mirror of
https://github.com/torvalds/linux.git
synced 2024-11-23 04:31:50 +00:00
module: simplify load_module.
Linus' recent catch of stack overflow in load_module lead me to look at the code. A couple of helpers to get a section address and get objects from a section can help clean things up a little. (And in case you're wondering, the stack size also dropped from 328 to 284 bytes). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell
parent
2515ddc6db
commit
5e458cc0f4
@ -277,7 +277,7 @@ struct module
|
||||
|
||||
/* Exception table */
|
||||
unsigned int num_exentries;
|
||||
const struct exception_table_entry *extable;
|
||||
struct exception_table_entry *extable;
|
||||
|
||||
/* Startup function. */
|
||||
int (*init)(void);
|
||||
|
||||
235
kernel/module.c
235
kernel/module.c
@ -132,6 +132,29 @@ static unsigned int find_sec(Elf_Ehdr *hdr,
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* Find a module section, or NULL. */
|
||||
static void *section_addr(Elf_Ehdr *hdr, Elf_Shdr *shdrs,
|
||||
const char *secstrings, const char *name)
|
||||
{
|
||||
/* Section 0 has sh_addr 0. */
|
||||
return (void *)shdrs[find_sec(hdr, shdrs, secstrings, name)].sh_addr;
|
||||
}
|
||||
|
||||
/* Find a module section, or NULL. Fill in number of "objects" in section. */
|
||||
static void *section_objs(Elf_Ehdr *hdr,
|
||||
Elf_Shdr *sechdrs,
|
||||
const char *secstrings,
|
||||
const char *name,
|
||||
size_t object_size,
|
||||
unsigned int *num)
|
||||
{
|
||||
unsigned int sec = find_sec(hdr, sechdrs, secstrings, name);
|
||||
|
||||
/* Section 0 has sh_addr 0 and sh_size 0. */
|
||||
*num = sechdrs[sec].sh_size / object_size;
|
||||
return (void *)sechdrs[sec].sh_addr;
|
||||
}
|
||||
|
||||
/* Provided by the linker */
|
||||
extern const struct kernel_symbol __start___ksymtab[];
|
||||
extern const struct kernel_symbol __stop___ksymtab[];
|
||||
@ -1789,32 +1812,20 @@ static inline void add_kallsyms(struct module *mod,
|
||||
}
|
||||
#endif /* CONFIG_KALLSYMS */
|
||||
|
||||
static void dynamic_printk_setup(struct mod_debug *debug, unsigned int num)
|
||||
{
|
||||
#ifdef CONFIG_DYNAMIC_PRINTK_DEBUG
|
||||
static void dynamic_printk_setup(Elf_Shdr *sechdrs, unsigned int verboseindex)
|
||||
{
|
||||
struct mod_debug *debug_info;
|
||||
unsigned long pos, end;
|
||||
unsigned int num_verbose;
|
||||
unsigned int i;
|
||||
|
||||
pos = sechdrs[verboseindex].sh_addr;
|
||||
num_verbose = sechdrs[verboseindex].sh_size /
|
||||
sizeof(struct mod_debug);
|
||||
end = pos + (num_verbose * sizeof(struct mod_debug));
|
||||
|
||||
for (; pos < end; pos += sizeof(struct mod_debug)) {
|
||||
debug_info = (struct mod_debug *)pos;
|
||||
register_dynamic_debug_module(debug_info->modname,
|
||||
debug_info->type, debug_info->logical_modname,
|
||||
debug_info->flag_names, debug_info->hash,
|
||||
debug_info->hash2);
|
||||
for (i = 0; i < num; i++) {
|
||||
register_dynamic_debug_module(debug[i].modname,
|
||||
debug[i].type,
|
