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mirror of https://git.FreeBSD.org/src.git synced 2024-12-24 11:29:10 +00:00
freebsd/sys/i386/isa/npx.c
Justin T. Gibbs 76acc41fb7 Implement vector callback for PVHVM and unify event channel implementations
Re-structure Xen HVM support so that:
	- Xen is detected and hypercalls can be performed very
	  early in system startup.
	- Xen interrupt services are implemented using FreeBSD's native
	  interrupt delivery infrastructure.
	- the Xen interrupt service implementation is shared between PV
	  and HVM guests.
	- Xen interrupt handlers can optionally use a filter handler
	  in order to avoid the overhead of dispatch to an interrupt
	  thread.
	- interrupt load can be distributed among all available CPUs.
	- the overhead of accessing the emulated local and I/O apics
	  on HVM is removed for event channel port events.
	- a similar optimization can eventually, and fairly easily,
	  be used to optimize MSI.

Early Xen detection, HVM refactoring, PVHVM interrupt infrastructure,
and misc Xen cleanups:

Sponsored by: Spectra Logic Corporation

Unification of PV & HVM interrupt infrastructure, bug fixes,
and misc Xen cleanups:

Submitted by: Roger Pau Monné
Sponsored by: Citrix Systems R&D

sys/x86/x86/local_apic.c:
sys/amd64/include/apicvar.h:
sys/i386/include/apicvar.h:
sys/amd64/amd64/apic_vector.S:
sys/i386/i386/apic_vector.s:
sys/amd64/amd64/machdep.c:
sys/i386/i386/machdep.c:
sys/i386/xen/exception.s:
sys/x86/include/segments.h:
	Reserve IDT vector 0x93 for the Xen event channel upcall
	interrupt handler.  On Hypervisors that support the direct
	vector callback feature, we can request that this vector be
	called directly by an injected HVM interrupt event, instead
	of a simulated PCI interrupt on the Xen platform PCI device.
	This avoids all of the overhead of dealing with the emulated
	I/O APIC and local APIC.  It also means that the Hypervisor
	can inject these events on any CPU, allowing upcalls for
	different ports to be handled in parallel.

sys/amd64/amd64/mp_machdep.c:
sys/i386/i386/mp_machdep.c:
	Map Xen per-vcpu area during AP startup.

sys/amd64/include/intr_machdep.h:
sys/i386/include/intr_machdep.h:
	Increase the FreeBSD IRQ vector table to include space
	for event channel interrupt sources.

sys/amd64/include/pcpu.h:
sys/i386/include/pcpu.h:
	Remove Xen HVM per-cpu variable data.  These fields are now
	allocated via the dynamic per-cpu scheme.  See xen_intr.c
	for details.

sys/amd64/include/xen/hypercall.h:
sys/dev/xen/blkback/blkback.c:
sys/i386/include/xen/xenvar.h:
sys/i386/xen/clock.c:
sys/i386/xen/xen_machdep.c:
sys/xen/gnttab.c:
	Prefer FreeBSD primatives to Linux ones in Xen support code.

sys/amd64/include/xen/xen-os.h:
sys/i386/include/xen/xen-os.h:
sys/xen/xen-os.h:
sys/dev/xen/balloon/balloon.c:
sys/dev/xen/blkback/blkback.c:
sys/dev/xen/blkfront/blkfront.c:
sys/dev/xen/console/xencons_ring.c:
sys/dev/xen/control/control.c:
sys/dev/xen/netback/netback.c:
sys/dev/xen/netfront/netfront.c:
sys/dev/xen/xenpci/xenpci.c:
sys/i386/i386/machdep.c:
sys/i386/include/pmap.h:
sys/i386/include/xen/xenfunc.h:
sys/i386/isa/npx.c:
sys/i386/xen/clock.c:
sys/i386/xen/mp_machdep.c:
sys/i386/xen/mptable.c:
sys/i386/xen/xen_clock_util.c:
sys/i386/xen/xen_machdep.c:
sys/i386/xen/xen_rtc.c:
sys/xen/evtchn/evtchn_dev.c:
sys/xen/features.c:
sys/xen/gnttab.c:
sys/xen/gnttab.h:
sys/xen/hvm.h:
sys/xen/xenbus/xenbus.c:
sys/xen/xenbus/xenbus_if.m:
sys/xen/xenbus/xenbusb_front.c:
sys/xen/xenbus/xenbusvar.h:
sys/xen/xenstore/xenstore.c:
sys/xen/xenstore/xenstore_dev.c:
sys/xen/xenstore/xenstorevar.h:
	Pull common Xen OS support functions/settings into xen/xen-os.h.

sys/amd64/include/xen/xen-os.h:
sys/i386/include/xen/xen-os.h:
sys/xen/xen-os.h:
	Remove constants, macros, and functions unused in FreeBSD's Xen
	support.

sys/xen/xen-os.h:
sys/i386/xen/xen_machdep.c:
sys/x86/xen/hvm.c:
	Introduce new functions xen_domain(), xen_pv_domain(), and
	xen_hvm_domain().  These are used in favor of #ifdefs so that
	FreeBSD can dynamically detect and adapt to the presence of
	a hypervisor.  The goal is to have an HVM optimized GENERIC,
	but more is necessary before this is possible.

sys/amd64/amd64/machdep.c:
sys/dev/xen/xenpci/xenpcivar.h:
sys/dev/xen/xenpci/xenpci.c:
sys/x86/xen/hvm.c:
sys/sys/kernel.h:
	Refactor magic ioport, Hypercall table and Hypervisor shared
	information page setup, and move it to a dedicated HVM support
	module.

	HVM mode initialization is now triggered during the
	SI_SUB_HYPERVISOR phase of system startup.  This currently
	occurs just after the kernel VM is fully setup which is
	just enough infrastructure to allow the hypercall table
	and shared info page to be properly mapped.

sys/xen/hvm.h:
sys/x86/xen/hvm.c:
	Add definitions and a method for configuring Hypervisor event
	delievery via a direct vector callback.

sys/amd64/include/xen/xen-os.h:
sys/x86/xen/hvm.c:

sys/conf/files:
sys/conf/files.amd64:
sys/conf/files.i386:
	Adjust kernel build to reflect the refactoring of early
	Xen startup code and Xen interrupt services.

sys/dev/xen/blkback/blkback.c:
sys/dev/xen/blkfront/blkfront.c:
sys/dev/xen/blkfront/block.h:
sys/dev/xen/control/control.c:
sys/dev/xen/evtchn/evtchn_dev.c:
sys/dev/xen/netback/netback.c:
sys/dev/xen/netfront/netfront.c:
sys/xen/xenstore/xenstore.c:
sys/xen/evtchn/evtchn_dev.c:
sys/dev/xen/console/console.c:
sys/dev/xen/console/xencons_ring.c
	Adjust drivers to use new xen_intr_*() API.

sys/dev/xen/blkback/blkback.c:
	Since blkback defers all event handling to a taskqueue,
	convert this task queue to a "fast" taskqueue, and schedule
	it via an interrupt filter.  This avoids an unnecessary
	ithread context switch.

sys/xen/xenstore/xenstore.c:
	The xenstore driver is MPSAFE.  Indicate as much when
	registering its interrupt handler.

sys/xen/xenbus/xenbus.c:
sys/xen/xenbus/xenbusvar.h:
	Remove unused event channel APIs.

sys/xen/evtchn.h:
	Remove all kernel Xen interrupt service API definitions
	from this file.  It is now only used for structure and
	ioctl definitions related to the event channel userland
	device driver.

	Update the definitions in this file to match those from
	NetBSD.  Implementing this interface will be necessary for
	Dom0 support.

sys/xen/evtchn/evtchnvar.h:
	Add a header file for implemenation internal APIs related
	to managing event channels event delivery.  This is used
	to allow, for example, the event channel userland device
	driver to access low-level routines that typical kernel
	consumers of event channel services should never access.

sys/xen/interface/event_channel.h:
sys/xen/xen_intr.h:
	Standardize on the evtchn_port_t type for referring to
	an event channel port id.  In order to prevent low-level
	event channel APIs from leaking to kernel consumers who
	should not have access to this data, the type is defined
	twice: Once in the Xen provided event_channel.h, and again
	in xen/xen_intr.h.  The double declaration is protected by
	__XEN_EVTCHN_PORT_DEFINED__ to ensure it is never declared
	twice within a given compilation unit.

sys/xen/xen_intr.h:
sys/xen/evtchn/evtchn.c:
sys/x86/xen/xen_intr.c:
sys/dev/xen/xenpci/evtchn.c:
sys/dev/xen/xenpci/xenpcivar.h:
	New implementation of Xen interrupt services.  This is
	similar in many respects to the i386 PV implementation with
	the exception that events for bound to event channel ports
	(i.e. not IPI, virtual IRQ, or physical IRQ) are further
	optimized to avoid mask/unmask operations that aren't
	necessary for these edge triggered events.

