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| Current File : //sys/amd64/amd64/fpu.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/amd64/amd64/fpu.c 235688 2012-05-20 14:15:13Z kib $");
#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/sysctl.h>
#include <machine/bus.h>
#include <sys/rman.h>
#include <sys/signalvar.h>
#include <machine/cputypes.h>
#include <machine/frame.h>
#include <machine/intr_machdep.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>
/*
* Floating point support.
*/
#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 fnstcw(addr) __asm __volatile("fnstcw %0" : "=m" (*(addr)))
#define fnstsw(addr) __asm __volatile("fnstsw %0" : "=am" (*(addr)))
#define fxrstor(addr) __asm __volatile("fxrstor %0" : : "m" (*(addr)))
#define fxsave(addr) __asm __volatile("fxsave %0" : "=m" (*(addr)))
#define ldmxcsr(csr) __asm __volatile("ldmxcsr %0" : : "m" (csr))
#define start_emulating() __asm __volatile( \
"smsw %%ax; orb %0,%%al; lmsw %%ax" \
: : "n" (CR0_TS) : "ax")
#define stop_emulating() __asm __volatile("clts")
static __inline void
xrstor(char *addr, uint64_t mask)
{
uint32_t low, hi;
low = mask;
hi = mask >> 32;
/* xrstor (%rdi) */
__asm __volatile(".byte 0x0f,0xae,0x2f" : :
"a" (low), "d" (hi), "D" (addr));
}
static __inline void
xsave(char *addr, uint64_t mask)
{
uint32_t low, hi;
low = mask;
hi = mask >> 32;
/* xsave (%rdi) */
__asm __volatile(".byte 0x0f,0xae,0x27" : :
"a" (low), "d" (hi), "D" (addr) : "memory");
}
static __inline void
xsetbv(uint32_t reg, uint64_t val)
{
uint32_t low, hi;
low = val;
hi = val >> 32;
__asm __volatile(".byte 0x0f,0x01,0xd1" : :
"c" (reg), "a" (low), "d" (hi));
}
#else /* !(__GNUCLIKE_ASM && !lint) */
void fldcw(u_short cw);
void fnclex(void);
void fninit(void);
void fnstcw(caddr_t addr);
void fnstsw(caddr_t addr);
void fxsave(caddr_t addr);
void fxrstor(caddr_t addr);
void ldmxcsr(u_int csr);
void start_emulating(void);
void stop_emulating(void);
void xrstor(char *addr, uint64_t mask);
void xsave(char *addr, uint64_t mask);
void xsetbv(uint32_t reg, uint64_t val);
#endif /* __GNUCLIKE_ASM && !lint */
#define GET_FPU_CW(thread) ((thread)->td_pcb->pcb_save->sv_env.en_cw)
#define GET_FPU_SW(thread) ((thread)->td_pcb->pcb_save->sv_env.en_sw)
CTASSERT(sizeof(struct savefpu) == 512);
CTASSERT(sizeof(struct xstate_hdr) == 64);
CTASSERT(sizeof(struct savefpu_ymm) == 832);
/*
* This requirement is to make it easier for asm code to calculate
* offset of the fpu save area from the pcb address. FPU save area
* must be 64-byte aligned.
*/
CTASSERT(sizeof(struct pcb) % XSAVE_AREA_ALIGN == 0);
static void fpu_clean_state(void);
SYSCTL_INT(_hw, HW_FLOATINGPT, floatingpoint, CTLFLAG_RD,
NULL, 1, "Floating point instructions executed in hardware");
int use_xsave; /* non-static for cpu_switch.S */
uint64_t xsave_mask; /* the same */
static struct savefpu *fpu_initialstate;
void
fpusave(void *addr)
{
if (use_xsave)
xsave((char *)addr, xsave_mask);
else
fxsave((char *)addr);
}
static void
fpurestore(void *addr)
{
if (use_xsave)
xrstor((char *)addr, xsave_mask);
else
fxrstor((char *)addr);
}
/*
* Enable XSAVE if supported and allowed by user.
* Calculate the xsave_mask.