||||
debug[i].logical_modname,
|
||||
debug[i].flag_names,
|
||||
debug[i].hash, debug[i].hash2);
|
||||
}
|
||||
}
|
||||
#else
|
||||
static inline void dynamic_printk_setup(Elf_Shdr *sechdrs,
|
||||
unsigned int verboseindex)
|
||||
{
|
||||
}
|
||||
#endif /* CONFIG_DYNAMIC_PRINTK_DEBUG */
|
||||
}
|
||||
|
||||
static void *module_alloc_update_bounds(unsigned long size)
|
||||
{
|
||||
@ -1843,37 +1854,14 @@ static noinline struct module *load_module(void __user *umod,
|
||||
unsigned int i;
|
||||
unsigned int symindex = 0;
|
||||
unsigned int strindex = 0;
|
||||
unsigned int setupindex;
|
||||
unsigned int exindex;
|
||||
unsigned int exportindex;
|
||||
unsigned int modindex;
|
||||
unsigned int obsparmindex;
|
||||
unsigned int infoindex;
|
||||
unsigned int gplindex;
|
||||
unsigned int crcindex;
|
||||
unsigned int gplcrcindex;
|
||||
unsigned int versindex;
|
||||
unsigned int pcpuindex;
|
||||
unsigned int gplfutureindex;
|
||||
unsigned int gplfuturecrcindex;
|
||||
unsigned int modindex, versindex, infoindex, pcpuindex;
|
||||
unsigned int unwindex = 0;
|
||||
#ifdef CONFIG_UNUSED_SYMBOLS
|
||||
unsigned int unusedindex;
|
||||
unsigned int unusedcrcindex;
|
||||
unsigned int unusedgplindex;
|
||||
unsigned int unusedgplcrcindex;
|
||||
#endif
|
||||
unsigned int markersindex;
|
||||
unsigned int markersstringsindex;
|
||||
unsigned int verboseindex;
|
||||
unsigned int tracepointsindex;
|
||||
unsigned int tracepointsstringsindex;
|
||||
unsigned int mcountindex;
|
||||
unsigned int num_kp, num_mcount;
|
||||
struct kernel_param *kp;
|
||||
struct module *mod;
|
||||
long err = 0;
|
||||
void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */
|
||||
void *mseg;
|
||||
struct exception_table_entry *extable;
|
||||
unsigned long *mseg;
|
||||
mm_segment_t old_fs;
|
||||
|
||||
DEBUGP("load_module: umod=%p, len=%lu, uargs=%p\n",
|
||||
@ -1937,6 +1925,7 @@ static noinline struct module *load_module(void __user *umod,
|
||||
err = -ENOEXEC;
|
||||
goto free_hdr;
|
||||
}
|
||||
/* This is temporary: point mod into copy of data. */
|
||||
mod = (void *)sechdrs[modindex].sh_addr;
|
||||
|
||||
if (symindex == 0) {
|
||||
@ -1946,22 +1935,6 @@ static noinline struct module *load_module(void __user *umod,
|
||||
goto free_hdr;
|
||||
}
|
||||
|
||||
/* Optional sections */
|
||||
exportindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab");
|
||||
gplindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_gpl");
|
||||
gplfutureindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_gpl_future");
|
||||
crcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab");
|
||||
gplcrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_gpl");
|
||||
gplfuturecrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_gpl_future");
|
||||
#ifdef CONFIG_UNUSED_SYMBOLS
|
||||
unusedindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_unused");
|
||||
unusedgplindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_unused_gpl");
