module: Add comments describing how the "strmap" logic works

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Kevin Cernekee 2011-11-12 19:08:55 -08:00 committed by Rusty Russell
parent 2485a4b610
commit 70b1e9161e

View File

@ -2193,6 +2193,13 @@ static void layout_symtab(struct module *mod, struct load_info *info)
src = (void *)info->hdr + symsect->sh_offset;
nsrc = symsect->sh_size / sizeof(*src);
/*
* info->strmap has a '1' bit for each byte of .strtab we want to
* keep resident in mod->core_strtab. Everything else in .strtab
* is unreferenced by the symbols in mod->core_symtab, and will be
* discarded when add_kallsyms() compacts the string table.
*/
for (ndst = i = 1; i < nsrc; ++i, ++src)
if (is_core_symbol(src, info->sechdrs, info->hdr->e_shnum)) {
unsigned int j = src->st_name;
@ -2215,6 +2222,8 @@ static void layout_symtab(struct module *mod, struct load_info *info)
/* Append room for core symbols' strings at end of core part. */
info->stroffs = mod->core_size;
/* First strtab byte (and first symtab entry) are zeroes. */
__set_bit(0, info->strmap);
mod->core_size += bitmap_weight(info->strmap, strsect->sh_size);
}