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freebsd-dev/sys/x86/include/reg.h
John Baldwin 9e2154ff1c Cleanups related to debug exceptions on x86. 
- Add constants for fields in DR6 and the reserved fields in DR7.  Use
  these constants instead of magic numbers in most places that use DR6
  and DR7.
- Refer to T_TRCTRAP as "debug exception" rather than a "trace trap"
  as it is not just for trace exceptions.
- Always read DR6 for debug exceptions and only clear TF in the flags
  register for user exceptions where DR6.BS is set.
- Clear DR6 before returning from a debug exception handler as
  recommended by the SDM dating all the way back to the 386.  This
  allows debuggers to determine the cause of each exception.  For
  kernel traps, clear DR6 in the T_TRCTRAP case and pass DR6 by value
  to other parts of the handler (namely, user_dbreg_trap()).  For user
  traps, wait until after trapsignal to clear DR6 so that userland
  debuggers can read DR6 via PT_GETDBREGS while the thread is stopped
  in trapsignal().

Reviewed by:	kib, rgrimes
MFC after:	1 month
Differential Revision:	https://reviews.freebsd.org/D15189
2018-05-22 00:45:00 +00:00

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/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 2003 Peter Wemm.
* 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.
* 3. 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: @(#)reg.h 5.5 (Berkeley) 1/18/91
* $FreeBSD$
*/
#ifndef _MACHINE_REG_H_
#define _MACHINE_REG_H_
#include <machine/_types.h>
#ifdef __i386__
/*
* Indices for registers in `struct trapframe' and `struct regs'.
*
* This interface is deprecated. In the kernel, it is only used in FPU
* emulators to convert from register numbers encoded in instructions to
* register values. Everything else just accesses the relevant struct
* members. In userland, debuggers tend to abuse this interface since
* they don't understand that `struct regs' is a struct. I hope they have
* stopped accessing the registers in the trap frame via PT_{READ,WRITE}_U
* and we can stop supporting the user area soon.
*/
#define tFS (0)
#define tES (1)
#define tDS (2)
#define tEDI (3)
#define tESI (4)
#define tEBP (5)
#define tISP (6)
#define tEBX (7)
#define tEDX (8)
#define tECX (9)
#define tEAX (10)
#define tERR (12)
#define tEIP (13)
#define tCS (14)
#define tEFLAGS (15)
#define tESP (16)
#define tSS (17)
/*
* Indices for registers in `struct regs' only.
*
* Some registers live in the pcb and are only in an "array" with the
* other registers in application interfaces that copy all the registers
* to or from a `struct regs'.
*/
#define tGS (18)
#endif /* __i386__ */
/* Rename the structs below depending on the machine architecture. */
#ifdef __i386__
#define __reg32 reg
#define __fpreg32 fpreg
#define __dbreg32 dbreg
#else
#define __reg32 reg32
#define __reg64 reg
#define __fpreg32 fpreg32
#define __fpreg64 fpreg
#define __dbreg32 dbreg32
#define __dbreg64 dbreg
#define __HAVE_REG32
#endif
/*
* Register set accessible via /proc/$pid/regs and PT_{SET,GET}REGS.
*/
struct __reg32 {
__uint32_t r_fs;
__uint32_t r_es;
__uint32_t r_ds;
__uint32_t r_edi;
__uint32_t r_esi;
__uint32_t r_ebp;
__uint32_t r_isp;
__uint32_t r_ebx;
__uint32_t r_edx;
__uint32_t r_ecx;
__uint32_t r_eax;
__uint32_t r_trapno;
__uint32_t r_err;
__uint32_t r_eip;
__uint32_t r_cs;
__uint32_t r_eflags;
__uint32_t r_esp;
__uint32_t r_ss;
__uint32_t r_gs;
};
struct __reg64 {
__int64_t r_r15;
__int64_t r_r14;
__int64_t r_r13;
__int64_t r_r12;
__int64_t r_r11;
__int64_t r_r10;
__int64_t r_r9;
__int64_t r_r8;
__int64_t r_rdi;
__int64_t r_rsi;
__int64_t r_rbp;
__int64_t r_rbx;
__int64_t r_rdx;
__int64_t r_rcx;
__int64_t r_rax;
__uint32_t r_trapno;
__uint16_t r_fs;
__uint16_t r_gs;
__uint32_t r_err;
__uint16_t r_es;
__uint16_t r_ds;
__int64_t r_rip;
__int64_t r_cs;
__int64_t r_rflags;
__int64_t r_rsp;
__int64_t r_ss;
};
/*
* Register set accessible via /proc/$pid/fpregs.