*/
static void
fpuinit_bsp1(void)
{
u_int cp[4];
uint64_t xsave_mask_user;
if ((cpu_feature2 & CPUID2_XSAVE) != 0) {
use_xsave = 1;
TUNABLE_INT_FETCH("hw.use_xsave", &use_xsave);
}
if (!use_xsave)
return;
cpuid_count(0xd, 0x0, cp);
xsave_mask = XFEATURE_ENABLED_X87 | XFEATURE_ENABLED_SSE;
if ((cp[0] & xsave_mask) != xsave_mask)
panic("CPU0 does not support X87 or SSE: %x", cp[0]);
xsave_mask = ((uint64_t)cp[3] << 32) | cp[0];
xsave_mask_user = xsave_mask;
TUNABLE_ULONG_FETCH("hw.xsave_mask", &xsave_mask_user);
xsave_mask_user |= XFEATURE_ENABLED_X87 | XFEATURE_ENABLED_SSE;
xsave_mask &= xsave_mask_user;
}
/*
* Calculate the fpu save area size.
*/
static void
fpuinit_bsp2(void)
{
u_int cp[4];
if (use_xsave) {
cpuid_count(0xd, 0x0, cp);
cpu_max_ext_state_size = cp[1];
/*
* Reload the cpu_feature2, since we enabled OSXSAVE.
*/
do_cpuid(1, cp);
cpu_feature2 = cp[2];
} else
cpu_max_ext_state_size = sizeof(struct savefpu);
}
/*
* Initialize the floating point unit.
*/
void
fpuinit(void)
{
register_t saveintr;
u_int mxcsr;
u_short control;
if (IS_BSP())
fpuinit_bsp1();
if (use_xsave) {
load_cr4(rcr4() | CR4_XSAVE);
xsetbv(XCR0, xsave_mask);
}
/*
* XCR0 shall be set up before CPU can report the save area size.
*/
if (IS_BSP())
fpuinit_bsp2();
/*
* It is too early for critical_enter() to work on AP.
*/
saveintr = intr_disable();
stop_emulating();
fninit();
control = __INITIAL_FPUCW__;
fldcw(control);
mxcsr = __INITIAL_MXCSR__;
ldmxcsr(mxcsr);
start_emulating();
intr_restore(saveintr);
}
/*
* On the boot CPU we generate a clean state that is used to
* initialize the floating point unit when it is first used by a
* process.
*/
static void
fpuinitstate(void *arg __unused)
{
register_t saveintr;
fpu_initialstate = malloc(cpu_max_ext_state_size, M_DEVBUF,
M_WAITOK | M_ZERO);
saveintr = intr_disable();
stop_emulating();
fpusave(fpu_initialstate);
if (fpu_initialstate->sv_env.en_mxcsr_mask)
cpu_mxcsr_mask = fpu_initialstate->sv_env.en_mxcsr_mask;
else
cpu_mxcsr_mask = 0xFFBF;
/*
* The fninit instruction does not modify XMM registers. The
* fpusave call dumped the garbage contained in the registers
* after reset to the initial state saved. Clear XMM
* registers file image to make the startup program state and
* signal handler XMM register content predictable.
*/
bzero(&fpu_initialstate->sv_xmm[0], sizeof(struct xmmacc));
start_emulating();
intr_restore(saveintr);
}
SYSINIT(fpuinitstate, SI_SUB_DRIVERS, SI_ORDER_ANY, fpuinitstate, NULL);
/*
* Free coprocessor (if we have it).
*/
void
fpuexit(struct thread *td)
{
critical_enter();
if (curthread == PCPU_GET(fpcurthread)) {
stop_emulating();
fpusave(PCPU_GET(curpcb)->pcb_save);
start_emulating();
PCPU_SET(fpcurthread, 0);
}
critical_exit();
}
int
fpuformat()
{
return (_MC_FPFMT_XMM);
}
/*
* 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
fputrap()
{
u_short control, status;
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;
void
fpudna(void)
{
struct pcb *pcb;
critical_enter();
if (PCPU_GET(fpcurthread) == curthread) {
printf("fpudna: fpcurthread == curthread %d times\n",
++err_count);
stop_emulating();
critical_exit();
return;
}
if (PCPU_GET(fpcurthread) != NULL) {
printf("fpudna: fpcurthread = %p (%d), curthread = %p (%d)\n",
PCPU_GET(fpcurthread),
PCPU_GET(fpcurthread)->td_proc->p_pid,
curthread, curthread->td_proc->p_pid);
panic("fpudna");
}
stop_emulating();
/*
* Record new context early in case frstor causes a trap.
