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module: refactor load_module part 5
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1) Extract out the relocation loop into apply_relocations
2) Extract license and version checks into check_module_license_and_versions
3) Extract icache flushing into flush_module_icache
4) Move __obsparm warning into find_module_sections
5) Move license setting into check_modinfo.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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Rusty Russell committed Aug 5, 2010
1 parent 9f85a4b commit 22e268e
Showing 1 changed file with 106 additions and 76 deletions.
182 changes: 106 additions & 76 deletions kernel/module.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1698,6 +1698,39 @@ static int simplify_symbols(Elf_Shdr *sechdrs,
return ret;
}

static int apply_relocations(struct module *mod,
Elf_Ehdr *hdr,
Elf_Shdr *sechdrs,
unsigned int symindex,
unsigned int strindex)
{
unsigned int i;
int err = 0;

/* Now do relocations. */
for (i = 1; i < hdr->e_shnum; i++) {
const char *strtab = (char *)sechdrs[strindex].sh_addr;
unsigned int info = sechdrs[i].sh_info;

/* Not a valid relocation section? */
if (info >= hdr->e_shnum)
continue;

/* Don't bother with non-allocated sections */
if (!(sechdrs[info].sh_flags & SHF_ALLOC))
continue;

if (sechdrs[i].sh_type == SHT_REL)
err = apply_relocate(sechdrs, strtab, symindex, i, mod);
else if (sechdrs[i].sh_type == SHT_RELA)
err = apply_relocate_add(sechdrs, strtab, symindex, i,
mod);
if (err < 0)
break;
}
return err;
}

/* Additional bytes needed by arch in front of individual sections */
unsigned int __weak arch_mod_section_prepend(struct module *mod,
unsigned int section)
Expand Down Expand Up @@ -2179,6 +2212,10 @@ static int check_modinfo(struct module *mod,
" the quality is unknown, you have been warned.\n",
mod->name);
}

/* Set up license info based on the info section */
set_license(mod, get_modinfo(sechdrs, infoindex, "license"));

return 0;
}

Expand Down Expand Up @@ -2245,6 +2282,10 @@ static void find_module_sections(struct module *mod, Elf_Ehdr *hdr,
sizeof(*mod->ftrace_callsites),
&mod->num_ftrace_callsites);
#endif

if (section_addr(hdr, sechdrs, secstrings, "__obsparm"))
printk(KERN_WARNING "%s: Ignoring obsolete parameters\n",
mod->name);
}

static struct module *move_module(struct module *mod,
Expand Down Expand Up @@ -2311,6 +2352,60 @@ static struct module *move_module(struct module *mod,
return mod;
}

static int check_module_license_and_versions(struct module *mod,
Elf_Shdr *sechdrs)
{
/*
* ndiswrapper is under GPL by itself, but loads proprietary modules.
* Don't use add_taint_module(), as it would prevent ndiswrapper from
* using GPL-only symbols it needs.
*/
if (strcmp(mod->name, "ndiswrapper") == 0)
add_taint(TAINT_PROPRIETARY_MODULE);

/* driverloader was caught wrongly pretending to be under GPL */
if (strcmp(mod->name, "driverloader") == 0)
add_taint_module(mod, TAINT_PROPRIETARY_MODULE);

#ifdef CONFIG_MODVERSIONS
if ((mod->num_syms && !mod->crcs)
|| (mod->num_gpl_syms && !mod->gpl_crcs)
|| (mod->num_gpl_future_syms && !mod->gpl_future_crcs)
#ifdef CONFIG_UNUSED_SYMBOLS
|| (mod->num_unused_syms && !mod->unused_crcs)
|| (mod->num_unused_gpl_syms && !mod->unused_gpl_crcs)
#endif
) {
return try_to_force_load(mod,
"no versions for exported symbols");
}
#endif
return 0;
}

static void flush_module_icache(const struct module *mod)
{
mm_segment_t old_fs;

/* flush the icache in correct context */
old_fs = get_fs();
set_fs(KERNEL_DS);

/*
* Flush the instruction cache, since we've played with text.
* Do it before processing of module parameters, so the module
* can provide parameter accessor functions of its own.
*/
if (mod->module_init)
flush_icache_range((unsigned long)mod->module_init,
(unsigned long)mod->module_init
+ mod->init_size);
flush_icache_range((unsigned long)mod->module_core,
(unsigned long)mod->module_core + mod->core_size);

set_fs(old_fs);
}

/* Allocate and load the module: note that size of section 0 is always
zero, and we rely on this for optional sections. */
static noinline struct module *load_module(void __user *umod,
Expand All @@ -2331,8 +2426,6 @@ static noinline struct module *load_module(void __user *umod,
struct _ddebug *debug = NULL;
unsigned int num_debug = 0;

mm_segment_t old_fs;

