On Tue, Nov 24, 2020 at 8:22 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
>
> Reorder the filter_functions function so we can add
> processing of kernel modules in following patch.
>
> There's no functional change intended.
>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
> btf_encoder.c | 57 +++++++++++++++++++++++++++++++++------------------
> 1 file changed, 37 insertions(+), 20 deletions(-)
>
> diff --git a/btf_encoder.c b/btf_encoder.c
> index c40f059580da..467c4657b2c0 100644
> --- a/btf_encoder.c
> +++ b/btf_encoder.c
> @@ -101,14 +101,17 @@ static int addrs_cmp(const void *_a, const void *_b)
> return *a < *b ? -1 : 1;
> }
>
> -static int filter_functions(struct btf_elf *btfe, struct funcs_layout *fl)
> +static int get_vmlinux_addrs(struct btf_elf *btfe, struct funcs_layout *fl,
> + unsigned long **paddrs, unsigned long *pcount)
> {
> - unsigned long *addrs, count, offset, i;
> - int functions_valid = 0;
> + unsigned long *addrs, count, offset;
> Elf_Data *data;
> GElf_Shdr shdr;
> Elf_Scn *sec;
>
> + if (!fl->mcount_start || !fl->mcount_stop)
> + return 0;
> +
probably better to explicitly assign paddrs and pcount to NULL and 0 here
> /*
> * Find mcount addressed marked by __start_mcount_loc
> * and __stop_mcount_loc symbols and load them into
> @@ -138,7 +141,32 @@ static int filter_functions(struct btf_elf *btfe, struct funcs_layout *fl)
> }
>
> memcpy(addrs, data->d_buf + offset, count * sizeof(addrs[0]));
> + *paddrs = addrs;
> + *pcount = count;
> + return 0;
> +}
> +
> +static int setup_functions(struct btf_elf *btfe, struct funcs_layout *fl)
> +{
> + unsigned long *addrs = NULL, count, i;
> + int functions_valid = 0;
> +
> + /*
> + * Check if we are processing vmlinux image and
> + * get mcount data if it's detected.
> + */
> + if (get_vmlinux_addrs(btfe, fl, &addrs, &count))
> + return -1;
> +
> + if (!addrs) {
> + if (btf_elf__verbose)
> + printf("ftrace symbols not detected, falling back to DWARF data\n");
> + delete_functions();
> + return 0;
> + }
> +
> qsort(addrs, count, sizeof(addrs[0]), addrs_cmp);
> + qsort(functions, functions_cnt, sizeof(functions[0]), functions_cmp);
>
> /*
> * Let's got through all collected functions and filter
> @@ -162,6 +190,9 @@ static int filter_functions(struct btf_elf *btfe, struct funcs_layout *fl)
>
> functions_cnt = functions_valid;
> free(addrs);
> +
> + if (btf_elf__verbose)
> + printf("Found %d functions!\n", functions_cnt);
> return 0;
> }
>
> @@ -470,11 +501,6 @@ static void collect_symbol(GElf_Sym *sym, struct funcs_layout *fl)
> fl->mcount_stop = sym->st_value;
> }
>
> -static int has_all_symbols(struct funcs_layout *fl)
> -{
> - return fl->mcount_start && fl->mcount_stop;
> -}
> -
> static int collect_symbols(struct btf_elf *btfe, bool collect_percpu_vars)
> {
> struct funcs_layout fl = { };
> @@ -501,18 +527,9 @@ static int collect_symbols(struct btf_elf *btfe, bool collect_percpu_vars)
> printf("Found %d per-CPU variables!\n", percpu_var_cnt);
> }
>
> - if (functions_cnt && has_all_symbols(&fl)) {
> - qsort(functions, functions_cnt, sizeof(functions[0]), functions_cmp);
> - if (filter_functions(btfe, &fl)) {
> - fprintf(stderr, "Failed to filter dwarf functions\n");
> - return -1;
> - }
> - if (btf_elf__verbose)
> - printf("Found %d functions!\n", functions_cnt);
> - } else {
> - if (btf_elf__verbose)
> - printf("ftrace symbols not detected, falling back to DWARF data\n");
> - delete_functions();
> + if (functions_cnt && setup_functions(btfe, &fl)) {
> + fprintf(stderr, "Failed to filter dwarf functions\n");
DWARF
> + return -1;
> }
>
> return 0;
> --
> 2.26.2
>