*/
PCPU_SET(fpcurthread, curthread);
pcb = PCPU_GET(curpcb);
fpu_clean_state();
if ((pcb->pcb_flags & PCB_FPUINITDONE) == 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.
*/
fpurestore(fpu_initialstate);
if (pcb->pcb_initial_fpucw != __INITIAL_FPUCW__)
fldcw(pcb->pcb_initial_fpucw);
if (PCB_USER_FPU(pcb))
set_pcb_flags(pcb,
PCB_FPUINITDONE | PCB_USERFPUINITDONE);
else
set_pcb_flags(pcb, PCB_FPUINITDONE);
} else
fpurestore(pcb->pcb_save);
critical_exit();
}
void
fpudrop()
{
struct thread *td;
td = PCPU_GET(fpcurthread);
KASSERT(td == curthread, ("fpudrop: fpcurthread != curthread"));
CRITICAL_ASSERT(td);
PCPU_SET(fpcurthread, NULL);
clear_pcb_flags(td->td_pcb, PCB_FPUINITDONE);
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
fpugetregs(struct thread *td)
{
struct pcb *pcb;
pcb = td->td_pcb;
if ((pcb->pcb_flags & PCB_USERFPUINITDONE) == 0) {
bcopy(fpu_initialstate, get_pcb_user_save_pcb(pcb),
cpu_max_ext_state_size);
get_pcb_user_save_pcb(pcb)->sv_env.en_cw =
pcb->pcb_initial_fpucw;
fpuuserinited(td);
return (_MC_FPOWNED_PCB);
}
critical_enter();
if (td == PCPU_GET(fpcurthread) && PCB_USER_FPU(pcb)) {
fpusave(get_pcb_user_save_pcb(pcb));
critical_exit();
return (_MC_FPOWNED_FPU);
} else {
critical_exit();
return (_MC_FPOWNED_PCB);
}
}
void
fpuuserinited(struct thread *td)
{
struct pcb *pcb;
pcb = td->td_pcb;
if (PCB_USER_FPU(pcb))
set_pcb_flags(pcb,
PCB_FPUINITDONE | PCB_USERFPUINITDONE);
else
set_pcb_flags(pcb, PCB_FPUINITDONE);
}
int
fpusetxstate(struct thread *td, char *xfpustate, size_t xfpustate_size)
{
struct xstate_hdr *hdr, *ehdr;
size_t len, max_len;
uint64_t bv;
/* XXXKIB should we clear all extended state in xstate_bv instead ? */
if (xfpustate == NULL)
return (0);
if (!use_xsave)
return (EOPNOTSUPP);
len = xfpustate_size;
if (len < sizeof(struct xstate_hdr))
return (EINVAL);
max_len = cpu_max_ext_state_size - sizeof(struct savefpu);
if (len > max_len)
return (EINVAL);
ehdr = (struct xstate_hdr *)xfpustate;
bv = ehdr->xstate_bv;
/*
* Avoid #gp.
*/
if (bv & ~xsave_mask)
return (EINVAL);
if ((bv & (XFEATURE_ENABLED_X87 | XFEATURE_ENABLED_SSE)) !=
(XFEATURE_ENABLED_X87 | XFEATURE_ENABLED_SSE))
return (EINVAL);
hdr = (struct xstate_hdr *)(get_pcb_user_save_td(td) + 1);
hdr->xstate_bv = bv;
bcopy(xfpustate + sizeof(struct xstate_hdr),
(char *)(hdr + 1), len - sizeof(struct xstate_hdr));
return (0);
}
/*
* Set the state of the FPU.
