freebsd-skq/sys/amd64/include/fpu.h
kib 2d77212fe4 Introduce the x86 kernel interfaces to allow kernel code to use
FPU/SSE hardware. Caller should provide a save area that is chained
into the stack of the areas; pcb save_area for usermode FPU state is
on top. The pcb now contains a pointer to the current FPU saved area,
used during FPUDNA handling and context switches.  There is also a
facility to allow the kernel thread to use pcb save_area.

Change the dreaded warnings "npxdna in kernel mode!" into the panics
when FPU usage is not registered.

KPI discussed with:	fabient
Tested by:    pho, fabient
Hardware provided by:	Sentex Communications
MFC after:    1 month
2010-06-05 15:59:59 +00:00

135 lines
4.4 KiB
C

/*-
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* William Jolitz.
*
* 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.h 5.3 (Berkeley) 1/18/91
* $FreeBSD$
*/
/*
* Floating Point Data Structures and Constants
* W. Jolitz 1/90
*/
#ifndef _MACHINE_FPU_H_
#define _MACHINE_FPU_H_
/* Contents of each x87 floating point accumulator */
struct fpacc87 {
u_char fp_bytes[10];
};
/* Contents of each SSE extended accumulator */
struct xmmacc {
u_char xmm_bytes[16];
};
struct envxmm {
u_int16_t en_cw; /* control word (16bits) */
u_int16_t en_sw; /* status word (16bits) */
u_int8_t en_tw; /* tag word (8bits) */
u_int8_t en_zero;
u_int16_t en_opcode; /* opcode last executed (11 bits ) */
u_int64_t en_rip; /* floating point instruction pointer */
u_int64_t en_rdp; /* floating operand pointer */
u_int32_t en_mxcsr; /* SSE sontorol/status register */
u_int32_t en_mxcsr_mask; /* valid bits in mxcsr */
};
struct savefpu {
struct envxmm sv_env;
struct {
struct fpacc87 fp_acc;
u_char fp_pad[6]; /* padding */
} sv_fp[8];
struct xmmacc sv_xmm[16];
u_char sv_pad[96];
} __aligned(16);
#ifdef _KERNEL
struct fpu_kern_ctx {
struct savefpu hwstate;
struct savefpu *prev;
uint32_t flags;
};
#define FPU_KERN_CTX_FPUINITDONE 0x01
#define PCB_USER_FPU(pcb) (((pcb)->pcb_flags & PCB_KERNFPU) == 0)
#endif
/*
* The hardware default control word for i387's and later coprocessors is
* 0x37F, giving:
*
* round to nearest
* 64-bit precision
* all exceptions masked.
*
* FreeBSD/i386 uses 53 bit precision for things like fadd/fsub/fsqrt etc
* because of the difference between memory and fpu register stack arguments.
* If its using an intermediate fpu register, it has 80/64 bits to work
* with. If it uses memory, it has 64/53 bits to work with. However,
* gcc is aware of this and goes to a fair bit of trouble to make the
* best use of it.
*
* This is mostly academic for AMD64, because the ABI prefers the use
* SSE2 based math. For FreeBSD/amd64, we go with the default settings.
*/
#define __INITIAL_FPUCW__ 0x037F
#define __INITIAL_FPUCW_I386__ 0x127F
#define __INITIAL_MXCSR__ 0x1F80
#define __INITIAL_MXCSR_MASK__ 0xFFBF
#ifdef _KERNEL
void fpudna(void);
void fpudrop(void);
void fpuexit(struct thread *td);
int fpuformat(void);
int fpugetregs(struct thread *td, struct savefpu *addr);
int fpugetuserregs(struct thread *td, struct savefpu *addr);
void fpuinit(void);
void fpusetregs(struct thread *td, struct savefpu *addr);
void fpusetuserregs(struct thread *td, struct savefpu *addr);
int fputrap(void);
int fpu_kern_enter(struct thread *td, struct fpu_kern_ctx *ctx,
u_int flags);
int fpu_kern_leave(struct thread *td, struct fpu_kern_ctx *ctx);
int fpu_kern_thread(u_int flags);
int is_fpu_kern_thread(u_int flags);
/*
* Flags for fpu_kern_enter() and fpu_kern_thread().
*/
#define FPU_KERN_NORMAL 0x0000
#endif
#endif /* !_MACHINE_FPU_H_ */