addr); /* fnop(); */ start_emulating(); npxproc = NULL; #else /* SMP */ 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 /* SMP */ } #ifdef I586_CPU static long timezero(funcname, func) const char *funcname; void (*func) __P((void *buf, size_t len)); { void *buf; #define BUFSIZE 1000000 long usec; struct timeval finish, start; buf = malloc(BUFSIZE, M_TEMP, M_NOWAIT); if (buf == NULL) return (BUFSIZE); microtime(&start); (*func)(buf, BUFSIZE); microtime(&finish); usec = 1000000 * (finish.tv_sec - start.tv_sec) + finish.tv_usec - start.tv_usec; if (usec <= 0) usec = 1; if (bootverbose) printf("%s bandwidth = %ld bytes/sec\n", funcname, (long)(BUFSIZE * 1000000ll / usec)); free(buf, M_TEMP); return (usec); } #endif /* I586_CPU */ #endif /* NNPX > 0 */