freebsd-dev/sys/amd64/include/fpu.h
Konstantin Belousov 8c6f8f3d5b Add support for the extended FPU states on amd64, both for native
64bit and 32bit ABIs.  As a side-effect, it enables AVX on capable
CPUs.

In particular:

- Query the CPU support for XSAVE, list of the supported extensions
  and the required size of FPU save area. The hw.use_xsave tunable is
  provided for disabling XSAVE, and hw.xsave_mask may be used to
  select the enabled extensions.

- Remove the FPU save area from PCB and dynamically allocate the
  (run-time sized) user save area on the top of the kernel stack,
  right above the PCB. Reorganize the thread0 PCB initialization to
  postpone it after BSP is queried for save area size.

- The dumppcb, stoppcbs and susppcbs now do not carry the FPU state as
  well. FPU state is only useful for suspend, where it is saved in
  dynamically allocated suspfpusave area.

- Use XSAVE and XRSTOR to save/restore FPU state, if supported and
  enabled.

- Define new mcontext_t flag _MC_HASFPXSTATE, indicating that
  mcontext_t has a valid pointer to out-of-struct extended FPU
  state. Signal handlers are supplied with stack-allocated fpu
  state. The sigreturn(2) and setcontext(2) syscall honour the flag,
  allowing the signal handlers to inspect and manipilate extended
  state in the interrupted context.

- The getcontext(2) never returns extended state, since there is no
  place in the fixed-sized mcontext_t to place variable-sized save
  area. And, since mcontext_t is embedded into ucontext_t, makes it
  impossible to fix in a reasonable way.  Instead of extending
  getcontext(2) syscall, provide a sysarch(2) facility to query
  extended FPU state.

- Add ptrace(2) support for getting and setting extended state; while
  there, implement missed PT_I386_{GET,SET}XMMREGS for 32bit binaries.

- Change fpu_kern KPI to not expose struct fpu_kern_ctx layout to
  consumers, making it opaque. Internally, struct fpu_kern_ctx now
  contains a space for the extended state. Convert in-kernel consumers
  of fpu_kern KPI both on i386 and amd64.

First version of the support for AVX was submitted by Tim Bird
<tim.bird am sony com> on behalf of Sony. This version was written
from scratch.

Tested by:	pho (previous version), Yamagi Burmeister <lists yamagi org>
MFC after:	1 month
2012-01-21 17:45:27 +00:00

167 lines
5.0 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 {
uint8_t fp_bytes[10];
};
/* Contents of each SSE extended accumulator */
struct xmmacc {
uint8_t xmm_bytes[16];
};
/* Contents of the upper 16 bytes of each AVX extended accumulator */
struct ymmacc {
uint8_t ymm_bytes[16];
};
struct envxmm {
uint16_t en_cw; /* control word (16bits) */
uint16_t en_sw; /* status word (16bits) */
uint8_t en_tw; /* tag word (8bits) */
uint8_t en_zero;
uint16_t en_opcode; /* opcode last executed (11 bits ) */
uint64_t en_rip; /* floating point instruction pointer */
uint64_t en_rdp; /* floating operand pointer */
uint32_t en_mxcsr; /* SSE sontorol/status register */
uint32_t en_mxcsr_mask; /* valid bits in mxcsr */
};
struct savefpu {
struct envxmm sv_env;
struct {
struct fpacc87 fp_acc;
uint8_t fp_pad[6]; /* padding */
} sv_fp[8];
struct xmmacc sv_xmm[16];
uint8_t sv_pad[96];
} __aligned(16);
struct xstate_hdr {
uint64_t xstate_bv;
uint8_t xstate_rsrv0[16];
uint8_t xstate_rsrv[40];
};
struct savefpu_xstate {
struct xstate_hdr sx_hd;
struct ymmacc sx_ymm[16];
};
struct savefpu_ymm {
struct envxmm sv_env;
struct {
struct fpacc87 fp_acc;
int8_t fp_pad[6]; /* padding */
} sv_fp[8];
struct xmmacc sv_xmm[16];
uint8_t sv_pad[96];
struct savefpu_xstate sv_xstate;
} __aligned(64);
#ifdef _KERNEL
struct fpu_kern_ctx;
#define PCB_USER_FPU(pcb) (((pcb)->pcb_flags & PCB_KERNFPU) == 0)
#define XSAVE_AREA_ALIGN 64
#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);
void fpuinit(void);
void fpusave(void *addr);
int fpusetregs(struct thread *td, struct savefpu *addr,
char *xfpustate, size_t xfpustate_size);
int fpusetxstate(struct thread *td, char *xfpustate,
size_t xfpustate_size);
int fputrap(void);
void fpuuserinited(struct thread *td);
struct fpu_kern_ctx *fpu_kern_alloc_ctx(u_int flags);
void fpu_kern_free_ctx(struct fpu_kern_ctx *ctx);
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_alloc_ctx(), fpu_kern_enter() and fpu_kern_thread().
*/
#define FPU_KERN_NORMAL 0x0000
#define FPU_KERN_NOWAIT 0x0001
#endif
#endif /* !_MACHINE_FPU_H_ */