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authorRusty Russell <rusty@rustcorp.com.au>2008-10-22 10:00:13 -0500
committerRusty Russell <rusty@rustcorp.com.au>2008-10-22 10:00:15 +1100
commit5e458cc0f4770eea45d3c07110f01b3a94c72aa5 (patch)
tree97966d9ac8f9621073fad39a88ed37765c959a9d /kernel
parent2515ddc6db8eb49a79f0fe5e67ff09ac7c81eab4 (diff)
downloadlinux-linaro-5e458cc0f4770eea45d3c07110f01b3a94c72aa5.tar.gz
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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/module.c235
1 files changed, 99 insertions, 136 deletions
diff --git a/kernel/module.c b/kernel/module.c
index 0d8d21ee792..3d256681ab6 100644
--- a/kernel/module.c
+++ b/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 */
-#ifdef CONFIG_DYNAMIC_PRINTK_DEBUG
-static void dynamic_printk_setup(Elf_Shdr *sechdrs, unsigned int verboseindex)
+static void dynamic_printk_setup(struct mod_debug *debug, unsigned int num)
{
- struct mod_debug *debug_info;
- unsigned long pos, end;
- unsigned int num_verbose;
-
- pos = sechdrs[verboseindex].sh_addr;
- num_verbose = sechdrs[verboseindex].sh_size /
- sizeof(struct mod_debug);
- end = pos + (num_verbose * sizeof(struct mod_debug));
+#ifdef CONFIG_DYNAMIC_PRINTK_DEBUG
+ unsigned int i;
- 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);