|
||||
unusedcrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_unused");
|
||||
unusedgplcrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_unused_gpl");
|
||||
#endif
|
||||
setupindex = find_sec(hdr, sechdrs, secstrings, "__param");
|
||||
exindex = find_sec(hdr, sechdrs, secstrings, "__ex_table");
|
||||
obsparmindex = find_sec(hdr, sechdrs, secstrings, "__obsparm");
|
||||
versindex = find_sec(hdr, sechdrs, secstrings, "__versions");
|
||||
infoindex = find_sec(hdr, sechdrs, secstrings, ".modinfo");
|
||||
pcpuindex = find_pcpusec(hdr, sechdrs, secstrings);
|
||||
@ -2117,42 +2090,57 @@ static noinline struct module *load_module(void __user *umod,
|
||||
if (err < 0)
|
||||
goto cleanup;
|
||||
|
||||
/* Set up EXPORTed & EXPORT_GPLed symbols (section 0 is 0 length) */
|
||||
mod->num_syms = sechdrs[exportindex].sh_size / sizeof(*mod->syms);
|
||||
mod->syms = (void *)sechdrs[exportindex].sh_addr;
|
||||
if (crcindex)
|
||||
mod->crcs = (void *)sechdrs[crcindex].sh_addr;
|
||||
mod->num_gpl_syms = sechdrs[gplindex].sh_size / sizeof(*mod->gpl_syms);
|
||||
mod->gpl_syms = (void *)sechdrs[gplindex].sh_addr;
|
||||
if (gplcrcindex)
|
||||
mod->gpl_crcs = (void *)sechdrs[gplcrcindex].sh_addr;
|
||||
mod->num_gpl_future_syms = sechdrs[gplfutureindex].sh_size /
|
||||
sizeof(*mod->gpl_future_syms);
|
||||
mod->gpl_future_syms = (void *)sechdrs[gplfutureindex].sh_addr;
|
||||
if (gplfuturecrcindex)
|
||||
mod->gpl_future_crcs = (void *)sechdrs[gplfuturecrcindex].sh_addr;
|
||||
/* Now we've got everything in the final locations, we can
|
||||
* find optional sections. */
|
||||
kp = section_objs(hdr, sechdrs, secstrings, "__param", sizeof(*kp),
|
||||
&num_kp);
|
||||
mod->syms = section_objs(hdr, sechdrs, secstrings, "__ksymtab",
|
||||
sizeof(*mod->syms), &mod->num_syms);
|
||||
mod->crcs = section_addr(hdr, sechdrs, secstrings, "__kcrctab");
|
||||
mod->gpl_syms = section_objs(hdr, sechdrs, secstrings, "__ksymtab_gpl",
|
||||
sizeof(*mod->gpl_syms),
|
||||
&mod->num_gpl_syms);
|
||||
mod->gpl_crcs = section_addr(hdr, sechdrs, secstrings, "__kcrctab_gpl");
|
||||
mod->gpl_future_syms = section_objs(hdr, sechdrs, secstrings,
|
||||
"__ksymtab_gpl_future",
|
||||
sizeof(*mod->gpl_future_syms),
|
||||
&mod->num_gpl_future_syms);
|
||||
mod->gpl_future_crcs = section_addr(hdr, sechdrs, secstrings,
|
||||
"__kcrctab_gpl_future");
|
||||
|
||||
#ifdef CONFIG_UNUSED_SYMBOLS
|
||||
mod->num_unused_syms = sechdrs[unusedindex].sh_size /
|
||||
sizeof(*mod->unused_syms);
|
||||
mod->num_unused_gpl_syms = sechdrs[unusedgplindex].sh_size /
|
||||
sizeof(*mod->unused_gpl_syms);
|
||||
mod->unused_syms = (void *)sechdrs[unusedindex].sh_addr;
|
||||
if (unusedcrcindex)
|
||||
mod->unused_crcs = (void *)sechdrs[unusedcrcindex].sh_addr;
|
||||
mod->unused_gpl_syms = (void *)sechdrs[unusedgplindex].sh_addr;
|
||||
if (unusedgplcrcindex)
|
||||
mod->unused_gpl_crcs
|
||||
= (void *)sechdrs[unusedgplcrcindex].sh_addr;
|
||||
