Re: [RESEND][PATCH v2] unwind: Add sframe_(un)register() system calls

[Florian Weimer <fweimer@redhat.com>]

* Steven Rostedt:

> From: Steven Rostedt <rostedt@goodmis.org>
>
> Add system calls to register and unregister sframes that can be used by
> dynamic linkers to tell the kernel where the sframe section is in memory
> for libraries it loads.
>
> Both system calls take a pointer to a new structure:
>
>   struct sframe_setup {
> 	__u64			sframe_start;
> 	__u64			sframe_size;
> 	__u64			text_start;
> 	__u64			text_size;
>   };
>
> and a size of the passed in structure. If the system call needs to be
> extended, then the structure could be changed and the size of that
> structure will tell the kernel that it is the new version. If the kernel
> does not recognize the structure size, it will return -EINVAL.
>
>   sframe_start - The virtual address of the sframe section
>   sframe_size  - The length of the sframe section
>   text_start   - the text section the sframe represents
>   test_size    - the length of the section
>
> If other stack tracing functionality is added, it will require a new
> system call.

Would it make sense to have a more general mechanism to attach metadata
to code memory?  For example, a JIT generator might want to provide a
hint how to obtain debuginfo for the code.

Thanks,
Florian