Re: module: Remove const attribute from alias for MODULE_DEVICE_TABLE
On 2017-08-28 10:41, Kees Cook wrote: > On Mon, Aug 28, 2017 at 10:38 AM, Nick Desaulniers >wrote: >> I think Kees' proposal is a better solution; rather than require all >> usage of device table to remember to add const, have the macro add it >> for all users. Otherwise if you require caller's to add it, they may >> forget. > > And with the coccinelle script, it should be easy to invert the logic > and remove const from the callers... > I tried to reproduce my findings again but was not successful :-( I must have changed .config or something in between and draw wrong conclusions... So removing the const in the module.h alias actually did not change anything... It did not help for drivers which forget to constify... I think even the alias in module.h was actually illegal according to C standard: (C89, 6.2.7p2) "All declarations that refer to the same object or function shall have compatible type; otherwise the behavior is undefined." I guess it would still make sense to constify the structs for most of the 620 drivers which do not have it const currently. I found some driver actually change the table at runtime, e.g. drivers/net/usb/pegasus.c, so we would have to exclude them. -- Stefan
Re: module: Remove const attribute from alias for MODULE_DEVICE_TABLE
On 2017-08-28 10:41, Kees Cook wrote: > On Mon, Aug 28, 2017 at 10:38 AM, Nick Desaulniers > wrote: >> I think Kees' proposal is a better solution; rather than require all >> usage of device table to remember to add const, have the macro add it >> for all users. Otherwise if you require caller's to add it, they may >> forget. > > And with the coccinelle script, it should be easy to invert the logic > and remove const from the callers... > I tried to reproduce my findings again but was not successful :-( I must have changed .config or something in between and draw wrong conclusions... So removing the const in the module.h alias actually did not change anything... It did not help for drivers which forget to constify... I think even the alias in module.h was actually illegal according to C standard: (C89, 6.2.7p2) "All declarations that refer to the same object or function shall have compatible type; otherwise the behavior is undefined." I guess it would still make sense to constify the structs for most of the 620 drivers which do not have it const currently. I found some driver actually change the table at runtime, e.g. drivers/net/usb/pegasus.c, so we would have to exclude them. -- Stefan
Re: module: Remove const attribute from alias for MODULE_DEVICE_TABLE
On Mon, Aug 28, 2017 at 10:38 AM, Nick Desaulnierswrote: > I think Kees' proposal is a better solution; rather than require all > usage of device table to remember to add const, have the macro add it > for all users. Otherwise if you require caller's to add it, they may > forget. And with the coccinelle script, it should be easy to invert the logic and remove const from the callers... -Kees -- Kees Cook Pixel Security
Re: module: Remove const attribute from alias for MODULE_DEVICE_TABLE
On Mon, Aug 28, 2017 at 10:38 AM, Nick Desaulniers wrote: > I think Kees' proposal is a better solution; rather than require all > usage of device table to remember to add const, have the macro add it > for all users. Otherwise if you require caller's to add it, they may > forget. And with the coccinelle script, it should be easy to invert the logic and remove const from the callers... -Kees -- Kees Cook Pixel Security
Re: module: Remove const attribute from alias for MODULE_DEVICE_TABLE
