|
|
#ifndef _LINUX_HW_BREAKPOINT_H
#define _LINUX_HW_BREAKPOINT_H
#ifdef __KERNEL__
#include <linux/list.h>
#include <linux/types.h>
#include <linux/kallsyms.h>
/**
* struct hw_breakpoint - unified kernel/user-space hardware breakpoint
* @triggered: callback invoked after target address access
* @info: arch-specific breakpoint info (address, length, and type)
*
* %hw_breakpoint structures are the kernel's way of representing
* hardware breakpoints. These are data breakpoints
* (also known as "watchpoints", triggered on data access), and the breakpoint's
* target address can be located in either kernel space or user space.
*
* The breakpoint's address, length, and type are highly
* architecture-specific. The values are encoded in the @info field; you
* specify them when registering the breakpoint. To examine the encoded
* values use hw_breakpoint_get_{kaddress,uaddress,len,type}(), declared
* below.
*
* The address is specified as a regular kernel pointer (for kernel-space
* breakponts) or as an %__user pointer (for user-space breakpoints).
* With register_user_hw_breakpoint(), the address must refer to a
* location in user space. The breakpoint will be active only while the
* requested task is running. Conversely with
* register_kernel_hw_breakpoint(), the address must refer to a location
* in kernel space, and the breakpoint will be active on all CPUs
* regardless of the current task.
*
* The length is the breakpoint's extent in bytes, which is subject to
* certain limitations. include/asm/hw_breakpoint.h contains macros
* defining the available lengths for a specific architecture. Note that
* the address's alignment must match the length. The breakpoint will
* catch accesses to any byte in the range from address to address +
* (length - 1).
*
* The breakpoint's type indicates the sort of access that will cause it
* to trigger. Possible values may include:
*
* %HW_BREAKPOINT_RW (triggered on read or write access),
* %HW_BREAKPOINT_WRITE (triggered on write access), and
* %HW_BREAKPOINT_READ (triggered on read access).
*
* Appropriate macros are defined in include/asm/hw_breakpoint.h; not all
* possibilities are available on all architectures. Execute breakpoints
* must have length equal to the special value %HW_BREAKPOINT_LEN_EXECUTE.
*
* When a breakpoint gets hit, the @triggered callback is
* invoked in_interrupt with a pointer to the %hw_breakpoint structure and the
* processor registers.
* Data breakpoints occur after the memory access has taken place.
* Breakpoints are disabled during execution @triggered, to avoid
* recursive traps and allow unhindered access to breakpointed memory.
*
* This sample code sets a breakpoint on pid_max and registers a callback
* function for writes to that variable. Note that it is not portable
* as written, because not all architectures support HW_BREAKPOINT_LEN_4.
*
* ----------------------------------------------------------------------
*
* #include <asm/hw_breakpoint.h>
*
* struct hw_breakpoint my_bp;
*
* static void my_triggered(struct hw_breakpoint *bp, struct pt_regs *regs)
* {
* printk(KERN_DEBUG "Inside triggered routine of breakpoint exception\n");
* dump_stack();
* .......<more debugging output>........
* }
*
* static struct hw_breakpoint my_bp;
*
* static int init_module(void)
* {
* ..........<do anything>............
* my_bp.info.type = HW_BREAKPOINT_WRITE;
* my_bp.info.len = HW_BREAKPOINT_LEN_4;
*
* my_bp.installed = (void *)my_bp_installed;
*
* rc = register_kernel_hw_breakpoint(&my_bp);
* ..........<do anything>............
* }
*
* static void cleanup_module(void)
* {
* ..........<do anything>............
* unregister_kernel_hw_breakpoint(&my_bp);
* ..........<do anything>............
* }
*
* ----------------------------------------------------------------------
*/
struct hw_breakpoint {
void (*triggered)(struct hw_breakpoint *, struct pt_regs *);
struct arch_hw_breakpoint info;
};
/*
* len and type values are defined in include/asm/hw_breakpoint.h.
* Available values vary according to the architecture. On i386 the
* possibilities are:
*
* HW_BREAKPOINT_LEN_1
* HW_BREAKPOINT_LEN_2
* HW_BREAKPOINT_LEN_4
* HW_BREAKPOINT_RW
* HW_BREAKPOINT_READ
*
* On other architectures HW_BREAKPOINT_LEN_8 may be available, and the
* 1-, 2-, and 4-byte lengths may be unavailable. There also may be
* HW_BREAKPOINT_WRITE. You can use #ifdef to check at compile time.
*/
extern int register_user_hw_breakpoint(struct task_struct *tsk,
struct hw_breakpoint *bp);
extern int modify_user_hw_breakpoint(struct task_struct *tsk,
struct hw_breakpoint *bp);
extern void unregister_user_hw_breakpoint(struct task_struct *tsk,
struct hw_breakpoint *bp);
/*
* Kernel breakpoints are not associated with any particular thread.
*/
extern int register_kernel_hw_breakpoint(struct hw_breakpoint *bp);
extern void unregister_kernel_hw_breakpoint(struct hw_breakpoint *bp);
extern unsigned int hbp_kernel_pos;
#endif /* __KERNEL__ */
#endif /* _LINUX_HW_BREAKPOINT_H */
|
