On Wed, Feb 16, 2022 at 11:39:31AM -0500, Joe Lawrence wrote:
>
> [ ... snip ... ]
>
> +/*
> + * Checks if rela conversion is supported in given section
> + */
> +static bool supported_section(struct section *sec, char *object_name)
> +{
> +#if 0
> + /*
> + * klp-relocations forbidden in sections that otherwise would
> + * match in allowed_prefixes[]
> + */
> + static const char * const not_allowed[] = {
> + ".rela.data.rel.ro",
> + ".rela.data.rel.ro.local",
> + ".rela.data..ro_after_init",
> + NULL
> + };
> +#endif
> +
> + /* klp-relocations allowed in sections only for vmlinux */
> + static const char * const allowed_vmlinux[] = {
> + ".rela__jump_table",
> + NULL
> + };
> +
> + /* klp-relocations allowed in sections with prefixes */
> + static const char * const allowed_prefixes[] = {
> + ".rela.data",
> + ".rela.rodata", // supported ???
> + ".rela.sdata",
> + ".rela.text",
> + ".rela.toc",
> + NULL
> + };
> +
> + const char * const *name;
> +
> +#if 0
> + for (name = not_allowed; *name; name++)
> + if (strcmp(sec->name, *name) == 0)
> + return false;
> +#endif
I wasn't sure if relocations in .rela.<read-only> sections should be
supported or not, particularly in the late relocation use case. For
most, I think they can be easily avoided by the livepatch author
changing the storage class for the C pointer that is relocated. On the
other hand, this may be disruptive to automated tools like
kpatch-build... or maybe there is no issue at all for late relocating
.rela.<read-only>?
-- Joe
