From 70b1e9161e903a9e1682aca3a832ed29ef876a4d Mon Sep 17 00:00:00 2001 From: Kevin Cernekee Date: Sat, 12 Nov 2011 19:08:55 -0800 Subject: [PATCH] module: Add comments describing how the "strmap" logic works Signed-off-by: Kevin Cernekee Signed-off-by: Rusty Russell --- kernel/module.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/kernel/module.c b/kernel/module.c index 178333c48d1..cf9f1b6b326 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -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); } -- 2.20.1