2005-04-17 05:20:36 +07:00
|
|
|
#ifndef _ASM_KPROBES_H
|
|
|
|
|
#define _ASM_KPROBES_H
|
|
|
|
|
/*
|
|
|
|
|
* Kernel Probes (KProbes)
|
|
|
|
|
* include/asm-x86_64/kprobes.h
|
|
|
|
|
*
|
|
|
|
|
* This program is free software; you can redistribute it and/or modify
|
|
|
|
|
* it under the terms of the GNU General Public License as published by
|
|
|
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
|
|
|
* (at your option) any later version.
|
|
|
|
|
*
|
|
|
|
|
* This program is distributed in the hope that it will be useful,
|
|
|
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
|
|
|
* GNU General Public License for more details.
|
|
|
|
|
*
|
|
|
|
|
* You should have received a copy of the GNU General Public License
|
|
|
|
|
* along with this program; if not, write to the Free Software
|
|
|
|
|
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
|
|
|
|
|
*
|
|
|
|
|
* Copyright (C) IBM Corporation, 2002, 2004
|
|
|
|
|
*
|
|
|
|
|
* 2004-Oct Prasanna S Panchamukhi <prasanna@in.ibm.com> and Jim Keniston
|
|
|
|
|
* kenistoj@us.ibm.com adopted from i386.
|
|
|
|
|
*/
|
|
|
|
|
#include <linux/types.h>
|
|
|
|
|
#include <linux/ptrace.h>
|
2005-11-07 16:00:12 +07:00
|
|
|
#include <linux/percpu.h>
|
2005-04-17 05:20:36 +07:00
|
|
|
|
2006-01-10 11:52:41 +07:00
|
|
|
#define __ARCH_WANT_KPROBES_INSN_SLOT
|
|
|
|
|
|
2005-04-17 05:20:36 +07:00
|
|
|
struct pt_regs;
|
|
|
|
|
|
|
|
|
|
typedef u8 kprobe_opcode_t;
|
|
|
|
|
#define BREAKPOINT_INSTRUCTION 0xcc
|
|
|
|
|
#define MAX_INSN_SIZE 15
|
|
|
|
|
#define MAX_STACK_SIZE 64
|
|
|
|
|
#define MIN_STACK_SIZE(ADDR) (((MAX_STACK_SIZE) < \
|
|
|
|
|
(((unsigned long)current_thread_info()) + THREAD_SIZE - (ADDR))) \
|
|
|
|
|
? (MAX_STACK_SIZE) \
|
|
|
|
|
: (((unsigned long)current_thread_info()) + THREAD_SIZE - (ADDR)))
|
|
|
|
|
|
|
|
|
|
#define JPROBE_ENTRY(pentry) (kprobe_opcode_t *)pentry
|
[PATCH] x86_64 specific function return probes
The following patch adds the x86_64 architecture specific implementation
for function return probes.
Function return probes is a mechanism built on top of kprobes that allows
a caller to register a handler to be called when a given function exits.
For example, to instrument the return path of sys_mkdir:
static int sys_mkdir_exit(struct kretprobe_instance *i, struct pt_regs *regs)
{
printk("sys_mkdir exited\n");
return 0;
}
static struct kretprobe return_probe = {
.handler = sys_mkdir_exit,
};
<inside setup function>
return_probe.kp.addr = (kprobe_opcode_t *) kallsyms_lookup_name("sys_mkdir");
if (register_kretprobe(&return_probe)) {
printk(KERN_DEBUG "Unable to register return probe!\n");
/* do error path */
}
<inside cleanup function>
unregister_kretprobe(&return_probe);
The way this works is that:
* At system initialization time, kernel/kprobes.c installs a kprobe
on a function called kretprobe_trampoline() that is implemented in
the arch/x86_64/kernel/kprobes.c (More on this later)
* When a return probe is registered using register_kretprobe(),
kernel/kprobes.c will install a kprobe on the first instruction of the
targeted function with the pre handler set to arch_prepare_kretprobe()
which is implemented in arch/x86_64/kernel/kprobes.c.
