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Current File : //sys/i386/isa/npx.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. * 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 */ #include <sys/cdefs.h> __FBSDID("$FreeBSD: release/9.1.0/sys/i386/isa/npx.c 231979 2012-02-21 20:56:03Z kib $"); #include "opt_cpu.h" #include "opt_isa.h" #include "opt_npx.h" #include <sys/param.h> #include <sys/systm.h> #include <sys/bus.h> #include <sys/kernel.h> #include <sys/lock.h> #include <sys/malloc.h> #include <sys/module.h> #include <sys/mutex.h> #include <sys/mutex.h> #include <sys/proc.h> #include <sys/smp.h> #include <sys/sysctl.h> #include <machine/bus.h> #include <sys/rman.h> #ifdef NPX_DEBUG #include <sys/syslog.h> #endif #include <sys/signalvar.h> #include <machine/asmacros.h> #include <machine/cputypes.h> #include <machine/frame.h> #include <machine/md_var.h> #include <machine/pcb.h> #include <machine/psl.h> #include <machine/resource.h> #include <machine/specialreg.h> #include <machine/segments.h> #include <machine/ucontext.h> #include <machine/intr_machdep.h> #ifdef XEN #include <machine/xen/xen-os.h> #include <xen/hypervisor.h> #endif #ifdef DEV_ISA #include <isa/isavar.h> #endif #if !defined(CPU_DISABLE_SSE) && defined(I686_CPU) #define CPU_ENABLE_SSE #endif /* * 387 and 287 Numeric Coprocessor Extension (NPX) Driver. */ #if defined(__GNUCLIKE_ASM) && !defined(lint) #define fldcw(cw) __asm __volatile("fldcw %0" : : "m" (cw)) #define fnclex() __asm __volatile("fnclex") #define fninit() __asm __volatile("fninit") #define fnsave(addr) __asm __volatile("fnsave %0" : "=m" (*(addr))) #define fnstcw(addr) __asm __volatile("fnstcw %0" : "=m" (*(addr))) #define fnstsw(addr) __asm __volatile("fnstsw %0" : "=am" (*(addr))) #define fp_divide_by_0() __asm __volatile( \ "fldz; fld1; fdiv %st,%st(1); fnop") #define frstor(addr) __asm __volatile("frstor %0" : : "m" (*(addr))) #ifdef CPU_ENABLE_SSE #define fxrstor(addr) __asm __volatile("fxrstor %0" : : "m" (*(addr))) #define fxsave(addr) __asm __volatile("fxsave %0" : "=m" (*(addr))) #endif #ifdef XEN #define start_emulating() (HYPERVISOR_fpu_taskswitch(1)) #define stop_emulating() (HYPERVISOR_fpu_taskswitch(0)) #else #define start_emulating() __asm __volatile( \ "smsw %%ax; orb %0,%%al; lmsw %%ax" \ : : "n" (CR0_TS) : "ax") #define stop_emulating() __asm __volatile("clts") #endif #else /* !(__GNUCLIKE_ASM && !lint) */ void fldcw(u_short cw); void fnclex(void); void fninit(void); void fnsave(caddr_t addr); void fnstcw(caddr_t addr); void fnstsw(caddr_t addr); void fp_divide_by_0(void); void frstor(caddr_t addr); #ifdef CPU_ENABLE_SSE void fxsave(caddr_t addr); void fxrstor(caddr_t addr); #endif void start_emulating(void); void stop_emulating(void); #endif /* __GNUCLIKE_ASM && !lint */ #ifdef CPU_ENABLE_SSE #define GET_FPU_CW(thread) \ (cpu_fxsr ? \ (thread)->td_pcb->pcb_save->sv_xmm.sv_env.en_cw : \ (thread)->td_pcb->pcb_save->sv_87.sv_env.en_cw) #define GET_FPU_SW(thread) \ (cpu_fxsr ? \ (thread)->td_pcb->pcb_save->sv_xmm.sv_env.en_sw : \ (thread)->td_pcb->pcb_save->sv_87.sv_env.en_sw) #define SET_FPU_CW(savefpu, value) do { \ if (cpu_fxsr) \ (savefpu)->sv_xmm.sv_env.en_cw = (value); \ else \ (savefpu)->sv_87.sv_env.en_cw = (value); \ } while (0) #else /* CPU_ENABLE_SSE */ #define GET_FPU_CW(thread) \ (thread->td_pcb->pcb_save->sv_87.sv_env.en_cw) #define GET_FPU_SW(thread) \ (thread->td_pcb->pcb_save->sv_87.sv_env.en_sw) #define SET_FPU_CW(savefpu, value) \ (savefpu)->sv_87.sv_env.en_cw = (value) #endif /* CPU_ENABLE_SSE */ typedef u_char bool_t; #ifdef CPU_ENABLE_SSE static void fpu_clean_state(void); #endif static void fpusave(union savefpu *); static void fpurstor(union savefpu *); static int npx_attach(device_t dev); static void npx_identify(driver_t *driver, device_t parent); static int npx_probe(device_t dev); int hw_float; SYSCTL_INT(_hw, HW_FLOATINGPT, floatingpoint, CTLFLAG_RD, &hw_float, 0, "Floating point instructions executed in hardware"); static volatile u_int npx_traps_while_probing; static union savefpu npx_initialstate; alias_for_inthand_t probetrap; __asm(" \n\ .text \n\ .p2align 2,0x90 \n\ .type " __XSTRING(CNAME(probetrap)) ",@function \n\ " __XSTRING(CNAME(probetrap)) ": \n\ ss \n\ incl " __XSTRING(CNAME(npx_traps_while_probing)) " \n\ fnclex \n\ iret \n\ "); /* * Identify routine. Create a connection point on our parent for probing. */ static void npx_identify(driver, parent) driver_t *driver; device_t parent; { device_t child; child = BUS_ADD_CHILD(parent, 0, "npx", 0); if (child == NULL) panic("npx_identify"); } /* * Probe routine. Set flags to tell npxattach() what to do. Set up an * interrupt handler if npx needs to use interrupts. */ static int npx_probe(device_t dev) { struct gate_descriptor save_idt_npxtrap; u_short control, status; device_set_desc(dev, "math processor"); /* * Modern CPUs all have an FPU that uses the INT16 interface * and provide a simple way to verify that, so handle the * common case right away. */ if (cpu_feature & CPUID_FPU) { hw_float = 1; device_quiet(dev); return (0); } save_idt_npxtrap = idt[IDT_MF]; setidt(IDT_MF, probetrap, SDT_SYS386TGT, SEL_KPL, GSEL(GCODE_SEL, SEL_KPL)); /* * 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 npx_intr() 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_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) { /* * We have an npx, now divide by 0 to see if exception * 16 works. */ control &= ~(1 << 2); /* enable divide by 0 trap */ fldcw(control); #ifdef FPU_ERROR_BROKEN /* * FPU error signal doesn't work on some CPU * accelerator board. */ hw_float = 1; return (0); #endif npx_traps_while_probing = 0; fp_divide_by_0(); if (npx_traps_while_probing != 0) { /* * Good, exception 16 works. */ hw_float = 1; goto cleanup; } device_printf(dev, "FPU does not use exception 16 for error reporting\n"); goto cleanup; } } /* * Probe failed. Floating point simply won't work. * Notify user and disable FPU/MMX/SSE instruction execution. */ device_printf(dev, "WARNING: no FPU!\n"); __asm __volatile("smsw %%ax; orb %0,%%al; lmsw %%ax" : : "n" (CR0_EM | CR0_MP) : "ax"); cleanup: idt[IDT_MF] = save_idt_npxtrap; return (hw_float ? 