linux/include/asm-i386/ptrace.h

#ifndef _I386_PTRACE_H
#define _I386_PTRACE_H

#define EBX 0
#define ECX 1
#define EDX 2
#define ESI 3
#define EDI 4
#define EBP 5
#define EAX 6
#define DS 7
#define ES 8
#define FS 9
#define GS 10
#define ORIG_EAX 11
#define EIP 12
#define CS  13
#define EFL 14
#define UESP 15
#define SS   16
#define FRAME_SIZE 17

/* this struct defines the way the registers are stored on the 
   stack during a system call. */

struct pt_regs {
	long ebx;
	long ecx;
	long edx;
	long esi;
	long edi;
	long ebp;
	long eax;
	int  xds;
	int  xes;
	long orig_eax;
	long eip;
	int  xcs;
	long eflags;
	long esp;
	int  xss;
};

/* Arbitrarily choose the same ptrace numbers as used by the Sparc code. */
#define PTRACE_GETREGS            12
#define PTRACE_SETREGS            13
#define PTRACE_GETFPREGS          14
#define PTRACE_SETFPREGS          15
#define PTRACE_GETFPXREGS         18
#define PTRACE_SETFPXREGS         19

#define PTRACE_OLDSETOPTIONS         21

#define PTRACE_GET_THREAD_AREA    25
#define PTRACE_SET_THREAD_AREA    26

#define PTRACE_SYSEMU		  31
#define PTRACE_SYSEMU_SINGLESTEP  32

#ifdef __KERNEL__

#include <asm/vm86.h>

struct task_struct;
extern void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code);

/*
 * user_mode_vm(regs) determines whether a register set came from user mode.
 * This is true if V8086 mode was enabled OR if the register set was from
 * protected mode with RPL-3 CS value.  This tricky test checks that with
 * one comparison.  Many places in the kernel can bypass this full check
 * if they have already ruled out V8086 mode, so user_mode(regs) can be used.
 */
static inline int user_mode(struct pt_regs *regs)
{
	return (regs->xcs & 3) != 0;
}
static inline int user_mode_vm(struct pt_regs *regs)
{
	return ((regs->xcs & 3) | (regs->eflags & VM_MASK)) != 0;
}
#define instruction_pointer(regs) ((regs)->eip)
#if defined(CONFIG_SMP) && defined(CONFIG_FRAME_POINTER)
extern unsigned long profile_pc(struct pt_regs *regs);
#else
#define profile_pc(regs) instruction_pointer(regs)
#endif
#endif /* __KERNEL__ */

#endif