From: Masahiro Yamada <masahiroy@kernel.org>
To: linux-kbuild@vger.kernel.org
Cc: linux-kernel@vger.kernel.org,
Masahiro Yamada <masahiroy@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Michal Marek <michal.lkml@markovi.net>
Subject: [PATCH v2 03/10] modpost: remove useless export_from_sec()
Date: Tue, 5 Apr 2022 23:02:22 +0900 [thread overview]
Message-ID: <20220405140229.2895394-4-masahiroy@kernel.org> (raw)
In-Reply-To: <20220405140229.2895394-1-masahiroy@kernel.org>
With commit 1743694eb235 ("modpost: stop symbol preloading for
modversion CRC") applied, now export_from_sec() is useless.
handle_symbol() is called for every symbol in the ELF.
When 'symname' does not start with "__ksymtab", export_from_sec() is
called, and the returned value is stored in 'export'.
It is used in the last part of handle_symbol():
if (strstarts(symname, "__ksymtab_")) {
name = symname + strlen("__ksymtab_");
sym_add_exported(name, mod, export);
}
'export' is used only when 'symname' starts with "__ksymtab_".
So, the value returned by export_from_sec() is never used.
Remove useless export_from_sec(). This makes further cleanups possible.
I put the temporary code:
export = export_unknown;
Otherwise, I would get the compiler warning:
warning: 'export' may be used uninitialized in this function [-Wmaybe-uninitialized]
This is apparently false positive because
if (strstarts(symname, "__ksymtab_")
... is a stronger condition than:
if (strstarts(symname, "__ksymtab")
Anyway, this part will be cleaned up by the next commit.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
---
Changes in v2:
- Fix compiler warning
scripts/mod/modpost.c | 17 ++---------------
scripts/mod/modpost.h | 4 ----
2 files changed, 2 insertions(+), 19 deletions(-)
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index ed9d056d2108..eebb32689816 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -369,16 +369,6 @@ static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
return export_unknown;
}
-static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
-{
- if (sec == elf->export_sec)
- return export_plain;
- else if (sec == elf->export_gpl_sec)
- return export_gpl;
- else
- return export_unknown;
-}
-
static const char *namespace_from_kstrtabns(const struct elf_info *info,
const Elf_Sym *sym)
{
@@ -576,10 +566,7 @@ static int parse_elf(struct elf_info *info, const char *filename)
fatal("%s has NOBITS .modinfo\n", filename);
info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
info->modinfo_len = sechdrs[i].sh_size;
- } else if (strcmp(secname, "__ksymtab") == 0)
- info->export_sec = i;
- else if (strcmp(secname, "__ksymtab_gpl") == 0)
- info->export_gpl_sec = i;
+ }
if (sechdrs[i].sh_type == SHT_SYMTAB) {
unsigned int sh_link_idx;
@@ -703,7 +690,7 @@ static void handle_symbol(struct module *mod, struct elf_info *info,
if (strstarts(symname, "__ksymtab"))
export = export_from_secname(info, get_secindex(info, sym));
else
- export = export_from_sec(info, get_secindex(info, sym));
+ export = export_unknown;
switch (sym->st_shndx) {
case SHN_COMMON:
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index 0c47ff95c0e2..a85dcec3669a 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -25,7 +25,6 @@
#define Elf_Sym Elf32_Sym
#define Elf_Addr Elf32_Addr
#define Elf_Sword Elf64_Sword
-#define Elf_Section Elf32_Half
#define ELF_ST_BIND ELF32_ST_BIND
#define ELF_ST_TYPE ELF32_ST_TYPE
@@ -40,7 +39,6 @@
#define Elf_Sym Elf64_Sym
#define Elf_Addr Elf64_Addr
#define Elf_Sword Elf64_Sxword
-#define Elf_Section Elf64_Half
#define ELF_ST_BIND ELF64_ST_BIND
#define ELF_ST_TYPE ELF64_ST_TYPE
@@ -138,8 +136,6 @@ struct elf_info {
Elf_Shdr *sechdrs;
Elf_Sym *symtab_start;
Elf_Sym *symtab_stop;
- Elf_Section export_sec;
- Elf_Section export_gpl_sec;
char *strtab;
char *modinfo;
unsigned int modinfo_len;
--
2.32.0
next prev parent reply other threads:[~2022-04-05 20:16 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-05 14:02 [PATCH v2 00/10] kbuild: misc cleanups Masahiro Yamada
2022-04-05 14:02 ` [PATCH v2 01/10] kbuild: factor out genksyms command from cmd_gensymtypes_{c,S} Masahiro Yamada
2022-04-05 14:02 ` [PATCH v2 02/10] kbuild: do not remove empty *.symtypes explicitly Masahiro Yamada
2022-04-05 14:02 ` Masahiro Yamada [this message]
2022-04-05 14:02 ` [PATCH v2 04/10] modpost: move export_from_secname() call to more relevant place Masahiro Yamada
2022-04-05 14:02 ` [PATCH v2 05/10] modpost: remove redundant initializes for static variables Masahiro Yamada
2022-04-05 14:02 ` [PATCH v2 06/10] modpost: remove annoying namespace_from_kstrtabns() Masahiro Yamada
2022-04-05 14:02 ` [PATCH v2 07/10] kbuild: get rid of duplication in the first line of *.mod files Masahiro Yamada
2022-04-05 14:02 ` [PATCH v2 08/10] kbuild: split the second line of *.mod into *.usyms Masahiro Yamada
2022-04-05 14:02 ` [PATCH v2 09/10] kbuild: refactor cmd_modversions_c Masahiro Yamada
2022-04-05 14:02 ` [PATCH v2 10/10] kbuild: refactor cmd_modversions_S Masahiro Yamada
-- strict thread matches above, loose matches on Subject: below --
2022-04-05 11:33 [PATCH v2 00/10] kbuild: misc cleanups Masahiro Yamada
2022-04-05 11:33 ` [PATCH v2 03/10] modpost: remove useless export_from_sec() Masahiro Yamada
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