0 : ENXIO); } /* * Attach routine - announce which it is, and wire into system */ static int npx_attach(device_t dev) { npxinit(); critical_enter(); stop_emulating(); fpusave(&npx_initialstate); start_emulating(); #ifdef CPU_ENABLE_SSE if (cpu_fxsr) { if (npx_initialstate.sv_xmm.sv_env.en_mxcsr_mask) cpu_mxcsr_mask = npx_initialstate.sv_xmm.sv_env.en_mxcsr_mask; else cpu_mxcsr_mask = 0xFFBF; bzero(npx_initialstate.sv_xmm.sv_fp, sizeof(npx_initialstate.sv_xmm.sv_fp)); bzero(npx_initialstate.sv_xmm.sv_xmm, sizeof(npx_initialstate.sv_xmm.sv_xmm)); /* XXX might need even more zeroing. */ } else #endif bzero(npx_initialstate.sv_87.sv_ac, sizeof(npx_initialstate.sv_87.sv_ac)); critical_exit(); return (0); } /* * Initialize floating point unit. */ void npxinit(void) { static union savefpu dummy; register_t saveintr; u_short control; if (!hw_float) 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 fpcurthread = NULL as important side effects. * * It is too early for critical_enter() to work on AP. */ saveintr = intr_disable(); npxsave(&dummy); stop_emulating(); #ifdef CPU_ENABLE_SSE /* XXX npxsave() doesn't actually initialize the fpu in the SSE case. */ if (cpu_fxsr) fninit(); #endif control = __INITIAL_NPXCW__; fldcw(control); start_emulating(); intr_restore(saveintr); } /* * Free coprocessor (if we have it). */ void npxexit(td) struct thread *td; { critical_enter(); if (curthread == PCPU_GET(fpcurthread)) npxsave(PCPU_GET(curpcb)->pcb_save); critical_exit(); #ifdef NPX_DEBUG if (hw_float) { u_int masked_exceptions; masked_exceptions = GET_FPU_CW(td) & GET_FPU_SW(td) & 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", td->td_proc->p_pid, td->td_proc->p_comm, masked_exceptions); } #endif } int npxformat() { if (!hw_float) return (_MC_FPFMT_NODEV); #ifdef CPU_ENABLE_SSE if (cpu_fxsr) return (_MC_FPFMT_XMM); #endif return (_MC_FPFMT_387); } /* * The following mechanism is used to ensure that the FPE_... value * that is passed as a trapcode to the signal handler of the user * process does not have more than one bit set. * * Multiple bits may be set if the user process modifies the control * word while a status word bit is already set. While this is a sign * of bad coding, we have no choise than to narrow them down to one * bit, since we must not send a trapcode that is not exactly one of * the FPE_ macros. * * The mechanism has a static table with 127 entries. Each combination * of the 7 FPU status word exception bits directly translates to a * position in this table, where a single FPE_... value is stored. * This FPE_... value stored there is considered the "most important" * of the exception bits and will be sent as the signal code. The * precedence of the bits is based upon Intel Document "Numerical * Applications", Chapter "Special Computational Situations". * * The macro to choose one of these values does these steps: 1) Throw * away status word bits that cannot be masked. 2) Throw away the bits * currently masked in the control word, assuming the user isn't * interested in them anymore. 3) Reinsert status word bit 7 (stack * fault) if it is set, which cannot be masked but must be presered. * 4) Use the remaining bits to point into the trapcode table. * * The 6 maskable bits in order of their preference, as stated in the * above referenced Intel manual: * 1 Invalid operation (FP_X_INV) * 1a Stack underflow * 1b Stack overflow * 1c Operand of unsupported format * 1d SNaN operand. * 2 QNaN operand (not an exception, irrelavant here) * 3 Any other invalid-operation not mentioned above or zero divide * (FP_X_INV, FP_X_DZ) * 4 Denormal operand (FP_X_DNML) * 5 Numeric over/underflow (FP_X_OFL, FP_X_UFL) * 6 Inexact result (FP_X_IMP) */ static char fpetable[128] = { 0, FPE_FLTINV, /* 1 - INV */ FPE_FLTUND, /* 