*/
int
fpusetregs(struct thread *td, struct savefpu *addr, char *xfpustate,
size_t xfpustate_size)
{
struct pcb *pcb;
int error;
pcb = td->td_pcb;
critical_enter();
if (td == PCPU_GET(fpcurthread) && PCB_USER_FPU(pcb)) {
error = fpusetxstate(td, xfpustate, xfpustate_size);
if (error != 0) {
critical_exit();
return (error);
}
bcopy(addr, get_pcb_user_save_td(td), sizeof(*addr));
fpurestore(get_pcb_user_save_td(td));
critical_exit();
set_pcb_flags(pcb, PCB_FPUINITDONE | PCB_USERFPUINITDONE);
} else {
critical_exit();
error = fpusetxstate(td, xfpustate, xfpustate_size);
if (error != 0)
return (error);
bcopy(addr, get_pcb_user_save_td(td), sizeof(*addr));
fpuuserinited(td);
}
return (0);
}
/*
* 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));
}
/*
* This really sucks. We want the acpi version only, but it requires
* the isa_if.h file in order to get the definitions.
*/
#include "opt_isa.h"
#ifdef DEV_ISA
#include <isa/isavar.h>
/*
* This sucks up the legacy ISA support assignments from PNPBIOS/ACPI.
*/
static struct isa_pnp_id fpupnp_ids[] = {
{ 0x040cd041, "Legacy ISA coprocessor support" }, /* PNP0C04 */
{ 0 }
};
static int
fpupnp_probe(device_t dev)
{
int result;
result = ISA_PNP_PROBE(device_get_parent(dev), dev, fpupnp_ids);
if (result <= 0)
device_quiet(dev);
return (result);
}
static int
fpupnp_attach(device_t dev)
{
return (0);
}
static device_method_t fpupnp_methods[] = {
/* Device interface */
DEVMETHOD(device_probe, fpupnp_probe),
DEVMETHOD(device_attach, fpupnp_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 fpupnp_driver = {
"fpupnp",
fpupnp_methods,
1, /* no softc */
};
static devclass_t fpupnp_devclass;
DRIVER_MODULE(fpupnp, acpi, fpupnp_driver, fpupnp_devclass, 0, 0);
#endif /* DEV_ISA */
static MALLOC_DEFINE(M_FPUKERN_CTX, "fpukern_ctx",
"Kernel contexts for FPU state");
#define FPU_KERN_CTX_FPUINITDONE 0x01
struct fpu_kern_ctx {
struct 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 +
cpu_max_ext_state_size;
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 struct 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 ((struct 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 ==
get_pcb_user_save_pcb(pcb), ("mangled pcb_save"));
ctx->flags = 0;
if ((pcb->pcb_flags & PCB_FPUINITDONE) != 0)
ctx->flags |= FPU_KERN_CTX_FPUINITDONE;
fpuexit(td);
ctx->prev = pcb->pcb_save;
pcb->pcb_save = fpu_kern_ctx_savefpu(ctx);
set_pcb_flags(pcb, PCB_KERNFPU);
clear_pcb_flags(pcb, PCB_FPUINITDONE);
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))
fpudrop();
critical_exit();
pcb->pcb_save = ctx->prev;
if (pcb->pcb_save == get_pcb_user_save_pcb(pcb)) {
if ((pcb->pcb_flags & PCB_USERFPUINITDONE) != 0) {
set_pcb_flags(pcb, PCB_FPUINITDONE);
clear_pcb_flags(pcb, PCB_KERNFPU);
} else
clear_pcb_flags(pcb, PCB_FPUINITDONE | PCB_KERNFPU);
} else {
if ((ctx->flags & FPU_KERN_CTX_FPUINITDONE) != 0)
set_pcb_flags(pcb, PCB_FPUINITDONE);
else
clear_pcb_flags(pcb, PCB_FPUINITDONE);
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 == get_pcb_user_save_pcb(pcb),
("mangled pcb_save"));
KASSERT(PCB_USER_FPU(pcb), ("recursive call"));
set_pcb_flags(pcb, PCB_KERNFPU);
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_KERNFPU) != 0);
}