	Stubs exist for supporting physical IRQ binding, but will
	need additional work before this implementation can be
	fully shared between PV and HVM.

sys/amd64/amd64/mp_machdep.c:
sys/i386/i386/mp_machdep.c:
sys/i386/xen/mp_machdep.c
sys/x86/xen/hvm.c:
	Add support for placing vcpu_info into an arbritary memory
	page instead of using HYPERVISOR_shared_info->vcpu_info.
	This allows the creation of domains with more than 32 vcpus.

sys/i386/i386/machdep.c:
sys/i386/xen/clock.c:
sys/i386/xen/xen_machdep.c:
sys/i386/xen/exception.s:
	Add support for new event channle implementation.
2013-08-29 19:52:18 +00:00

1119 lines
31 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.
* 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("$FreeBSD$");
#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 <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)))
#define stmxcsr(addr) __asm __volatile("stmxcsr %0" : : "m" (*(addr)))
#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);
void stmxcsr(u_int *csr);
#endif
#endif /* __GNUCLIKE_ASM && !lint */
#ifdef XEN
#define start_emulating() (HYPERVISOR_fpu_taskswitch(1))
#define stop_emulating() (HYPERVISOR_fpu_taskswitch(0))
#else
#define start_emulating() load_cr0(rcr0() | CR0_TS)
#define stop_emulating() clts()
#endif
#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(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 */
};
/*
* Read the FP status and control words, then generate si_code value
* for SIGFPE. 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.
*
* Some time ago, we cleared the x87 exceptions with FNCLEX there.
* Clearing exceptions was necessary mainly to avoid IRQ13 bugs. The
* usermode code which understands the FPU hardware enough to enable
* the exceptions, can also handle clearing the exception state in the
* handler. The only consequence of not clearing the exception is the
* rethrow of the SIGFPE on return from the signal handler and
* reexecution of the corresponding instruction.
*
* For XMM traps, the exceptions were never cleared.
*/
int
npxtrap_x87(void)
{
u_short control, status;
if (!hw_float) {
printf(
"npxtrap_x87: 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);
}
critical_exit();
return (fpetable[status & ((~control & 0x3f) | 0x40)]);
}
#ifdef CPU_ENABLE_SSE
int
npxtrap_sse(void)
{
u_int mxcsr;
if (!hw_float) {
printf(
"npxtrap_sse: fpcurthread = %p, curthread = %p, hw_float = %d\n",
PCPU_GET(fpcurthread), curthread, hw_float);
panic("npxtrap from nowhere");
}
critical_enter();
if (PCPU_GET(fpcurthread) != curthread)
mxcsr = curthread->td_pcb->pcb_save->sv_xmm.sv_env.en_mxcsr;
else
stmxcsr(&mxcsr);
critical_exit();
return (fpetable[(mxcsr & (~mxcsr >> 7)) & 0x3f]);
}
#endif
/*
* 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)
{
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);
#ifdef CPU_ENABLE_SSE
if (cpu_fxsr)
fpu_clean_state();
#endif
if ((curpcb->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 (curpcb->pcb_initial_npxcw != __INITIAL_NPXCW__)
fldcw(curpcb->pcb_initial_npxcw);
curpcb->pcb_flags |= PCB_NPXINITDONE;
if (PCB_USER_FPU(curpcb))
curpcb->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(curpcb->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 = curpcb;
KASSERT((curthread->td_pflags & TDP_KTHREAD) != 0,
("Only kthread may use fpu_kern_thread"));
KASSERT(curpcb->pcb_save == &curpcb->pcb_user_save,
("mangled pcb_save"));
KASSERT(PCB_USER_FPU(curpcb), ("recursive call"));
curpcb->pcb_flags |= PCB_KERNNPX;
return (0);
}
int
is_fpu_kern_thread(u_int flags)
{
if ((curthread->td_pflags & TDP_KTHREAD) == 0)
return (0);
return ((curpcb->pcb_flags & PCB_KERNNPX) != 0);
}