2 - DNML */ FPE_FLTINV, /* 3 - INV | DNML */ FPE_FLTDIV, /* 4 - DZ */ FPE_FLTINV, /* 5 - INV | DZ */ FPE_FLTDIV, /* 6 - DNML | DZ */ FPE_FLTINV, /* 7 - INV | DNML | DZ */ FPE_FLTOVF, /* 8 - OFL */ FPE_FLTINV, /* 9 - INV | OFL */ FPE_FLTUND, /* A - DNML | OFL */ FPE_FLTINV, /* B - INV | DNML | OFL */ FPE_FLTDIV, /* C - DZ | OFL */ FPE_FLTINV, /* D - INV | DZ | OFL */ FPE_FLTDIV, /* E - DNML | DZ | OFL */ FPE_FLTINV, /* F - INV | DNML | DZ | OFL */ FPE_FLTUND, /* 10 - UFL */ FPE_FLTINV, /* 11 - INV | UFL */ FPE_FLTUND, /* 12 - DNML | UFL */ FPE_FLTINV, /* 13 - INV | DNML | UFL */ FPE_FLTDIV, /* 14 - DZ | UFL */ FPE_FLTINV, /* 15 - INV | DZ | UFL */ FPE_FLTDIV, /* 16 - DNML | DZ | UFL */ FPE_FLTINV, /* 17 - INV | DNML | DZ | UFL */ FPE_FLTOVF, /* 18 - OFL | UFL */ FPE_FLTINV, /* 19 - INV | OFL | UFL */ FPE_FLTUND, /* 1A - DNML | OFL | UFL */ FPE_FLTINV, /* 1B - INV | DNML | OFL | UFL */ FPE_FLTDIV, /* 1C - DZ | OFL | UFL */ FPE_FLTINV, /* 1D - INV | DZ | OFL | UFL */ FPE_FLTDIV, /* 1E - DNML | DZ | OFL | UFL */ FPE_FLTINV, /* 1F - INV | DNML | DZ | OFL | UFL */ FPE_FLTRES, /* 20 - IMP */ FPE_FLTINV, /* 21 - INV | IMP */ FPE_FLTUND, /* 22 - DNML | IMP */ FPE_FLTINV, /* 23 - INV | DNML | IMP */ FPE_FLTDIV, /* 24 - DZ | IMP */ FPE_FLTINV, /* 25 - INV | DZ | IMP */ FPE_FLTDIV, /* 26 - DNML | DZ | IMP */ FPE_FLTINV, /* 27 - INV | DNML | DZ | IMP */ FPE_FLTOVF, /* 28 - OFL | IMP */ FPE_FLTINV, /* 29 - INV | OFL | IMP */ FPE_FLTUND, /* 2A - DNML | OFL | IMP */ FPE_FLTINV, /* 2B - INV | DNML | OFL | IMP */ FPE_FLTDIV, /* 2C - DZ | OFL | IMP */ FPE_FLTINV, /* 2D - INV | DZ | OFL | IMP */ FPE_FLTDIV, /* 2E - DNML | DZ | OFL | IMP */ FPE_FLTINV, /* 2F - INV | DNML | DZ | OFL | IMP */ FPE_FLTUND, /* 30 - UFL | IMP */ FPE_FLTINV, /* 31 - INV | UFL | IMP */ FPE_FLTUND, /* 32 - DNML | UFL | IMP */ FPE_FLTINV, /* 33 - INV | DNML | UFL | IMP */ FPE_FLTDIV, /* 34 - DZ | UFL | IMP */ FPE_FLTINV, /* 35 - INV | DZ | UFL | IMP */ FPE_FLTDIV, /* 36 - DNML | DZ | UFL | IMP */ FPE_FLTINV, /* 37 - INV | DNML | DZ | UFL | IMP */ FPE_FLTOVF, /* 38 - OFL | UFL | IMP */ FPE_FLTINV, /* 39 - INV | OFL | UFL | IMP */ FPE_FLTUND, /* 3A - DNML | OFL | UFL | IMP */ FPE_FLTINV, /* 3B - INV | DNML | OFL | UFL | IMP */ FPE_FLTDIV, /* 3C - DZ | OFL | UFL | IMP */ FPE_FLTINV, /* 3D - INV | DZ | OFL | UFL | IMP */ FPE_FLTDIV, /* 3E - DNML | DZ | OFL | UFL | IMP */ FPE_FLTINV, /* 3F - INV | DNML | DZ | OFL | UFL | IMP */ FPE_FLTSUB, /* 40 - STK */ FPE_FLTSUB, /* 41 - INV | STK */ FPE_FLTUND, /* 42 - DNML | STK */ FPE_FLTSUB, /* 43 - INV | DNML | STK */ FPE_FLTDIV, /* 44 - DZ | STK */ FPE_FLTSUB, /* 45 - INV | DZ | STK */ FPE_FLTDIV, /* 46 - DNML | DZ | STK */ FPE_FLTSUB, /* 47 - INV | DNML | DZ | STK */ FPE_FLTOVF, /* 48 - OFL | STK */ FPE_FLTSUB, /* 49 - INV | OFL | STK */ FPE_FLTUND, /* 4A - DNML | OFL | STK */ FPE_FLTSUB, /* 4B - INV | DNML | OFL | STK */ FPE_FLTDIV, /* 4C - DZ | OFL | STK */ FPE_FLTSUB, /* 4D - INV | DZ | OFL | STK */ FPE_FLTDIV, /* 4E - DNML | DZ | OFL | STK */ FPE_FLTSUB, /* 4F - INV | DNML | DZ | OFL | STK */ FPE_FLTUND, /* 50 - UFL | STK */ FPE_FLTSUB, /* 51 - INV | UFL | STK */ FPE_FLTUND, /* 52 - DNML | UFL | STK */ FPE_FLTSUB, /* 53 - INV | DNML | UFL | STK */ FPE_FLTDIV, /* 54 - DZ | UFL | STK */ FPE_FLTSUB, /* 55 - INV | DZ | UFL | STK */ FPE_FLTDIV, /* 56 - DNML | DZ | UFL | STK */ FPE_FLTSUB, /* 57 - INV | DNML | DZ | UFL | STK */ FPE_FLTOVF, /* 58 - OFL | UFL | STK */ FPE_FLTSUB, /* 59 - INV | OFL | UFL | STK */ FPE_FLTUND, /* 5A - DNML | OFL | UFL | STK */ FPE_FLTSUB, /* 5B - INV | DNML | OFL | UFL | STK */ FPE_FLTDIV, /* 5C - DZ | OFL | UFL | STK */ FPE_FLTSUB, /* 5D - INV | DZ | OFL | UFL | STK */ FPE_FLTDIV, /* 5E - DNML | DZ | OFL | UFL | STK */ FPE_FLTSUB, /* 5F - INV | DNML | DZ | OFL | UFL | STK */ FPE_FLTRES, /* 60 - IMP | STK */ FPE_FLTSUB, /* 61 - INV | IMP | STK */ FPE_FLTUND, /* 62 - DNML | IMP | STK */ FPE_FLTSUB, /* 63 - INV | DNML | IMP | STK */ FPE_FLTDIV, /* 64 - DZ | IMP | STK */ FPE_FLTSUB, /* 65 - INV | DZ | IMP | STK */ FPE_FLTDIV, /* 66 - DNML | DZ | IMP | STK */ FPE_FLTSUB, /* 67 - INV | DNML | DZ | IMP | STK */ FPE_FLTOVF, /* 68 - OFL | IMP | STK */ FPE_FLTSUB, /* 69 - INV | OFL | IMP | STK */ FPE_FLTUND, /* 6A - DNML | OFL | IMP | STK */ FPE_FLTSUB, /* 6B - INV | DNML | OFL | IMP | STK */ FPE_FLTDIV, /* 6C - DZ | OFL | IMP | STK */ FPE_FLTSUB, /* 6D - INV | DZ | OFL | IMP | STK */ FPE_FLTDIV, /* 6E - DNML | DZ | OFL | IMP | STK */ FPE_FLTSUB, /* 6F - INV | DNML | DZ | OFL | IMP | STK */ FPE_FLTUND, /* 70 - UFL | IMP | STK */ FPE_FLTSUB, /* 71 - INV | UFL | IMP | STK */ FPE_FLTUND, /* 72 - DNML | UFL | IMP | STK */ FPE_FLTSUB, /* 73 - INV | DNML | UFL | IMP | STK */ FPE_FLTDIV, /* 74 - DZ | UFL | IMP | STK */ FPE_FLTSUB, /* 75 - INV | DZ | UFL | IMP | STK */ FPE_FLTDIV, /* 76 - DNML | DZ | UFL | IMP | STK */ FPE_FLTSUB, /* 77 - INV | DNML | DZ | UFL | IMP | STK */ FPE_FLTOVF, /* 78 - OFL | UFL | IMP | STK */ FPE_FLTSUB, /* 79 - INV | OFL | UFL | IMP | STK */ FPE_FLTUND, /* 7A - DNML | OFL | UFL | IMP | STK */ FPE_FLTSUB, /* 7B - INV | DNML | OFL | UFL | IMP | STK */ FPE_FLTDIV, /* 7C - DZ | OFL | UFL | IMP | STK */ FPE_FLTSUB, /* 7D - INV | DZ | OFL | UFL | IMP | STK */ FPE_FLTDIV, /* 7E - DNML | DZ | OFL | UFL | IMP | STK */ FPE_FLTSUB, /* 7F - INV | DNML | DZ | OFL | UFL | IMP | STK */ }; /* * 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. * * The error code chosen will be one of the FPE_... macros. It will be * sent as the second argument to old BSD-style signal handlers and as * "siginfo_t->si_code" (second argument) to SA_SIGINFO signal handlers. * * 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. */ int npxtrap() { u_short control, status; if (!hw_float) { printf("npxtrap: fpcurthread = %p, curthread = %p, hw_float = %d\n", PCPU_GET(fpcurthread), curthread, hw_float); panic("npxtrap from nowhere"); } critical_enter(); /* * Interrupt handling (for another interrupt) may have pushed the * state to memory. Fetch the relevant parts of the state from * wherever they are. */ if (PCPU_GET(fpcurthread) != curthread) { control = GET_FPU_CW(curthread); status = GET_FPU_SW(curthread); } else { fnstcw(&control); fnstsw(&status); } if (PCPU_GET(fpcurthread) == curthread) fnclex(); critical_exit(); return (fpetable[status & ((~control & 0x3f) | 0x40)]); } /* * Implement device not available (DNA) exception * * It would be better to switch FP context here (if curthread != fpcurthread) * and not necessarily for every context switch, but it is too hard to * access foreign pcb's. */ static int err_count = 0; int npxdna(void) { struct pcb *pcb; if (!hw_float) return (0); critical_enter(); if (PCPU_GET(fpcurthread) == curthread) { printf("npxdna: fpcurthread == curthread %d times\n", ++err_count); stop_emulating(); critical_exit(); return (1); } if (PCPU_GET(fpcurthread) != NULL) { printf("npxdna: fpcurthread = %p (%d), curthread = %p (%d)\n", PCPU_GET(fpcurthread), PCPU_GET(fpcurthread)->td_proc->p_pid, curthread, curthread->td_proc->p_pid); panic("npxdna"); } stop_emulating(); /* * Record new context early in case frstor causes an IRQ13. */ PCPU_SET(fpcurthread, curthread); pcb = PCPU_GET(curpcb); #ifdef CPU_ENABLE_SSE if (cpu_fxsr) fpu_clean_state(); #endif if ((pcb->pcb_flags & PCB_NPXINITDONE) == 0) { /* * This is the first time this thread has used the FPU or * the PCB doesn't contain a clean FPU state. Explicitly * load an initial state. */ fpurstor(&npx_initialstate); if (pcb->pcb_initial_npxcw != __INITIAL_NPXCW__) fldcw(pcb->pcb_initial_npxcw); pcb->pcb_flags |= PCB_NPXINITDONE; if (PCB_USER_FPU(pcb)) pcb->pcb_flags |= PCB_NPXUSERINITDONE; } else { /* * The following fpurstor() 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. */ fpurstor(pcb->pcb_save); } critical_exit(); return (1); } /* * Wrapper for fnsave instruction, partly to handle hardware bugs. When npx * exceptions are reported via IRQ13, spurious IRQ13's may be triggered by * no-wait npx instructions. See the Intel application note AP-578 for * details. This doesn't cause any additional complications here. IRQ13's * are inherently asynchronous unless the CPU is frozen to deliver them -- * one that started in userland may be delivered many instructions later, * after the process has entered the kernel. It may even be delivered after * the fnsave here completes. A spurious IRQ13 for the fnsave is handled in * the same way as a very-late-arriving non-spurious IRQ13 from user mode: * it is normally ignored at first because we set fpcurthread to NULL; it is * normally retriggered in npxdna() after return to user mode. * * npxsave() must be called with interrupts disabled, so that it clears * fpcurthread atomically with saving the state. We require callers to do the * disabling, since most callers need to disable interrupts anyway to call * npxsave() atomically with checking fpcurthread. * * A previous version of npxsave() went to great lengths to excecute fnsave * with interrupts enabled in case executing it froze the CPU. This case * can't happen, at least for Intel CPU/NPX's. Spurious IRQ13's don't imply * spurious freezes. */ void npxsave(addr) union savefpu *addr; { stop_emulating(); fpusave(addr); start_emulating(); PCPU_SET(fpcurthread, NULL); } void npxdrop() { struct thread *td; /* * Discard pending exceptions in the !cpu_fxsr case so that unmasked * ones don't cause a panic on the next frstor. */ #ifdef CPU_ENABLE_SSE if (!cpu_fxsr) #endif fnclex(); td = PCPU_GET(fpcurthread); KASSERT(td == curthread, ("fpudrop: fpcurthread != curthread")); CRITICAL_ASSERT(td); PCPU_SET(fpcurthread, NULL); td->td_pcb->pcb_flags &= ~PCB_NPXINITDONE; start_emulating(); } /* * Get the user state of the FPU into pcb->pcb_user_save without * dropping ownership (if possible). It returns the FPU ownership * status. */ int npxgetregs(struct thread *td) { struct pcb *pcb; if (!hw_float) return (_MC_FPOWNED_NONE); pcb = td->td_pcb; if ((pcb->pcb_flags & PCB_NPXINITDONE) == 