mod->unused_syms = section_objs(hdr, sechdrs, secstrings,
|
||||
"__ksymtab_unused",
|
||||
sizeof(*mod->unused_syms),
|
||||
&mod->num_unused_syms);
|
||||
mod->unused_crcs = section_addr(hdr, sechdrs, secstrings,
|
||||
"__kcrctab_unused");
|
||||
mod->unused_gpl_syms = section_objs(hdr, sechdrs, secstrings,
|
||||
"__ksymtab_unused_gpl",
|
||||
sizeof(*mod->unused_gpl_syms),
|
||||
&mod->num_unused_gpl_syms);
|
||||
mod->unused_gpl_crcs = section_addr(hdr, sechdrs, secstrings,
|
||||
"__kcrctab_unused_gpl");
|
||||
#endif
|
||||
|
||||
#ifdef CONFIG_MARKERS
|
||||
mod->markers = section_objs(hdr, sechdrs, secstrings, "__markers",
|
||||
sizeof(*mod->markers), &mod->num_markers);
|
||||
#endif
|
||||
#ifdef CONFIG_TRACEPOINTS
|
||||
mod->tracepoints = section_objs(hdr, sechdrs, secstrings,
|
||||
"__tracepoints",
|
||||
sizeof(*mod->tracepoints),
|
||||
&mod->num_tracepoints);
|
||||
#endif
|
||||
|
||||
#ifdef CONFIG_MODVERSIONS
|
||||
if ((mod->num_syms && !crcindex)
|
||||
|| (mod->num_gpl_syms && !gplcrcindex)
|
||||
|| (mod->num_gpl_future_syms && !gplfuturecrcindex)
|
||||
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 && !unusedcrcindex)
|
||||
|| (mod->num_unused_gpl_syms && !unusedgplcrcindex)
|
||||
|| (mod->num_unused_syms && !mod->unused_crcs)
|
||||
|| (mod->num_unused_gpl_syms && !mod->unused_gpl_crcs)
|
||||
#endif
|
||||
) {
|
||||
printk(KERN_WARNING "%s: No versions for exported symbols.\n", mod->name);
|
||||
@ -2161,16 +2149,6 @@ static noinline struct module *load_module(void __user *umod,
|
||||
goto cleanup;
|
||||
}
|
||||
#endif
|
||||
markersindex = find_sec(hdr, sechdrs, secstrings, "__markers");
|
||||
markersstringsindex = find_sec(hdr, sechdrs, secstrings,
|
||||
"__markers_strings");
|
||||
verboseindex = find_sec(hdr, sechdrs, secstrings, "__verbose");
|
||||
tracepointsindex = find_sec(hdr, sechdrs, secstrings, "__tracepoints");
|
||||
tracepointsstringsindex = find_sec(hdr, sechdrs, secstrings,
|
||||
"__tracepoints_strings");
|
||||
|
||||
mcountindex = find_sec(hdr, sechdrs, secstrings,
|
||||
"__mcount_loc");
|
||||
|
||||
/* Now do relocations. */
|
||||
for (i = 1; i < hdr->e_shnum; i++) {
|
||||
@ -2193,28 +2171,16 @@ static noinline struct module *load_module(void __user *umod,
|
||||
if (err < 0)
|
||||
goto cleanup;
|
||||
}
|
||||
#ifdef CONFIG_MARKERS
|
||||
mod->markers = (void *)sechdrs[markersindex].sh_addr;
|
||||
mod->num_markers =
|
||||
sechdrs[markersindex].sh_size / sizeof(*mod->markers);
|
||||
#endif
|
||||
#ifdef CONFIG_TRACEPOINTS
|
||||
mod->tracepoints = (void *)sechdrs[tracepointsindex].sh_addr;
|
||||
mod->num_tracepoints =
|
||||
sechdrs[tracepointsindex].sh_size / sizeof(*mod->tracepoints);
|
||||
#endif
|
||||
|
||||
|
||||
/* Find duplicate symbols */
|
||||
err = verify_export_symbols(mod);
|
||||
|
||||
if (err < 0)
|
||||
goto cleanup;
|
||||
|
||||
/* Set up and sort exception table */
|
||||
mod->num_exentries = sechdrs[exindex].sh_size / sizeof(*mod->extable);