I think Kees' proposal is a better solution; rather than require all usage of device table to remember to add const, have the macro add it for all users. Otherwise if you require caller's to add it, they may forget. On Mon, Aug 28, 2017 at 10:20 AM, Kees Cookwrote: > On Sun, Aug 27, 2017 at 4:52 PM, Stefan Agner wrote: >> On 2017-07-24 18:27, Matthias Kaehlcke wrote: >>> MODULE_DEVICE_TABLE(type, name) creates an alias of type 'extern const >>> typeof(name)'. If 'name' is already constant the 'const' attribute is >>> specified twice, which is not allowed in C89 (see discussion at >>> https://lkml.org/lkml/2017/5/23/1440). Since the kernel is built with >>> -std=gnu89 clang generates warnings like this: >>> >>> drivers/thermal/x86_pkg_temp_thermal.c:509:1: warning: duplicate 'const' >>> declaration specifier >>> [-Wduplicate-decl-specifier] >>> MODULE_DEVICE_TABLE(x86cpu, pkg_temp_thermal_ids); >>> ^ >>> ./include/linux/module.h:212:8: note: expanded from macro >>> 'MODULE_DEVICE_TABLE' >>> extern const typeof(name) __mod_##type##__##name##_device_table >>> >>> Remove the const attribute from the alias to avoid the duplicate >>> specifier. After all it is only an alias and the attribute shouldn't >>> have any effect. >> >> Unfortunately, it has effect where const is missing in the original >> variable declaration: >> >> Before this patch: >> 13:10 $ size drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko >>textdata bss dec hex filename >>8825 728 40 9593 2579 >> drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko >> >> After this patch: >> 13:12 $ size drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko >>textdata bss dec hex filename >>8747 800 4095872573 >> drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko >> >> >> Ideally we would fix all MODULE_DEVICE_TABLE usage sites. This would >> also made it clearly visible that the device tables are const. >> >> I created a semantic patch, it turns out that 620 sites are affected >> (out of 4499)... >> >> // >> // Cocinelle Semantic Patch to constify module device tables >> // >> // Author: Stefan Agner >> // >> @ module_device_table @ >> declarer name MODULE_DEVICE_TABLE; >> identifier moduletype; >> identifier name; >> @@ >> MODULE_DEVICE_TABLE(moduletype, name); >> >> @ add_const depends on module_device_table disable optional_qualifier @ >> identifier module_device_table.name; >> type T; >> @@ >> +const >> T name[] = { >> ... >> }; >> >> Thoughts? >> >> -- >> Stefan >> >> >>> >>> Signed-off-by: Matthias Kaehlcke >>> --- >>> include/linux/module.h | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/include/linux/module.h b/include/linux/module.h >>> index e7bdd549e527..fe5aa3736707 100644 >>> --- a/include/linux/module.h >>> +++ b/include/linux/module.h >>> @@ -209,7 +209,7 @@ extern void cleanup_module(void); >>> #ifdef MODULE >>> /* Creates an alias so file2alias.c can find device table. */ >>> #define MODULE_DEVICE_TABLE(type, name) >>> \ >>> -extern const typeof(name) __mod_##type##__##name##_device_table >>> \ >>> +extern typeof(name) __mod_##type##__##name##_device_table\ >>>__attribute__ ((unused, alias(__stringify(name >>> #else /* !MODULE */ >>> #define MODULE_DEVICE_TABLE(type, name) > > Perhaps the reverse is the better solution? Leave "const" in > MODULE_DEVICE_TABLE and remove the redundant usage. This means new > cases of missing the const will never happen (which was the intent > originally of putting const into the MODULE_DEVICE_TABLE macro, I > assume). > > -Kees > > -- > Kees Cook > Pixel Security -- Thanks, ~Nick Desaulniers
Re: module: Remove const attribute from alias for MODULE_DEVICE_TABLE
I think Kees' proposal is a better solution; rather than require all usage of device table to remember to add const, have the macro add it for all users. Otherwise if you require caller's to add it, they may forget. On Mon, Aug 28, 2017 at 10:20 AM, Kees Cook wrote: > On Sun, Aug 27, 2017 at 4:52 PM, Stefan Agner wrote: >> On 2017-07-24 18:27, Matthias Kaehlcke wrote: >>> MODULE_DEVICE_TABLE(type, name) creates an alias of type 'extern const >>> typeof(name)'. If 'name' is already constant the 'const' attribute is >>> specified twice, which is not allowed in C89 (see discussion at >>> https://lkml.org/lkml/2017/5/23/1440). Since the kernel is built with >>> -std=gnu89 clang generates warnings like this: >>> >>> drivers/thermal/x86_pkg_temp_thermal.c:509:1: warning: duplicate 'const' >>> declaration specifier >>> [-Wduplicate-decl-specifier] >>> MODULE_DEVICE_TABLE(x86cpu, pkg_temp_thermal_ids); >>> ^ >>> ./include/linux/module.h:212:8: note: expanded from macro >>> 'MODULE_DEVICE_TABLE' >>> extern const