* arch_prepare_kretprobe() will prepare a kretprobe instance that stores:
- nodes for hanging this instance in an empty or free list
- a pointer to the return probe
- the original return address
- a pointer to the stack address
With all this stowed away, arch_prepare_kretprobe() then sets the return
address for the targeted function to a special trampoline function called
kretprobe_trampoline() implemented in arch/x86_64/kernel/kprobes.c
* The kprobe completes as normal, with control passing back to the target
function that executes as normal, and eventually returns to our trampoline
function.
* Since a kprobe was installed on kretprobe_trampoline() during system
initialization, control passes back to kprobes via the architecture
specific function trampoline_probe_handler() which will lookup the
instance in an hlist maintained by kernel/kprobes.c, and then call
the handler function.
* When trampoline_probe_handler() is done, the kprobes infrastructure
single steps the original instruction (in this case just a top), and
then calls trampoline_post_handler(). trampoline_post_handler() then
looks up the instance again, puts the instance back on the free list,
and then makes a long jump back to the original return instruction.
So to recap, to instrument the exit path of a function this implementation
will cause four interruptions:
- A breakpoint at the very beginning of the function allowing us to
switch out the return address
- A single step interruption to execute the original instruction that
we replaced with the break instruction (normal kprobe flow)
- A breakpoint in the trampoline function where our instrumented function
returned to
- A single step interruption to execute the original instruction that
we replaced with the break instruction (normal kprobe flow)
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-23 14:09:23 +07:00
|
|
|
#define ARCH_SUPPORTS_KRETPROBES
|
|
|
|
|
|
|
|
|
|
void kretprobe_trampoline(void);
|
2005-04-17 05:20:36 +07:00
|
|
|
|
|
|
|
|
/* Architecture specific copy of original instruction*/
|
|
|
|
|
struct arch_specific_insn {
|
|
|
|
|
/* copy of the original instruction */
|
|
|
|
|
kprobe_opcode_t *insn;
|
|
|
|
|
};
|
|
|
|
|
|
2005-11-07 16:00:12 +07:00
|
|
|
struct prev_kprobe {
|
|
|
|
|
struct kprobe *kp;
|
|
|
|
|
unsigned long status;
|
|
|
|
|
unsigned long old_rflags;
|
|
|
|
|
unsigned long saved_rflags;
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
/* per-cpu kprobe control block */
|
|
|
|
|
struct kprobe_ctlblk {
|
|
|
|
|
unsigned long kprobe_status;
|
|
|
|
|
unsigned long kprobe_old_rflags;
|
|
|
|
|
unsigned long kprobe_saved_rflags;
|
|
|
|
|
long *jprobe_saved_rsp;
|
|
|
|
|
struct pt_regs jprobe_saved_regs;
|
|
|
|
|
kprobe_opcode_t jprobes_stack[MAX_STACK_SIZE];
|
|
|
|
|
struct prev_kprobe prev_kprobe;
|
|
|
|
|
};
|
|
|
|
|
|
2005-04-17 05:20:36 +07:00
|
|
|
/* trap3/1 are intr gates for kprobes. So, restore the status of IF,
|
|
|
|
|
* if necessary, before executing the original int3/1 (trap) handler.
|
|
|
|
|
*/
|
|
|
|
|
static inline void restore_interrupts(struct pt_regs *regs)
|
|
|
|
|
{
|
|
|
|
|
if (regs->eflags & IF_MASK)
|
|
|
|
|
local_irq_enable();
|
|
|
|
|
}
|
|
|
|
|
|
2006-01-10 11:52:45 +07:00
|
|
|
extern void arch_remove_kprobe(struct kprobe *p, struct semaphore *s);
|
2005-04-17 05:20:36 +07:00
|
|
|
extern int post_kprobe_handler(struct pt_regs *regs);
|
|
|
|
|
extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr);
|
|
|
|
|
extern int kprobe_handler(struct pt_regs *regs);
|
|
|
|
|
|
|
|
|
|
extern int kprobe_exceptions_notify(struct notifier_block *self,
|
|
|
|
|
unsigned long val, void *data);
|
|
|
|
|
#endif /* _ASM_KPROBES_H */
|