/*
 * Tracing hooks
 *
 * Copyright (C) 2008-2009 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License v.2.
 *
 * This file defines hook entry points called by core code where
 * user tracing/debugging support might need to do something.  These
 * entry points are called tracehook_*().  Each hook declared below
 * has a detailed kerneldoc comment giving the context (locking et
 * al) from which it is called, and the meaning of its return value.
 *
 * Each function here typically has only one call site, so it is ok
 * to have some nontrivial tracehook_*() inlines.  In all cases, the
 * fast path when no tracing is enabled should be very short.
 *
 * The purpose of this file and the tracehook_* layer is to consolidate
 * the interface that the kernel core and arch code uses to enable any
 * user debugging or tracing facility (such as ptrace).  The interfaces
 * here are carefully documented so that maintainers of core and arch
 * code do not need to think about the implementation details of the
 * tracing facilities.  Likewise, maintainers of the tracing code do not
 * need to understand all the calling core or arch code in detail, just
 * documented circumstances of each call, such as locking conditions.
 *
 * If the calling core code changes so that locking is different, then
 * it is ok to change the interface documented here.  The maintainer of
 * core code changing should notify the maintainers of the tracing code
 * that they need to work out the change.
 *
 * Some tracehook_*() inlines take arguments that the current tracing
 * implementations might not necessarily use.  These function signatures
 * are chosen to pass in all the information that is on hand in the
 * caller and might conceivably be relevant to a tracer, so that the
 * core code won't have to be updated when tracing adds more features.
 * If a call site changes so that some of those parameters are no longer
 * already on hand without extra work, then the tracehook_* interface
 * can change so there is no make-work burden on the core code.  The
 * maintainer of core code changing should notify the maintainers of the
 * tracing code that they need to work out the change.
 */

#ifndef _LINUX_TRACEHOOK_H
#define _LINUX_TRACEHOOK_H	1

#include <linux/sched.h>
#include <linux/ptrace.h>
#include <linux/security.h>
struct linux_binprm;

static inline int ptrace_report_syscall(struct pt_regs *regs)
{
	int ptrace = current->ptrace;

	if (!(ptrace & PT_PTRACED))
		return 0;

	ptrace_notify(SIGTRAP | ((ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));

	if (current->exit_code) {
		send_sig(current->exit_code, current, 1);
		current->exit_code = 0;
	}

	return fatal_signal_pending(current);
}

static inline __must_check int tracehook_report_syscall_entry(
	struct pt_regs *regs)
{
	return ptrace_report_syscall(regs);
}

static inline void tracehook_report_syscall_exit(struct pt_regs *regs, int step)
{
	if (step) {
		siginfo_t info;
		user_single_step_siginfo(current, regs, &info);
		force_sig_info(SIGTRAP, &info, current);
		return;
	}

	ptrace_report_syscall(regs);
}

static inline void tracehook_signal_handler(int sig, siginfo_t *info,
					    const struct k_sigaction *ka,
					    struct pt_regs *regs, int stepping)
{
	if (stepping)
		ptrace_notify(SIGTRAP);
}

#ifdef TIF_NOTIFY_RESUME
static inline void set_notify_resume(struct task_struct *task)
{
	if (!test_and_set_tsk_thread_flag(task, TIF_NOTIFY_RESUME))
		kick_process(task);
}

static inline void tracehook_notify_resume(struct pt_regs *regs)
{
}
#endif	

#endif