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Diffstat (limited to 'include/linux/hw_breakpoint.h')
| -rw-r--r-- | include/linux/hw_breakpoint.h | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/include/linux/hw_breakpoint.h b/include/linux/hw_breakpoint.h new file mode 100644 index 000000000000..61ccc8f17eac --- /dev/null +++ b/include/linux/hw_breakpoint.h @@ -0,0 +1,136 @@ +#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 */ |