From 7934a8dd8692b56714ce9b36421e316445d94a77 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Fri, 6 Jun 2025 13:10:23 +0900 Subject: module: remove meaningless 'name' parameter from __MODULE_INFO() The symbol names in the .modinfo section are never used and already randomized by the __UNIQUE_ID() macro. Therefore, the second parameter of __MODULE_INFO() is meaningless and can be removed to simplify the code. With this change, the symbol names in the .modinfo section will be prefixed with __UNIQUE_ID_modinfo, making it clearer that they originate from MODULE_INFO(). [Before] $ objcopy -j .modinfo vmlinux.o modinfo.o $ nm -n modinfo.o | head -n10 0000000000000000 r __UNIQUE_ID_license560 0000000000000011 r __UNIQUE_ID_file559 0000000000000030 r __UNIQUE_ID_description558 0000000000000074 r __UNIQUE_ID_license580 000000000000008e r __UNIQUE_ID_file579 00000000000000bd r __UNIQUE_ID_description578 00000000000000e6 r __UNIQUE_ID_license581 00000000000000ff r __UNIQUE_ID_file580 0000000000000134 r __UNIQUE_ID_description579 0000000000000179 r __UNIQUE_ID_uncore_no_discover578 [After] $ objcopy -j .modinfo vmlinux.o modinfo.o $ nm -n modinfo.o | head -n10 0000000000000000 r __UNIQUE_ID_modinfo560 0000000000000011 r __UNIQUE_ID_modinfo559 0000000000000030 r __UNIQUE_ID_modinfo558 0000000000000074 r __UNIQUE_ID_modinfo580 000000000000008e r __UNIQUE_ID_modinfo579 00000000000000bd r __UNIQUE_ID_modinfo578 00000000000000e6 r __UNIQUE_ID_modinfo581 00000000000000ff r __UNIQUE_ID_modinfo580 0000000000000134 r __UNIQUE_ID_modinfo579 0000000000000179 r __UNIQUE_ID_modinfo578 Signed-off-by: Masahiro Yamada Reviewed-by: Petr Pavlu --- include/linux/moduleparam.h | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'include/linux/moduleparam.h') diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h index bfb85fd13e1f..00166f747e27 100644 --- a/include/linux/moduleparam.h +++ b/include/linux/moduleparam.h @@ -20,18 +20,19 @@ /* Chosen so that structs with an unsigned long line up. */ #define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long)) -#define __MODULE_INFO(tag, name, info) \ - static const char __UNIQUE_ID(name)[] \ +/* Generic info of form tag = "info" */ +#define MODULE_INFO(tag, info) \ + static const char __UNIQUE_ID(modinfo)[] \ __used __section(".modinfo") __aligned(1) \ = __MODULE_INFO_PREFIX __stringify(tag) "=" info #define __MODULE_PARM_TYPE(name, _type) \ - __MODULE_INFO(parmtype, name##type, #name ":" _type) + MODULE_INFO(parmtype, #name ":" _type) /* One for each parameter, describing how to use it. Some files do multiple of these per line, so can't just use MODULE_INFO. */ #define MODULE_PARM_DESC(_parm, desc) \ - __MODULE_INFO(parm, _parm, #_parm ":" desc) + MODULE_INFO(parm, #_parm ":" desc) struct kernel_param; -- cgit v1.2.3 From bdc877ba6b7ff1b6d2ebeff11e63da4a50a54854 Mon Sep 17 00:00:00 2001 From: Petr Pavlu Date: Mon, 30 Jun 2025 16:32:34 +0200 Subject: module: Restore the moduleparam prefix length check The moduleparam code allows modules to provide their own definition of MODULE_PARAM_PREFIX, instead of using the default KBUILD_MODNAME ".". Commit 730b69d22525 ("module: check kernel param length at compile time, not runtime") added a check to ensure the prefix doesn't exceed MODULE_NAME_LEN, as this is what param_sysfs_builtin() expects. Later, commit 58f86cc89c33 ("VERIFY_OCTAL_PERMISSIONS: stricter checking for sysfs perms.") removed this check, but there is no indication this was intentional. Since the check is still useful for param_sysfs_builtin() to function properly, reintroduce it in __module_param_call(), but in a modernized form using static_assert(). While here, clean up the __module_param_call() comments. In particular, remove the comment "Default value instead of permissions?", which comes from commit 9774a1f54f17 ("[PATCH] Compile-time check re world-writeable module params"). This comment was related to the test variable __param_perm_check_##name, which was removed in the previously mentioned commit 58f86cc89c33. Fixes: 58f86cc89c33 ("VERIFY_OCTAL_PERMISSIONS: stricter checking for sysfs perms.") Signed-off-by: Petr Pavlu Reviewed-by: Daniel Gomez Link: https://lore.kernel.org/r/20250630143535.267745-4-petr.pavlu@suse.com Signed-off-by: Daniel Gomez --- include/linux/moduleparam.