|
||||
mod->extable = extable = (void *)sechdrs[exindex].sh_addr;
|
||||
sort_extable(extable, extable + mod->num_exentries);
|
||||
mod->extable = section_objs(hdr, sechdrs, secstrings, "__ex_table",
|
||||
sizeof(*mod->extable), &mod->num_exentries);
|
||||
sort_extable(mod->extable, mod->extable + mod->num_exentries);
|
||||
|
||||
/* Finally, copy percpu area over. */
|
||||
percpu_modcopy(mod->percpu, (void *)sechdrs[pcpuindex].sh_addr,
|
||||
@ -2223,11 +2189,17 @@ static noinline struct module *load_module(void __user *umod,
|
||||
add_kallsyms(mod, sechdrs, symindex, strindex, secstrings);
|
||||
|
||||
if (!mod->taints) {
|
||||
struct mod_debug *debug;
|
||||
unsigned int num_debug;
|
||||
|
||||
#ifdef CONFIG_MARKERS
|
||||
marker_update_probe_range(mod->markers,
|
||||
mod->markers + mod->num_markers);
|
||||
#endif
|
||||
dynamic_printk_setup(sechdrs, verboseindex);
|
||||
debug = section_objs(hdr, sechdrs, secstrings, "__verbose",
|
||||
sizeof(*debug), &num_debug);
|
||||
dynamic_printk_setup(debug, num_debug);
|
||||
|
||||
#ifdef CONFIG_TRACEPOINTS
|
||||
tracepoint_update_probe_range(mod->tracepoints,
|
||||
mod->tracepoints + mod->num_tracepoints);
|
||||
@ -2235,8 +2207,9 @@ static noinline struct module *load_module(void __user *umod,
|
||||
}
|
||||
|
||||
/* sechdrs[0].sh_size is always zero */
|
||||
mseg = (void *)sechdrs[mcountindex].sh_addr;
|
||||
ftrace_init_module(mseg, mseg + sechdrs[mcountindex].sh_size);
|
||||
mseg = section_objs(hdr, sechdrs, secstrings, "__mcount_loc",
|
||||
sizeof(*mseg), &num_mcount);
|
||||
ftrace_init_module(mseg, mseg + num_mcount);
|
||||
|
||||
err = module_finalize(hdr, sechdrs, mod);
|
||||
if (err < 0)
|
||||
@ -2261,7 +2234,7 @@ static noinline struct module *load_module(void __user *umod,
|
||||
set_fs(old_fs);
|
||||
|
||||
mod->args = args;
|
||||
if (obsparmindex)
|
||||
if (section_addr(hdr, sechdrs, secstrings, "__obsparm"))
|
||||
printk(KERN_WARNING "%s: Ignoring obsolete parameters\n",
|
||||
mod->name);
|
||||
|
||||
@ -2270,21 +2243,11 @@ static noinline struct module *load_module(void __user *umod,
|
||||
* strong_try_module_get() will fail. */
|
||||
stop_machine(__link_module, mod, NULL);
|
||||
|
||||
/* Size of section 0 is 0, so this works well if no params */
|
||||
err = parse_args(mod->name, mod->args,
|
||||
(struct kernel_param *)
|
||||
sechdrs[setupindex].sh_addr,
|
||||
sechdrs[setupindex].sh_size
|
||||
/ sizeof(struct kernel_param),
|
||||
NULL);
|
||||
err = parse_args(mod->name, mod->args, kp, num_kp, NULL);
|
||||
if (err < 0)
|
||||
goto unlink;
|
||||
|
||||
err = mod_sysfs_setup(mod,
|
||||
(struct kernel_param *)
|
||||
sechdrs[setupindex].sh_addr,
|
||||
sechdrs[setupindex].sh_size
|
||||
/ sizeof(struct kernel_param));
|
||||
err = mod_sysfs_setup(mod, kp, num_kp);
|
||||
if (err < 0)
|
||||
goto unlink;
|
||||
add_sect_attrs(mod, hdr->e_shnum, secstrings, sechdrs);
|
||||
|
||||
Loading…
Reference in New Issue
Block a user