diff options
| author | Jessica Yu <jeyu@kernel.org> | 2021-03-23 13:15:41 +0100 |
|---|---|---|
| committer | Jessica Yu <jeyu@kernel.org> | 2021-03-29 13:08:53 +0200 |
| commit | 33121347fb1c359bd6e3e680b9f2c6ced5734a81 (patch) | |
| tree | c38eadcabd9f0d7caed67f8051cebc3f5bcf7f82 /kernel/module.c | |
| parent | 1e28eed17697bcf343c6743f0028cc3b5dd88bf0 (diff) | |
module: treat exit sections the same as init sections when !CONFIG_MODULE_UNLOAD
Dynamic code patching (alternatives, jump_label and static_call) can
have sites in __exit code, even it __exit is never executed. Therefore
__exit must be present at runtime, at least for as long as __init code
is.
Additionally, for jump_label and static_call, the __exit sites must also
identify as within_module_init(), such that the infrastructure is aware
to never touch them after module init -- alternatives are only ran once
at init and hence don't have this particular constraint.
By making __exit identify as __init for MODULE_UNLOAD, the above is
satisfied.
So, when !CONFIG_MODULE_UNLOAD, the section ordering should look like the
following, with the .exit sections moved to the init region of the module.
Core section allocation order:
.text
.rodata
__ksymtab_gpl
__ksymtab_strings
.note.* sections
.bss
.data
.gnu.linkonce.this_module
Init section allocation order:
.init.text
.exit.text
.symtab
.strtab
[jeyu: thanks to Peter Zijlstra for most of changelog]
Link: https://lore.kernel.org/lkml/YFiuphGw0RKehWsQ@gunter/
Link: https://lore.kernel.org/r/20210323142756.11443-1-jeyu@kernel.org
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Diffstat (limited to 'kernel/module.c')
| -rw-r--r-- | kernel/module.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/kernel/module.c b/kernel/module.c index 30479355ab85..173a09175511 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2802,7 +2802,11 @@ void * __weak module_alloc(unsigned long size) bool __weak module_init_section(const char *name) { +#ifndef CONFIG_MODULE_UNLOAD + return strstarts(name, ".init") || module_exit_section(name); +#else return strstarts(name, ".init"); +#endif } bool __weak module_exit_section(const char *name) @@ -3116,11 +3120,6 @@ static int rewrite_section_headers(struct load_info *info, int flags) */ shdr->sh_addr = (size_t)info->hdr + shdr->sh_offset; -#ifndef CONFIG_MODULE_UNLOAD - /* Don't load .exit sections */ - if (module_exit_section(info->secstrings+shdr->sh_name)) - shdr->sh_flags &= ~(unsigned long)SHF_ALLOC; -#endif } /* Track but don't keep modinfo and version sections. */ |