> CODE_UNREGISTER,
I wonder if this should be the first enum. That is, "0" is to unregister.
That way, all non-zero options will be for what is being registered, and
"0" is for unregistering any of them.
> };
>
> * arg1: void * @info
>
> /* if (@option == CODE_REGISTER_ELF) */
>
> /*
> * text_start, text_end, sframe_start, sframe_end allow unwinding of the
> * call stack.
> *
> * elf_start, elf_end, pathname, and either build_id or debug_link allows
> * mapping instruction pointers to file, symbol, offset, and source file
> * location.
> */
> struct code_elf_info {
> : __u64 elf_start;
> __u64 elf_end;
Perhaps:
__u64 file_start;
__u64 file_end;
?
And call it "struct code_sframe_info"
> __u64 text_start;
> __u64 text_end;
> __u64 sframe_start;
> __u64 sframe_end;
What is the above "sframe" for?
> __u64 pathname; /* char *, NULL if unavailable. */
>
> __u64 build_id; /* char *, NULL if unavailable. */
> __u64 debug_link_pathname; /* char *, NULL if unavailable. */
Maybe just list the above three as "optional" ?
It may be available, but the implementer just doesn't want to implement it.
> __u32 build_id_len;
> __u32 debug_link_crc;
> };
>
>
> /* if (@option == CODE_REGISTER_JIT) */
>
> /*
> * Registration of sorted JIT unwind table: The reserved memory area is
> * of size reserved_len. Userspace increases used_len as new code is
> * populated between text_start and text_end. This area is populated in
> * increasing address order, and its ABI requires to have no overlapping
> * fre. This fits the common use-case where JITs populate code into
> * a given memory area by increasing address order. The sorted unwind
> * tables can be chained with a singly-linked list as they become full.
> * Consecutive chained tables are also in sorted text address order.
> *
> * Note: if there is an eventual use-case for unsorted jit unwind table,
> * this would be introduced as a new "code option".
> */
>
> struct code_jit_info {
> __u64 text_start; /* text_start >= addr */
> __u64 text_end; /* addr < text_end */
> __u64 unwind_head; /* struct code_jit_unwind_table * */
> };
>
> struct code_jit_unwind_fre {
> /*
> * Contains info similar to sframe, allowing unwind for a given
> * code address range.
> */
> __u32 size;
> __u32 ip_off; /* offset from text_start */
> __s32 cfa_off;
> __s32 ra_off;
> __s32 fp_off;
> __u8 info;
> };
>
> struct code_jit_unwind_table {
> __u64 reserved_len;
> __u64 used_len; /*
> * Incremented by userspace (store-release), read by
> * the kernel (load-acquire).
> */
> __u64 next; /* Chain with next struct code_jit_unwind_table. */
> struct code_jit_unwind_fre fre[];
> };
I wonder if we should avoid the "jit" portion completely for now until we
know what exactly we need.
Thanks,
-- Steve
>
> /* if (@option == CODE_UNREGISTER) */
>
> void *info
>
> * arg2: size_t info_size
>
> /*
> * Size of @info structure, allowing extensibility. See
> * copy_struct_from_user().
> */
>
> * arg3: unsigned int flags (0)
>
> /* Flags for extensibility. */
>
> Your feedback is welcome,
>
> Thanks,
>
> Mathieu
>
> [1] https://babeltrace.org/docs/v2.0/man7/babeltrace2-filter.lttng-utils.debug-info.7/
>