typeof(name) __mod_##type##__##name##_device_table >>> >>> Remove the const attribute from the alias to avoid the duplicate >>> specifier. After all it is only an alias and the attribute shouldn't >>> have any effect. >> >> Unfortunately, it has effect where const is missing in the original >> variable declaration: >> >> Before this patch: >> 13:10 $ size drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko >>textdata bss dec hex filename >>8825 728 40 9593 2579 >> drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko >> >> After this patch: >> 13:12 $ size drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko >>textdata bss dec hex filename >>8747 800 4095872573 >> drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko >> >> >> Ideally we would fix all MODULE_DEVICE_TABLE usage sites. This would >> also made it clearly visible that the device tables are const. >> >> I created a semantic patch, it turns out that 620 sites are affected >> (out of 4499)... >> >> // >> // Cocinelle Semantic Patch to constify module device tables >> // >> // Author: Stefan Agner >> // >> @ module_device_table @ >> declarer name MODULE_DEVICE_TABLE; >> identifier moduletype; >> identifier name; >> @@ >> MODULE_DEVICE_TABLE(moduletype, name); >> >> @ add_const depends on module_device_table disable optional_qualifier @ >> identifier module_device_table.name; >> type T; >> @@ >> +const >> T name[] = { >> ... >> }; >> >> Thoughts? >> >> -- >> Stefan >> >> >>> >>> Signed-off-by: Matthias Kaehlcke >>> --- >>> include/linux/module.h | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/include/linux/module.h b/include/linux/module.h >>> index e7bdd549e527..fe5aa3736707 100644 >>> --- a/include/linux/module.h >>> +++ b/include/linux/module.h >>> @@ -209,7 +209,7 @@ extern void cleanup_module(void); >>> #ifdef MODULE >>> /* Creates an alias so file2alias.c can find device table. */ >>> #define MODULE_DEVICE_TABLE(type, name) >>> \ >>> -extern const typeof(name) __mod_##type##__##name##_device_table >>> \ >>> +extern typeof(name) __mod_##type##__##name##_device_table\ >>>__attribute__ ((unused, alias(__stringify(name >>> #else /* !MODULE */ >>> #define MODULE_DEVICE_TABLE(type, name) > > Perhaps the reverse is the better solution? Leave "const" in > MODULE_DEVICE_TABLE and remove the redundant usage. This means new > cases of missing the const will never happen (which was the intent > originally of putting const into the MODULE_DEVICE_TABLE macro, I > assume). > > -Kees > > -- > Kees Cook > Pixel Security -- Thanks, ~Nick Desaulniers
Re: module: Remove const attribute from alias for MODULE_DEVICE_TABLE
On Sun, Aug 27, 2017 at 4:52 PM, Stefan Agnerwrote: > On 2017-07-24 18:27, Matthias Kaehlcke wrote: >> MODULE_DEVICE_TABLE(type, name) creates an alias of type 'extern const >> typeof(name)'. If 'name' is already constant the 'const' attribute is >> specified twice, which is not allowed in C89 (see discussion at >> https://lkml.org/lkml/2017/5/23/1440). Since the kernel is built with >> -std=gnu89 clang generates warnings like this: >> >> drivers/thermal/x86_pkg_temp_thermal.c:509:1: warning: duplicate 'const' >> declaration specifier >> [-Wduplicate-decl-specifier] >> MODULE_DEVICE_TABLE(x86cpu, pkg_temp_thermal_ids); >> ^ >> ./include/linux/module.h:212:8: note: expanded from macro >> 'MODULE_DEVICE_TABLE' >> extern const typeof(name) __mod_##type##__##name##_device_table >> >> Remove the const attribute from the alias to avoid the duplicate >> specifier. After all it is only an alias and the attribute shouldn't >> have any effect. > > Unfortunately, it has effect where const is missing in the original > variable declaration: > > Before this patch: > 13:10 $ size drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko >textdata bss dec hex filename >8825 728 40 9593 2579 > drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko > > After this patch: > 13:12 $ size drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko >textdata bss dec hex filename >8747 800 4095872573 > drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko > > > Ideally we would fix all MODULE_DEVICE_TABLE usage sites. This would > also