On Wed, Jun 17, 2020 at 9:21 AM Andrii Nakryiko <andriin@xxxxxx> wrote:
>
> Switch existing Kconfig externs to be just one of few possible kinds of more
> generic externs. This refactoring is in preparation for ksymbol extern
> support, added in the follow up patch. There are no functional changes
> intended.
>
> Signed-off-by: Andrii Nakryiko <andriin@xxxxxx>
> ---
[...]
> @@ -5572,30 +5635,33 @@ static int bpf_object__resolve_externs(struct bpf_object *obj,
> {
> bool need_config = false;
> struct extern_desc *ext;
> + void *kcfg_data;
> int err, i;
> - void *data;
>
> if (obj->nr_extern == 0)
> return 0;
>
> - data = obj->maps[obj->kconfig_map_idx].mmaped;
> + if (obj->kconfig_map_idx >= 0)
> + kcfg_data = obj->maps[obj->kconfig_map_idx].mmaped;
>
> for (i = 0; i < obj->nr_extern; i++) {
> ext = &obj->externs[i];
>
> - if (strcmp(ext->name, "LINUX_KERNEL_VERSION") == 0) {
> - void *ext_val = data + ext->data_off;
> + if (ext->type == EXT_KCFG &&
> + strcmp(ext->name, "LINUX_KERNEL_VERSION") == 0) {
> + void *ext_val = kcfg_data + ext->kcfg.data_off;
> __u32 kver = get_kernel_version();
>
> if (!kver) {
> pr_warn("failed to get kernel version\n");
> return -EINVAL;
> }
> - err = set_ext_value_num(ext, ext_val, kver);
> + err = set_kcfg_value_num(ext, ext_val, kver);
> if (err)
> return err;
> - pr_debug("extern %s=0x%x\n", ext->name, kver);
> - } else if (strncmp(ext->name, "CONFIG_", 7) == 0) {
> + pr_debug("extern (kcfg) %s=0x%x\n", ext->name, kver);
> + } else if (ext->type == EXT_KCFG &&
> + strncmp(ext->name, "CONFIG_", 7) == 0) {
> need_config = true;
> } else {
> pr_warn("unrecognized extern '%s'\n", ext->name);
Ah, we need to initialize kcfg_data, otherwise the compiler will give
a warning on potentially uninitialized data.