*
* XXX should get struct from fpu.h. Here we give a slightly
* simplified struct. This may be too much detail. Perhaps
* an array of unsigned longs is best.
*/
struct __fpreg32 {
__uint32_t fpr_env[7];
__uint8_t fpr_acc[8][10];
__uint32_t fpr_ex_sw;
__uint8_t fpr_pad[64];
};
struct __fpreg64 {
__uint64_t fpr_env[4];
__uint8_t fpr_acc[8][16];
__uint8_t fpr_xacc[16][16];
__uint64_t fpr_spare[12];
};
/*
* Register set accessible via PT_GETXMMREGS (i386).
*/
struct xmmreg {
/*
* XXX should get struct from npx.h. Here we give a slightly
* simplified struct. This may be too much detail. Perhaps
* an array of unsigned longs is best.
*/
__uint32_t xmm_env[8];
__uint8_t xmm_acc[8][16];
__uint8_t xmm_reg[8][16];
__uint8_t xmm_pad[224];
};
/*
* Register set accessible via /proc/$pid/dbregs.
*/
struct __dbreg32 {
__uint32_t dr[8]; /* debug registers */
/* Index 0-3: debug address registers */
/* Index 4-5: reserved */
/* Index 6: debug status */
/* Index 7: debug control */
};
struct __dbreg64 {
__uint64_t dr[16]; /* debug registers */
/* Index 0-3: debug address registers */
/* Index 4-5: reserved */
/* Index 6: debug status */
/* Index 7: debug control */
/* Index 8-15: reserved */
};
#define DBREG_DR6_RESERVED1 0xffff0ff0
#define DBREG_DR6_BMASK 0x000f
#define DBREG_DR6_B(i) (1 << (i))
#define DBREG_DR6_BD 0x2000
#define DBREG_DR6_BS 0x4000
#define DBREG_DR6_BT 0x8000
#define DBREG_DR7_RESERVED1 0x0400
#define DBREG_DR7_LOCAL_ENABLE 0x01
#define DBREG_DR7_GLOBAL_ENABLE 0x02
#define DBREG_DR7_LEN_1 0x00 /* 1 byte length */
#define DBREG_DR7_LEN_2 0x01
#define DBREG_DR7_LEN_4 0x03
#define DBREG_DR7_LEN_8 0x02
#define DBREG_DR7_EXEC 0x00 /* break on execute */
#define DBREG_DR7_WRONLY 0x01 /* break on write */
#define DBREG_DR7_RDWR 0x03 /* break on read or write */
#define DBREG_DR7_MASK(i) \
((__u_register_t)(0xf) << ((i) * 4 + 16) | 0x3 << (i) * 2)
#define DBREG_DR7_SET(i, len, access, enable) \
((__u_register_t)((len) << 2 | (access)) << ((i) * 4 + 16) | \
(enable) << (i) * 2)
#define DBREG_DR7_GD 0x2000
#define DBREG_DR7_ENABLED(d, i) (((d) & 0x3 << (i) * 2) != 0)
#define DBREG_DR7_ACCESS(d, i) ((d) >> ((i) * 4 + 16) & 0x3)
#define DBREG_DR7_LEN(d, i) ((d) >> ((i) * 4 + 18) & 0x3)
#define DBREG_DRX(d,x) ((d)->dr[(x)]) /* reference dr0 - dr7 by
register number */
#undef __reg32
#undef __reg64
#undef __fpreg32
#undef __fpreg64
#undef __dbreg32
#undef __dbreg64
#ifdef _KERNEL
struct thread;
/*
* XXX these interfaces are MI, so they should be declared in a MI place.
*/
int fill_regs(struct thread *, struct reg *);
int fill_frame_regs(struct trapframe *, struct reg *);
int set_regs(struct thread *, struct reg *);
int fill_fpregs(struct thread *, struct fpreg *);
int set_fpregs(struct thread *, struct fpreg *);
int fill_dbregs(struct thread *, struct dbreg *);
int set_dbregs(struct thread *, struct dbreg *);
#ifdef COMPAT_FREEBSD32
int fill_regs32(struct thread *, struct reg32 *);
int set_regs32(struct thread *, struct reg32 *);
int fill_fpregs32(struct thread *, struct fpreg32 *);
int set_fpregs32(struct thread *, struct fpreg32 *);
int fill_dbregs32(struct thread *, struct dbreg32 *);
int set_dbregs32(struct thread *, struct dbreg32 *);
#endif
#endif
#endif /* !_MACHINE_REG_H_ */
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