0) { bcopy(&npx_initialstate, &pcb->pcb_user_save, sizeof(npx_initialstate)); SET_FPU_CW(&pcb->pcb_user_save, pcb->pcb_initial_npxcw); npxuserinited(td); return (_MC_FPOWNED_PCB); } critical_enter(); if (td == PCPU_GET(fpcurthread)) { fpusave(&pcb->pcb_user_save); #ifdef CPU_ENABLE_SSE if (!cpu_fxsr) #endif /* * fnsave initializes the FPU and destroys whatever * context it contains. Make sure the FPU owner * starts with a clean state next time. */ npxdrop(); critical_exit(); return (_MC_FPOWNED_FPU); } else { critical_exit(); return (_MC_FPOWNED_PCB); } } void npxuserinited(struct thread *td) { struct pcb *pcb; pcb = td->td_pcb; if (PCB_USER_FPU(pcb)) pcb->pcb_flags |= PCB_NPXINITDONE; pcb->pcb_flags |= PCB_NPXUSERINITDONE; } void npxsetregs(struct thread *td, union savefpu *addr) { struct pcb *pcb; if (!hw_float) return; pcb = td->td_pcb; critical_enter(); if (td == PCPU_GET(fpcurthread) && PCB_USER_FPU(pcb)) { #ifdef CPU_ENABLE_SSE if (!cpu_fxsr) #endif fnclex(); /* As in npxdrop(). */ if (((uintptr_t)addr & 0xf) != 0) { bcopy(addr, &pcb->pcb_user_save, sizeof(*addr)); fpurstor(&pcb->pcb_user_save); } else fpurstor(addr); critical_exit(); pcb->pcb_flags |= PCB_NPXUSERINITDONE | PCB_NPXINITDONE; } else { critical_exit(); bcopy(addr, &pcb->pcb_user_save, sizeof(*addr)); npxuserinited(td); } } static void fpusave(addr) union savefpu *addr; { #ifdef CPU_ENABLE_SSE if (cpu_fxsr) fxsave(addr); else #endif fnsave(addr); } #ifdef CPU_ENABLE_SSE /* * On AuthenticAMD processors, the fxrstor instruction does not restore * the x87's stored last instruction pointer, last data pointer, and last * opcode values, except in the rare case in which the exception summary * (ES) bit in the x87 status word is set to 1. * * In order to avoid leaking this information across processes, we clean * these values by performing a dummy load before executing fxrstor(). */ static void fpu_clean_state(void) { static float dummy_variable = 0.0; u_short status; /* * Clear the ES bit in the x87 status word if it is currently * set, in order to avoid causing a fault in the upcoming load. */ fnstsw(&status); if (status & 0x80) fnclex(); /* * Load the dummy variable into the x87 stack. This mangles * the x87 stack, but we don't care since we're about to call * fxrstor() anyway. */ __asm __volatile("ffree %%st(7); flds %0" : : "m" (dummy_variable)); } #endif /* CPU_ENABLE_SSE */ static void fpurstor(addr) union savefpu *addr; { #ifdef CPU_ENABLE_SSE if (cpu_fxsr) fxrstor(addr); else #endif frstor(addr); } static device_method_t npx_methods[] = { /* Device interface */ DEVMETHOD(device_identify, npx_identify), DEVMETHOD(device_probe, npx_probe), DEVMETHOD(device_attach, npx_attach), DEVMETHOD(device_detach, bus_generic_detach), DEVMETHOD(device_shutdown, bus_generic_shutdown), DEVMETHOD(device_suspend, bus_generic_suspend), DEVMETHOD(device_resume, bus_generic_resume), { 0, 0 } }; static driver_t npx_driver = { "npx", npx_methods, 1, /* no softc */ }; static devclass_t npx_devclass; /* * We prefer to attach to the root nexus so that the usual case (exception 16) * doesn't describe the processor as being `on isa'. */ DRIVER_MODULE(npx, nexus, npx_driver, npx_devclass, 0, 0); #ifdef DEV_ISA /* * This sucks up the legacy ISA support assignments from PNPBIOS/ACPI. */ static struct isa_pnp_id npxisa_ids[] = { { 