mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 19:00:25 +00:00
![Thomas Gleixner](/assets/img/avatar_default.png)
Based on 1 normalized pattern(s): 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 45 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Steve Winslow <swinslow@gmail.com> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190528170027.342746075@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
191 lines
6.9 KiB
C
191 lines
6.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
|
|
/*
|
|
* Tracing hooks
|
|
*
|
|
* Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved.
|
|
*
|
|
* 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>
|
|
#include <linux/task_work.h>
|
|
#include <linux/memcontrol.h>
|
|
#include <linux/blk-cgroup.h>
|
|
struct linux_binprm;
|
|
|
|
/*
|
|
* ptrace report for syscall entry and exit looks identical.
|
|
*/
|
|
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));
|
|
|
|
/*
|
|
* this isn't the same as continuing with a signal, but it will do
|
|
* for normal use. strace only continues with a signal if the
|
|
* stopping signal is not SIGTRAP. -brl
|
|
*/
|
|
if (current->exit_code) {
|
|
send_sig(current->exit_code, current, 1);
|
|
current->exit_code = 0;
|
|
}
|
|
|
|
return fatal_signal_pending(current);
|
|
}
|
|
|
|
/**
|
|
* tracehook_report_syscall_entry - task is about to attempt a system call
|
|
* @regs: user register state of current task
|
|
*
|
|
* This will be called if %TIF_SYSCALL_TRACE or %TIF_SYSCALL_EMU have been set,
|
|
* when the current task has just entered the kernel for a system call.
|
|
* Full user register state is available here. Changing the values
|
|
* in @regs can affect the system call number and arguments to be tried.
|
|
* It is safe to block here, preventing the system call from beginning.
|
|
*
|
|
* Returns zero normally, or nonzero if the calling arch code should abort
|
|
* the system call. That must prevent normal entry so no system call is
|
|
* made. If @task ever returns to user mode after this, its register state
|
|
* is unspecified, but should be something harmless like an %ENOSYS error
|
|
* return. It should preserve enough information so that syscall_rollback()
|
|
* can work (see asm-generic/syscall.h).
|
|
*
|
|
* Called without locks, just after entering kernel mode.
|
|
*/
|
|
static inline __must_check int tracehook_report_syscall_entry(
|
|
struct pt_regs *regs)
|
|
{
|
|
return ptrace_report_syscall(regs);
|
|
}
|
|
|
|
/**
|
|
* tracehook_report_syscall_exit - task has just finished a system call
|
|
* @regs: user register state of current task
|
|
* @step: nonzero if simulating single-step or block-step
|
|
*
|
|
* This will be called if %TIF_SYSCALL_TRACE has been set, when the
|
|
* current task has just finished an attempted system call. Full
|
|
* user register state is available here. It is safe to block here,
|
|
* preventing signals from being processed.
|
|
*
|
|
* If @step is nonzero, this report is also in lieu of the normal
|
|
* trap that would follow the system call instruction because
|
|
* user_enable_block_step() or user_enable_single_step() was used.
|
|
* In this case, %TIF_SYSCALL_TRACE might not be set.
|
|
*
|
|
* Called without locks, just before checking for pending signals.
|
|
*/
|
|
static inline void tracehook_report_syscall_exit(struct pt_regs *regs, int step)
|
|
{
|
|
if (step)
|
|
user_single_step_report(regs);
|
|
else
|
|
ptrace_report_syscall(regs);
|
|
}
|
|
|
|
/**
|
|
* tracehook_signal_handler - signal handler setup is complete
|
|
* @stepping: nonzero if debugger single-step or block-step in use
|
|
*
|
|
* Called by the arch code after a signal handler has been set up.
|
|
* Register and stack state reflects the user handler about to run.
|
|
* Signal mask changes have already been made.
|
|
*
|
|
* Called without locks, shortly before returning to user mode
|
|
* (or handling more signals).
|
|
*/
|
|
static inline void tracehook_signal_handler(int stepping)
|
|
{
|
|
if (stepping)
|
|
ptrace_notify(SIGTRAP);
|
|
}
|
|
|
|
/**
|
|
* set_notify_resume - cause tracehook_notify_resume() to be called
|
|
* @task: task that will call tracehook_notify_resume()
|
|
*
|
|
* Calling this arranges that @task will call tracehook_notify_resume()
|
|
* before returning to user mode. If it's already running in user mode,
|
|
* it will enter the kernel and call tracehook_notify_resume() soon.
|
|
* If it's blocked, it will not be woken.
|
|
*/
|
|
static inline void set_notify_resume(struct task_struct *task)
|
|
{
|
|
#ifdef TIF_NOTIFY_RESUME
|
|
if (!test_and_set_tsk_thread_flag(task, TIF_NOTIFY_RESUME))
|
|
kick_process(task);
|
|
#endif
|
|
}
|
|
|
|
/**
|
|
* tracehook_notify_resume - report when about to return to user mode
|
|
* @regs: user-mode registers of @current task
|
|
*
|
|
* This is called when %TIF_NOTIFY_RESUME has been set. Now we are
|
|
* about to return to user mode, and the user state in @regs can be
|
|
* inspected or adjusted. The caller in arch code has cleared
|
|
* %TIF_NOTIFY_RESUME before the call. If the flag gets set again
|
|
* asynchronously, this will be called again before we return to
|
|
* user mode.
|
|
*
|
|
* Called without locks.
|
|
*/
|
|
static inline void tracehook_notify_resume(struct pt_regs *regs)
|
|
{
|
|
/*
|
|
* The caller just cleared TIF_NOTIFY_RESUME. This barrier
|
|
* pairs with task_work_add()->set_notify_resume() after
|
|
* hlist_add_head(task->task_works);
|
|
*/
|
|
smp_mb__after_atomic();
|
|
if (unlikely(current->task_works))
|
|
task_work_run();
|
|
|
|
mem_cgroup_handle_over_high();
|
|
blkcg_maybe_throttle_current();
|
|
}
|
|
|
|
#endif /* <linux/tracehook.h> */
|