DEBUGP("load_module: umod=%p, len=%lu, uargs=%p\n",
umod, len, uargs);

Expand Down Expand Up @@ -2453,20 +2546,13 @@ static noinline struct module *load_module(void __user *umod,
if (err)
goto free_init;

/* Set up license info based on the info section */
set_license(mod, get_modinfo(sechdrs, infoindex, "license"));

/*
* ndiswrapper is under GPL by itself, but loads proprietary modules.
* Don't use add_taint_module(), as it would prevent ndiswrapper from
* using GPL-only symbols it needs.
*/
if (strcmp(mod->name, "ndiswrapper") == 0)
add_taint(TAINT_PROPRIETARY_MODULE);
/* Now we've got everything in the final locations, we can
* find optional sections. */
find_module_sections(mod, hdr, sechdrs, secstrings);

/* driverloader was caught wrongly pretending to be under GPL */
if (strcmp(mod->name, "driverloader") == 0)
add_taint_module(mod, TAINT_PROPRIETARY_MODULE);
err = check_module_license_and_versions(mod, sechdrs);
if (err)
goto free_unload;

/* Set up MODINFO_ATTR fields */
setup_modinfo(mod, sechdrs, infoindex);
Expand All @@ -2477,47 +2563,9 @@ static noinline struct module *load_module(void __user *umod,
if (err < 0)
goto cleanup;

/* Now we've got everything in the final locations, we can
* find optional sections. */
find_module_sections(mod, hdr, sechdrs, secstrings);

#ifdef CONFIG_MODVERSIONS
if ((mod->num_syms && !mod->crcs)
|| (mod->num_gpl_syms && !mod->gpl_crcs)
|| (mod->num_gpl_future_syms && !mod->gpl_future_crcs)
#ifdef CONFIG_UNUSED_SYMBOLS
|| (mod->num_unused_syms && !mod->unused_crcs)
|| (mod->num_unused_gpl_syms && !mod->unused_gpl_crcs)
#endif
) {
err = try_to_force_load(mod,
"no versions for exported symbols");
if (err)
goto cleanup;
}
#endif

/* Now do relocations. */
for (i = 1; i < hdr->e_shnum; i++) {
const char *strtab = (char *)sechdrs[strindex].sh_addr;
unsigned int info = sechdrs[i].sh_info;

/* Not a valid relocation section? */
if (info >= hdr->e_shnum)
continue;

/* Don't bother with non-allocated sections */
if (!(sechdrs[info].sh_flags & SHF_ALLOC))
continue;

if (sechdrs[i].sh_type == SHT_REL)
err = apply_relocate(sechdrs, strtab, symindex, i,mod);
else if (sechdrs[i].sh_type == SHT_RELA)
err = apply_relocate_add(sechdrs, strtab, symindex, i,
mod);
if (err < 0)
goto cleanup;
}
err = apply_relocations(mod, hdr, sechdrs, symindex, strindex);
if (err < 0)
goto cleanup;

/* Set up and sort exception table */
mod->extable = section_objs(hdr, sechdrs, secstrings, "__ex_table",
Expand All @@ -2541,28 +2589,9 @@ static noinline struct module *load_module(void __user *umod,
if (err < 0)
goto cleanup;

/* flush the icache in correct context */
old_fs = get_fs();
set_fs(KERNEL_DS);

/*
* Flush the instruction cache, since we've played with text.
* Do it before processing of module parameters, so the module
* can provide parameter accessor functions of its own.
*/
if (mod->module_init)
flush_icache_range((unsigned long)mod->module_init,
(unsigned long)mod->module_init
+ mod->init_size);
flush_icache_range((unsigned long)mod->module_core,
(unsigned long)mod->module_core + mod->core_size);

set_fs(old_fs);
flush_module_icache(mod);

mod->args = args;
if (section_addr(hdr, sechdrs, secstrings, "__obsparm"))
printk(KERN_WARNING "%s: Ignoring obsolete parameters\n",
mod->name);

/* Now sew it into the lists so we can get lockdep and oops
* info during argument parsing. Noone should access us, since
Expand Down Expand Up @@ -2619,6 +2648,7 @@ static noinline struct module *load_module(void __user *umod,
module_arch_cleanup(mod);
cleanup:
free_modinfo(mod);
free_unload:
module_unload_free(mod);
free_init:
module_free(mod, mod->module_init);
Expand Down

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