0x040cd041, "Legacy ISA coprocessor support" }, /* PNP0C04 */ { 0 } }; static int npxisa_probe(device_t dev) { int result; if ((result = ISA_PNP_PROBE(device_get_parent(dev), dev, npxisa_ids)) <= 0) { device_quiet(dev); } return(result); } static int npxisa_attach(device_t dev) { return (0); } static device_method_t npxisa_methods[] = { /* Device interface */ DEVMETHOD(device_probe, npxisa_probe), DEVMETHOD(device_attach, npxisa_attach), DEVMETHOD(device_detach, bus_generic_detach), DEVMETHOD(device_shutdown, bus_generic_shutdown), DEVMETHOD(device_suspend, bus_generic_suspend), DEVMETHOD(device_resume, bus_generic_resume), { 0, 0 } }; static driver_t npxisa_driver = { "npxisa", npxisa_methods, 1, /* no softc */ }; static devclass_t npxisa_devclass; DRIVER_MODULE(npxisa, isa, npxisa_driver, npxisa_devclass, 0, 0); #ifndef PC98 DRIVER_MODULE(npxisa, acpi, npxisa_driver, npxisa_devclass, 0, 0); #endif #endif /* DEV_ISA */ static MALLOC_DEFINE(M_FPUKERN_CTX, "fpukern_ctx", "Kernel contexts for FPU state"); #define XSAVE_AREA_ALIGN 64 #define FPU_KERN_CTX_NPXINITDONE 0x01 struct fpu_kern_ctx { union savefpu *prev; uint32_t flags; char hwstate1[]; }; struct fpu_kern_ctx * fpu_kern_alloc_ctx(u_int flags) { struct fpu_kern_ctx *res; size_t sz; sz = sizeof(struct fpu_kern_ctx) + XSAVE_AREA_ALIGN + sizeof(union savefpu); res = malloc(sz, M_FPUKERN_CTX, ((flags & FPU_KERN_NOWAIT) ? M_NOWAIT : M_WAITOK) | M_ZERO); return (res); } void fpu_kern_free_ctx(struct fpu_kern_ctx *ctx) { /* XXXKIB clear the memory ? */ free(ctx, M_FPUKERN_CTX); } static union savefpu * fpu_kern_ctx_savefpu(struct fpu_kern_ctx *ctx) { vm_offset_t p; p = (vm_offset_t)&ctx->hwstate1; p = roundup2(p, XSAVE_AREA_ALIGN); return ((union savefpu *)p); } int fpu_kern_enter(struct thread *td, struct fpu_kern_ctx *ctx, u_int flags) { struct pcb *pcb; pcb = td->td_pcb; KASSERT(!PCB_USER_FPU(pcb) || pcb->pcb_save == &pcb->pcb_user_save, ("mangled pcb_save")); ctx->flags = 0; if ((pcb->pcb_flags & PCB_NPXINITDONE) != 0) ctx->flags |= FPU_KERN_CTX_NPXINITDONE; npxexit(td); ctx->prev = pcb->pcb_save; pcb->pcb_save = fpu_kern_ctx_savefpu(ctx); pcb->pcb_flags |= PCB_KERNNPX; pcb->pcb_flags &= ~PCB_NPXINITDONE; return (0); } int fpu_kern_leave(struct thread *td, struct fpu_kern_ctx *ctx) { struct pcb *pcb; pcb = td->td_pcb; critical_enter(); if (curthread == PCPU_GET(fpcurthread)) npxdrop(); critical_exit(); pcb->pcb_save = ctx->prev; if (pcb->pcb_save == &pcb->pcb_user_save) { if ((pcb->pcb_flags & PCB_NPXUSERINITDONE) != 0) pcb->pcb_flags |= PCB_NPXINITDONE; else pcb->pcb_flags &= ~PCB_NPXINITDONE; pcb->pcb_flags &= ~PCB_KERNNPX; } else { if ((ctx->flags & FPU_KERN_CTX_NPXINITDONE) != 0) pcb->pcb_flags |= PCB_NPXINITDONE; else pcb->pcb_flags &= ~PCB_NPXINITDONE; KASSERT(!PCB_USER_FPU(pcb), ("unpaired fpu_kern_leave")); } return (0); } int fpu_kern_thread(u_int flags) { struct pcb *pcb; pcb = PCPU_GET(curpcb); KASSERT((curthread->td_pflags & TDP_KTHREAD) != 0, ("Only kthread may use fpu_kern_thread")); KASSERT(pcb->pcb_save == &pcb->pcb_user_save, ("mangled pcb_save")); KASSERT(PCB_USER_FPU(pcb), ("recursive call")); pcb->pcb_flags |= PCB_KERNNPX; return (0); } int is_fpu_kern_thread(u_int flags) { if ((curthread->td_pflags & TDP_KTHREAD) == 0) return (0); return ((PCPU_GET(curpcb)->pcb_flags & PCB_KERNNPX) != 0); }