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'include/linux/moduleparam.h') diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h index bfb85fd13e1f..110e9d09de24 100644 --- a/include/linux/moduleparam.h +++ b/include/linux/moduleparam.h @@ -282,10 +282,9 @@ struct kparam_array #define __moduleparam_const const #endif -/* This is the fundamental function for registering boot/module - parameters. */ +/* This is the fundamental function for registering boot/module parameters. */ #define __module_param_call(prefix, name, ops, arg, perm, level, flags) \ - /* Default value instead of permissions? */ \ + static_assert(sizeof(""prefix) - 1 <= MAX_PARAM_PREFIX_LEN); \ static const char __param_str_##name[] = prefix #name; \ static struct kernel_param __moduleparam_const __param_##name \ __used __section("__param") \ -- cgit v1.2.3 From 40a826bd6c82ae45cfd3a19cd2a60a10f56b74c0 Mon Sep 17 00:00:00 2001 From: Petr Pavlu Date: Mon, 30 Jun 2025 16:32:36 +0200 Subject: module: Rename MAX_PARAM_PREFIX_LEN to __MODULE_NAME_LEN The maximum module name length (MODULE_NAME_LEN) is somewhat confusingly defined in terms of the maximum parameter prefix length (MAX_PARAM_PREFIX_LEN), when in fact the dependency is in the opposite direction. This split originates from commit 730b69d22525 ("module: check kernel param length at compile time, not runtime"). The code needed to use MODULE_NAME_LEN in moduleparam.h, but because module.h requires moduleparam.h, this created a circular dependency. It was resolved by introducing MAX_PARAM_PREFIX_LEN in moduleparam.h and defining MODULE_NAME_LEN in module.h in terms of MAX_PARAM_PREFIX_LEN. Rename MAX_PARAM_PREFIX_LEN to __MODULE_NAME_LEN for clarity. This matches the similar approach of defining MODULE_INFO in module.h and __MODULE_INFO in moduleparam.h. Signed-off-by: Petr Pavlu Reviewed-by: Daniel Gomez Link: https://lore.kernel.org/r/20250630143535.267745-6-petr.pavlu@suse.com Signed-off-by: Daniel Gomez --- include/linux/module.h | 2 +- include/linux/moduleparam.h | 12 ++++++++---- 2 files changed, 9 insertions(+), 5 deletions(-) (limited to 'include/linux/moduleparam.h') diff --git a/include/linux/module.h b/include/linux/module.h index 5fe812de2d84..313ecb8e5181 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -33,7 +33,7 @@ #include #include -#define MODULE_NAME_LEN MAX_PARAM_PREFIX_LEN +#define MODULE_NAME_LEN __MODULE_NAME_LEN struct modversion_info { unsigned long crc; diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h index 110e9d09de24..a04a2bc4f51e 100644 --- a/include/linux/moduleparam.h +++ b/include/linux/moduleparam.h @@ -6,6 +6,13 @@ #include #include +/* + * The maximum module name length, including the NUL byte. + * Chosen so that structs with an unsigned long line up, specifically + * modversion_info. + */ +#define __MODULE_NAME_LEN (64 - sizeof(unsigned long)) + /* You can override this manually, but generally this should match the module name. */ #ifdef MODULE @@ -17,9 +24,6 @@ #define __MODULE_INFO_PREFIX KBUILD_MODNAME "." #endif -/* Chosen so that structs with an unsigned long line up. */ -#define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long)) - #define __MODULE_INFO(tag, name, info) \ static const char __UNIQUE_ID(name)[] \ __used __section(".modinfo") __aligned(1) \ @@ -284,7 +288,7 @@ struct kparam_array /* This is the fundamental function for registering boot/module parameters. */ #define __module_param_call(prefix, name, ops, arg, perm, level, flags) \ - static_assert(sizeof(""prefix) - 1 <= MAX_PARAM_PREFIX_LEN); \ + static_assert(sizeof(""prefix) - 1 <= __MODULE_NAME_LEN); \ static const char __param_str_##name[] = prefix #name; \ static struct kernel_param __moduleparam_const __param_##name \ __used __section("__param") \ -- cgit v1.2.3