freebsd-skq/sys/amd64/include/ucontext.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

104 lines
3.3 KiB
C

/*-
* Copyright (c) 2003 Peter Wemm
* Copyright (c) 1999 Marcel Moolenaar
* 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
* in this position and unchanged.
* 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.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*
* $FreeBSD$
*/
#ifndef _MACHINE_UCONTEXT_H_
#define _MACHINE_UCONTEXT_H_
/*
* mc_trapno bits. Shall be in sync with TF_XXX.
*/
#define _MC_HASSEGS 0x1
#define _MC_HASBASES 0x2
#define _MC_HASFPXSTATE 0x4
#define _MC_FLAG_MASK (_MC_HASSEGS | _MC_HASBASES | _MC_HASFPXSTATE)
typedef struct __mcontext {
/*
* The definition of mcontext_t must match the layout of
* struct sigcontext after the sc_mask member. This is so
* that we can support sigcontext and ucontext_t at the same
* time.
*/
__register_t mc_onstack; /* XXX - sigcontext compat. */
__register_t mc_rdi; /* machine state (struct trapframe) */
__register_t mc_rsi;
__register_t mc_rdx;
__register_t mc_rcx;
__register_t mc_r8;
__register_t mc_r9;
__register_t mc_rax;
__register_t mc_rbx;
__register_t mc_rbp;
__register_t mc_r10;
__register_t mc_r11;
__register_t mc_r12;
__register_t mc_r13;
__register_t mc_r14;
__register_t mc_r15;
__uint32_t mc_trapno;
__uint16_t mc_fs;
__uint16_t mc_gs;
__register_t mc_addr;
__uint32_t mc_flags;
__uint16_t mc_es;
__uint16_t mc_ds;
__register_t mc_err;
__register_t mc_rip;
__register_t mc_cs;
__register_t mc_rflags;
__register_t mc_rsp;
__register_t mc_ss;
long mc_len; /* sizeof(mcontext_t) */
#define _MC_FPFMT_NODEV 0x10000 /* device not present or configured */
#define _MC_FPFMT_XMM 0x10002
long mc_fpformat;
#define _MC_FPOWNED_NONE 0x20000 /* FP state not used */
#define _MC_FPOWNED_FPU 0x20001 /* FP state came from FPU */
#define _MC_FPOWNED_PCB 0x20002 /* FP state came from PCB */
long mc_ownedfp;
/*
* See <machine/fpu.h> for the internals of mc_fpstate[].
*/
long mc_fpstate[64] __aligned(16);
__register_t mc_fsbase;
__register_t mc_gsbase;
__register_t mc_xfpustate;
__register_t mc_xfpustate_len;
long mc_spare[4];
} mcontext_t;
#endif /* !_MACHINE_UCONTEXT_H_ */