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authorDmitry Torokhov <dtor@vmware.com>2011-02-07 16:02:25 -0800
committerRusty Russell <rusty@rustcorp.com.au>2011-05-19 16:55:24 +0930
commitb4bc842802db3314f9a657094da0450a903ea619 (patch)
treedb9cadf46624dcd7e780850e8bda34b569a229b0
parent61c4f2c81c61f73549928dfd9f3e8f26aa36a8cf (diff)
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module: deal with alignment issues in built-in module versions
On m68k natural alignment is 2-byte boundary but we are trying to align structures in __modver section on sizeof(void *) boundary. This causes trouble when we try to access elements in this section in array-like fashion when create "version" attributes for built-in modules. Moreover, as DaveM said, we can't reliably put structures into independent objects, put them into a special section, and then expect array access over them (via the section boundaries) after linking the objects together to just "work" due to variable alignment choices in different situations. The only solution that seems to work reliably is to make an array of plain pointers to the objects in question and put those pointers in the special section. Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Dmitry Torokhov <dtor@vmware.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
-rw-r--r--include/linux/module.h10
-rw-r--r--kernel/params.c9
2 files changed, 11 insertions, 8 deletions
diff --git a/include/linux/module.h b/include/linux/module.h
index 5de42043dff0..4cfebc211695 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -174,10 +174,7 @@ extern struct module __this_module;
#define MODULE_VERSION(_version) \
extern ssize_t __modver_version_show(struct module_attribute *, \
struct module *, char *); \
- static struct module_version_attribute __modver_version_attr \
- __used \
- __attribute__ ((__section__ ("__modver"),aligned(sizeof(void *)))) \
- = { \
+ static struct module_version_attribute ___modver_attr = { \
.mattr = { \
.attr = { \
.name = "version", \
@@ -187,7 +184,10 @@ extern struct module __this_module;
}, \
.module_name = KBUILD_MODNAME, \
.version = _version, \
- }
+ }; \
+ static const struct module_version_attribute \
+ __used __attribute__ ((__section__ ("__modver"))) \
+ * __moduleparam_const __modver_attr = &___modver_attr
#endif
/* Optional firmware file (or files) needed by the module
diff --git a/kernel/params.c b/kernel/params.c
index 7ab388a48a2e..28c5d5c83f6b 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -821,15 +821,18 @@ ssize_t __modver_version_show(struct module_attribute *mattr,
return sprintf(buf, "%s\n", vattr->version);
}
-extern struct module_version_attribute __start___modver[], __stop___modver[];
+extern const struct module_version_attribute *__start___modver[];
+extern const struct module_version_attribute *__stop___modver[];
static void __init version_sysfs_builtin(void)
{
- const struct module_version_attribute *vattr;
+ const struct module_version_attribute **p;
struct module_kobject *mk;
int err;
- for (vattr = __start___modver; vattr < __stop___modver; vattr++) {
+ for (p = __start___modver; p < __stop___modver; p++) {
+ const struct module_version_attribute *vattr = *p;
+
mk = locate_module_kobject(vattr->module_name);
if (mk) {
err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);