made it clearly visible that the device tables are const. > > I created a semantic patch, it turns out that 620 sites are affected > (out of 4499)... > > // > // Cocinelle Semantic Patch to constify module device tables > // > // Author: Stefan Agner > // > @ module_device_table @ > declarer name MODULE_DEVICE_TABLE; > identifier moduletype; > identifier name; > @@ > MODULE_DEVICE_TABLE(moduletype, name); > > @ add_const depends on module_device_table disable optional_qualifier @ > identifier module_device_table.name; > type T; > @@ > +const > T name[] = { > ... > }; > > Thoughts? > > -- > Stefan > > >> >> Signed-off-by: Matthias Kaehlcke >> --- >> include/linux/module.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/include/linux/module.h b/include/linux/module.h >> index e7bdd549e527..fe5aa3736707 100644 >> --- a/include/linux/module.h >> +++ b/include/linux/module.h >> @@ -209,7 +209,7 @@ extern void cleanup_module(void); >> #ifdef MODULE >> /* Creates an alias so file2alias.c can find device table. */ >> #define MODULE_DEVICE_TABLE(type, name) >> \ >> -extern const typeof(name) __mod_##type##__##name##_device_table >> \ >> +extern typeof(name) __mod_##type##__##name##_device_table\ >>__attribute__ ((unused, alias(__stringify(name >> #else /* !MODULE */ >> #define MODULE_DEVICE_TABLE(type, name) Perhaps the reverse is the better solution? Leave "const" in MODULE_DEVICE_TABLE and remove the redundant usage. This means new cases of missing the const will never happen (which was the intent originally of putting const into the MODULE_DEVICE_TABLE macro, I assume). -Kees -- Kees Cook Pixel Security
Re: module: Remove const attribute from alias for MODULE_DEVICE_TABLE
On Sun, Aug 27, 2017 at 4:52 PM, Stefan Agner wrote: > On 2017-07-24 18:27, Matthias Kaehlcke wrote: >> MODULE_DEVICE_TABLE(type, name) creates an alias of type 'extern const >> typeof(name)'. If 'name' is already constant the 'const' attribute is >> specified twice, which is not allowed in C89 (see discussion at >> https://lkml.org/lkml/2017/5/23/1440). Since the kernel is built with >> -std=gnu89 clang generates warnings like this: >> >> drivers/thermal/x86_pkg_temp_thermal.c:509:1: warning: duplicate 'const' >> declaration specifier >> [-Wduplicate-decl-specifier] >> MODULE_DEVICE_TABLE(x86cpu, pkg_temp_thermal_ids); >> ^ >> ./include/linux/module.h:212:8: note: expanded from macro >> 'MODULE_DEVICE_TABLE' >> extern const typeof(name) __mod_##type##__##name##_device_table >> >> Remove the const attribute from the alias to avoid the duplicate >> specifier. After all it is only an alias and the attribute shouldn't >> have any effect. > > Unfortunately, it has effect where const is missing in the original > variable declaration: > > Before this patch: > 13:10 $ size drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko >textdata bss dec hex filename >8825 728 40 9593 2579 > drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko > > After this patch: > 13:12 $ size drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko >textdata bss dec hex filename >8747 800 4095872573 > drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko > > > Ideally we would fix all MODULE_DEVICE_TABLE usage sites. This would > also made it clearly visible that the device tables are const. > > I created a semantic patch, it turns out that 620 sites are affected > (out of 4499)... > > // > // Cocinelle Semantic Patch to constify module device tables > // > // Author: Stefan Agner > // > @ module_device_table @ > declarer name MODULE_DEVICE_TABLE; > identifier moduletype; > identifier name; > @@ > MODULE_DEVICE_TABLE(moduletype, name); > > @ add_const depends on module_device_table disable optional_qualifier @ > identifier module_device_table.name; > type T; > @@ > +const > T name[] = { > ... > }; > > Thoughts? > > -- > Stefan > > >> >> Signed-off-by: Matthias Kaehlcke >> --- >> include/linux/module.