0326f5a94d
Uprobes uses exception notifiers to get to know if a thread hit a breakpoint or a singlestep exception. When a thread hits a uprobe or is singlestepping post a uprobe hit, the uprobe exception notifier sets its TIF_UPROBE bit, which will then be checked on its return to userspace path (do_notify_resume() ->uprobe_notify_resume()), where the consumers handlers are run (in task context) based on the defined filters. Uprobe hits are thread specific and hence we need to maintain information about if a task hit a uprobe, what uprobe was hit, the slot where the original instruction was copied for xol so that it can be singlestepped with appropriate fixups. In some cases, special care is needed for instructions that are executed out of line (xol). These are architecture specific artefacts, such as handling RIP relative instructions on x86_64. Since the instruction at which the uprobe was inserted is executed out of line, architecture specific fixups are added so that the thread continues normal execution in the presence of a uprobe. Postpone the signals until we execute the probed insn. post_xol() path does a recalc_sigpending() before return to user-mode, this ensures the signal can't be lost. Uprobes relies on DIE_DEBUG notification to notify if a singlestep is complete. Adds x86 specific uprobe exception notifiers and appropriate hooks needed to determine a uprobe hit and subsequent post processing. Add requisite x86 fixups for xol for uprobes. Specific cases needing fixups include relative jumps (x86_64), calls, etc. Where possible, we check and skip singlestepping the breakpointed instructions. For now we skip single byte as well as few multibyte nop instructions. However this can be extended to other instructions too. Credits to Oleg Nesterov for suggestions/patches related to signal, breakpoint, singlestep handling code. Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jim Keniston <jkenisto@linux.vnet.ibm.com> Cc: Linux-mm <linux-mm@kvack.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20120313180011.29771.89027.sendpatchset@srdronam.in.ibm.com [ Performed various cleanliness edits ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
126 lines
3.7 KiB
C
126 lines
3.7 KiB
C
#ifndef _LINUX_UPROBES_H
|
|
#define _LINUX_UPROBES_H
|
|
/*
|
|
* User-space Probes (UProbes)
|
|
*
|
|
* 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, 2008-2012
|
|
* Authors:
|
|
* Srikar Dronamraju
|
|
* Jim Keniston
|
|
* Copyright (C) 2011-2012 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
|
|
*/
|
|
|
|
#include <linux/errno.h>
|
|
#include <linux/rbtree.h>
|
|
|
|
struct vm_area_struct;
|
|
|
|
#ifdef CONFIG_ARCH_SUPPORTS_UPROBES
|
|
# include <asm/uprobes.h>
|
|
#endif
|
|
|
|
/* flags that denote/change uprobes behaviour */
|
|
|
|
/* Have a copy of original instruction */
|
|
#define UPROBE_COPY_INSN 0x1
|
|
|
|
/* Dont run handlers when first register/ last unregister in progress*/
|
|
#define UPROBE_RUN_HANDLER 0x2
|
|
/* Can skip singlestep */
|
|
#define UPROBE_SKIP_SSTEP 0x4
|
|
|
|
struct uprobe_consumer {
|
|
int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs);
|
|
/*
|
|
* filter is optional; If a filter exists, handler is run
|
|
* if and only if filter returns true.
|
|
*/
|
|
bool (*filter)(struct uprobe_consumer *self, struct task_struct *task);
|
|
|
|
struct uprobe_consumer *next;
|
|
};
|
|
|
|
#ifdef CONFIG_UPROBES
|
|
enum uprobe_task_state {
|
|
UTASK_RUNNING,
|
|
UTASK_BP_HIT,
|
|
UTASK_SSTEP,
|
|
UTASK_SSTEP_ACK,
|
|
UTASK_SSTEP_TRAPPED,
|
|
};
|
|
|
|
/*
|
|
* uprobe_task: Metadata of a task while it singlesteps.
|
|
*/
|
|
struct uprobe_task {
|
|
enum uprobe_task_state state;
|
|
struct arch_uprobe_task autask;
|
|
|
|
struct uprobe *active_uprobe;
|
|
|
|
unsigned long xol_vaddr;
|
|
unsigned long vaddr;
|
|
};
|
|
|
|
extern int __weak set_swbp(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr);
|
|
extern int __weak set_orig_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr, bool verify);
|
|
extern bool __weak is_swbp_insn(uprobe_opcode_t *insn);
|
|
extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
|
|
extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
|
|
extern int uprobe_mmap(struct vm_area_struct *vma);
|
|
extern void uprobe_free_utask(struct task_struct *t);
|
|
extern void uprobe_copy_process(struct task_struct *t);
|
|
extern unsigned long __weak uprobe_get_swbp_addr(struct pt_regs *regs);
|
|
extern int uprobe_post_sstep_notifier(struct pt_regs *regs);
|
|
extern int uprobe_pre_sstep_notifier(struct pt_regs *regs);
|
|
extern void uprobe_notify_resume(struct pt_regs *regs);
|
|
extern bool uprobe_deny_signal(void);
|
|
extern bool __weak arch_uprobe_skip_sstep(struct arch_uprobe *aup, struct pt_regs *regs);
|
|
#else /* !CONFIG_UPROBES */
|
|
static inline int
|
|
uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
|
|
{
|
|
return -ENOSYS;
|
|
}
|
|
static inline void
|
|
uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
|
|
{
|
|
}
|
|
static inline int uprobe_mmap(struct vm_area_struct *vma)
|
|
{
|
|
return 0;
|
|
}
|
|
static inline void uprobe_notify_resume(struct pt_regs *regs)
|
|
{
|
|
}
|
|
static inline bool uprobe_deny_signal(void)
|
|
{
|
|
return false;
|
|
}
|
|
static inline unsigned long uprobe_get_swbp_addr(struct pt_regs *regs)
|
|
{
|
|
return 0;
|
|
}
|
|
static inline void uprobe_free_utask(struct task_struct *t)
|
|
{
|
|
}
|
|
static inline void uprobe_copy_process(struct task_struct *t)
|
|
{
|
|
}
|
|
#endif /* !CONFIG_UPROBES */
|
|
#endif /* _LINUX_UPROBES_H */
|