[PATCH] hw_breakpoint: remove sample code from hw_breakpoint.h

[PATCH] hw_breakpoint: remove sample code from hw_breakpoint.h

[Li Zefan]

The sample code is a bit out-dated, and there's already a
sample in sample/hw_breakpoint/.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
 include/asm-generic/hw_breakpoint.h |   41 +---------------------------------
 1 files changed, 2 insertions(+), 39 deletions(-)

diff --git a/include/asm-generic/hw_breakpoint.h b/include/asm-generic/hw_breakpoint.h
index 9bf2d12..30ab37c 100644
--- a/include/asm-generic/hw_breakpoint.h
+++ b/include/asm-generic/hw_breakpoint.h
@@ -60,45 +60,8 @@
  * 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>............
- * }
- *
- * ----------------------------------------------------------------------
+ * See sample/hw_breakpoint/ for a sample that sets a breakpoint on
+ * a specified kernel symbol.
  */
 struct hw_breakpoint {
 	void (*triggered)(struct hw_breakpoint *, struct pt_regs *);
-- 
1.5.4.rc3

Re: [PATCH] hw_breakpoint: remove sample code from hw_breakpoint.h

[Frederic Weisbecker]

On Tue, Jul 07, 2009 at 01:40:11PM +0800, Li Zefan wrote:
> The sample code is a bit out-dated, and there's already a
> sample in sample/hw_breakpoint/.


IMHO these bits of comments are useful and don't overlap the role
of the samples in sample/
They only stand there as a quick summup.

No?

 
> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
> ---
>  include/asm-generic/hw_breakpoint.h |   41 +---------------------------------
>  1 files changed, 2 insertions(+), 39 deletions(-)
> 
> diff --git a/include/asm-generic/hw_breakpoint.h b/include/asm-generic/hw_breakpoint.h
> index 9bf2d12..30ab37c 100644
> --- a/include/asm-generic/hw_breakpoint.h
> +++ b/include/asm-generic/hw_breakpoint.h
> @@ -60,45 +60,8 @@
>   * 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>............
> - * }
> - *
> - * ----------------------------------------------------------------------
> + * See sample/hw_breakpoint/ for a sample that sets a breakpoint on
> + * a specified kernel symbol.
>   */
>  struct hw_breakpoint {
>  	void (*triggered)(struct hw_breakpoint *, struct pt_regs *);
> -- 
> 1.5.4.rc3

Re: [PATCH] hw_breakpoint: remove sample code from hw_breakpoint.h

[Li Zefan]

(sorry for the late reply, I didn't see this mail..)

Frederic Weisbecker wrote:
> On Tue, Jul 07, 2009 at 01:40:11PM +0800, Li Zefan wrote:
>> The sample code is a bit out-dated, and there's already a
>> sample in sample/hw_breakpoint/.
> 
> 
> IMHO these bits of comments are useful and don't overlap the role
> of the samples in sample/
> They only stand there as a quick summup.
> 
> No?
> 

The sample here sets a breakpoint on pid_max, which is what the sample
in sample/ does.

And the code here is out-dated (and incomplete). We can fix it, but
whenver someone changes the APIs, he may forget to update the comments.
We know comments never catch up with code.

So I inclined to delete it, and add a link to sample/.