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/include/linux/module.h b/include/linux/module.h >> index e7bdd549e527..fe5aa3736707 100644 >> --- a/include/linux/module.h >> +++ b/include/linux/module.h >> @@ -209,7 +209,7 @@ extern void cleanup_module(void); >> #ifdef MODULE >> /* Creates an alias so file2alias.c can find device table. */ >> #define MODULE_DEVICE_TABLE(type, name) >> \ >> -extern const typeof(name) __mod_##type##__##name##_device_table >> \ >> +extern typeof(name) __mod_##type##__##name##_device_table\ >>__attribute__ ((unused, alias(__stringify(name >> #else /* !MODULE */ >> #define MODULE_DEVICE_TABLE(type, name) Perhaps the reverse is the better solution? Leave "const" in MODULE_DEVICE_TABLE and remove the redundant usage. This means new cases of missing the const will never happen (which was the intent originally of putting const into the MODULE_DEVICE_TABLE macro, I assume). -Kees -- Kees Cook Pixel Security
Re: module: Remove const attribute from alias for MODULE_DEVICE_TABLE
On 2017-07-24 18:27, Matthias Kaehlcke wrote: > MODULE_DEVICE_TABLE(type, name) creates an alias of type 'extern const > typeof(name)'. If 'name' is already constant the 'const' attribute is > specified twice, which is not allowed in C89 (see discussion at > https://lkml.org/lkml/2017/5/23/1440). Since the kernel is built with > -std=gnu89 clang generates warnings like this: > > drivers/thermal/x86_pkg_temp_thermal.c:509:1: warning: duplicate 'const' > declaration specifier > [-Wduplicate-decl-specifier] > MODULE_DEVICE_TABLE(x86cpu, pkg_temp_thermal_ids); > ^ > ./include/linux/module.h:212:8: note: expanded from macro > 'MODULE_DEVICE_TABLE' > extern const typeof(name) __mod_##type##__##name##_device_table > > Remove the const attribute from the alias to avoid the duplicate > specifier. After all it is only an alias and the attribute shouldn't > have any effect. Unfortunately, it has effect where const is missing in the original variable declaration: Before this patch: 13:10 $ size drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko textdata bss dec hex filename 8825 728 4095932579 drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko After this patch: 13:12 $ size drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko textdata bss dec hex filename 8747 800 4095872573 drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko Ideally we would fix all MODULE_DEVICE_TABLE usage sites. This would also made it clearly visible that the device tables are const. I created a semantic patch, it turns out that 620 sites are affected (out of 4499)... // // Cocinelle Semantic Patch to constify module device tables // // Author: Stefan Agner// @ module_device_table @ declarer name MODULE_DEVICE_TABLE; identifier moduletype; identifier name; @@ MODULE_DEVICE_TABLE(moduletype, name); @ add_const depends on module_device_table disable optional_qualifier @ identifier module_device_table.name; type T; @@ +const T name[] = { ... }; Thoughts? -- Stefan > > Signed-off-by: Matthias Kaehlcke > --- > include/linux/module.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/module.h b/include/linux/module.h > index e7bdd549e527..fe5aa3736707 100644 > --- a/include/linux/module.h > +++ b/include/linux/module.h > @@ -209,7 +209,7 @@ extern void cleanup_module(void); > #ifdef MODULE > /* Creates an alias so file2alias.c can find device table. */ > #define MODULE_DEVICE_TABLE(type, name) > \ > -extern const typeof(name) __mod_##type##__##name##_device_table > \ > +extern typeof(name) __mod_##type##__##name##_device_table\ >__attribute__ ((unused, alias(__stringify(name > #else /* !MODULE */ > #define MODULE_DEVICE_TABLE(type, name)
Re: module: Remove const attribute from alias for MODULE_DEVICE_TABLE
On 2017-07-24 18:27, Matthias Kaehlcke wrote: > MODULE_DEVICE_TABLE(type, name) creates an alias of type 'extern const > typeof(name)'. If 'name' is already constant the 'const' attribute is > specified twice, which is not allowed in C89 (see discussion at > https://lkml.org/lkml/2017/5/23/1440). Since the kernel is built with > -std=gnu89 clang generates warnings like this: > > drivers/thermal/x86_pkg_temp_thermal.c:509:1: warning: duplicate 'const' > declaration specifier > [-Wduplicate-decl-specifier] > MODULE_DEVICE_TABLE(x86cpu, pkg_temp_thermal_ids); > ^ > ./include/linux/module.h:212:8: note: expanded from macro > 'MODULE_DEVICE_TABLE' > extern const typeof(name) __mod_##type##__##name##_device_table > > Remove the const attribute from the alias to avoid the duplicate > specifier. After all it is only an alias and the attribute shouldn't > have any effect. Unfortunately, it has effect where const is missing in the original variable declaration: Before this patch: 13:10 $ size drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko textdata bss dec hex filename 8825 728 4095932579 drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko After this patch: 13:12 $ size drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko textdata bss dec hex filename 8747 800 4095872573 drivers/net/wireless/ath/ath6kl/ath6kl_usb.ko Ideally we would fix all MODULE_DEVICE_TABLE usage sites. This would also made it clearly visible that the device tables are const. I created a semantic patch, it turns out that 620 sites are affected (out of 4499)... // // Cocinelle Semantic Patch to constify module device tables // // Author: Stefan Agner // @ module_device_table @ declarer name MODULE_DEVICE_TABLE; identifier moduletype; identifier name; @@ MODULE_DEVICE_TABLE(moduletype, name); @ add_const depends on module_device_table disable optional_qualifier @ identifier module_device_table.name; type T; @@ +const T name[] = { ... }; Thoughts? -- Stefan > > Signed-off-by: Matthias Kaehlcke > --- > include/linux/module.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/module.h b/include/linux/module.h > index e7bdd549e527..fe5aa3736707 100644 > --- a/include/linux/module.h > +++ b/include/linux/module.h > @@ -209,7 +209,7 @@ extern void cleanup_module(void); > #ifdef MODULE > /* Creates an alias so file2alias.c can find device table. */ > #define MODULE_DEVICE_TABLE(type, name) > \ > -extern const typeof(name) __mod_##type##__##name##_device_table > \ > +extern typeof(name) __mod_##type##__##name##_device_table\ >__attribute__ ((unused, alias(__stringify(name > #else /* !MODULE */ > #define MODULE_DEVICE_TABLE(type, name)
Re: module: Remove const attribute from alias for MODULE_DEVICE_TABLE
+++ Matthias Kaehlcke [24/07/17 18:27 -0700]: MODULE_DEVICE_TABLE(type, name) creates an alias of type 'extern const typeof(name)'. If 'name' is already constant the 'const' attribute is specified twice, which is not allowed in C89 (see discussion at https://lkml.org/lkml/2017/5/23/1440). Since the kernel is built with -std=gnu89 clang generates warnings like this: drivers/thermal/x86_pkg_temp_thermal.c:509:1: warning: duplicate 'const' declaration specifier [-Wduplicate-decl-specifier] MODULE_DEVICE_TABLE(x86cpu, pkg_temp_thermal_ids); ^ ./include/linux/module.h:212:8: note: expanded from macro 'MODULE_DEVICE_TABLE' extern const typeof(name) __mod_##type##__##name##_device_table Remove the const attribute from the alias to avoid the duplicate specifier. After all it is only an alias and the attribute shouldn't have any effect. Signed-off-by: Matthias KaehlckeApplied, thanks! Jessica include/linux/module.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/module.h b/include/linux/module.h index e7bdd549e527..fe5aa3736707 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -209,7 +209,7 @@ extern void cleanup_module(void); #ifdef MODULE /* Creates an alias so file2alias.c can find device table. */ #define MODULE_DEVICE_TABLE(type, name) \ -extern const typeof(name) __mod_##type##__##name##_device_table \ +extern typeof(name) __mod_##type##__##name##_device_table \ __attribute__ ((unused, alias(__stringify(name #else /* !MODULE */ #define MODULE_DEVICE_TABLE(type, name) -- 2.14.0.rc0.284.gd933b75aa4-goog
Re: module: Remove const attribute from alias for MODULE_DEVICE_TABLE
+++ Matthias Kaehlcke [24/07/17 18:27 -0700]: MODULE_DEVICE_TABLE(type, name) creates an alias of type 'extern const typeof(name)'. If 'name' is already constant the 'const' attribute is specified twice, which is not allowed in C89 (see discussion at https://lkml.org/lkml/2017/5/23/1440). Since the kernel is built with -std=gnu89 clang generates warnings like this: drivers/thermal/x86_pkg_temp_thermal.c:509:1: warning: duplicate 'const' declaration specifier [-Wduplicate-decl-specifier] MODULE_DEVICE_TABLE(x86cpu, pkg_temp_thermal_ids); ^ ./include/linux/module.h:212:8: note: expanded from macro 'MODULE_DEVICE_TABLE' extern const typeof(name) __mod_##type##__##name##_device_table Remove the const attribute from the alias to avoid the duplicate specifier. After all it is only an alias and the attribute shouldn't have any effect. Signed-off-by: Matthias Kaehlcke Applied, thanks! Jessica include/linux/module.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/module.h b/include/linux/module.h index e7bdd549e527..fe5aa3736707 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -209,7 +209,7 @@ extern void cleanup_module(void); #ifdef MODULE /* Creates an alias so file2alias.c can find device table. */ #define MODULE_DEVICE_TABLE(type, name) \ -extern const typeof(name) __mod_##type##__##name##_device_table \ +extern typeof(name) __mod_##type##__##name##_device_table \ __attribute__ ((unused, alias(__stringify(name #else /* !MODULE */ #define MODULE_DEVICE_TABLE(type, name) -- 2.14.0.rc0.284.gd933b75aa4-goog
[PATCH] module: Remove const attribute from alias for MODULE_DEVICE_TABLE
MODULE_DEVICE_TABLE(type, name) creates an alias of type 'extern const typeof(name)'. If 'name' is already constant the 'const' attribute is specified twice, which is not allowed in C89 (see discussion at https://lkml.org/lkml/2017/5/23/1440). Since the kernel is built with -std=gnu89 clang generates warnings like this: drivers/thermal/x86_pkg_temp_thermal.c:509:1: warning: duplicate 'const' declaration specifier [-Wduplicate-decl-specifier] MODULE_DEVICE_TABLE(x86cpu, pkg_temp_thermal_ids); ^ ./include/linux/module.h:212:8: note: expanded from macro 'MODULE_DEVICE_TABLE' extern const typeof(name) __mod_##type##__##name##_device_table Remove the const attribute from the alias to avoid the duplicate specifier. After all it is only an alias and the attribute shouldn't have any effect. Signed-off-by: Matthias Kaehlcke--- include/linux/module.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/module.h b/include/linux/module.h index e7bdd549e527..fe5aa3736707 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -209,7 +209,7 @@ extern void cleanup_module(void); #ifdef MODULE /* Creates an alias so file2alias.c can find device table. */ #define MODULE_DEVICE_TABLE(type, name) \ -extern const typeof(name) __mod_##type##__##name##_device_table \ +extern typeof(name) __mod_##type##__##name##_device_table \ __attribute__ ((unused, alias(__stringify(name #else /* !MODULE */ #define MODULE_DEVICE_TABLE(type, name) -- 2.14.0.rc0.284.gd933b75aa4-goog
[PATCH] module: Remove const attribute from alias for MODULE_DEVICE_TABLE
MODULE_DEVICE_TABLE(type, name) creates an alias of type 'extern const typeof(name)'. If 'name' is already constant the 'const' attribute is specified twice, which is not allowed in C89 (see discussion at https://lkml.org/lkml/2017/5/23/1440). Since the kernel is built with -std=gnu89 clang generates warnings like this: drivers/thermal/x86_pkg_temp_thermal.c:509:1: warning: duplicate 'const' declaration specifier [-Wduplicate-decl-specifier] MODULE_DEVICE_TABLE(x86cpu, pkg_temp_thermal_ids); ^ ./include/linux/module.h:212:8: note: expanded from macro 'MODULE_DEVICE_TABLE' extern const typeof(name) __mod_##type##__##name##_device_table Remove the const attribute from the alias to avoid the duplicate specifier. After all it is only an alias and the attribute shouldn't have any effect. Signed-off-by: Matthias Kaehlcke --- include/linux/module.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/module.h b/include/linux/module.h index e7bdd549e527..fe5aa3736707 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -209,7 +209,7 @@ extern void cleanup_module(void); #ifdef MODULE /* Creates an alias so file2alias.c can find device table. */ #define MODULE_DEVICE_TABLE(type, name) \ -extern const typeof(name) __mod_##type##__##name##_device_table \ +extern typeof(name) __mod_##type##__##name##_device_table \ __attribute__ ((unused, alias(__stringify(name #else /* !MODULE */ #define MODULE_DEVICE_TABLE(type, name) -- 2.14.0.rc0.284.gd933b75aa4-goog